Lower Urinary Tract Function in Spinocerebellar Ataxia 6

Objective: To investigate lower urinary tract function in spinocerebellar ataxia type 6 (SCA6). Methods: We recruited, without bias, nine SCA6 patients with a mean cytosine-adenine-guanine repeat length of 24.3 (21-26, normal < 18). They were four men, five women; mean age 58.6 years; mean disease duration 8.2 years. We performed a urinary symptom questionnaire and a urodynamics. Results: Urinary symptoms were observed in five of nine patients (56%) and urinary frequency in three of nine patients (33%), and none had urinary retention. Urodynamic abnormalities included detrusor overactivity in one (11%) and weak detrusor on voiding in two, but none had postvoid residual urine. Sphincter electromyography revealed, while mild in degree, neurogenic change in five of the eight patients (63%) on whom the test was performed. Conclusion: We observed urinary frequency in 33%; detrusor overactivity in only 11%; and neurogenic change in the sphincter electromyography in 63% of our nine SCA6 patients. These findings might be relevant to the cerebellar and spinal cord pathologies of this disease.