Disorders of micturition have been reported only sporadically in patients with progressive supranuclear palsy (PSP). We report the results of a clinicopathological study of 3 patients with a definite diagnosis of PSP at various stages of their illness with sphincter abnormalities. Electromyography of the sphincter muscles was performed in all 3 patients and was abnormal in 2. Morphological and morphometric evaluation of Onuf's nucleus in the sacral spinal cord, which is involved in sphincter control, showed severe cell loss, presence of neurofibrillary tangles, neuropil threads, and glial inclusions. We conclude that bladder dysfunction and abnormal sphincter electromyographic results are due to pathological changes in Onuf's nucleus, and we propose that sphincter abnormalities should be included in the list of possible symptoms of PSP.
