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![Localization of the thalamic neurons overlaid on the human motor thalamus atlas [20]. Purple defines the pallidal afferent territory (VAp) and green is cerebellar afferent zone (VLdVLv). Red points depict burst pattern neurons while yellow are single-spike pattern. Abbreviations: GPi, globus pallidus interna; GPe, globus pallidus externa; STN, subthalamic nucleus; R, red nucleus; Pul, pulvinar](publication/345721157/figure/fig1/AS:962755666391051@1606550246459/Localization-of-the-thalamic-neurons-overlaid-on-the-human-motor-thalamus-atlas-20.png)
Localization of the thalamic neurons overlaid on the human motor thalamus atlas [20]. Purple defines the pallidal afferent territory (VAp) and green is cerebellar afferent zone (VLdVLv). Red points depict burst pattern neurons while yellow are single-spike pattern. Abbreviations: GPi, globus pallidus interna; GPe, globus pallidus externa; STN, subthalamic nucleus; R, red nucleus; Pul, pulvinar
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Cervical dystonia (CD) is a movement disorder characterized by a stereotyped pattern of involuntary turning or tilting of the head, often combined with jerky or tremulous movements. Hypotheses for the origin of CD have traditionally focused on the basal ganglia, but the contemporary discussion has considered the potential role of altered cerebellar...
Citations
... It is particularly important to understand the relationship of neck tremor and CD because they are most common of all other types of tremor dystonia combinations. CD and jerky repetitive neck movements have different pathophysiological correlates compared to more sinusoidal neck oscillations that appear like tremor seen with essential tremor [22,23]. To understand the relationships between neck tremor and CD, it is necessary to support the expert consensus-based opinions with empiric evidence. ...
Background: Cervical dystonia (CD) is the most common form of focal dystonia encountered in the clinic. Approximately one-third of CD patients have co-existing tremor in the head and hands. Assessment of tremor as regular or irregular in context of its oscillation trajectory, frequency, and amplitude is a major clinical challenge and can confound the diagnosis of CD. The misdiagnosis may lead to therapeutic failures, poor quality of life, and poor utilization of medical and financial resources. Methods: We analyzed the largest cohort of CD patients (n = 3117) available to date, collected from 37 movement disorder centers in North America, Europe, and Asia. We used machine learning to determine what clinical features from clinician reports predicted the presence of tremor as well as its regular or irregular appearance. Results: Out of 3,117 CD patients, 1,367 had neck tremor. The neck tremor was interpreted as irregular in 1,022, regular in 345, and mixed (both irregular and regular) in 442. A feature importance analysis determined that greater severity of CD, longer disease duration, and older age, in descending order, predicted the presence of neck tremor. The probability of neck tremor was reduced if the dystonia affected other body parts in addition to the neck. We also found a significantly heightened risk for developing neck tremor in women. An additional feature importance analysis indicated that increased severity of dystonia affecting other body parts, severity of CD, and prolonged disease duration was associated with a lower likelihood of regular neck tremor while increased age predicted a higher likelihood. Conclusion: Machine learning recognized the most relevant clinical features that can predict concurrent neck tremor and its irregularity in a large multi-center dystonia cohort. These results may facilitate a more accurate description of neck tremor and improved care path in CD.
... One hypothesis to explain ST-related theta desynchronization is that it may result from the modulation of abnormal theta oscillations at the subcortical level (Hutchison et al., 2004;Halje et al., 2019). Following this hypothesis, several recent studies in CD patients investigating local field potentials have highlighted increased theta activity synchronization in the GPi and subthalamic nucleus (Chen et al., 2006;Neumann et al., 2012Neumann et al., , 2017Geng et al., 2017;Schrock et al., 2009;Silberstein et al., 2003;Semenova et al., 2021). Moreover, previous evidence in CD patients suggests that propagation of theta-mu oscillatory activity from the GPi to the cortex contributes to CD pathophysiology (Chen et al., 2006, Neumann et al., 2012. ...
