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Introduction of automated systems to evaluate touch-pressure, vibration, and thermal cutaneous sensation in man
Abstract
Systems for automatic assessment of cutaneous touch-pressure, vibratory, and thermal sensation have been developed. These systems use stimuli which are quantified and reproducible, a two-alternative forced-choice technique, and programmed steps to test, score, and report. If normal responses from series of healthy persons have been measured, percentile values specific for test, site, age, and sex can be determined. Abnormality, as in neurological disease, can then be defined as the response which has a value greater than that of the 95th (or other) percentile. These systems may be used to detect and validate abnormalities of sensation in neurological disease and in persons at risk from new medications or from industrial toxins, and to monitor worsening or improvement of sensation in follow-up of a patient or in evaluation of therapeutic regimens.
... QST assessments have been established as an efficient, precise, and reproducible method for sensory testing [23][24][25]. The Computer-Aided Sensory Evaluator IV (CASE IV) is an automated system that delivers precise, standardized, computer-generated stimuli, based on the study of physiologic perception thresholds and "just noticeable difference" (JND) of heat, cold, vibration, and touch pressure [26,27]. QST has been used with high-frequency electroacupuncture to measure acupuncture-induced changes in sensation [20]. ...
... Vibration stimuli were delivered as 25 discrete levels ranging from 0.0 to 350 lm of displacement, based on previously established JND values [26,27]. Each stimulus was presented with an exponential onset and turned off with an exponential decay in order to eliminate the touch-pressure artifact, which is caused by an instantaneous on/off. ...
... The thermal stimulator is used both for heating and cooling stimuli and produces a specified temperature on a 9.0-cm 2 stimulating surface. For highmagnitude thermal (cooling) stimuli, the absolute temperature is limited to 8 C [26,27]. Thermal stimulation in the leg was delivered at the proximal anterior calf ( Figure 1) and at the mid-dorsum of the hand, as recommended by the CASE IV system manual ( Figure 3). ...
Objective:
This study aims to assess whether acupuncture analgesia's effects are local or systemic and whether there is a dose response for these effects.
Methods:
Twenty-eight healthy volunteers aged 18-45 were randomized to two doses of acupuncture using points closely associated with peripheral nerves in the legs. The lower-dose group involved acupoints overlying the deep peroneal nerve (DP), and the higher-dose involved acupoints overlying the deep peroneal and posterior tibial nerves (DPTN). Baseline and acupuncture quantitative sensory testing (QST) assessments were obtained locally in the calf and great toe and systemically in the hand. Results were analyzed using factorial repeated-measures analysis of variance for each of the QST variables-cold detection threshold (CDT), vibration detection threshold (VDT), heat pain threshold (HP0.5), and heat pain perception of 5/10 (HP5.0). Location (leg/hand) and time (baseline/acupuncture) were within-subject factors. Intervention (DP/DPTN) was a between-subject factor.
Results:
CDT was increased in the calf (P < 0.001) and in the hand (P < 0.001). VDT was increased in the toe (P < 0.001) but not in the hand. HP0.5 was increased in the calf (P < 0.001) and in the hand (P < 0.001). HP5.0 was increased in the calf (P = 0.002) and in the hand (P < 0.001), with the local effect being significantly greater than the systemic (P = 0.004). In all of the above QST modalities, there was no difference between the low-dose (DP) and high-dose (DPTN) acupuncture groups.
Conclusions:
Acupuncture caused comparable local and systemic analgesic effects in cold detection and heat pain perception and only local effects in vibration perception. There was no clear acupuncture dose response to these effects.
... QST assessments have been established as an efficient, precise, and reproducible method for sensory testing [23][24][25]. The Computer-Aided Sensory Evaluator IV (CASE IV) is an automated system that delivers precise, standardized, computer-generated stimuli, based on the study of physiologic perception thresholds and "just noticeable difference" (JND) of heat, cold, vibration, and touch pressure [26,27]. QST has been used with high-frequency electroacupuncture to measure acupuncture-induced changes in sensation [20]. ...
... Vibration stimuli were delivered as 25 discrete levels ranging from 0.0 to 350 lm of displacement, based on previously established JND values [26,27]. Each stimulus was presented with an exponential onset and turned off with an exponential decay in order to eliminate the touch-pressure artifact, which is caused by an instantaneous on/off. ...
... The thermal stimulator is used both for heating and cooling stimuli and produces a specified temperature on a 9.0-cm 2 stimulating surface. For highmagnitude thermal (cooling) stimuli, the absolute temperature is limited to 8 C [26,27]. Thermal stimulation in the leg was delivered at the proximal anterior calf ( Figure 1) and at the mid-dorsum of the hand, as recommended by the CASE IV system manual ( Figure 3). ...
... Quantitative sensory testing (QST) has been used for decades for diagnosing and quantifying the severity of DPN [1][2][3][4][5] and painful neuropathy [4,[6][7][8][9][10][11]. Indeed several guidelines endorse the use of QST for the diagnosis of sensory abnormalities in diabetic neuropathy [2,12]. QST is an automated psychophysical method used to test vibration and thermal sensation which may help to risk stratify patients for the development of painful neuropathy, foot ulceration and amputation [13]. ...
... Easily deployed and inexpensive tests such as the tuning folk, pin-prick, VibraTip and 10 g monofilament can detect moderate to severe sensory loss but for early detection of sensory impairment, particularly in clinical trials, QST is required. It provides standardised and quantified stimuli which enable accurate quantification of sensory deficits [14] for vibration, a large fibre measure and thermal threshold testing for the detection of small fibre neuropathy [1][2][3]15]. ...
... Dysfunction of small nerve fibres is thought to be responsible for many painful peripheral neuropathies [30]. These small fibre neuropathies cannot be evaluated using standard electrophysiological testing [1][2][3]15]. Our study shows that NerveCheck has both high sensitivity 84% and high specificity 81% for vibration testing and high sensitivity and moderate specificity for thermal testing. ...
Aims:
Sensory neuropathy is central to the development of painful neuropathy, and foot ulceration in patients with diabetes. Currently, available QST devices take considerable time to perform and are expensive. NerveCheck is the first inexpensive ($500), portable QST device to perform both vibration and thermal testing and hence evaluate diabetic peripheral neuropathy (DPN). This study was undertaken to establish the reproducibility and diagnostic validity of NerveCheck for detecting neuropathy.
Methods:
130 subjects (28 with DPN, 46 without DPN and 56 control subjects) underwent QST assessment with NerveCheck; vibration perception and thermal testing. DPN was defined according to the Toronto criteria.
Results:
NerveCheck's intra correlation coefficient for vibration, cold and warm sensation testing was 0.79 (95% LOA: -4.20 to 6.60), 0.86 (95% LOA: -1.38 to 2.72) and 0.71 (95% LOA: -2.36 to 3.83), respectively. The diagnostic accuracy (AUC) for vibration, cold and warm sensation testing was 86% (SE: 0.038, 95% CI 0.79-0.94), 79% (SE: 0.058, 95% CI 0.68-0.91) and 72% (SE: 0.058, 95% CI 0.60-0.83), respectively.
Conclusions:
This study shows that NerveCheck has good reproducibility and comparable diagnostic accuracy to established QST equipment for the diagnosis of DPN.
... In peripheral nerves, C-type nerve fibers are involved in the perception of thermal stimuli, while Aδ nerve fibers are cold stimuli. Although the quantifying intraepidermal nerve fiber density from a skin biopsy has confirmed the standard for diagnosing small fiber neuropathy in diabetes (Feldman et al., 2019), quantitative thermal testing (QTT) is considered a reliable tool for the diagnosis of somatic small fiber neuropathy in clinical practice and also be used for monitoring progression in follow-up studies (Dyck et al., 1978;Shy et al., 2003;Chong and Cros, 2004) because it is quantifiable and reproducible. ...
