The case of a patient with essential tremor in whom tremor disappeared on the right side after a homolateral cerebellar infarct is reported. The pathophysiology of essential tremor remains unknown. Vascular and surgical lesions of dentorubrothalamic pathway have been reported to improve various kinds of tremor including essential tremor. In this patient, a lesion of this pathway related to the cerebellar infarct probably explains the homolateral cessation of essential tremor.

Improvement of a patient's essential tremor (ET) after a stroke has rarely been reported. In such patients, cerebral imaging could help to identify structures involved in the maintenance of ET and improves the knowledge of its physiopathology. This article reports the disappearance of ET, after a stroke in 4 patients and reviews similar previously published cases. These cases suggest that the interruption of cerebellar loops during a stroke could be responsible for the disappearance of ET.

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BackgroundThere is need for a cognitive test battery that can be easily used in clinical practice to detect or monitor cognitive performance in patients with multiple sclerosis (MS). In order to conduct, in this patient group, a preliminary investigation of the validity and utility of a brief computerized battery, the Cognitive Drug Research (CDR) battery, we longitudinally assessed cognition in patients with relapsing remitting (RR) MS.MethodsForty-three mildly disabled, clinically active RRMS patients were repeatedly assessed with the Digit Symbol Substitution Test (DSST), Paced Auditory Serial Addition Test (PASAT) and five composite scores derived from the CDR computerized cognitive test system (CDR System): Power of Attention, Continuity of Attention, Quality of Working Memory, Quality of Episodic Memory and Speed of Memory. The Multiple Sclerosis Functional Composite (MSFC) and Expanded Disability Status Scale (EDSS) measured disability.ResultsThe composite scores from the CDR battery generally showed excellent test-retest reliability over the repeated assessments, though was low on occasions for the Quality of Working Memory and Quality of Episodic Memory measures. The CDR measures tended to be highly correlated with other measures of cognition (DSST and PASAT) and were also strongly related to disability (EDSS and MSFC). Baseline scores indicated large impairments to visual information processing speed and attention (DSST, Cohen's d 1.1; Power of Attention d 1.4 [reaction time on tasks of focussed and sustained attention]), and a moderate impairment both to sustained attention (Continuity of Attention d 0.6) and complex information processing speed (Speed of memory d 0.7 [reaction time on tasks of working and episodic Memory]), when compared to normative data derived from healthy volunteers enrolled in a series of separate, prior clinical trials. Working memory (Quality of Working Memory) and episodic memory (Quality of Episodic Memory) were unimpaired.ConclusionsPreliminary validation of the CDR System indicated that for most, but not all measures psychometric properties were adequate and the measures were related to disability (EDSS and MSFC) and other measures of cognition.