Table 7.

Multivariate regression analyses for Groton Maze Learning (GML) ^a.

	Subacute Cognitive Performance (GML)
	GML Correct Moves Per Second			GML Total Errors
HRV Variable	β	sR2	p	β	sR2	p
Resting State
HR dispersion	−0.117	0.011	0.407	0.287	0.068	0.057
SDNN	−0.318	0.087	0.019 *	0.144	0.018	0.340
RMSSD	−0.346	0.101	0.011 *	0.139	0.016	0.359
SampEn	0.196	0.031	0.170	−0.093	0.007	0.552
Isometric Handgrip Contraction
HR dispersion	−0.278	0.074	0.031 *	0.071	0.004	0.621
SDNN	−0.224	0.045	0.095	0.011	0.000	0.940
RMSSD	−0.249	0.057	0.059	0.030	0.001	0.839
	Post-Acute Cognitive Performance (GML)
Resting State
HR dispersion	−0.006	0.000	0.964	0.147	0.019	0.274
SDNN	−0.151	0.020	0.266	−0.023	0.000	0.865
RMSSD	−0.143	0.017	0.298	−0.035	0.001	0.795
SampEn	0.298	0.070	0.032 *	−0.130	0.013	0.353
Isometric Handgrip Contraction
HR dispersion	−0.247	0.059	0.052	0.028	0.001	0.830
SDNN	−0.167	0.023	0.208	−0.152	0.020	0.247
RMSSD	−0.093	0.008	0.480	−0.127	0.015	0.327

^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.