... Clinical studies have demonstrated that the QTT can identify 93% of patients with impaired glucose tolerance or T2DM (Vlckova-Moravcova et al., 2008) and one-half of asymptomatic participants with T2DM with a normal NCS (Jimenez-Cohl et al., 2012). The QTT can also be valid for monitoring the progression of the disease at follow-up, which has been demonstrated in previous studies (Dyck et al., 1978;Shy et al., 2003;Chong and Cros, 2004) and in our study. The prospective 5-year longitudinal study showed particularly neuropathic deficits, intraepidermal nerve fiber density (IENFD), and NCS could produce clinically meaningful degrees of progression and regression (Ziegler et al., 2021). ...
Introduction
The diagnosis and assessment of neuropathy severity of diabetic sensorimotor polyneuropathy (DSPN) are mainly based on clinical neuropathy scores and electrophysiologic studies. This study aimed to determine whether quantitative thermal testing (QTT) can be used as a screening and follow-up tool for DSPN of prediabetes and type 2 diabetes at baseline and at 1-year follow-up.
Methods
All patients were assessed using the Toronto Clinical Neuropathy Score (TCNS) and underwent electrophysiological testing, including a nerve conduction study (NCS) and QTT, at baseline and at a 1-year follow-up. The TCNS and the composite scores of nerve conduction were used to assess the severity of DSPN. The DSPN status at the 1-year follow-up was classified as remaining no DSPN, remaining DSPN, regression to no DSPN, or progression to DSPN.
Results
Diabetic sensorimotor polyneuropathy was initially diagnosed in 89 patients with prediabetes and type 2 diabetes (22%). The regressed to no DSPN in 29 patients and progressed to DSPN in 20 patients at the 1-year follow-up. TCNS was significantly correlated with composite scores of nerve conduction, hand cold detection threshold (CDT), hand warm detection threshold (WDT), foot CDT, and foot WDT. Stepwise logistic regression demonstrated that the foot CDT (p < 0.0001) was independently associated with the presence of DSPN. The TCNS, composite scores of the nerve conduction, hand WDT, hand CDT, foot WDT, and foot CDT were all statistically significant among the four different DSPN status groups at two different time periods (baseline and the 1-year follow-up).
Conclusion
The foot CDT can be used as an initial screening tool for DSPN alternatively. The characteristics of nerve damage after 1 year of DSPN can be progressive or reversible, and the neurological functions of large and small fibers have a parallel trend, which can be objectively measured by NCS and QTT.
... Quantitative sensory testing was performed using the Computer Aided Sensory Evaluator IV (CASE IV; WR Medical Electronics, Stillwater, MN) system based on the method of levels. [24][25][26] This QST devise has been previously used to assess heat pain perception at our pain treatment program. 16,17,19,27,28 A series of heat stimuli of variable magnitude interspersed with null stimuli are delivered by the CASE IV system in random order through a thermode with a surface area of 10 cm 2 . ...
... The protocol includes standardized test instructions and procedures, stimulus wave form, null stimulus, and nonrepeating stepping algorithm between the different levels of heat stimuli. [24][25][26]29 During testing, the subject is masked to the stimulus magnitude including all null stimuli. Following each stimulus, the intensity is rated by the subject on an 11point scale (0 denotes no pain, 10 denotes the most intense possible pain). ...
The catechol-O-methyltransferase Val158Met polymorphism has been associated with alterations in pain perception, but the influence of the polymorphism on pain perception in patients with chronic pain receiving daily opioid therapy has not been previously reported. The primary aim of this study was to investigate the effects of the catechol-O-methyltransferase Val158Met polymorphism on heat pain perception in a cohort of adults receiving daily opioid therapy for chronic pain. Adults with chronic pain consecutively admitted to an outpatient pain rehabilitation program who met inclusion criteria and were receiving daily opioid therapy were recruited for study participation (N = 142). Individuals were genotyped for catechol-O-methyltransferase Val158Met (rs4680), and the polymorphism was analyzed using an additive and codominant genotype models. The distribution of the Val158Met genotypes was 25% for Val/Val, 41% for Val/Met and 34% for Met/Met (Hardy-Weinberg, P > 0.05). A main effect of genotype was observed for heat pain perception ( P = 0.028). Under the codominant model of allele effects, exploratory post hoc pairwise comparisons adjusted for morphine equivalent dose and pain catastrophizing demonstrated that individuals with the Val/Met genotype were hyperalgesic compared to individuals with the Val/Val ( P = 0.039) and Met/Met ( P = 0.023) genotypes. No significant association was observed between heat pain perception and genotype under the additive model of allele effects. Among patients with chronic pain who were receiving daily opioids, the Val/Met genotype was associated with hyperalgesia using a measure of heat pain perception that has been previously indicative of opioid-induced hyperalgesia in other heterogeneous samples of adults with chronic pain. This study contributes to the emerging understanding of how catechol-O-methyltransferase activity affects pain perception in the context of daily opioid use, and these findings may be useful in the design of future trials aimed at investigating the potential efficacy of ß-2 adrenergic receptor antagonism for opioid-induced hyperalgesia.
... Vibration detection threshold Vibration stimuli will be delivered as 25 discrete levels ranging from 0.0 to 350 μm of displacement, based on previously established "just noticeable difference" (JND) values [43,44]. Each stimulus is presented with an exponential onset and turns off with an exponential decay, in order to eliminate the touch-pressure artifact, which is caused by an instantaneous on/off. ...
... Thermal stimuli are approximately 6 s in duration. CDT will be assessed over the thenar eminence and hypothenar eminence with the hand on an even surface, palm facing up [43,44]. ...
Background
While acupuncture’s mechanism of action is not fully understood, there is consensus that the nervous system plays a key role in processing its effects. This research is based on the structural theory of acupuncture, which aims to correlate the location of acupuncture points to peripheral nerves, spinal segments, and spinal plexuses. This mechanistic study explores the close anatomical association between the Pericardium meridian/median nerve and the Heart meridian/ulnar nerve in an attempt to produce electrophysiologic data measuring acupuncture’s direct, nerve-specific effect on the underlying nerves. Specifically, the purpose of this research is to use nerve conduction studies (NCSs) and quantitative sensory testing (QST) to assess for any local, nerve-specific effect of three acupuncture modalities on two anatomically distinct nerves in the forearm — the median and ulnar nerves — in subjects with carpal tunnel syndrome (CTS). The choice of CTS as an injured nerve model allows for comparisons between the response in an injured nerve (median) to that of a healthy one (ulnar).
Methods
Subjects with mild to moderate CTS will be randomized to three intervention groups: manual acupuncture and low- and high-frequency electroacupuncture. Each subject will receive two treatments, 1 week apart, to points in the forearm, which overlay the median nerve (Pericardium meridian) or the ulnar nerve (Heart meridian). Acupuncture will be administered in random order to minimize learning effects in sensory testing. During Week 1, baseline NCS and QST (vibration and cold detection thresholds) will be obtained in both nerve territories, followed by acupuncture and post-acupuncture NCS and QST measurements in both nerve territories. During Week 2, repeat baseline QST and NCS measurements will be obtained, followed by acupuncture to points overlying the nerve not treated in Week 1, followed by post-acupuncture NCS and QST measurements in both nerve distributions.
Discussion
This works aims to capture and characterize the local effects of acupuncture on an underlying nerve and compare them to those on a neighboring nerve. Quantifying acupuncture’s effects using physiologic parameters and discrete values could standardize treatment regimens and help assess their therapeutic effect.
Trial registration
ClinicalTrials.gov, NCT03036657. Registered on 30 January 2017. Retrospectively registered.
Electronic supplementary material
The online version of this article (10.1186/s13063-018-3094-5) contains supplementary material, which is available to authorized users.
