Differential effects of thyrotropin releasing hormone (TRH) on motor execution and motor adaptation process in patients with spinocerebellar degeneration

• Published in: Journal of the neurological sciences 2020-08, Vol.415, p.116927-116927, Article 116927
• Main Authors: Shimizu, Takahiro, Tsutsumi, Ryosuke, Shimizu, Kazutaka, Tominaga, Naomi, Nagai, Makiko, Ugawa, Yoshikazu, Nishiyama, Kazutoshi, Hanajima, Ritsuko
• Format: Article
• Language: English
• Subjects: Cerebellar Ataxia; Cerebellum; Humans; Japan; Prism adaptation; Sensori-motor adaptation; Spinocerebellar Ataxias - drug therapy; Spinocerebellar degeneration (SCD); Spinocerebellar Degenerations - drug therapy; Thyrotropin releasing hormone (TRH); Thyrotropin-Releasing Hormone
• ISSN: 0022-510X; 1878-5883
• DOI: 10.1016/j.jns.2020.116927

The cerebellum is known to play a crucial role in sensori-motor adaptation, which includes the prism adaptation. TRH has been widely used as a treatment for cerebellar ataxia in Japan, however effects of TRH on cerebellar adaptation process have not been studied. Here, we studied effects of TRH treatment on the prism adaptation task. Eighteen spinocerebellar degeneration (SCD) patients 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 aftereffect (AE) of the prism adaptation task between before and after TRH therapy. TRH therapy improved SARA significantly (p = .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 = .021), while unaffected AEs (p = .252). TRH differentially affected clinical cerebellar ataxia 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 sensori-motor adaptation and simple motor execution (clinically evaluated cerebellar ataxia). •We studied effects of TRH in patients with SCD.•TRH improved clinically evaluated cerebellar ataxia, especially axial symptoms.•TRH had no effects on adaptation process in the prism adaptation task.