Table 4.

Coefficient estimates, standard error, z-test statistics, and P values from pairwise linear mixed-effect models for exploring associations between Bluetooth features and the depressive symptom severity (8-item Patient Health Questionnaire).

Featurea		Estimate	SE	z score	Adjusted P valueb,c
Second-order statistics
	Min_Max	−0.052	0.012	−4.431	<.001
	Mean_max	−0.016	0.006	−2.809	.005
	Max_Std	−0.015	0.006	−2.657	.008
	Min_Std	−0.215	0.056	−3.838	<.001
	Mean_Std	−0.065	0.023	−2.802	.005
	Std_Std	−0.048	0.020	−2.385	.02
	Max_Mean	−0.030	0.008	−3.498	<.001
	Min_Mean	−0.093	0.046	−2.036	.04
	Mean_Mean	−0.083	0.026	−3.225	.001
	Std_Mean	−0.095	0.027	−3.464	.001
Multiscale entropy (MSE)
	MSE_1	0.642	0.225	2.853	.005
	MSE_2	0.433	0.192	2.255	.02
	MSE_3	0.401	0.202	1.985	.04
	MSE_16	−0.102	0.042	−2.429	.01
	MSE_22	−0.123	0.043	−2.860	.005
Frequency domain (FD)
	LFd_sum	−0.021	0.005	−3.865	<.001
	MFe_sum	−0.067	0.014	−4.766	<.001
	HFf_sum	−0.027	0.010	−2.606	.009
	MF_pctg	−1.834	0.812	−2.259	.02
	HF_seh	3.821	1.820	2.099	.04

^aDefinitions of Bluetooth features in this table are shown in Table 1.

^bOnly significant associations (adjusted P value <.05) are reported.

^cP values were adjusted by the Benjamini-Hochberg method for correction of multiple comparisons.

^dLF: low frequency (0-0.75 cycles/day).

^eMF: middle frequency (0.75-1.25 cycles/day).

^fHF: high frequency (>1.25 cycles/day).

^gpct: percentage of spectrum power.

^hse: spectral entropy.