... Therefore, the primary aim of this study was to determine the associations between opioid use and HP perception in a sample of community-dwelling adults with chronic pain consecutively admitted to an outpatient interdisciplinary pain treatment (IPT) program. perception was assessed one day following admission to the IPT program using the automated Computer Aided Sensory Evaluator IV (CASE IV; WR Electronics, Stillwater, MN) system [18][19][20] as previously described [28,29]. The CASE IV system delivered discrete magnitudes of heat stimuli units, termed "just noticeable difference" (JND), interspersed with null stimuli in random order through a 10 cm 2 thermode applied to the skin. ...
... These disparate findings could be due, in part, to 1) the use of nonstandardized values of pain perception, 2) lower dosages of opioids, and 3) the confounding effects of opioid tolerance. First, the testing protocols for QST, including the method of levels as used herein, have been validated [18][19][20]46] and have good reproducibility over time [43,46,57]. However, standardized normative values adjusted for individual differences in anthropometric characteristics known to influence pain perception [15,46] were not used in the aforementioned studies of OIH in patients with chronic pain. ...
The hyperalgesic effects of long-term opioid use in community-dwelling adults with chronic pain have not been widely reported. Therefore, the primary aim of this study was to determine the associations between opioid use and heat pain (HP) perception in a sample of community-dwelling adults with chronic pain. The study cohort involved 187 adults (85 opioid, 102 nonopioid) with chronic pain consecutively admitted to an outpatient interdisciplinary pain treatment program. HP pain perception was assessed using a validated quantitative sensory test method of levels. An effect of opioid use was observed for nonstandardized (P=.004) and standardized (P=.005) values of HP 5-0.5 where values of the opioid group were lower (more hyperalgesic) compared to the nonopioid group. HP 5-0.5 is a measure of the slope of the line connecting HP 0.5 (HP threshold) and HP 5 (intermediate measure of HP tolerance). In univariable (P=.019) and multiple variable (P=.003) linear regression analyses (adjusted for age, sex, BMI, work status, pain diagnosis, pain severity, depression, and pain catastrophizing), opioid use was associated with lower (more hyperalgesic) nonstandardized values of HP 5-0.5. Similarly, in univariable (P=.004) and multiple variable (P=.011) linear regression analyses (adjusted for work status, pain diagnosis, pain severity, depression, and pain catastrophizing), opioid use was associated with lower standardized values of HP 5-0.5. In this sample of community-dwelling adults, these observations suggest long-term opioid use was associated with hyperalgesia independent of other clinical factors known to influence HP perception.
... Vibration detection threshold Vibration stimuli will be delivered as 25 discrete levels ranging from 0.0 to 350 μm of displacement, based on previously established "just noticeable difference" (JND) values [43,44]. Each stimulus is presented with an exponential onset and turns off with an exponential decay, in order to eliminate the touch-pressure artifact, which is caused by an instantaneous on/off. ...
... Thermal stimuli are approximately 6 s in duration. CDT will be assessed over the thenar eminence and hypothenar eminence with the hand on an even surface, palm facing up [43,44]. ...
... Heat pain perception was assessed using the automated Computer Aided Sensory Evaluator IV (CASE IV; WR Electronics, Stillwater, MN) system based on the method of levels [26-28], as previously described [16]. The CASE IV system delivers discrete magnitudes of heat stimuli, in units termed “just noticeable difference” (JND), interspersed with null stimuli in random order through a thermode with a surface area of 10 cm2. ...
... Heat pain 5–0.5 was the difference between HP 5 and HP 0.5, and has been termed the pain-stimulus response slope. The standardized test procedures, stimulus waveform, null stimulus, and the non-repeating stepping algorithm between the different levels of heat stimuli have been validated, and the HP test algorithm requires less than 5 minutes to complete [26-28,31]. ...
The triallelic serotonin transporter gene linked polymorphic region (5-HTTLPR) has been associated with alterations in thermal pain perception. The primary aim of this study was to investigate the associations between heat pain (HP) perception and the triallelic 5-HTTLPR in a large cohort of adults with chronic pain.
The cohort included 277 adults with chronic pain who met inclusion criteria, and were consecutively admitted to an outpatient pain rehabilitation program from March 2009 through March 2010. Individuals were genotyped for the triallelic 5-HTTLPR (including rs25531) and categorized as high, intermediate, or low expressors of the serotonin transporter. Standardized measures of HP perception were obtained using a validated quantitative sensory test method of levels.
The distribution of the high, intermediate, and low expressing genotypes was 61 (22%), 149 (54%) and 67 (24%), respectively. The Hardy-Weinberg P-value was 0.204 which indicated no departure from equilibrium. A significant effect of genotype was observed for values of HP threshold (P = 0.029). Individual group comparisons showed that values of HP threshold were significantly greater in the intermediate compared to the high expressing group (P = 0.009) but not the low expressing group (P > 0.1). In a multiple variable linear regression model, the intermediate group (P = 0.034) and male sex (P = 0.021) were associated with significantly greater values of HP 0.5, but no significant genotype-by-sex interaction effect was observed.
In this study that involved adults with chronic pain, the intermediate triallelic 5-HTTLPR expressing group, but not the low expressing group, was associated with greater HP thresholds compared to the high expressing group.
... Each stimulus would have different units to ascend through the levels and a specific stimulation time. For instance, the vibration stimulus should ascend in amplitude since nociceptors only respond to 250 Hz (Dyck et al., 1978). Also, every stimulus should have its particular stimulation zone, because the Fig. 9. Proposal for an integral methodology consisting of two sessions. ...
The management of chronic neuropathic pain remains a challenge, because pain is subjective, and measuring it
objectively is usually out of question. However, neuropathic pain is also a signal provided by maladaptive
neuronal activity. Thus, the integral management of chronic neuropathic pain should not only rely on the
subjective perception of the patient, but also on objective data that measures the evolution of neuronal activity.
We will discuss different objective and subjective methods for the characterization of neuropathic pain. Additionally,
the gaps and proposals for an integral management of chronic neuropathic pain will also be discussed.
The current management that relies mostly on subjective measures has not been sufficient, therefore, this has
hindered advances in pain management and clinical trials. If an integral characterization is achieved, clinical
management and stratification for clinical trials could be based on both questionnaires and neuronal activity.
Appropriate characterization may lead to an increased effectiveness for new therapies, and a better quality of life
for neuropathic pain sufferers.
... In somatic peripheral nerves, the same C-type nerve fibers are involved in the perception of warm stimuli and in the slow component of pain. The first studies on thermal quantitative sensory testing (TQST) were published in the 1970s (Dyck et al., 1978;Fruhstorfer et al., 1976). Currently, TQST is an integral part of the diagnosis of somatic small fiber neuropathy in clinical practice within the frame of quantitative sensory testing. ...
Introduction
Electrophysiological diagnosis of cardiac autonomic neuropathy (CAN) is based on the evaluation of cardiovascular autonomic reflex tests (CARTs). CARTs are relatively time consuming and must be performed under standardized conditions. This study aimed to determine whether thermal quantitative sensory testing (TQST) can be used as a screening tool to identify patients with diabetes at a higher risk of CAN.
Methods
Eighty‐five patients with diabetes and 49 healthy controls were included in the study. Neurological examination, CARTs, TQST, biochemical analyses, and neuropathy symptom questionnaires were performed.
Results
CAN was diagnosed in 46 patients with diabetes (54%). CAN‐positive patients with diabetes had significantly higher warm detection thresholds (WDT) and significantly lower cold detection thresholds (CDT) in all tested regions (thenar, tibia, and the dorsum of the foot). CDT on the dorsum < 21.8°C in combination with CDT on the tibia < 23.15°C showed the best diagnostic ability in CAN prediction, with 97.4 % specificity, 60.9% sensitivity, 96.6% positive predictive value, and 67.3% negative predictive value.
