The intermuscular 3–7 Hz drive is not affected by distal proprioceptive input in myoclonus-dystonia

In dystonia, both sensory malfunctioning and an abnormal intermuscular low-frequency drive of 3–7 Hz have been found, although cause and effect are unknown. It is hypothesized that sensory processing is primarily disturbed and induces this drive. Accordingly, experimenter-controlled sensory input should be able to influence the frequency of the drive. In six genetically confirmed myoclonus-dystonia (MD) patients and six matched controls, the low-frequency drive was studied with intermuscular coherence analysis. External perturbations were applied mechanically to the wrist joint in small frequency bands (0–4, 4–8 and 8–12 Hz; ‘angle protocol) and at single frequencies (1, 5, 7 and 9 Hz; ‘torque’ protocol). The low-frequency drive was found in the neck muscles of 4 MD patients. In these patients, its frequency did not shift due to the perturbation. In the torque protocol, the externally applied frequencies could be detected in all controls and in the two patients without the common drive. The common low-frequency drive was not be affected by external perturbations in MD patients. Furthermore, the torque protocol did not induce intermuscular coherences at the applied frequencies in these patients, as was the case in healthy controls and in patients without the drive. This suggests that the dystonic 3–7 Hz drive is caused by a sensory-independent motor drive and sensory malfunctioning in MD might rather be a consequence than a cause of dystonia

Psychiatric disorders, myoclonus dystonia and SGCE:An international study

OBJECTIVE: Myoclonus-dystonia (M-D) is a hyperkinetic movement disorder, typically alcohol-responsive upper body myoclonus and dystonia. The majority of autosomal dominant familial cases are caused by epsilon-sarcoglycan gene (SGCE) mutations. Previous publications have observed increased rates of psychiatric disorders amongst SGCE mutation-positive populations. We analyzed the psychiatric data from four international centers, forming the largest cohort to date, to further determine the extent and type of psychiatric disorders in M-D.METHODS: Psychiatric data from SGCE mutation-positive M-D cohorts, collected by movement disorder specialists in the Netherlands, United Kingdom, United States, and Germany, were analyzed. These data were collected using standardized, systematic questionnaires allowing classification of symptoms according to Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) criteria. Based on motor findings and SGCE mutation analysis, participants were classified into one of three groups: manifesting carriers, nonmanifesting carriers and noncarriers.RESULTS: Data from 307 participants were evaluated (140 males, 167 females, mean age at examination: 42.5 years). Two-thirds of motor affected mutation carriers (n = 132) had ≥1 psychiatric diagnosis, specific, and social phobias being most common followed by alcohol dependence and obsessive-compulsive disorder (OCD). Compared to familial controls, affected mutation carriers had significantly elevated overall rates of psychiatric disorders (P &lt; 0.001). The most significant differences were observed with alcohol dependence (P &lt; 0.001), OCD (P &lt; 0.001), social and specific phobias (P &lt; 0.001).INTERPRETATION: M-D due to SGCE mutations is associated with specific psychiatric disorders, most commonly OCD, anxiety-related disorders, and alcohol dependence. These suggest either a potential pleiotropic function for SGCE within the central nervous system or a secondary effect of the motor disorder.</p

The pedunculopontine nucleus is related to visual hallucinations in Parkinson’s disease: preliminary results of a voxel-based morphometry study

Visual hallucinations (VH) are common in Parkinson’s disease (PD) and lead to a poor quality of life. For a long time, dopaminergic therapy was considered to be the most important risk factor for the development of VH in PD. Recently, the cholinergic system, including the pedunculopontine nucleus (PPN), has been implicated in the pathophysiology of VH. The aim of the present study was to investigate grey matter density of the PPN region and one of its projection areas, the thalamus. Thirteen non-demented PD patients with VH were compared to 16 non-demented PD patients without VH, 13 demented PD patients (PDD) with VH and 11 patients with dementia with Lewy bodies (DLB). Isotropic 3-D T1-weighted MRI images (3T) were analysed using voxel-based morphometry (VBM) with the PPN region and thalamus as ROIs. PD and PDD patients with VH showed grey matter reductions of the PPN region and the thalamus compared to PD patients without VH. VH in PD(D) patients are associated with atrophy of the PPN region and its thalamic target area, suggesting that a cholinergic deficit may be involved in the development of VH in PD(D)

Myoclonus-Dystonia/Essential Myoclonus

Myoclonus-dystonia (M-D, formerly known as 'Hereditary essential myoclonus') is a rare movement disorder characterized by myoclonic jerks and dystonic movements or postures. M-D has an autosomal dominant inheritance with reduced penetrance because of maternal imprinting and is caused by mutations in the ε-sarcoglycan gene (SGCE) on chromosome 7q21

Myoclonus-Dystonia/Essential Myoclonus

Myoclonus-dystonia (M-D, formerly known as 'Hereditary essential myoclonus') is a rare movement disorder characterized by myoclonic jerks and dystonic movements or postures. M-D has an autosomal dominant inheritance with reduced penetrance because of maternal imprinting and is caused by mutations in the ε-sarcoglycan gene (SGCE) on chromosome 7q21

Progressive dysarthria - Case reports and a review of the literature.

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