1,721,245 research outputs found
Unravelling of the paroxysmal dyskinesias
Full text linkParoxysmal dyskinesias (PxD) refer to a rare group of clinically and genetically heterogeneous disorders presenting with recurrent attacks of abnormal movements, typically dystonia, chorea or a combination thereof, without loss of consciousness. Classically, PxD have been categorised according to their triggers and duration of the attacks, but increasing evidence suggests that there is a certain degree of clinical and genetic overlap and challenges the concept that one phenotype is attributable to one single aetiology. Here we review the increasing spectrum of genetic conditions, as well as of other non-genetic disorders, that might present with PxD, provide criteria for case definition and propose a diagnostic workup to reach a definitive diagnosis, on which treatment is heavily dependent
Rare tremors and tremors occurring in other neurological disorders
No full textAlthough tremor is deemed to be the commonest movement disorder, in adults the differential diagnosis usually boils down to whether the patient has Essential Tremor or Parkinson's Disease, which has likely led to an overdiagnosis of these conditions; yet, many important rare syndromes should be considered in the differential diagnosis of patients with tremor. The aim of this review is to focus on rare forms of tremor, also in view of the new tremor classification, as well as on tremor occurring in other neurological disorders to aid their recognition. Some of the conditions reviewed here are treatable and therefore should not be missed. This review includes orthostatic tremor, focal and task-specific tremors, Holmes tremor, palatal and oculopalatal tremor, cortical tremor, some genetic forms of tremor including fragile X-associated tremor/ataxia syndrome as well as tremor associated with neuromuscular disorders, multiple sclerosis and Wilson's disease, providing an array of demonstrative videos. The recognition of these disorders should aid the physician to make a correct diagnosis and guide a prompt intervention
Proprioceptive drift is affected by the intermanual distance rather than the distance from the body’s midline in the rubber hand illusion
No full textIn the rubber hand illusion (RHI), simultaneous brush stroking of a subject’s hidden hand and a visible rubber hand induces a transient illusion of the latter to “feel like it’s my hand” and a proprioceptive drift of the hidden own hand toward the rubber hand. Recent accounts of the RHI have suggested that the illusion would only occur if weighting of conflicting sensory information and their subsequent integration results in a statistically plausible compromise. In three different experiments, we investigated the role of distance between the two hands as well as their proximity to the body’s midline in influencing the occurrence of the illusion. Overall, the results suggest that the illusion is abolished when placing the two hands apart, therefore increasing the mismatch between the visual and proprioceptive modality, whereas the proximity of the two hands to the body’s midline plays only a minor role on the subjective report of the illusion. This might be driven by the response properties of visuotactile bimodal cells encoding the peripersonal space around the hand
The Spectrum of PRRT2-Associated Disorders: Update on Clinical Features and Pathophysiology
No full textMutations in the PRRT2 (proline-rich transmembrane protein 2) gene have been identified as the main cause of an expanding spectrum of disorders, including paroxysmal kinesigenic dyskinesia and benign familial infantile epilepsy, which places this gene at the border between epilepsy and movement disorders. The clinical spectrum has largely expanded to include episodic ataxia, hemiplegic migraine, and complex neurodevelopmental disorders in cases with biallelic mutations. Prior to the discovery of PRRT2 as the causative gene for this spectrum of disorders, the sensitivity of paroxysmal kinesigenic dyskinesia to anticonvulsant drugs regulating ion channel function as well as the co-occurrence of epilepsy in some patients or families fostered the hypothesis this could represent a channelopathy. However, recent evidence implicates PRRT2 in synapse functioning, which disproves the “channel hypothesis” (although PRRT2 modulates ion channels at the presynaptic level), and justifies the classification of these conditions as synaptopathies, an emerging rubric of brain disorders. This review aims to provide an update of the clinical and pathophysiologic features of PRRT2-associated disorders
A (single case) rehabilitation program based on cueing for freezing of speech
No full textFreezing of speech (FoS) and other repetitive speech behaviours can frequently occur in parkinsonian syndromes, worsening the efficacy of language functioning, hampering social interactions, and thus reducing quality of life. Pharmacological treatment are ineffective and other interventions have not specifically developed so far
High frequency somatosensory stimulation in dystonia: Evidence for defective inhibitory plasticity
No full textBackground: Apart from motor symptoms, multiple deficits of sensory processing have been demonstrated in dystonia. The most consistent behavioural measure of this is abnormal somatosensory temporal discrimination threshold, which has recently been associated with physiological measures of reduced inhibition within the primary somatosensory area. High-frequency repetitive sensory stimulation is a patterned electric stimulation applied to the skin through surface electrodes that has been recently reported to shorten somatosensory temporal discrimination in healthy subjects and to increase the resting level of excitability in several different types of inhibitory interaction in the somatosensory and even motor areas.
Objectives: We tested whether high-frequency repetitive sensory stimulation could augment cortical inhibition and, in turn, ameliorate somatosensory temporal discrimination in cervical dystonia.
Methods: Somatosensory temporal discrimination and a number of electrophysiological measures of sensorimotor inhibition and facilitation were measured before and after 45 minutes of high-frequency repetitive sensory stimulation.
Results: As compared with a group of healthy volunteers of similar age, in whom high-frequency repetitive sensory stimulation increased inhibition and shortened somatosensory temporal discrimination, patients with cervical dystonia showed a consistent, paradoxical response: they had reduced suppression of paired-pulse somatosensory evoked potentials, as well as reduced high-frequency oscillations, lateral inhibition, and short interval intracortical inhibition. Somatosensory temporal discrimination deteriorated after the stimulation protocol, and correlated with reduced measures of inhibition within the primary somatosensory cortex.
Conclusions: We suggest that patients with dystonia have abnormal homeostatic inhibitory plasticity within the sensorimotor cortex and that this is responsible for their paradoxical response to high-frequency repetitive sensory stimulation
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