Seventeen patients with a progressive bradykinetic syndrome and post-mortem findings of neurofibrillary degeneration in cerebral cortex, subcortical nuclei and brainstem were studied. Seven fulfilled currently accepted clinical diagnostic criteria for Steele-Richardson-Olszewski syndrome, whereas the remainder who lacked supranuclear gaze palsy had alternative clinical diagnoses (idiopathic Parkinson's disease, six cases; cerebrovascular disease, two cases; Parkinson's syndrome, one case; Alzheimer's disease, one case). The clinical and pathological findings of the two groups were compared in an attempt to better define the spectrum of Steele-Richardson-Olszewski disease.