Five-year follow-up study of hyperechogenicity of the substantia nigra in Parkinson's disease.

Using transcranial sonography, an area of hyperechogenicity at the substantia nigra (SN) may be detected as a typical marker in patients with Parkinson's disease (PD) as well as in approximately 9% of healthy subjects vulnerable to nigrostriatal impairment. In this longitudinal study, we provide evidence that the area of SN hyperechogenicity does not change in the course of PD. In conjunction with earlier findings in children and adolescents, this evidence indicates that, from late adolescence onward, this ultrasound finding is a trait marker for nigrostriatal vulnerability.