EARLY-ONSET CEREBELLAR-ATAXIA (EOCA) WITH RETAINED REFLEXES - REDUCEDCEREBELLAR BENZODIAZEPINE-RECEPTOR BINDING, PROGRESSIVE METABOLIC ANDCOGNITIVE IMPAIRMENT

A family with two members who had early-onset cerebellar ataxia (EOCA) with retained tendon reflexes had, in addition to their motor deficit s, a progressive impairment of cognitive and visuospatial abilities. W e used positron emission tomography (PET) with C-11-flumazenil to stud y gamma-aminobutyric type A/benzodiazepine receptor binding (BZR) and F-18-2-fluoro-2-deoxy-D-glucose to analyze longitudinally regional cer ebral glucose metabolism. Flumazenil-PET demonstrated loss of BZR bind ing that has not been shown in Friedreich's ataxia and olivopontocereb ellar atrophy. These findings may be useful for differentiation of EOC A from other types of cerebellar ataxia. In comparison to age-matched control subjects, these patients showed a global metabolic decline and predominant hypometabolism in the thalamus and cerebellum. The progre ssive metabolic derangement may be explainable by a disturbed integrit y of cognition-related networks resulting: from secondary degeneration of cerebello-thalamo-cortical projections.