Patients with cervical dystonia (CD) often show an improvement in dystonic posture after sensory trick (ST), though the mechanisms underlying ST remain unclear. In this study, we aimed to investigate the effects of ST on cortical activity in patients with CD and to explore the contribution of motor and sensory components to ST mechanisms. To this purpose, we studied 15 CD patients with clinically effective ST, 17 without ST, and 14 healthy controls (HCs) who mimicked the ST. We used electroencephalographic (EEG) recordings and electromyography (EMG) data from bilateral sternocleidomastoid (SCM) muscles. We compared ST-related EEG spectral changes from sensorimotor and posterior parietal areas and EMG power changes between groups. To better understand the contribution of motor and sensory components to ST, we tested EEG and EMG correlates of three different conditions mimicking ST, the first without skin touch ("no touch" condition), the second without voluntary movements ("passive" condition), and finally without arm movements ("examiner touch" condition). Results showed ST-related alpha desynchronization in the sensorimotor cortex and theta desynchronization in the sensorimotor and posterior parietal cortex. Both spectral changes were more significant during maneuver execution in CD patients with ST than in CD patients without ST and HCs who mimicked the ST. Differently, the "no touch", "passive", or "examiner touch" conditions did not show significant differences in EEG or EMG changes determined by ST execution/mimicking between CD patients with or without ST. A higher desynchronization within alpha and theta bands in the sensorimotor and posterior parietal areas correlated with a more significant activity decrease in the contralateral SCM muscle, Findings from this study suggest that ST-related changes in the activity of sensorimotor and posterior parietal areas may restore dystonic posture and that both motor and sensory components contribute to the ST effect.
... As described below, changed neuronal activity patterns induced by GPi-or STN-DBS seem to be essential for beneficial effects (Tisch and Limousin, 2020). However, in the concept of the pathophysiology of dystonia and mechanisms of DBS, it should be considered that there are several lines of evidence for an involvement of the cerebellum in types of dystonia, such as cervical dystonia which responds to GPi-DBS (Fan et al., 2021;Jinnah et al., 2017;Miterko et al., 2019;Semenova et al., 2021). ...
During the last decades deep brain stimulation (DBS) has become an important treatment option for a variety of neurological disorders such as drug-intractable dystonia. Yet, the mechanisms of action of DBS are still largely unknown. Dystonia is a heterogenous movement disorder characterized by involuntary muscle contractions causing abnormal movements, postures, or both. The underlying pathophysiological processes remain unclear, but a dysfunction of the basal ganglia circuit is critically involved as supported by the effectiveness of DBS of the globus pallidus internus (GPi) in various types of dystonia. However, the degree of clinical improvement differs among the types of dystonia, as well as from patient to patient, and the delayed response to GPi-DBS in dystonia patients hampers the adjustment and optimization of stimulation parameters. Preclinical studies in suitable animal models can contribute decisively to detect the underlying mechanisms of DBS and biomarkers, to identify new possible stimulation targets and to optimize stimulation patterns. In this review, we give an overview of previous research on DBS in animal models of dystonia. With regard to the aims of research we discuss the opportunities and limitations concerning different available animal models of dystonia and technical challenges.
... We interpret the brain-ocular coherence at 4 Hz as reflecting theta-band oscillations across long-range connections between middle temporal, cerebellar, and other areas. This interpretation is generally in line with a known feature of theta-band oscillations [38][39][40] . With the definition of coherence by Gross et al. 26 , one can also regard the brain-ocular coherence as reflecting the neuronal communications between the eyes and specific brain areas. ...
Horizontal and vertical vergence eye movements play a central role in binocular coordination. Neurophysiological studies suggest that cortical and subcortical regions in animals and humans are involved in horizontal vergence. However, little is known about the extent to which the neural mechanism underlying vertical vergence overlaps with that of horizontal vergence. In this study, to explore neural computation for horizontal and vertical vergence, we simultaneously recorded electrooculography (EOG) and whole-head magnetoencephalography (MEG) while presenting large-field stereograms for 29 healthy human adults. The stereograms were designed to produce vergence responses by manipulating horizontal and vertical binocular disparities. A model-based approach was used to assess neural sensitivity to horizontal and vertical disparities via MEG source estimation and the theta-band (4 Hz) coherence between brain activity and EOG vergence velocity. We found similar time-locked neural responses to horizontal and vertical disparity in cortical and cerebellar areas at around 100–250 ms after stimulus onset. In contrast, the low-frequency oscillatory neural activity associated with the execution of vertical vergence differed from that of horizontal vergence. These findings indicate that horizontal and vertical vergence involve partially shared but distinct computations in large-scale cortico-cerebellar networks.
