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Anosognosia for hemiplegia and models of motor control: Insights from lesional data
... Due to this association between neglect and anosognosia, it has been suggested that the rehabilitation of anosognosia for hemiplegia also requires improvement of neglect (Bottini et al., 2010). Indeed, cases have been reported of patients whose lack of awareness for motor impairment was ameliorated by caloric vestibular stimulation together with an improvement of their neglect (Cappa, Sterzi, Vallar, & Bisiach, 1987;Rode, Perennin, Honore, & Boisson, 1998;Vallar, Sterzi, Bottini Cappa, & Rusconi, 1990). ...
... The effects of these treatments on anosognosia have rarely been formally investigated (Rossetti & Rode, 2002;Bottini et al., 2010). This was the purpose of this study. ...
... We showed that, at least in one case (patient 1), all the three treatments tested had a transient effect only on anosognosia, while on two further cases only prismatic stimulation (patients 2 and 3) or TENS (patient 3) proved to be beneficial, albeit temporarily. This confirms earlier observations (Rossetti & Rode, 2002;Bottini et al., 2010) that some of the treatments proposed to alleviate neglect, might sometimes also be used to improve anosognosia. ...
Different techniques, such as optokinetic stimulation, adaptation to prismatic shift of the visual field to the right, or transcutaneous electrical nerve stimulation (TENS), have been shown to alleviate neglect, at least temporarily. We assessed the effect of these techniques on anosognosia and whether their therapeutic effect, if any, matches that on neglect. The effect of the three types of treatment on anosognosia and neglect was investigated in five patients presenting with both severe anosognosia and neglect. Patient 1 was treatment responsive to anosognosia but not to neglect, whereas patients 4 and 5 showed the reverse pattern, i.e., they were treatment responsive to neglect but not to anosognosia. This "treatment response bias" proved to be a valid means to investigate different effects of treatments in the same patient.
... Several years later, Joseph Francois Felix Babinski (1914) provided the name anosognosia (in French, anosognosie) to describe what has been the most common, classic form of this disorder (Prigatano & Schacter, 1991;Prigatano, 2010). Following a large right hemisphere stroke typically involving the middle cerebral artery (MCA), the patient may become hemiplegic and not report experiencing any disturbance in his or her motor functioning (Bisiach & Geminiani, 1991a;Bottini et al., 2010). This striking phenomenon has come to be called anosognosia for hemiplegia (AHP) and is observed in about 20 to 30% of patients with large right hemisphere strokes involving the MCA (Bisiach et al., 1986;Pederson et al., 1996;Baier & Karnath, 2005). ...
... Denial is considered a "defense mechanism" that automatically (i.e., non-consciously and reflexively) protects the individual from experiencing anxiety (DSM-IV, 1994:765, Glossary of Technical Terms). There is very little, if any evidence to suggest that AHP is a non-conscious, reflexive, motivated response to protect the individual from experiencing anxiety (see Bottini et al., 2010;Cocchini & Della Sala, 2010). This does not mean, however, that when a person experiences, perhaps for the first time, a significant disturbance in motor functioning, they do not automatically become anxious (Cocchini, Beschin & Della Sala, 2002). ...
Clinical neuropsychologists frequently evaluate patients who present with poor self-awareness of their neurological and/or neuropsychological status. Understanding the nature of various disturbances of phenomenological experience may be important for differential diagnosis, psychotherapy, and brain injury rehabilitation. In this paper, an attempt is made to briefly review anosognosia and associated disturbances in phenomenological states. This is followed by a brief discussion of impaired self-awareness (ISA) seen in individuals who have a history of severe traumatic brain injury (TBI). It is suggested that in this latter group, ISA represents a partial syndrome of anosognosia. Extensive rehabilitative work with these individuals further suggests that persons with severe TBI may show both ISA and denial as a method of coping. This paper then discusses briefly the phenomenon of denial and how it may be manifested. Suggestions for measuring ISA, denial of disability (DD) and denial of ability (DA) are then made.
