Urodynamic evaluation of patients with hereditary ataxias.

Seventeen patients with Friedreich's ataxia or spastic ataxia were subjected to an urodynamic evaluation. Fifty-three per cent (53%) of the patients presented with urinary symptoms consisting of urgent micturition and urgency incontinence. Cystometric evaluation showed a lack of inhibition of the detrusor in 7 patients (41%). Abnormal electric hyperactivity of the external sphincter was documented in 6 cases (37.5%) by electromyography. Some hypotheses are presented to explain the etiology of these abnormal findings.