Figure 1

Percentage of patients with different ultrasound findings in the two groups. a showed the percentage of cases with different sonographic findings in total patients. b showed the percentage of cases with different sonographic findings in the subgroup of patients with disease duration ≤3 years. Black: percentage of patients with a marked substantia nigra (SN) hyperechogenicity; grey: percentage of patients who exhibited a moderate increase in SN echogenicity; and white: percentage of patients with a normal SN echogenicity; non-TD PD, non-tremor dominant Parkinson’s disease; MSA-P, parkinsonian variant of multiple system atrophy.