... Indeed, under normal conditions, monitoring systems are thought to compare signals coding for the anticipation of changes due to the motor command (efferent copy) with signals providing the actual feedback from the executed movement (Wolpert et al., 1995). Several lines of evidence suggest that this comparator process could be damaged in motor anosognosia (Berti et al., 2005;Bottini et al., 2010;Frith et al., 2000). Thus, in patients with AHP, the impaired comparator may fail to detect the mismatch between intended but non-executed movements and real motor actions, presumably by mistaking the efferent copy of the intended movement with the actual feedback, which might then prevent patients to become aware of their motor deficit. ...
... Comparator processes monitoring the outcome of motor commands are presumably mediated by premotor cortical areas that normally integrate motor with proprioceptive information, as these brain regions have been found to be more often damaged in patients with AHP relative to patients without AHP (Bottini et al., 2010;. However, other brain regions implicated in more general monitoring functions, error detection, and subsequent behavioural/ cognitive adjustment are also more frequently damaged in patients with AHP, including ACC and insula as well as their connections in white-matter Karnath et al., 2004). ...
Every movement begins with action programming, and ends with a produced effect. Anosognosia for hemiplegia (AH), involving unawareness of motor deficits after brain damage, is a striking but also poorly understood symptom in clinical neurology. It has been suggested that it may result from a combination of cognitive and sensorimotor dysfunctions, including impairments in monitoring motor action and detecting the mismatch between intention and outcome. Here we investigated the relationship between motor action awareness and monitoring of self-produced movements by using a motor imaginary task, which was performed with either the intact or the affected limb. We tested 10 right brain-damaged patients, including 5 with AH, in comparison with 5 healthy controls. In a first phase, participants were asked to either realize or imagine a movement with their right or left arm. In a subsequent recognition phase, the participants had to recall whether the movement was a realized or imagined and which arm was used. AH patients performed significantly worse relative to no-AH patients and healthy controls for the left movements. Specifically, we found that AH patients believed they had realized movements with their (paralyzed) left arm even when they failed in the left execution condition. However, they also made more errors for movements actually realized with the right hand. These findings confirm that impaired action monitoring may contribute to AHP. Furthermore, our results support the notion of an action control system integrating "feedforward" signals through a comparison process between the intention and execution of movement, but also indicate that monitoring deficits in AHP are not strictly unilateral. Combined together, dysfunction of motor comparator processes and more general monitoring deficits may add up to lead to unawareness of paralysis.
Copyright © 2014 Elsevier Ltd. All rights reserved.
... Indeed, patients' counterintuitive behavior can unmask the inadequacies of theories on human brain functioning hidden from the view in the intact brain (see Churchland, 1986, for a discussion on this point). To this respect, one of the most informative neurological disorders is anosognosia for hemiplegia (hereinafter AHP), a condition in which movement cognition is dramatically distorted (see Bottini et al., 2010; Orfei et al., 2007; Pia et al., 2004 for reviews). AHP patients, affected by a complete paresis of the side of the body opposite to the brain damage (often the left side but see also Cocchini et al., 2009) deny that there is anything wrong with their contralesional limbs. ...
... In other words, patients may explicitly deny a deficit despite having some insight into it, as they correctly approach bimanual tasks according to their motor impairment (Cocchini et al., 2010). Delusional beliefs concerning the affected side of the body, such as somatoparaphrenia (i.e., the ownership of the limb is ascribed to another person as, for instance, the doctor or a relative), misoplegia (e.g., hatred toward the affected limbs), or limb personifications (e.g., the plegic limb is considered as an entity with an own identity) are usually considered as additional, thought independent, abnormal manifestations (see Bottini et al., 2010 for a discussion on this point). The interpretation of AHP is not straightforward. ...
In anosognosia for hemiplegia, patients may claim having performed willed actions with the paralyzed limb despite unambiguous evidence to the contrary. Does this false belief of having moved reflect the functioning of the same mechanisms that govern normal motor performance? Here, we examined whether anosognosics show the same temporal constraints known to exist during bimanual movements in healthy subjects. In these paradigms, when participants simultaneously reach for two targets of different difficulties, the motor programs of one hand affect the execution of the other. In detail, the movement time of the hand going to an easy target (i.e., near and large), while the other is going to a difficult target (i.e., far and small), is slowed with respect to unimanual movements (temporal coupling effect). One right-brain-damaged patient with left hemiplegia and anosognosia, six right-brain-damaged patients with left hemiplegia without anosognosia, and twenty healthy subjects were administered such a bimanual task. We recorded the movement times for easy and difficult targets, both in unimanual (one target) and bimanual (two targets) conditions. We found that, as healthy subjects, the anosognosic patient showed coupling effect. In bimanual asymmetric conditions (when one hand went to the easy target and the other went to the difficult target), the movement time of the non-paralyzed hand going to the easy target was slowed by the 'pretended' movement of the paralyzed hand going to the difficult target. This effect was not present in patients without anosognosia. We concluded that in anosognosic patients, the illusory movements of the paralyzed hand impose to the non-paralyzed hand the same motor constraints that emerge during the actual movements. Our data also support the view that coupling relies on central operations (i.e., activation of intention/programming system), rather than on online information from the periphery.
