Speech disorders in olivopontocerebellar atrophy correlate with positron emission tomography findings

Abstract

We compared the severity of ataxic and spastic dysarthria with local cerebral metabolic rates for glucose (ICMRGlc) in is patients with olivepenetecerebeilar atrophy (OPCA). Perceptual analysis was used to examine the speech disorders, and rating scales were devised to quantitate the degree of ataxia and spasticity in the speech of each patient. 1CMRGlc was measured with 18 F-2-fluoro-2-deoxy- D -glucose and positron emission tomography (PET). PET studies revealed marked hypometabolism in the cerebellar hemispheres, cerebellar vermis, and brainstem of OPCA patients compared with 30 control subjects. With data normalized to the cerebral cortex, a significant inverse correlation was found between the severity of ataxia in speech and the 1CMRG1c within the cerebellar vermis, cerebellar hemispheres, and brainstem, but not within the thalamus. No significant correlation was found between the severity of spasticity in speech and 1CMRG1c in any of these structures. The findings support the view that the severity of ataxia in speech in OPCA is related to the functional activity of the cerebellum and its connections in the brainstem.