Table I.

Demographic and clinical characteristics. Mean ± SD or frequency (%).

	Controls (n=146)	SD (n = 128)
Gender
Female	96 (66%)	101 (79%)	P = 0.02
Male	50 (34%)	27 (21%)
Race
White/Caucasian	102 (70%)	103 (80%)	P = 0.13
Black/African-American	36 (25%)	20 (16%)
Other	8 (5%)	5 (4%)
Age, years
Overall	55.0 ± 14.9	59.3 ± 12.4	P = 0.009
Patients with vocal tremor	68.4 ± 14.7	66.6 ± 11.5	P = 0.76
Patients with body tremor	67.1 ± 13.3	64.3 ± 14.7	P = 0.50
Tremor (any)	21 (14%)	41 (32%)	P < 0.001
Vocal tremor	5 (3%)	33 (26%)	P < 0.001
Non-vocal tremor	21 (14%)	27 (21%)	P = 0.14
SD subtype			N/A
ADSD	-	122 (95%)
ABSD	-	5 (4%)
Atypical	-	1 (1%)
Seen by neurologist for SD	-	45 (35%)	N/A