... However, a fMRI study demonstrated that the neural patterns activated, for the movement of both hands, were overlapping with the healthy subjects. [18] In conclusion, our results provided evidence of the activation of motor areas in a condition of unawareness of motor impairment, [41] in a patient with a left-brain lesion. This case highlighted an interest of the compensation mechanism that involved neural networks near brain lesions and some areas of the contro-lesional hemisphere suggesting that the synaptic plasticity permitted an intra and inter-hemispheric reorganization of the cerebral system [42] to modulate the residual ability to generate motor planning. ...
Objective:
The aim of this study is to verify the functional activation in a patient with anosognosia for hemiplegia following left brain lesions.
Methods:
We report a case of a 53-year-old right-handed female patient. She came to our rehabilitative unit with a diagnosis of an ischemic major stroke in the left internal carotid artery and important hemiplegia to the right side. She underwent functional magnetic resonance imaging (fMRI), during which she performed a motor imagery task.
Results:
The fMRI assessment showed an ischemic lesion in the frontotemporal and insular left areas. In the fMRI experiment, we revealed activation of the residual neural patterns of both hemispheres.
Conclusion:
We underlined an interest in the compensation mechanism that involved neural networks near brain lesions and some areas of the contro-lesional hemisphere, suggesting that the synaptic plasticity permitted an intra and inter-hemispheric reorganization of the cerebral system.
... When a given movement does not occur as intended and planned, a mismatch between predicted and actual sensory feedback is detected by a brain comparator that brings about conscious awareness of an error (Blakemore, Wolpert, & Frith, 2002;. In AHP, the symptoms derive from a defective functioning of the comparator which for some reason is incapable of detecting this mismatch (Bottini et al., 2010;Fotopoulou et al., 2008). ...
Anosognosia for hemiplegia is a lack of awareness of motor deficits following a right hemisphere lesion. Residual forms of awareness co-occur with an explicit denial of hemiplegia. The term emergent awareness refers to a condition in which awareness of motor deficits is reported verbally during the actual performance of an action involving the affected body part. In this study, two tasks were used to explore the potential effects of i) attempting actions which are impossible for sufferers of hemiplegia and ii) attempting actions which are potentially dangerous. Sixteen hemiplegic patients (8 anosognosic, and 8 non-anosognosic) were asked to perform both potentially dangerous and neutral actions. Our results confirm an increase in emergent awareness in anosognosic patients during the execution of both of these types of action. Moreover, actions that are potentially dangerous improved the degree of awareness. However, lesions in the fronto-temporal areas appear to be associated with a reduced effect of action execution (emergent awareness) while lesions in the basal ganglia and amygdale and the white matter underlying the insula and fronto-temporal areas are associated with a lesser degree of improvement resulting from attempting to perform dangerous actions.
... Seminal studies demonstrate a recovery of AHP after caloric vestibular stimulation (Cappa, Sterzi, Vallar, & Bisiach, 1987; case 5 and 3 in Geminiani & Bottini, 1992; Rode, Perenin, Honore, & Boisson, 1998; Vallar, Bottini, & Sterzi, 2003; Vallar, Sterzi, Bottini, Cappa, & Rusconi, 1990 ). In most of these studies the remission of AHP during CVS is generally transient (see review in Bottini et al., 2010), although in two cases described by Cappa and colleagues the remission outlasted the period of vestibular stimulation (Cappa et al., 1987). Beschin and collaborators (Beschin, Cocchini, Allen, & Della Sala, 2012 ) have recently tested the efficacy of a number of treatments including prism adaptation, optokinetic stimulation and transcutaneous electrical stimulation. ...
