A normoechogenic substantia nigra (SN) is a typical finding in transcranial sonography in patients with progressive supranuclear palsy (PSP), whereas in patients with Parkinson's disease a hyperechogenic SN is characteristic. A recent classification scheme recommends the differentiation of PSP patients into those with Richardson's syndrome (RS) and those with PSP-Parkinsonism (PSP-P). We investigated 34 PSP patients (27 RS, 7 PSP-P) with ultrasound of the substantia nigra in search of differentiations in the two groups. We found that most of the PSP-P patients, according to recently published criteria, had a hyperechogenic SN (6 of 7): right (cm(2)) median 0.22, 25% percentile 0.21 and 75% percentile 0.36 (cm(2)); left (cm(2)) median 0.21, 25% percentile 0.20 and 75% percentile 0.30 and a normal third ventricle (mean mm) +/-SD: 7.1 +/- 2.43). In RS patients a normoechogenic SN (26 of 27) and an enlarged third ventricle (mean mm) +/-SD: 10.3 +/- 2.41) was found. These differences may elucidate the pathological differences of RS and PSP-P.