Executive and Motor Impairment Correlation in SCA-3 (P2.131)

Objective: To characterize associations between executive dysfunction and motor impairment in SCA-3 Background: Spinocerebellar ataxias (SCAs) are a group of genetic neurodegenerative disorders with prominent cerebellar involvement. Increasing evidence has revealed the role of cerebellum in non-motor functions, including cognition. Deficits in executive function, spatial cognition and language have been associated with the cerebellar symptoms in different SCAs (Burk, 2007; Klinke et al., 2010; Orsi et al., 2011). The few studies correlating executive dysfunction with motor impairment in SCA found no association (Fancellu et al., 2013, Lopes et al., 2013). We compared cognitive and cerebellar motor functions in our cohort of SCA3 patients. Methods: Nine patients with SCA3 (part of the CRC-SCA study) had testing of verbal memory (California Verbal Learning Test), executive function (category fluency and design fluency), and working memory (backward digit span). Category fluency, design fluency and backwards digit span scores were combined into an “Executive mean score.” Cerebellar motor function was assessed using the Scale for the Assessment and Rating of Ataxia (SARA). Performance was compared to normative data from age-matched normal controls to generate Z-scores. Results: More than half of patients were significantly impaired on category fluency, whereas other domains were relatively spared. We found no impairments in memory, design fluency, backwards digits span. Worse SARA score correlated with decreased executive mean score (r2=0.32) and category fluency (r2=0.22), but not with verbal memory performance (r2=0.03). Conclusions: Patients with SCA3 have executive function impairments that increase with worsening motor impairment. Executive function measures may be a valid measurement of disease severity and burden in SCA, but more sensitive tests might be necessary for detecting subtle cognitive impairments independent of motor dysfunction. Study Supported by: Disclosure: Dr. Bang has nothing to disclose. Dr. Winer has nothing to disclose. Dr. Possin has nothing to disclose. Dr. Kramer has nothing to disclose. Dr. Geschwind has received personal compensation for activities with Best Doctors, Guidepoint Global, and Quest Diagnostics. Dr. Geschwind has received research support from the National Institutes of Health/National Institute of Aging, the Tau Consortium