Table 3.

Baseline predictors of annual change in Total Tremor Score

	ET cases enrolled in an epidemiological study (n=44)	ET cases enrolled in a brain donor programme (n=39)
Age (years)	r=−0.02, p=0.89	r=0.13, p=0.44
Gender
Male	0.24±0.82	0.59±1.31
Female	0.37±0.94	0.67±1.64
	p=0.64	p=0.88
Education (years)	r=−0.04, p=0.80	r=−0.18, p=0.27
Family history of ET or tremor
Yes	0.59±0.55	0.66±1.37
No	0.20±1.00	0.58±1.86
	p=0.19	p=0.89
Tremor duration (years)	r=−0.27, p=0.09	r=−0.02, p=0.89
Age of tremor onset (years)	r=0.22, p=0.17	r=0.05, p=0.77
Voice tremor on examination
Yes	0.15±0.95	1.03±1.87
No	0.41±0.89	0.49±0.86
	p=0.40	p=0.26
Head (neck) tremor on examination
Yes	0.49±0.85	0.41±1.08
No	0.23±0.92	0.83±1.77
	p=0.36	p=0.39
Jaw tremor on examination
Yes	−0.37±1.10	0.65±0.73
No	0.43±0.82	0.63±1.76
	p=0.04	p=0.96
Rest tremor on examination
Yes	0.06±1.09	1.17±0.18
No	0.35±0.88	0.18±1.12
	p=0.55	p=0.04
Tremor Asymmetry Index	r=0.07, p=0.66	r=0.01, p=0.97
Takes daily ET medication
Yes	0.14±1.04	0.59±1.42
No	0.53±0.66	0.72±1.65
	p=0.15	p=0.81
Takes ET medication only as needed
Yes	0.47±0.57	NA
No	0.32±0.91
	p=0.82

Pearson’s correlation coefficients and Student’s t tests.

Family history included first- and second-degree relatives.

Tremor Asymmetry Index=|tremor score right arm − tremor score left arm|; range 0–18.

ET, essential tremor; NA, not applicable.