Conclusion
TQST can be used as a screening tool for CAN before CART.
... Site difference in regard to sensory thresholds has been studied in depth by numerous investigators (Nielsen, 1975;Dyck et al, 1978;Goldberg & Lindblom, 1979;Jamal et al, 1985). It has been shown conclusively that there is significant difference between various sites of the one individual and the same site between different individuals owing to the anatomical variability of any particular site i.e. skin thickness. ...
The prediction of sensory loss following the extraction of third molars and the monitoring of sensory return following such injury is a matter of concern for oral surgeons. These factors were assessed in 500 patients, representing 957 lower third molar extractions. The preoperative orthopantomogram (OPG) was examined and the anatomical proximity of the third molar to the inferior alveolar nerve was graded into risk groups. Other clinical factors thought to contribute to sensory loss were assessed, those factors being surgical technique, difficulty of the operation and the type of impaction. For those patients who sustained a nerve injury, the sensory loss was monitored using eight different subjective tests. The sweat test was assessed as an objective test to monitor sensory loss in the face. It was found that while there was a trend for increased sensory loss in those teeth with a closer proximity, when looked at as high and low risk there was no statistical difference between the groups (p=0.33). More importantly, cases of sensory loss occurred when they were not anticipated. There was a higher incidence of sensory loss occurring in the more difficult cases. Horizontal impactions proved to cause the highest incidence of sensory loss. The lingual split technique produced the highest incidence of mental and lingual sensory loss. The recovery of the sensory modalities showed a trend towards fine touch, pin prick, cold sensation and electrical thresholds, all returning before tests of warm sensation, sharp/dull, two point discrimination and vibration. The objective sweat test for measuring sympathetic fibre supply to the face as a measure of sensory loss was of no clinical value. It was concluded that: 1. Preoperative radiographic prediction of nerve injury from third molar surgery is inaccurate; 2. Recovery of nerve injuries was best monitored by fine touch, pin prick, cold sensation, and electrical sensory thresholds.
... The VPT's reliability has been investigated since its beginning [31][32][33][34]. Recently, studies using the ICC have been published assessing the reliability of the big toe in a healthy population [35], finding excellent values for both the right foot (ICC = 0.75) and the left one (ICC = 0.99). ...
Background:
Diabetes mellitus is a chronic disease characterized by fasting hyperglycemia. It affects approximately 415 million people worldwide and involves a variety of complications. One of them is the loss of sensitivity to peripheral vibration.
Objective:
Our study aims to discover the test-retest reliability of a procedure for assessing vibration sensitivity in people with type 2 diabetes mellitus.
Methodology:
90 people with type 2 diabetes mellitus (56 men and 34 women) performed the vibration perception threshold (VPT) test using the Vibratron II device. A re-test was completed seven days after the first reading.
Results:
The relative reliability of the VPT test result is excellent (intraclass correlation coefficient = 0.96). The same applies to gender and obesity subgroups. Regarding absolute reliability, the standard error of measurement is 8.99%, and the small real difference is 24.94%.
Conclusions:
The relative and absolute reliability results of the vibration perception threshold in people with type 2 diabetes mellitus offer excellent results.
... Given the introduction of haptic devices, such as tablet PCs and smartphones operated by touch-screens, it is expected that studies on tactile perception, will gain increasing importance. There are three types of passive tactile perception: vibration perception, pressure perception, and thermal perception (Dyck et al. 1978). Of these, vibration perception is the most widely employed type of tactile perception in haptic devices. ...
This study explores the subjective use of adjectives to verbally communicate vibrotactile stimulation across multiple frequencies. In total, nine different vibrotactile stimulus frequencies (10–300 Hz) were utilized, and subjective evaluation methods, which involved adjectives, were used to assess the sensory representations of the participants (18 healthy male participants; mean age, 22.9 years; standard deviation, 3.5). Sensory terms such as ‘slow,’ ‘protruding,’ and ‘thick’ were used as representative expressions to describe low-frequency (10–100 Hz) vibrotactile stimulations, while ‘fast,’ ‘shallow,’ and ‘tickly’ were used to describe high-frequency (225–300 Hz) vibrotactile stimulations. At the frequencies of 150 and 200 Hz, no characteristic word was found because there was no difference in subjective evaluation scores from other low or high frequencies. The results suggest that vibrotactile stimulation at different frequencies induce diverse sensory representations, owing to not only the motion and shape of the stimuli but also the subjective responses of the perceivers. The results of this study could be utilized in developing affective haptic devices in the future.
... Baseline ATTRm disease status was measured using Coutinho Staging (Stage 1, walk unaided; Stage 2, walk with aid; Stage 3, wheelchair or bedbound) [21], polyneuropathy disability score (PND; Stage I, sensory disturbances in limbs without motor impairment; Stage II, difficulty walking without the need of a walking aid; Stage III, one stick or one crutch required for walking; Stage IV, two sticks or two crutches needed); and the modified neuropathy impairment score (mNIS þ7) which consists of two components, the NIS composite score and the modified þ7 composite score of physiological tests as previously described [22]. Nerve conduction, quantitative sensation testing (touch-pressure (TP) and heat as pain (HP) [22][23][24][25][26]) and heart rate with deep breathing (HRDB) were part of the modified þ7. Two mNIS þ7 assessments were performed prior to the first dose of study drug. ...
Background: Hereditary transthyretin (ATTRm) amyloidosis is a rare, progressive and fatal disease with a range of clinical manifestations.
Objective: This study comprehensively evaluates disease characteristics in a large, diverse cohort of patients with ATTRm amyloidosis.
Methods: Adult patients (N = 172) with Stage 1 or Stage 2 ATTRm amyloidosis who had polyneuropathy were screened and enrolled across 24 investigative sites and 10 countries in the NEURO-TTR trial (www.clinicaltrials.gov, NCT01737398). Medical and disease history, quality of life, laboratory data, and clinical assessments were analyzed.
Results: The NEURO-TTR patient population was diverse in age, disease severity, TTR mutation, and organ involvement. Twenty-seven different TTR mutations were present, with Val30Met being the most common (52%). One third of patients reported early onset disease (before age 50) and the average duration of neuropathy symptoms was 5.3 years. Symptoms affected multiple organs and systems, with nearly 70% of patients exhibiting broad involvement of weakness, sensory loss, and autonomic disturbance. Over 60% of patients had cardiomyopathy, with highest prevalence in the United States (72%) and lowest in South America/Australasia (33%). Cardiac biomarker NT-proBNP correlated with left ventricular wall thickness (p<.001). Quality of life, measured by Norfolk QoL-DN and SF-36 patient-reported questionnaires, was significantly impaired and correlated with disease severity.
Conclusions: Baseline data from the NEURO-TTR trial demonstrates ATTRm amyloidosis as a systemic disease with deficits in multiple organs and body systems, leading to decreased quality of life. We report concomitant presentation of polyneuropathy and cardiomyopathy in most patients, and early involvement of multiple body systems.
... The most common method for applying tactile information has involved vibration. Although tactile information can generally be divided into vibration, pressure, heating and others (Dyck et al., 1978), the application of vibrotactile information is preferred due to facilitated device utility; easily applicable devices mainly use vibrotactile information (Kim et al., 2010;Choi and Kuchenbecker, 2013). When considering the vast distribution and features of receptors used by humans to process tactile information, vibrotactile information is most closely related to Meissner's corpuscles and Pacinian corpuscles (Johansson and Vallbo, 1979;Bark et al., 2008). ...
