Neuropsychological test performance of patients with Friedreich's ataxia.

Although recognized as one of the most common hereditary diseases of the nervous system, the neuropsychological deficits in Friedreich's ataxia (FA) have rarely been studied. A protocol was constructed to assess the major cognitive areas in patients with FA and pair-matched normal controls. Motor difficulties, dysarthria and fatigability were taken into account. Neuropsychological assessment showed decreased motor and mental reaction times, reduced verbal span, deficits in letter fluency, impaired acquisition and consolidation of verbal information, proactive interference effect, and alterations in complex visuoperceptual and visuoconstructive abilities, in comparison with the control group. Magnetic resonance images showing cerebellar atrophy in the majority of patients suggest that cerebellar degeneration and the interruption of afferent and efferent cerebellar connections could be related to the cognitive deficits shown by our patients.