Les potentiels evoques somesthesiques precoces dans la dyssynergie cerebelleuse myoclonique progressive

Dyssynergia cerebellaris myoclonica (Ramsay Hunt syndrome): a condition unrelated to mitochondrial encephalomyopathies.

“…The amplitude of somatosensory evoked potentials was very exaggerated, as previously found in DCM. 26 These clinical and neurophysiological findings, summarised in the table, fit the diagnosis of DCM (Ramsay Hunt syndrome) defined in accordance with the clinical and EEG criteria proposed by Roger et al227 and Tassinari et al 28 Muscle changes have not been reported in Ramsay Hunt syndrome, and muscle biopsy specimens from our patients were normal and did not reveal any mitochondrial abnormalities. In MERRF, however, there is evidence of abnormal mitochondria in skeletal muscle; this recently recognised clinical entity is also characterised by myoclonus, cerebellar syndrome, epilepsy, and a variety of neurological and extraneurological signs."…”

The Ramsay Hunt syndrome revisited: Mediterranean myoclonus versus mitochondrial encephalomyopathy with ragged-red fibers and Baltic myoclonus

“…Tonic-clonic and clonic seizures (present in 39 patients) and massive myoclonic attacks (present in all) generally responded well to treatment, with valproate as the first choice drug and clonazepam and phenobarbital as add-on drug (phenytoin was systematically avoided or stopped). An increase in the number of seizures was noted in 5 patients; 10 became seizure-free, 10 had very rare seizures and 14 kept rare seizures at a stable level. As shown earlier by our group (6), the EEG tends to show less and less spontaneous or provoked spike-and-wave discharges in older patients; this may be because of the good response to valproate therapy, but may also represent a spontaneous evolution.…”

“…Five patients were bedridden after 6, 8,9,10,14 years of disease respectively; 2 of these died, one of pneumonia at age 16 and one during sleep at age 18. Fourteen patients (aged 14-39 years, duration of illness 3-24 years) have lost their autonomy and need constant family or social help in daily life; one of these died of bronchial carcinoma at age 39.…”