This study was conducted to identify characteristics of the perceptual threshold level and electroencephalogram (EEG) responses to vibrotactile stimulations at various high frequencies, and to examine the possibility of distinguishing vibrotactile stimulations by frequency through such response characteristics. The vibrotactile stimulations of six frequencies (150, 200, 225, 250, 275 and 300 Hz) were exerted on the first joint of the right index finger. The perceptual threshold level was defined as the first minimum perceived intensity when the intensity stimulation was exerted step by step at each vibration frequency. EEG response characteristics were investigated by examining a single index corresponding to the peak or area of event-related desynchronization/synchronization (ERD/ERS) and seven specific indices derived by combining the single ERD/ERS indices. There was a significant difference in the perceptual threshold level across different frequencies. Specifically, the differences in vibration stimulus between 150 Hz and 200 Hz, and between 150 Hz and 225 Hz were significant. Of the EEG response characteristics, the single index of the peak or area of ERD/ERS did not show a significant difference by frequency. However, (ERS−ERD), ERD × (ERS−ERD), and ERS × (ERS−ERD) showed a significant difference between vibration stimulations at 150 Hz and 200 Hz, and between vibration stimulations at 150 Hz and 225 Hz, among the specific indices combined using the peak values of ERD/ERS. Furthermore, ERS × (ERS−ERD) showed a significant difference between 150 Hz and 225 Hz, and between 225 Hz and 275 Hz among the specific indices combined using the area of ERD/ERS. The perceptual threshold level and the specific indices of ERD/ERS suggested in the present study can be used as quantitative measurement indices to distinguish high-frequency vibration stimulation.
... Today, nylon filaments or fiber optic cables are used as von Frey filaments for QST. An automated method for the quantification of pressure, temperature perception, vibration, and touch was introduced in 1978 by the research group led by Peter Dyck [5]. This advancement led to the development of additional procedures and instruments, such as a thermal tester or pressure algometer for the determination of thermal or mechanical perception and pain thresholds. ...
Quantitative sensory testing (QST) is a standardized and formalized clinical sensitivity test. Testing describes a subjective (psychophysical) method that entails a cooperation of the person to be examined. Within its framework, calibrated stimuli are applied to capture perception and pain thresholds, thus providing information on the presence of sensory plus or minus signs. The presented QST battery imitates natural thermal or mechanical stimuli. The aim is to acquire symptom patterns of sensory loss (for the functioning of the thick and thin nerve fibers) as well as a gain of function (hyperalgesia, allodynia, hyperpathia) with a simultaneous detection of cutaneous and deep tissue sensibility. Most of the tested QST parameters are normally distributed only after a logarithmic transformation (secondary normal distribution)—except the number of paradoxical heat sensations, of cold and heat pain thresholds, and vibration detection thresholds. A complete QST profile can be measured within 1 h. QST is suitable not only for clinical trials but also in practice as a diagnostic method to characterize the function of the somatosensory system—from the peripheral nerve fiber receptor to the projection pathways to the brain.
... Consensus criteria on use and interpretation has been published under the auspices of the International Association for the Study of Pain [12]. The first automated systems to investigate different sensory modalities were developed in the 1970s [49,59]. Currently, over 15 types of devices are available and being used worldwide with a variety of methodological approaches for location, stimulus application, and sensation qualities examined, indicative of the lack of standardization of QST as a diagnostic, follow-up, and endpoint tool in patients [15,35,168]. ...
... Vibratory detection threshold (VDT), CDT, and HP 0.5 and an intermediate severity of heat pain (HP 5) were evaluated using CASE IVc (initially developed by us 16 and later manufactured by WR Medical Electronics, Maplewood, MN but without our proprietary involvement -see author disclosure). The 4, 2, and 1 stepping algorithm with null stimuli was used to determine VDT and CDT. ...
Introduction:
We assessed proficiency (accuracy and intra- and intertest reproducibility) of smart quantitative sensation tests (smart QSTs) in subjects without and with diabetic sensorimotor polyneuropathy (DSPN).
Methods:
Technologists from 3 medical centers using different but identical QSTs independently assessed 6 modalities of sensation of the foot (or leg) twice in patients without (n = 6) and with (n = 6) DSPN using smart computer assisted QSTs.
Results:
Low rates of test abnormalities were observed in health and high rates in DSPN. Very high intraclass correlations were obtained between continuous measures of QSTs and neuropathy signs, symptoms, or nerve conductions (NCs). No significant intra- or intertest differences were observed.
Conclusions:
These results provide proof of concept that smart QSTs provide accurate assessment of sensation loss without intra- or intertest differences useful for multicenter trials. Smart technology makes possible efficient testing of body surface area sensation loss in symmetric length-dependent sensorimotor polyneuropathies.
... To evaluate sensibility, quantitative sensory testing (QST) has frequently been used in different clinical, epidemiologic, and research studies [23]. There are various QST methods, such as a simple patient answer of yes or no whether stimuli could be identified [24], choice between one out of two time periods that include stimuli [25], or when the patient is asked to press a button when a vibration stimuli is perceived and to press again when the stimulus disappears (the method of limits) [26]. Sensibility studies using vibration as stimuli have shown that mechanoreceptors in the skin can detect vibration frequencies between 0.4 and 800 Hz [27]. ...
This study investigated detection thresholds of vibrometric stimuli in patients with transfemoral amputation supplied with osseointegrated (OI) and socket-suspended prostheses. It included 17 patients tested preoperatively with socket-suspended prostheses and after 2 yr with OI prostheses and a control group (n = 17) using socket-suspended prostheses, evaluated once. Assessments on the prosthetic and intact feet were conducted at six frequencies (8, 16, 32, 64, 125, and 250 Hz). Furthermore, measurements were conducted to investigate how vibrometric signals are transmitted through a test prosthesis. The results showed that the OI group had improved ability to detect vibrations through the prosthesis at 125 Hz (p = 0.01) at follow-up compared with the preoperative measurement. Compared with the control group, the OI group at follow-up had better ability to detect high frequency vibrations through the prosthesis (125 Hz, p = 0.02; 250 Hz, p = 0.03). The vibrometric signal transmitted through the test prosthesis was reduced at 8, 125, and 250 Hz but was amplified at 16, 32, and 64 Hz. Differences between the OI and the control groups were found in the highest frequencies in which the test prosthesis showed reduction of the vibrometric signal. The study provides insight into the mechanisms of vibration transmission between the exterior and bone-anchored as well as socket-suspended amputation prostheses.
Skin-integrated haptic interfaces that can relay a wealth of information from the machine to the human are of great interest. However, existing haptic devices are not yet able to produce haptic cues that are compatible with the skin. In this work, we present the stretchable soft actuators for haptic feedback, which can match the perception range, spatial resolution, and stretchability of the skin. Pressure-amplification structures are fabricated using a scalable self-assembly process to ensure an output pressure beyond the skin perception threshold. Due to the minimized device size, the actuator array can be fabricated with a sufficiently high spatial resolution, which makes the haptic device applicable for skin locations with the highest spatial acuity. A haptic feedback system is demonstrated by employing the developed soft actuators and highly sensitive pressure sensors. Two proof-of-concept applications are developed to illustrate the capability of transferring information related to surface textures and object shapes acquired at the robot side to the user side.
