Neuronal loss in Onuf's nucleus in three patients with progressive supranuclear palsy

Disorders of micturition have been reported only sporadically in patients w ith progressive supranuclear palsy (PSP). We report the results of a clinic opathological study of 3 patients with a definite diagnosis of PSP at vario us stages of their illness with sphincter abnormalities. Electromyography o f the sphincter muscles was performed in all 3 patients and was abnormal in 2. Morphological and morphometric evaluation of Onuf's nucleus in the sacr al spinal cord, which is involved in sphincter control, showed severe cell loss, presence of neurofibrillary tangles, neuropil threads, and glial incl usions. We conclude that bladder dysfunction and abnormal sphincter electro myographic results are due to pathological changes in Onuf's nucleus, and w e propose that sphincter abnormalities should be included in the list of po ssible symptoms of PSP.