Complexity

Research Article

New Perspectives for Computer-Aided Discrimination of Parkinson’s Disease and Essential Tremor

Table 2

Most discriminative tremor metrics, extracted from inertial recordings of ET and PD patients. The best cut-off value was selected as closest to upper left corner in the ROC curve. Normalization of values in postural condition to the ones in rest condition increased discriminative power of metrics.


Symbol	Metric	Task	Hand	Cut-off	Sensitivity (%)	Specificity (%)	AUC (95% CI)	PPV (%)	NPV (%)	value	value

M1	Mean Log power of all harmonics, modified from Muthuraman et al. [18]	AO	ND	−7.579	88.9	59.3	0.74 (0.60, 0.88)	68.6	84.2	190.0	0.003
		WE	D	−5.517	74.1	70.4	0.74 (0.60, 0.88)	71.4	73.1	189.0	0.002
		AO	ND	0.983	77.8	85.2	0.82 (0.71, 0.94)	84.0	79.3	128.0	<0.001
		WE	D	1.416	77.8	74.1	0.82 (0.71, 0.93)	75.0	76.9	129.0	<0.001

M2	Average of mean Log power of all the harmonics, modified from Muthuraman et al. [18]	AO, PO, WE, RE	D	−6.770	74.1	51.9	0.60 (0.44, 0.76)	60.6	66.7	292.0	0.210
		AO, PO, WE, RE	ND	−7.246	81.5	55.6	0.68 (0.54, 0.83)	64.7	75.0	231.0	0.021
		AO, PO, WE, RE	D	0.872	74.1	74.1	0.76 (0.62, 0.90)	74.1	74.1	175.0	0.001
		AO, PO, WE, RE	N	0.659	85.2	70.4	0.83 (0.71, 0.95)	74.2	82.6	126.0	<0.001
		AO, PO, WE	D	−6.251	77.8	63.0	0.72 (0.58, 0.86)	67.7	73.9	205.0	0.006
		AO, PO, WE	ND	−6.669	77.8	66.7	0.75 (0.61, 0.88)	70.0	75.0	185.0	0.002
		AO, PO, WE	D	1.494	66.7	81.5	0.82 (0.71, 0.93)	78.3	71.0	133.0	<0.001
		AO, PO, WE	ND	0.856	88.9	70.4	0.83 (0.71, 0.95)	75.0	86.4	123.0	<0.001

M3	Basic tremor frequency power, [18]	AO, PO, WE, RE	D	0.019	66.7	59.3	0.64 (0.49, 0.79)	62.1	64.0	264.0	0.082
		AO, PO, WE, RE	D	12.770	66.7	92.6	0.82 (0.71, 0.93)	90.0	73.5	131.0	<0.001
		AO, PO, WE	ND	0.011	74.1	66.7	0.74 (0.60, 0.87)	69.0	72.0	192.0	0.003
		AO, PO, WE	ND	12.820	74.1	81.5	0.78 (0.66, 0.92)	80.0	75.9	155.0	<0.001

M4	Mean power of the tremor harmonics, [18]	AO, PO, WE, RE	D	0.005	77.8	55.6	0.65 (0.49, 0.80)	63.6	71.4	258.0	0.065
		AO, PO, WE, RE	ND	0.003	77.8	63.0	0.71 (0.57, 0.85)	67.8	73.9	212.0	0.008
		AO, PO, WE, RE	D	7.901	66.7	85.2	0.82 (0.71, 0.93)	81.8	71.9	133.0	<0.001
		AO, PO, WE, RE	ND	7.567	66.7	81.5	0.79 (0.66, 0.92)	78.3	71.0	154.0	<0.001
		AO, PO, WE	D	0.013	66.7	85.2	0.74 (0.60, 0.88)	81.8	71.9	188.0	0.002
		AO, PO, WE	D	10.201	66.7	85.2	0.82 (0.71, 0.93)	81.8	71.9	131.0	<0.001

ET patients: positive cases; PD patients: negative cases; normalized to RE task; averaged through all tasks (not normalized to RE task); averaged through all the tasks and normalized to RE task; averaged on postural tasks (not normalized to RE task); averaged on postural tasks and normalized to RE task; D: dominant tremor hand; ND: nondominant tremor hand.