Right brain damage patients may not complain of a left sided paralysis up to the point of denying it or even claiming of having just moved an otherwise paralyzed limb. This condition is known as anosognosia for hemiplegia (AHP). Recent behavioural experiments suggest that some residual intentionality might be preserved in patients with anosognosia and that the false belief of having moved originates from a failure to notice discrepancies between movement expectancies and the actual state of the motor system. This failure may be caused by a lack of afferent sensory information concerning the movement or alternatively by a direct dysfunction of the brain regions involved in actions' motor monitoring (i.e., the comparator system). Here we examined the effect of anodal transcranial direct current stimulation (tDCS) of the right premotor cortex in a patient with a bilateral lesion, involving predominantly the right hemisphere, and a dense unawareness for his left hemiplegia. During sham or anodal tDCS the patient was requested to judge his ability to perform simple motor actions (i) without actually executing the movement itself (“offline” condition) and after having performed a series of verbally cued finger opposition movements (“online” condition) with (i) eyes-closed or (ii) eyes-open. We found that anodal tDCS induces a significant remission of the false experience of movement only when the patient is requested to actually perform the movement with eyes open. Conversely, the patient's awareness does not improve in both the “offline” condition (in which the patient does not attempt to perform the movement) and in the “online” condition, when vision is precluded (“online” condition, eyes-closed). We conclude that the stimulation of the premotor cortex by tDCS activates brain regions involved in motor monitoring, temporary restoring the ability of the motor comparator system to correctly appreciate afferent information and build up a veridical motor awareness.
... In AHP, patients show a paresis of the left (contralesional) side of the body following a right hemisphere lesion. Nevertheless, they obstinately deny their motor deficit and, when asked to move their paralyzed limb, they pretend to have performed the requested action (see Pia et al., 2004;Orfei et al., 2007;Bottini et al., 2010;Jenkinson and Fotopoulou, 2010 for reviews). This 'denial' may be due to lesions mainly involving pre-motor and insular areas, thought to provide the neural basis of a complex circuit related to motor monitoring (Berti et al., 2005;Karnath et al., 2005;Fotopoulou et al., 2010;Vocat et al., 2010;Moro et al., 2011;Garbarini et al., 2012). ...
When humans move simultaneously both hands strong coupling effects arise and neither of the two hands is able to perform independent actions. It has been suggested that such motor constraints are tightly linked to action representation rather than to movement execution. Hence, bimanual tasks can represent an ideal experimental tool to investigate internal motor representations in those neurological conditions in which the movement of one hand is impaired. Indeed, any effect on the “moving” (healthy) hand would be caused by the constraints imposed by the ongoing motor program of the ‘impaired’ hand. Here, we review recent studies that successfully utilized the above-mentioned paradigms to investigate some types of productive motor behaviors in stroke patients. Specifically, bimanual tasks have been employed in left hemiplegic patients who report illusory movements of their contralesional limbs (anosognosia for hemiplegia). They have also been administered to patients affected by a specific monothematic delusion of body ownership, namely the belief that another person’s arm and his/her voluntary action belong to them. In summary, the reviewed studies show that bimanual tasks are a simple and valuable experimental method apt to reveal information about the motor programs of a paralyzed limb. Therefore, it can be used to objectively examine the cognitive processes underpinning motor programming in patients with different delusions of motor behavior. Additionally, it also sheds light on the mechanisms subserving bimanual coordination in the intact brain suggesting that action representation might be sufficient to produce these effects.
... Some authors (Marcel et al., 2004; Cocchini et al., 2010; Fotopoulou et al., 2010) argue that different patients with AHP may have distinct cognitive impairments, possibly reflecting differences in the location and extent of brain damages (which may also differ between acute versus more chronic cases; see Vocat et al., 2010). Several authors have proposed that, at least in some cases, AHP may be conceptualized as a selective disorder of motor cognition (Gold et al., 1994; Frith et al., 2000; Berti et al., 2005; Coslett, 2005; Fotopoulou et al., 2008; Jenkinson et al. 2009; Bottini et al., 2010) related to recent computational models of motor production and motor control (Wolpert et al., 1995; Blakemore et al., 2002; Haggard, 2005). Such models posit that intentions to move and the corresponding motor commands normally lead also to a prediction (forward model) of the sensory consequences for the planned movement. ...
