Table 4. Results of multivariate analyses to determine smartphone tapper parameters discriminating idiopathic Parkinson’s disease from controls.

Age and gender were used as covariates in each analysis.

Parameters		laterality	Estimate	SE	p value
No. of correct taps	Mean	Average	-0.15	0.03	<0.0001
		Better	-0.13	0.03	<0.0001
		Worse	-0.13	0.03	<0.0001
	Variance in 3 trials	Better	-0.01	0.01	0.3100
		Worse	-0.06	0.02	0.0113
	Asymmetry index	mean	-0.68	2.77	0.8044
No. of tap errors	total number	Both	-0.06	0.03	0.0672
		Better	-0.05	0.05	0.3383
		Worse	-0.08	0.06	0.1779
	Variance in 3 trials	Both	-0.08	0.06	0.2152
		Better	-0.05	0.05	0.3383
		Worse	-0.03	0.07	0.6570
Total distance of finger movement, mean		Average	0.00	0.00	<0.0001
		Better	0.00	0.00	<0.0001
		Worse	0.00	0.00	<0.0001
		Asymmetry index	-5.71	2.94	0.5216
Inter-tap distance of correct taps, mean		Average	-0.02	0.00	<0.0001
		Better	-0.02	0.00	<0.0001
		Worse	-0.02	0.00	<0.0001
		Asymmetry index	-5.97	2.92	0.0412
Inter-tap distance of tap errors, mean		Better	0.00	0.00	0.0059
		Worse	0.00	0.00	0.2504
Dwelling time of correct taps, mean		Average	24.31	5.71	<0.0001
		Better	24.65	5.68	<0.0001
		Worse	19.21	4.74	0.0001
		Asymmetry index	6.10	3.29	0.0637
Dwelling time of tap errors, mean		Better	17.84	4.62	0.0001
		Worse	6.07	2.80	0.0304

Average, average of both hands; Better, the better hand; Worse, the worse hand; Both, sum of both hands