Midbrain transcranial sonography in Korean patients with Parkinson's disease

Transcranial sonography (TCS) is potentially useful for the diagnosis of Parkinson's disease (PD). However, studies on TCS have so far been restricted to European populations. To investigate the efficacy of TCS in Korean PD patients and its correlation with the clinical features, we carried out midbrain TCS in 43 PD patients and 35 normal controls and evaluated the area of the substantia nigra (SN) hyperechogenicity and its ratio to the area of the whole midbrain. In 16 subjects (21%), TCS was unsuccessful due to insufficient acoustic temporal bone windows. The mean area of bilateral SN hyperechogenicity and its ratio to the midbrain area were greater in the PD patients than that in the controls (P < 0.01). In the PD patients, the area of SN hyperechogenicity and its ratio to the individual midbrain area were moderately correlated with the PD duration (r = 0.526 and 0.536, P = 0.01, respectively) but not with the age, UPDRS motor scores or H-Y stage. There was no difference in the SN hyperechogenicity between the tremor-dominant, akinetic-rigid, and mixed-type PD patients. In conclusion, midbrain TCS is an effective diagnostic tool for detecting PD in the Korean population. However, it does not reflect the severity or phenotypes of parkinsonism.