A deficiency in serotonin has been proposed as a neurochemical mechanism underlying ataxia in degenerative cerebellar diseases. We evaluate by clinical and objective measurements the effectiveness of the levorotatory form of 5-hydroxytryptophan, a serotonin precursor, in treating patients with cortical cerebellar atrophy (CCA) (sporadic adult-onset ataxia). This is an open-label study in which 6 patients with CCA received the levorotatory form of 5-hydroxytryptophan for 6 months. Patients with Friedreich ataxia, spinocerebellar ataxia, or multiple system atrophy were not included. The setting was a research hospital. The main outcome measures were clinical assessment and neurophysiological study of fast single-joint and multijoint movements. For rapid single-joint movements (wrist flexions), we analyzed movement amplitudes and onset latencies of antagonist electromyographic (EMG) activity (extensor carpi radialis with respect to flexor carpi radialis). For fast multijoint movements (pointing movements in upper limb), we evaluated the decomposition index to assess the synchrony between elbow and shoulder.
Manto M, Hildebrand J, Godaux E, Roland H, Blum S, Jacquy J. Analysis of Fast Single-Joint and Multijoint Movements in Cerebellar Cortical Atrophy: Failure of L-Hydroxytryptophan to Improve Cerebellar Ataxia. Arch Neurol. 1997;54(10):1192-1194. doi:10.1001/archneur.1997.00550220008002