Quantitative sensory testing (QST), in particular using thermodes to apply defined warm and cold stimuli, is a well-established method to detect functional changes of Aδ- and C-fibers. Protocols have been established, and normative values have been determined in large cohorts. QST can be understood as an extension of clinical examination used to detect, confirm, and quantify subtle sensory abnormalities. Usually, thresholds for warm and cold detection, for pain induced by heat and cold, and for the detection of changes in temperature are assessed. The equipment, to date, is costly and bulky, but smaller and more affordable devices are being developed. To obtain intra- and interobserver comparability, it is important to observe a standardized method with fixed instructions given to the patient. As a psychophysical test, QST requires patient cooperation, and there may be errors due to lack of attention or malingering. Also, the range of normal is large, so that false-negative findings may result. Given these caveats, QST has been used by many groups and has been found a simple and moderately sensitive instrument to detect small fiber dysfunction both in small fiber neuropathy and in other conditions associated with damage to the small fibers. In particular, this noninvasive method can be used for intraindividual follow-up in prospective studies.KeywordsThermal detection thresholdsMechanical detection thresholdsPain thresholdsWindupDiabetes mellitusFabry diseaseChannelopathySarcoidosis
Background:
The adenosine triphosphate-binding cassette, subfamily B, member 1 gene (ABCB1) encodes P-glycoprotein (P-gp) that influences the intracellular transport of solutes including endogenous opioid peptides. The primary objective of this study was to determine the effects of the ABCB1 polymorphism c.3435C>T (rs10454642) on heat pain (HP) perception in a group of opioid-free adults with chronic pain.
Methods:
Opioid-free adults with chronic pain consecutively admitted to a pain rehabilitation program comprised the study cohort (N = 134). Individuals were genotyped for the c.3435C>T (rs10454642) polymorphism. The polymorphism was analyzed with nonparametric tests using a dominant (cytosine-cytosine [CC] versus cytosine-thymine [CT] + thymine-thymine [TT]) and recessive (CC + CT versus TT) model of allele effects. Quantitative sensory testing was performed using the Computer Aided Sensory Evaluator IV system.
Results:
The distribution of genotypes was 22% (N = 29) for CC, 45% (N = 60) for CT, and 33% (N = 45) for TT (Hardy-Weinberg, P > .1). A significant association was observed between the recessive model and HP threshold. Standardized values of HP threshold were significantly greater in the TT group than the CC + CT group (median difference, -0.77; 95% confidence interval [CI], -1.49 to -0.23; P = .005), and the effect size estimate was small (Cliff delta = 0.30). In the dominant model, no significant difference in HP threshold was observed between the CC and CT + TT groups (median difference, -0.45; 95% CI, -1.15 to 0.00; P = .108).
Conclusions:
These results posit that the efflux of endogenous opioid peptides is reduced in individuals with the TT genotype due to lower expression of P-gp, which, in turn, results in higher HP threshold. This study contributes to the emerging understanding of how the ABCB1 c.3435C>T polymorphism contributes to pain perception in opioid-free adults with chronic pain and provides the foundation for investigating the potential effects of this polymorphism on the clinical course of chronic pain.
See article on pages 141–146 in this issue.
Introduction:
For sequential and somatotopic assessment of small fiber neuropathy (SFN), heat pain (HP) tests of hypoalgesia might be used instead of decreased counts of epidermal nerve fibers (ENFs), but then healthy subject reference values of HP thresholds are needed.
Methods:
Using the CASE IVc system, HP thresholds of hypoalgesia were estimated for ten unilateral sites and counts of ENFs for four of them in healthy subjects.
Results:
In healthy subjects, small but statistically significant differences of both HP thresholds of hypoalgesia and counts of ENFs were observed among tested sites. Significant correlations between HP thresholds and counts of ENFs were not found.
Discussion:
For the studied somatotopic sites, we provide ≥95thand ≥99thpercentile reference limits for HP 0.5 and 5 of 1-10 HP thresholds of hypoalgesia and decreased counts of ENFs at ≤5thand ≤1stpercentile levels. This article is protected by copyright. All rights reserved.
The somatosensory system is comprised of a variety of sensory receptors located in the skin, muscle tendons, and visceral organs that are innervated by myelinated and nonmyelinated axons of the peripheral nervous system. These peripheral sensory nerve fibers in turn communicate somatosensory information to spinal reflex pathways and to the ascending sensory tracts and integration centers of the central nervous system. The consequences of somatosensory toxicity may appear as abnormal paresthesia, tingling or burning sensations, or deficits in sensitivity to touch, vibration, pain, temperature, or position sense. The evaluation of somatosensory function may be accomplished through a variety of behavioral and neurophysiological procedures. Somatosensory toxicity may follow exposure to industrial chemicals, natural toxins, or therapeutic agents. For example, somatosensory neurotoxicity may be an important dose-limiting side effect for several chemotherapeutic drugs. This chapter provides an overview of the anatomy and physiology of the somatosensory system, behavioral and neurophysiological assessment techniques, and selected chemicals or chemical classes that can produce somatosensory toxicity.
Technical advances are rapidly changing the clinical and instrumental approach to peripheral nerve diseases. Magnetic resonance neurography, diffusion tensor imaging and nerve ultrasonography are increasingly entering the diagnostic workup of peripheral neuropathies as tools that complement neurophysiology and enable investigation of proximal structures, such as plexuses and roots. Progress in the design of magnetic resonance scanners and sequences, and the development of high-frequency ultrasound probes mean that high-resolution peripheral nerve imaging is possible, enabling detailed examination of nerve size, morphology and internal fascicular structure that can integrate nerve conduction studies into clinical practice. In the growing field of small-fibre neuropathy, in which traditional nerve conduction studies are of little or no use, skin biopsy has become a reliable tool for diagnosis. Corneal confocal microscopy, nociceptive evoked potentials and microneurography are emerging techniques that are mainly used in clinical research settings, but have increasing relevance to clinical practice. We review these new and emerging techniques and their effects on diagnosis, treatment strategies and prognosis in a variety of peripheral neuropathies, including entrapments, brachial plexopathies, immune and inherited neuropathies, and small-fibre neuropathies. We discuss the most promising research findings and their potential for future application in clinical practice.
Objectives:
Despite its relative common occurrence, definitive diagnosis of small fiber neuropathy (SFN) remains problematic. In practice, patients with pain, numbness, and/or paresthesias in their lower limbs are diagnosed with SFN if found to have dissociated sensory loss in their feet, that is, impaired pinprick perception (PP) but relatively preserved vibration. We sought to assess the sensitivity and specificity of clinical examination and various diagnostic tools available for screening SFN.
Methods:
Medical records of 56 patients diagnosed with SFN were reviewed. Diagnosis was based on symptoms, detailed neurological examination that included PP, and abnormal results on at least one testing modality-quantitative sudomotor axon reflex (sweat) test (QSART), quantitative sensory testing (QST), and heart rate variability (HRV) testing.
Results:
Sensitivity of PP was relatively consistent between modalities of about 63% in presence of appropriate sensory symptoms. Laboratory testing diagnosed 88% of patients when both QSART and QST are employed. QST was most sensitive for detection of SFN with the heat-pain testing having higher sensitivity than cooling. Heart rate variability testing revealed low correlation across all groups.
Conclusions:
The diagnostic yield for SFN increases by combining clinical features with various testing modalities. In symptomatic patients, we propose the following diagnostic criteria for diagnosis of SFN: Definite SFN-abnormal neurological examination and both QSART and QST; Probable SFN-abnormal neurological examination, and either QSART or QST; Possible SFN-abnormal neurological exam, QSART, or QST.
Objective: To determine the diagnostic accuracy of the clinical tests like nerve palpation, monofilament test and voluntary muscle test for assessing peripheral nerve function impairment in leprosy. Methods: In this comparative cross-sectional study, 74 newly diagnosed leprosy patients without lepra reaction were enrolled. They underwent a thorough evaluation for peripheral nerve function using the above-mentioned clinical tests and nerve conduction study. The diagnostic accuracy of the clinical tests was determined by sensitivity, specificity, positive predictive value and negative predictive value considering nerve conduction study as a gold standard test. Data analysis was performed using SPSS version 11.5. Results: All clinical tests (nerve palpation, monofilament test and voluntary muscle test) were more specific but less sensitive. Amongst all, monofilament testing was the most specific one. Its specificity ranged between 93·54 –100%, whereas its sensitivity was 38·46 –68·75% only. Both nerve palpation and voluntary muscle testing had high specificity (. 90%) for all nerves, except nerve palpation for ulnar nerve; whereas both the tests had very low sensitivity (, 70%) for all the tested nerves. Conclusion: Though these clinical tests had higher specificity, their sensitivity was very low. So, along with clinical tests, nerve conduction study should be considered in leprosy patients for early detection of nerve function impairment whenever feasible.
