The Cerebellum contains ten percent of the total volume of the brain and receives brain, spinal cord and vestibular sensory input. The organization of vestibular and somato-sensory afferent informations are also reported to be impaired in patients with cerebellum dysfunctions. Ataxia and impaired balance control are common symptoms in individuals with spinocerebellar ataxia (SCA). Previous studies have shown that patient with cerebellar damage are usually agonist and antagonist muscle coordination problem. Past studies also found the regulation of reciprocal Ia inhibition was impaired in patients with spinaocerebellar ataxia. In chronic phase, weakness might be developed due to deconditioned. All deficits mentioned above might lead to a decrease functional ability. Therefore, increasing somato-sensory and vestibular input, normalizing the modulation of recriprocal inhibition, and improve muscle strength might be able to improve the functional abilities of individuals with SCA.

Recently, whole body vibration (WBV) has been trained for health groups. Studies showed that WBV training were able to improve muscle strength, balance control, and functional ability. However, there is no evidence showed that whether the whole body vibration training can affect the brain and spinal cord for the regulation of neural circuits. Whether also can affect for maximal voluntary contraction and improve central fatigue. No previous studies that whole body vibration training for SCA.

Therefore, the purpose of this research was to investigate the intracortical facilitation and inhibition, reciprocal Ia inhibition, low frequency depression, maximal voluntary contraction, interpolated twitch technique to compare the different between the SCA and health subject. Also to investigate the short term and long term effect of WBV.

Inclusion Criteria:

• Clinical diagnosis of spinocerebellar ataxia