Transcranial sonography in spinocerebellar ataxia type 2

Objective To study the use of transcranial brain parenchyma sonography (TCS), in particular the echogenic signal in the substantia nigra (SN), in patients with spinocerebellar ataxia type 2 (SCA2), recently recognized as an uncommon cause of parkinsonism. Methods Six consecutive and unrelated SCA2 patients without parkinsonian signs, 30 consecutive patients with Parkinson's disease (PD), and 30 healthy, age- and sex-matched controls were prospectively studied with TCS according to a standardized protocol. Results Four (67%) of the six SCA2 patients exhibited SN hyperechogenicity. In two patients, the hyperechogenicity was classified as moderate (unilateral in both) and in two as marked. Differences between the SN echogenicity of the SCA2 group or the PD group and controls were statistically significant (p < 0.001), while there was no difference between the two groups of patients. Conclusions Transcranial brain parenchyma sonography detects SN hyperechogenicity in the majority of patients with SCA2 without parkinsonian signs. It would be important to reproduce our TCS findings in a larger number of SCA2 patients, as well as to test their possible significance in differentiating SCA2 from other types of SCA.