Correlation Between Substantia Nigra Features Detected by Sonography and Parkinson Disease Symptoms

The aim of this study was to assess the correlation between substantia nigra (SN) echogenic features and area and the clinical symptoms in patients with Parkinson disease (PD).Clinical examinations and transcranial sonographic evaluations of the SN were performed in 115 consecutive patients with PD. The presence of tremors, rigidity, bradykinesia, gait disorders, speech disorders, and hypomimia was evaluated according to the motor portion of the Unified Parkinson Disease Rating Scale. The Mann-Whitney U test, the Kruskal-Wallis test, analysis of variance, and multivariate analysis were applied when assessing statistical significance.An enlarged and hyperechoic SN existed in 84.0% of patients with bilateral rigidity but in only 70.6% of patients with unilateral rigidity (P < .05). Similarly, 85.0% of patients with bilateral bradykinesia in comparison with 65.7% of patients with unilateral bradykinesia had an enlarged and hyperechoic SN (P < .05). A significant correlation was shown between the SN echogenicity and area (r = 0.705; P < .01). Conclusions. An enlarged and hyperechoic SN seems to be a marker of structural involvement of the SN in patients with PD. This structural involvement is expressed more in patients with bilateral rigidity and bradykinesia.