Progressive myoclonic ataxia (the Ramsay Hunt syndrome)
C. D. Marsden, A. E. Harding, J. A. Obeso and C. S. Lu
University Department of Clinical Neurology, Institutes of Neurology, London, England.
It has been suggested from studies of patients with progressive myoclonus
epilepsy that the term Ramsay Hunt syndrome should be abandoned, as its use
has led to nosologic confusion, and because, in the light of modern
diagnostic techniques, the majority of cases can be allocated to specific
disease categories, chiefly, Unverricht-Lundborg disease (Baltic myoclonus)
and mitochondrial encephalomyopathy. Review of 30 cases of this syndrome,
defined as progressive ataxia and myoclonus and infrequent seizures in the
absence of dementia, showed that a clinical or biochemically supported
diagnosis could not be made in 43%. This low diagnostic yield probably
reflects differences in ascertainment of patients; those described here
were referred with a syndrome of progressive myoclonic ataxia (the Ramsay
Hunt syndrome) rather than progressive myoclonus epilepsy. These two
syndromes share common causes, but a smaller proportion of patients with
progressive myoclonic ataxia can currently be diagnosed precisely during
life.