... 5 Conceptualising motor awareness within this model, anosognosia in AHP patients can be ascribed to a damage at a comparator system that, in normal conditions, compares movement anticipation with the feedback coming from movement execution. 6 Because of the brain lesion, the comparator cannot detect the mismatch between intended but not executed movements, causing the patient's unawareness of the motor deficits. However, the normal activity of the structures implementing motor intentionality gives rise to the subjective feeling of movement that AHP patients (erroneously) report experiencing. ...
Objectives:
To confront motor awareness in anosognosia for hemiplegia (AHP), where paralyzed patients deny their motor impairment, and in motor neglect (MN), where non-paralyzed patients behave as if they were paretic.
Methods:
Eight right-brain-damaged-patients, 4 hemiplegic (2 with and 2 without AHP) and 4 non-hemiplegic (2 with only perceptual-neglect and 2 with also MN) were evaluated with a bimanual motor battery, before and after examiner's reinforcement to use the contralesional limb. The requested bimanual movements could be either symmetric or asymmetric, either intransitive or transitive (with/without objects). We compared the examiner's evaluation of patients' performance with the patients' self-evaluation of their own motor capability (explicit knowledge). We also evaluated the presence/absence of compensatory unimanual strategies that, if present, suggests implicit knowledge of the motor deficit.
Results:
We found significant differences between conditions only in MN patients, whose performance was better after the examiner's reinforcement than before it, during symmetric than asymmetric movements and during intransitive than transitive movements. As for motor awareness, we found a lack of explicit and implicit knowledge in both AHP and MN patients.
Conclusion:
Although different in terms of motor intention and motor planning, AHP and MN are both characterised by anosognosia for the motor impairment.
... Several authors have proposed that, at least in some cases, AHP may be conceptualized as a selective disorder of motor cognition (Gold et al., 1994;Frith et al., 2000;Berti et al., 2005;Coslett, 2005;Fotopoulou et al., 2008;Jenkinson et al. 2009;Bottini et al., 2010) related to recent computational models of motor production and motor control (Wolpert et al., 1995;Blakemore et al., 2002;Haggard, 2005). Such models posit that intentions to move and the corresponding motor commands normally lead also to a prediction (forward model) of the sensory consequences for the planned movement. ...
Selective neurological impairments can shed light on different aspects of motor cognition. Brain-damaged patients with anosognosia for hemiplegia deny their motor deficit and believe they can still move the paralysed limb. Here we study, for the first time, if the anomalous subjective experience that their affected hand can still move, may have objective consequences that constrain movement execution with the opposite, intact hand. Using a bimanual motor task, in which anosognosic patients were asked to simultaneously trace out lines with their unaffected hand and circles with their paralysed hand, we found that the trajectories of the intact hand were influenced by the requested movement of the paralysed hand, with the intact hand tending to assume an oval trajectory (bimanual coupling effect). This effect was comparable to that of a group of healthy subjects who actually moved both hands. By contrast, brain-damaged patients with motor neglect or actual hemiplegia but no anosognosia did not show this bimanual constraint. We suggest that anosognosic patients may have intact motor intentionality and planning
for the plegic hand. Rather than being merely an inexplicable confabulation, anosognosia for the plegic hand can produce objective constraints on what the intact hand does.
... Several authors have proposed that, at least in some cases, AHP may be conceptualized as a selective disorder of motor cognition (Gold et al., 1994;Frith et al., 2000;Berti et al., 2005;Coslett, 2005;Fotopoulou et al., 2008;Jenkinson et al. 2009;Bottini et al., 2010) related to recent computational models of motor production and motor control (Wolpert et al., 1995;Blakemore et al., 2002;Haggard, 2005). Such models posit that intentions to move and the corresponding motor commands normally lead also to a prediction (forward model) of the sensory consequences for the planned movement. ...