Objective: To determine whether microscopic vasculitis explains the clinical and pathologic features of diabetic lumbosacral radiculoplexus neuropathy (DLSRPN). Background: DLSRPN is usually attributed to metabolic derangement or ischemic injury, but microscopic vasculitis as the sole cause needs consideration. Methods: We prospectively studied the clinical, laboratory, and EMG features as well as the pathology of distal cutaneous nerve biopsy specimens of patients with DLSRPN. Results: Study of DLSRPN nerve biopsy specimens (n = 33) compared with those from healthy controls (n = 14) and those with diabetic polyneuropathy (n = 21) provided strong evidence for ischemic injury (axonal degeneration, multifocal fiber loss, focal perineurial necrosis and thickening, injury neuroma, neovascularization, and swollen fibers with accumulated organelles), which we attribute to microscopic vasculitis (epineurial vascular and perivascular inflammation, vessel wall necrosis, and evidence of previous bleeding). Segmental demyelination was significantly associated with multifocal fiber loss. Conclusions: 1) This severe, debilitating neuropathy begins with symptoms unilaterally and focally in the leg, thigh, or buttock and spreads to involve the other regions of the same and then opposite side and is due to multifocal involvement of lumbosacral roots, plexus, and peripheral nerve (i.e., diabetic lumbosacral radiculoplexus neuropathy). 2) Motor, sensory, and autonomic fibers are all involved. 3) Ischemic injury explains the clinical features and pathologic abnormalities of nerve. 4) The proximate cause of the ischemic injury appears to be microscopic vasculitis. 5) The segmental demyelination is probably secondary to ischemic axonal dystrophy, thus providing a unifying hypothesis for both axonal degeneration and segmental demyelination.
In considering the mechanisms by which spinal cord systems transfer, modulate, and integrate incoming sensory signals, it is necessary to know something about the location and structure (see Winklemann, Chapter 2) and the properties of the cutaneous and deep receptors that transduce physical and chemical events impinging on them from the external and internal environment (Light and Perl, 1981; Boyd and Smith, 1984; Crago, 1984). As crucial to our understanding of sensory transduction as are the physical and electrophysiological studies of receptors is the information obtained from psychophysical responses evoked by stimuli transduced by these receptors. Cutaneous sensory detection thresholds in man with respect to site, sex, age, and disease are thus the focus of this chapter.
The diagnosis of autonomic neuropathy, which is considered an important cause of organic impotence [18, 46], is difficult. Symptoms of autonomic failure are not specific [37, 41, 50, 53], do not always correlate with impotence [38], and methods for the direct measurement and assessment of autonomic function in human subjects are not presently available.
Computer-assisted thermal threshold testing is a psychophysical semi-quantitative method of testing the function of small nerve fibres. At present, there is not enough data available on the effect of physiological variables on the threshold value and on the intra-individual variability of the test. Methods: Thermal threshold for heat and cold was determined in a group of 50 healthy volunteers (25 males and 25 females) in two localizations (thenar of the left upper extremity and dorsum of the right lower extremity). Each individual was examined with three different algorithms: two reaction time methods (reaction time inclusive - non-randomised and randomised variant of the Limits method) and one constant stimulus method (reaction time exclusive - randomised variant of the Levels method). To determine intra-individual variability, all tests were repeated in 30 individuals within one week and the upper normal limit of physiological intra-individual change of each test was determined. Results: Values of thermal threshold for cold decreased significantly whereas values for heat increased in examination of lower extremities, in men, and when using reaction time. The effect of age on thermal threshold was not significant. Intra-individual variability of threshold values expressed as the median of coefficients of intra-individual variability fell between 15 and 30% and was independent of test type, examined location, age or gender. Conclusions: Normal limits have to be determined with respect to gender, algorithm type and localization of the thermal element. Intra-individual variability of threshold values is acceptable, considering the psychophysical character of the test, is comparable to other quantitative tests of sensory perception and is not significantly influenced by test type or by physiological variables.
We define peripheral neuropathy as disease of peripheral motor, sensory, or autonomic neurons (axons), exclusive of spinal cord disease secondarily affecting motor neurons or posterior columns. By this definition, motor neuron disease and poliomyelitis are included with peripheral neuropathy; multiple sclerosis affecting fasciculus gracilis is not.
Sensory system examination is a very important part of clinical neurology. Quantitative sensory studies using automated systems to evaluate the sensory function are useful in clinical and experimental studies of peripheral neuropathies. This chapter discusses the sensory receptors, sensory examination, and a quantitative system designed to deliver sensory stimuli, including touch-pressure, vibration, thermal, and heat-pain sensory stimuli, in a quantifiable and reproducible manner. © 2014 Springer Science+Business Media New York. All rights are reserved.
Background:
The principle aim of this study was to investigate the associations between heat pain (HP) perception, pain catastrophizing, and pain-related anxiety in a heterogeneous cohort of community-dwelling adults with chronic pain admitted to a 3-week outpatient pain rehabilitation program.
Methods:
All adults consecutively admitted to an outpatient pain rehabilitation program from July 2009 through January 2011 were eligible for study recruitment (n=574). Upon admission, patients completed the Pain Catastrophizing Scale (PCS), the short version of the Pain Anxiety Symptoms Scale (PASS-20), and HP perception was assessed using a standardized quantitative sensory testing (QST) method of levels.
Results:
Greater PCS scores were significantly correlated with lower standardized values of HP threshold (HP 0.5) (P=0.006) and tolerance (HP 5) (P=0.003). In a multiple variable model adjusted for demographic and clinical factors known to influence HP perception, every 10 point increase in the PCS was associated with a -0.124 point change in HP 0.5 (P=0.014) and a -0.142 change in HP 5 (P=0.014) indicating that patients with higher PCS scores had lower HP thresholds and tolerances, respectively. Similarly, greater PASS-20 scores significantly correlated with lower standardized values of HP 0.5 and HP 5. In a multiple variable model, every 10 point increase in the PASS-20 was associated with a -0.084 point change in HP 0.5 (P=0.005) and a -0.116 point change in HP 5 (P=0.001) indicating that patients with higher PASS-20 scores had lower HP thresholds and tolerances, respectively.
Conclusions:
The findings of this study extend the use of a standardized method for assessing HP in a heterogeneous sample of adults with chronic pain. Although pain catastrophizing shares significant variance with pain-related anxiety, our findings suggest that either measure would be appropriate for use in future studies that incorporate the QST method of levels.
The somatosensory system is comprised of a variety of sensory receptors located in the skin, muscle tendons, and visceral organs that are innervated by myelinated and nonmyelinated axons of the peripheral nervous system. These peripheral sensory nerve fibers in turn communicate somatosensory information to spinal reflex pathways and to the ascending sensory tracts and integration centers of the central nervous system. The consequences of somatosensory toxicity may appear as abnormal paresthesia, tingling or burning sensations, or deficits in sensitivity to touch, vibration, pain, temperature, or position sense. The evaluation of somatosensory function may be accomplished through a variety of behavioral and neurophysiological procedures. Somatosensory toxicity may follow exposure to industrial chemicals, natural toxins, or therapeutic agents. For example, somatosensory neurotoxicity may be an important dose-limiting side effect for several chemotherapeutic drugs. This chapter provides an overview of the anatomy and physiology of the somatosensory system, behavioral and neurophysiological assessment techniques, and selected chemicals or chemical classes that can produce somatosensory toxicity.
