Table 8.

Multivariate regression analyses for Groton Maze Recall (GMR) ^a.

	Subacute Cognitive Performance (GMR)
	GMR Correct Moves per Second			GMR Total Errors
HRV Variable	β	sR2	p	β	sR2	p
Resting State
HR dispersion	−0.318	0.084	0.030 *	0.496	0.204	0.001 *
SDNN	0.096	0.008	0.531	−0.262	0.059	0.071
RMSSD	−0.251	0.053	0.087	0.041	0.001	0.792
SampEn	0.254	0.052	0.091	−0.170	0.023	0.282
Isometric Handgrip Contraction
HR dispersion	−0.188	0.033	0.175	0.109	0.011	0.452
SDNN	−0.186	0.031	0.193	0.069	0.004	0.645
RMSSD	−0.263	0.063	0.060	0.127	0.012	0.390
	Post-Acute Cognitive Performance (GMR)
Resting State
HR dispersion	−0.128	0.014	0.355	0.316	0.085	0.026 *
SDNN	−0.242	0.051	0.075	0.013	0.000	0.926
RMSSD	−0.268	0.061	0.050	0.037	0.001	0.798
SampEn	0.260	0.054	0.066	−0.087	0.006	0.564
Isometric Handgrip Contraction
HR dispersion	−0.213	0.043	0.101	−0.041	0.002	0.763
SDNN	−0.256	0.077	0.054	−0.081	0.006	0.566
RMSSD	−0.230	0.049	0.081	−0.090	0.007	0.517

^a Age, sex, history of concussion, BMI, time since injury, and athletic status were entered into adjusted models. * denotes predictor significance (p < 0.05). sR², squared semi-partial correlations. Abbreviations: HRV, heart rate variability; HR, heart rate; SDNN, standard deviation of NN intervals; RMSSD, root mean square of successive NN interval differences; and SampEn, sample entropy.