Frontotemporal cognitive function in X-linked spinal and bulbar muscular atrophy (SBMA): a controlled neuropsychological study of 20 patients.

A cross-sectional neuropsychological study of cognitive functions in 20 male patients with genetically proven spinal and bulbar muscular atrophy (SBMA) was performed, with a comparison of their cognitive performance with that of 20 age- and education-matched control subjects. Neuropsychological assessment covered executive functioning, memory, and attentional control. The SBMA patients revealed deficits in verbal and non-verbal fluency as well as concept formation. Additionally, they showed significant memory deficits in all of the investigated domains of working memory, short-term and long-term memory. With respect to attentional control, the SBMA patients underperformed in relevant subtests, although performance differences did not reach significance overall. We conclude that fronto-temporal cognitive functions are impaired in SMBA, although at a subclinical level. Thus, functional deficits in SBMA are not confined to motor neurons but also affect extramotor networks.