... The arterial supply of thalamus is divided into four regions: the anterior part is supplied by polar artery or thalamic tubercle artery; the paramedian is supplied by the paramedian artery or thalamic perforating artery; the inferolateral supplied by the thalamo-geniculate artery, and the posterior supplied by the posterior choroidal artery [1][2][3]. Perceron G [4] first described the artery of percheron (AOP) in 1973. It is a solitary arterial trunk of the bilateral thalamo-perforating artery originating from P1 segment of the posterior cerebral artery (PCA), which supplies bilaterally the paramedian thalamic territories. ...
Background
So far, the diagnosis of acute artery of percheron (AOP) infarction is uncommon. In this study, patients with acute AOP infarction were studied to explore the relationship of imaging findings, clinical manifestations and prognosis of acute AOP infarction.
Materials
A total of 23 patients with acute AOP infarction in our institution from 2014 to 2019 were reviewed retrospectively. All cases were evaluated by computed tomography (CT) and magnetic resonance imaging (MRI). The modified Rankin scale (MRS), blood examination, electrocardiogram and transthoracic echocardiography were used for detailed clinical and prognostic evaluation. All standard risk factors for these patients were recorded. The MRS scores were performed 90 days after discharge.
Results
Four different types of acute AOP infarction were identified: (a) bilateral paramedian thalamic infarction (BPTI, 52%); (b) bilateral paramedian thalamic with rostral midbrain infarction (BPTRMI, 30%), (c) bilateral paramedian and anterior thalamic infarction (BPATI, 13%), and (d) bilateral paramedian thalamic with red nuclei infarction (BPTRNI, 4%). These patients had consciousness disorder, memory dysfunctions, vertical gaze paresis and mesencephalothalamic syndrome. The 65% of patients with BPTI and BPATI experienced relatively good functional recovery and could carry out daily life activities (MRS score ≤ 2). However, patients with BPTRMI may have an unfavorable outcome.
Conclusions
Although the clinical features are variable, DWI or ADC map can improve the diagnosis of acute AOP infarction patterns. Acute AOP occlusion requires immediate diagnosis and treatment to obtain more favorable outcome and avoid additional unnecessary procedures.
This document presents a consensus on the diagnosis and classification of isolated cervical dystonia (iCD) with a review of proposed terminology. The International Parkinson and Movement Disorder Society Dystonia Study Group convened a panel of experts to review the main clinical and diagnostic issues related to iCD and to arrive at a consensus on diagnostic criteria and classification. These criteria are intended for use in clinical research, but also may be used to guide clinical practice. The benchmark is expert clinical observation and evaluation. The criteria aim to systematize the use of terminology as well as the diagnostic process, to make it reproducible across centers and applicable by expert and non-expert clinicians. Although motor abnormalities remain central, increasing recognition has been given to nonmotor manifestations, which are incorporated into the current criteria. Three iCD presentations are described in some detail: idiopathic (focal or segmental) iCD, genetic iCD, and acquired iCD. The relationship between iCD and isolated head tremor is also reviewed. Recognition of idiopathic iCD has two levels of certainty, definite or probable, supported by specific diagnostic criteria. Although a probable diagnosis is appropriate for clinical practice, a higher diagnostic level may be required for specific research studies. The consensus retains elements proven valuable in previous criteria and omits aspects that are no longer justified, thereby encapsulating diagnosis according to current knowledge. As understanding of iCD expands, these criteria will need continuous revision to accommodate new advances. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
Purpose of review:
Tremor is one of the most prevalent movement disorders in clinical practice. Here, we review new insights in the pathophysiology of tremor. We focus on the three most common tremor disorders: essential tremor (ET), dystonic tremor syndrome (DTS), and Parkinson's disease (PD) tremor.
Recent findings:
Converging evidence suggests that ET, DTS, and PD tremor are all associated with (partly) overlapping cerebral networks involving the basal ganglia and cerebello-thalamo-cortical circuit. Recent studies have assessed the role of these networks in tremor by measuring tremor-related activity and connectivity with electrophysiology and neuroimaging, and by perturbing network components using invasive and noninvasive brain stimulation. The cerebellum plays a more dominant and causal role in action tremors than in rest tremor, as exemplified by recent findings in ET, DTS, and re-emergent tremor in PD. Furthermore, the role of the cerebellum in DTS is related to clinical differences between patients, for example, whether or not the tremor occurs in a dystonic limb, and whether the tremor is jerky or sinusoidal.
Summary:
Insight into the pathophysiological mechanisms of tremor may provide a more direct window into mechanism-based treatment options than either the etiology or the clinical phenotype of a tremor syndrome.
