P-MD008. Differential effects of thyrotropin releasing hormone on motor performance and motor adaptation in patients with spinocerebellar degeneration

Abstract

Introduction . The cerebellum is known to play an important role in motor adaptation, including prism adaptation. Thyrotropin releasing hormone (TRH) has been used as a treatment for cerebellar ataxia in Japan. However, effects of TRH on cerebellar adaptation function have not been studied. Herein, we studied effects of TRH treatment on the prism adaptation task. Methods . Eighteen patients with spinocerebellar degeneration (SCD), including MSA-C, SCA3, SCA6, SCA31, participated in this study. The participants received intravenous injection of 2 mg/day protirelin tartrate once a day for 14 days. In the prism adaptation task, the participants reached to the target on the screen wearing wedge prisms. We compared the Scale for Assessment and Rating of Ataxia (SARA), baseline errors and the after effect (AE) of the prism adaptation task between before and after TRH therapy. We also performed correlation analysis between improvement of baseline errors or AE in the adaptation task, and 1) improvement of the total SARA score, 2) improvement of upper limb ataxia score, and 3) improvement of axial ataxia score. Results . TRH therapy significantly improved SARA (p = 0.005). Multiple regression analysis revealed that improvement of SARA score was mainly due to improvement of “Stance” category score. TRH decreased baseline errors of the prism adaptation task (p = 0.021), while unaffected AEs (p = 0.25). Correlation analysis revealed no significant correlation between any factors. Conclusion . TRH differentially affected cerebellar ataxic symptoms including baseline reaching performance in the prism adaptation task, whereas TRH did not affect the learning process of prism adaptation. Different cerebellar functional aspects may underlie the learning process of motor adaptation and simple motor performance (classical ataxia).