Clinical analysis in familial cortical myoclonic tremor allows differential diagnosis with essential tremor

Abstract

Familial cortical myoclonic tremor (FCMT) is a rare disorder often leading to a wrong clinical diagnosis of essential tremor. Electrophysiological data are usually considered to allow a correct diagnosis. We describe a FCMT French family with previously unreported clinical features such as sensitivity to glucose deprivation, vibration, repetitive visual patterns, and intense visual or auditory stimulation and contrasts. Electrophysiological studies of the propositus confirm the cortical reflex myoclonus elicited by photic stimulation and the absence of epileptic electroencephalographic discharges. We emphasize that a precise clinical analysis can lead to a correct diagnosis before electrophysiological confirmation. This is also the first-ever report of efficacy of levetiracetam in FCMT.

Dystonic tremor caused by mutation of the glucose transporter gene GLUT1

“…The slower frequencies (6-7 Hz) are too low for physiological tremor and too high for cerebellar tremor (Deuschl et al 1998;Elble 2003). Cortical tremor consists of shorter rhythmic myoclonus lasting less than 60 ms (Toro et al 1993;Bourdain et al 2006). Thus, the tremor is part of the dystonia caused by GLUT-1 mutation.…”

Augmented visual feedback counteracts the effects of surface muscular functional electrical stimulation on physiological tremor

“…It can also be anticipated that patients exhibiting tremor in context of a cortical myoclonus enhanced by vision might also be a category not responsive to FES. Indeed, these patients are particularly sensitive to intense visual stimulation [44]. Clinical studies are required to address these issues.…”

Familial Cortical Myoclonic Tremor with Epilepsy and Cerebellar Changes: Description of a New Pathology Case and Review of the Literature

“…Antiepileptic drugs, especially clonazepam and valproic acid, were generally reported to diminish the tremulous movements and epileptic seizures 1,5,8,14,26–28. More recent data suggest a beneficial antimyoclonic effect of levetiracetam 29, 30. Other AEDs, like clobazam, phenytoin, and carbamazepine, have been reported to be effective, usually in polydrug regimens.…”

“…Madia and colleagues6 provided evidence of an extended common founder haplotype in five Italian families. Linkage to 5p (FAME 3) has been found in one French pedigree 3, 15, 30. A South African pedigree resulting from intermarriage between people of European descent and original inhabitants with myoclonus and epilepsy, was reported as FAME 3 after exclusion of linkage to 8q and 2p 12.…”

“…Symptoms in European pedigrees seem to appear earlier (Table 3). In addition to the classical symptoms, pedigrees show atypical phenomena 3,4,12–15,23,30,35–37. Clinical and electrophysiological features suggest widespread involvement of cortical and subcortical areas, cerebellar involvement, and more progressive disease in the non-Japanese pedigrees.…”