SPINOCEREBELLAR DEGENERATIONS IN JAPAN - A NATIONWIDE EPIDEMIOLOGIC AND CLINICAL-STUDY

A nationwide survey of patients in Japan with spinocerebellar degenera tions (SCD), including SDS and SND, was conducted from 1988 to 1989. T he survey consisted of two parts. The first revealed that the estimate d total number of patients with SCD in Japan was 5,050 (range: 4,100-6 ,000) with an estimated prevalence of 4.53 per 100,000 in 1987. The se cond part investigated the neurological and functional status of patie nts with SCD. The percentages of those belonging to each subtype of SC D were: OPCA; 34.4%, LCCA; 15.2%, MHCA; 12.6%, HHCA; 7.5%, SDS; 7.0%, HSP; 3.9%, DRPLA: 2.5%, FA; 2.4%, MJD; 2.0% and SND;1.5%. Compared wit h European epidemiological studies Japan had a higher proportion of no n-hereditary types of SCD. Various clinical features of SCD subtypes w ere compared grouped by pathological lesion and heredity. HHCA and LCC A: cerebellar ataxia predominated in all stages, and neurological sign s other than cerebellar ataxia were rare. MHCA, DRPLA and MJD: in the early phase ataxia was the most common symptom in MHCA, the AC form of DRPLA and MJD, but ataxia was less common and chorea or epilepsy were often observed in ME and PH forms of DRPLA. Other frequently observed clinical features were parkinsonian rigidty in MHCA, abnormal movemen ts and posture in DRPLA and MJD, and disturbances of eye movements in MHCA, the AC form of DRPLA and MJD. OPCA, SDS and SND: dominant clinic al features were cerebellar ataxia in OPCA, autonomic disturbance in S DS, and parkinsonian rigidity in SND. FA and HSP: both were rare in Ja pan. Clinical features related to supra-supinal lesions were frequentl y observed in FA. Functional status of SCD: the severity of illness wa s significantly associated with the level of independence in each item of ADL. Activities not requiring dynamic balance were performed indep endently for a longer period than those requiring dynamic balance. Amo ng SCD subtypes, functional prognosis was poorest in non-hereditary, m ulti-systemic types (OPCA, SDS and SND) followed by hereditary multi-s ystemic types (MHCA, DRPLA and MJD), and better in spinal types (FA an d HSP) and cerebellar types (HHCA and LCCA).