In historical terms, the first report of unawareness of a neurological deficit seems to be the one described by Seneca in Liber V, Epistula IX (Bisiach & Geminiani, 1991). In a letter to his friend Lucilius, he described a woman who obstinately denied her blindness.“….You know that Harpestes, my wife’s fatuous companion, has remained in my home as an inherited burden….This foolish woman has suddenly lost her sight. Incredible as it might appear, what I am going to tell you is true: She does not know she is blind. Therefore, again and again she asks her guardian to take her elsewhere because she claims that my home is dark…..It is difficult to recover from a disease if you do not know to be ill….”. Interestingly, this description already underlined some of the most important features of anosognosia: the denial, the confabulation generated to justify the problem (“home is dark”), and the negative impact on the recovery (“It is difficult to recover from a disease if you do not know to be ill”).
. Neglect is associated with disability, unawareness, poor long-term outcome, and dependence from caregivers. No randomized trial has evaluated the effects of smooth pursuit eye movement training (SPT) and visual scanning training (VST) at the bedside on these variables.
. To compare the effects of SPT and VST in postacute stroke at 1 month with left neglect.
We carried out an assessor-blinded, randomized controlled trial. The 24 participants were randomly allocated to either SPT or VST (n = 12 each). They received 20 treatment sessions lasting 30 minutes each at the bedside over 4 weeks. Outcome measures included the Functional Neglect Index (FNI) based on 4 tasks: find objects on a tray, stick bisection, picture search, and gaze orientation. In addition, the Unawareness and Behavioral Neglect Index (UBNI) with 6 items about unawareness and 4 about neglect in activities of daily living, the Help index (required assistance in 10 functional activities), the Barthel Index, and the rehabilitation phase were rated by treatment-blinded assessors. Outcome measures were obtained before and immediately after the end of the interventions and at a 2-week follow-up.
. Significantly greater improvements were obtained after SPT versus VST treatment in the FNI and UBNI, and there were continued improvements selectively in the SPT group 2 weeks later.
. SPT accelerates recovery from functional neglect and reduces unawareness significantly. Bedside neglect treatment using SPT is effective and feasible early after stroke.
This study investigated impaired self-awareness of motor deficits in nondemented, nondepressed Parkinson's disease (PD) patients during a defined clinical on state.
Twenty-eight PD patients were examined. Patients' self-ratings and experts' ratings of patients' motor performance were compared. Patient-examiner discrepancies and level of impairment determined severity of impaired self-awareness. Motor exam assessed overall motor functioning, hemibody impairment, and 4 motor phenotypes. Neuropsychological tests were also conducted.
Signs of impaired self-awareness were present in 17 patients (60.7%). Higher severity of impaired self-awareness correlated significantly with higher postural-instability and gait-difficulty off scores (r = .575; P = .001), overall motor off scores (r = .569; P = .002), and higher left hemibody off scores (r = .490; P = .008). In multiple linear regression analyses, higher postural-instability and gait-difficulty off scores remained as the only significant predictor of impaired self-awareness severity.
Postural instability and gait difficulties, disease severity, and right hemisphere dysfunction seem to contribute to impaired self-awareness. © 2012 Movement Disorder Society.
Selective neurological impairments can shed light on different aspects of motor cognition. Brain-damaged patients with anosognosia for hemiplegia deny their motor deficit and believe they can still move the paralysed limb. Here we study, for the first time, if the anomalous subjective experience that their affected hand can still move, may have objective consequences that constrain movement execution with the opposite, intact hand. Using a bimanual motor task, in which anosognosic patients were asked to simultaneously trace out lines with their unaffected hand and circles with their paralysed hand, we found that the trajectories of the intact hand were influenced by the requested movement of the paralysed hand, with the intact hand tending to assume an oval trajectory (bimanual coupling effect). This effect was comparable to that of a group of healthy subjects who actually moved both hands. By contrast, brain-damaged patients with motor neglect or actual hemiplegia but no anosognosia did not show this bimanual constraint. We suggest that anosognosic patients may have intact motor intentionality and planning for the plegic hand. Rather than being merely an inexplicable confabulation, anosognosia for the plegic hand can produce objective constraints on what the intact hand does.
Data on patients with localized brain damage and on neurologically intact subjects show that normal motor control depends on the functionality of a chain of neurobiological events. These events, through the activation of internal representations of the desired, predicted, and actual condition of one's body with respect to the external world, contribute to the construction of conscious knowledge of voluntary actions and to self-awareness. (PsycINFO Database Record (c) 2006 APA, all rights reserved) (journal abstract)