This chapter provides an overview of the development and application of methods for sensory evaluation in toxicology, to review the current state of research in sensory neurotoxicology, and to identify practices and principles that will advance this field of investigation. The chapter starts with presenting a brief history of psychophysics pointing out that most of the classical psychophysical methods in use today were designed more than 100 years ago. The chapter distinguishes these psychophysical methods from the response paradigms used in the sensory evaluation process. The cardinal features of signal detection theory are then described. Contribution of this theory to the field of psychophysics is also emphasized. Some of the techniques available in animal psychophysics are reviewed. Salient examples are given of the use of sensory assessment in human and animal neurotoxicology. The chapter also reviews a number of technical and methodological flaws. This exercise leads to an enunciation of general principles in the design and conduct of neurotoxicological studies. The chapter concludes with some specific and general recommendations.
Diabetic nerve damage leads to a wide variety of unpleasant problems: painful sensations, muscle weakness, numb feet predisposing to ulcers, impotence, and a series of distressing effects due to autonomic dysfunction. At present, there is no single effective treatment for the many clinical syndromes — each of which may well have a different cause. Improved blood glucose control must remain the first line of treatment, hopefully to improve nerve structure and function but also to raise the pain threshold. A variety of sedatives and analgesics may also help some patients.
Inhibition of the enzyme aldose reductase with resultant interference with neural sorbitol and myo-inositol metabolism would seem to have a good theoretical basis in therapy, and detailed results of long term clinical trials of aldose reductase inhibitors such as sorbinil and tolrestat are awaited with interest. Their role in the future could be more important in prevention of nerve damage than in attempting to reverse gross end-stage nerve destruction. In diabetic subjects with loss of pain sensation in the foot due to neuropathy or in the more advanced state of foot ulceration, intensive educational and clinical efforts should be exerted to prevent this distressing and common problem.
In the future, a more detailed understanding of the biochemical abnormalities occurring in nerves and their effect on nerve function, structure and vasculature may lead to more satisfactory and logical treatments for this the commonest single complication of diabetes.
In the last two decades, analysis of cutaneous innervation in skin biopsies has become an established method for studying and diagnosing small fiber neuropathies. Consensus panels have now accepted the assessment of epidermal nerve fibers (ENFs) as objective valid indications of small sensory nerve fiber involvement in disease. Using immunohistochemistry, different nerve fiber types can be identified in skin giving several advantages over sural nerve biopsy. Recently, quantification of pilomotor and sudomotor nerves has expanded our knowledge of autonomic nervous system involvement in peripheral neuropathy. Finally, sampling myelinated fibers and mechanoreceptors, particularly in glabrous (smooth) skin, has enabled the study of myelin pathology in skin biopsies.
Quantitative sensory testing (QST) is a standardized and formalized set of clinical sensitivity tests based on subjective (psychophysical) methods, which depends on the cooperation of the subject being investigated. Calibrated stimuli are used to measure the perception and pain thresholds, which provide information on the presence of sensory plus or minus signs. The QST equipment presented mimics natural thermal or mechanical stimuli. The rationale is to test for patterns of functional sensory loss or gain by simultaneous assessment of both cutaneous and deep pain sensitivity. The majority of QST parameters are normally distributed only after logarithmic transformation (i.e. secondary normalization). With QST a complete somatosensory profile can be obtained within 1 h. The QST is a suitable method for characterizing the function of the somatosensory system in clinical trials and also in clinical practice as a diagnostic procedure.
What factors affect users' perceptions of physical human–robot interactions? To answer this question, this study examined whether the skin temperature of a social robot affected users' perceptions of the robot during physical interaction. Results from a between-subjects experiment (warm, intermediate, cool, or no interaction) with a dinosaur robot demonstrated that skin temperature significantly affects users' perceptions and evaluations of a socially interactive robot. Additionally, this study found that social presence had partial mediating effects on several dependent variables. Important implications and limitations for improving human–robot interactions are discussed here.
Stroke (CVA) is a major cause of disability among older persons. Even after costly and extensive rehabilitation, the majority of stroke survivors remain functionally affected. In the absence of any sensory deficits, many stroke patients are unable to recognize a stimulus (e.g. touch) with eyes occluded or fail to recognize it when simultaneously stimulated by a second stimulus. These dysfunctions called “neglect” and “extinction” may contribute significantly to their disabling condition and could be dangerous (e.g. as when ambulating). At present, physicians and therapists do not have a reliable diagnostic tool to detect tactile neglect and extinction in CVA and in similar patients (e.g. head-injured). The authors' study was aimed at the application of computer technology to develop a simple test to assess these deficits and to evaluate various therapies which may contribute to patient recovery
This paper studies methode given by Wetherill (1963) for estimating general percentage points of a quantal response curve. A new method of estimation is proposed which is both simple to compute and highly efficient. The use of this with the Up and Down Transformed Reaponse Rule (UDTR) is investigated, by exact calculation of probability distributions and by empirical sampling trials. The use of the UDTR to estimate the slope of a response curve is outlined.
Simple, inexpensive thermal stimulators, Minnesota Thermal Disks, were designed based on the differences in heat transfer of copper (C), stainless steel (S), glass (G), and polyvinyl chloride (P). In healthy persons, C and P almost always can be recognized as 'cold' and 'warm', respectively. The difference between C and S can be recognized only slightly (but significantly) better than by chance, and recognition of the difference between C and G is about halfway between that in the other two tests. Measurements on the forehead, hand and foot of 30 healthy persons of various ages showed evidence of decreased thermal discrimination with increasing age and of a difference in discrimination at various cutaneous sites.
Based on advances in signal detection theory, a method is proposed for the measurement of response to light touch. Comparison was made between this method and 2 others, including the commonly used clinical procedure. Three body areas of 12 male and 12 female subjects were tested by each of the 3 methods. Differences among body parts were discriminated best by the proposed procedure, a forced choice method, and were discriminated most poorly by the standard clinical procedure. No sex differences in sensitivity were found. A clinical method for testing light touch is presented that provides objective measures of changes in sensitivity over time or can compare an area of suspected sensory loss with a normal one.
Touch-pressure sensation at regularly spaced points on the index finger and great toe of humans of various ages was measured using a recently developed instrument which allows for exact placement of stylus tip, exact stylus area, and wide range of intensity of stimuli with defined and constant wave form. The threshold of touch-pressure sensation was higher in the toe than in the finger, in the old than in the young, and, in persons over the age of 40 years, in men than in women. If our sampling is sufficient, these differences cannot be explained entirely on the basis of a less-dense distribution of receptors.
The perception of mechanical vibration: I. History of a controversy; 11. The response of pressure receptors; 111. The frequency of function; IV. Is there a separate " vibratory sense
- Geldard
- Fa
Geldard FA: The perception of mechanical vibration: I. History of a controversy; 11. The response of pressure receptors; 111. The frequency of function; IV. Is there a separate " vibratory sense " ? J Gen Psychol 22:243, 271, 281, 291, 1940
Thermal sensations Handbook of Physiology
- Zotterrnan
Zotterrnan Y: Thermal sensations, in Field J, Magoun HW, Hall VE (eds): Handbook of Physiology. Washington, DC, American Physiological Society, 1959, vol 1, pp 431-458
Quantitation of cutaneous sensation in man Peripheral Neuropathy. Philadelphia, Saunders, 1975, chap 22, pp 465-479 and tabes dorsalis
- Dyck
- Pj
Dyck PJ: Quantitation of cutaneous sensation in man, in Dyck PJ, Thomas PK, Lambert EH (eds): Peripheral Neuropathy. Philadelphia, Saunders, 1975, chap 22, pp 465-479 and tabes dorsalis. Handbook of Electroencephalography and Clinical Neurophysiology 9:83-118, 197 1
- Nafe