Functional near-infrared spectroscopy to probe sensorimotor region activation during electrical stimulation-evoked movement


This study used non-invasive functional near-infrared spectroscopy (fNIRS) neuroimaging to monitor bilateral sensorimotor region activation during unilateral voluntary (VOL) and neuromuscular electrical stimulation (NMES)-evoked movements. Methods. In eight healthy male volunteers, fNIRS was used to measure relative changes in oxyhaemoglobin (O2Hb) and deoxyhaemoglobin (HHb) concentrations from a cortical sensorimotor region of interest in the left (LH) and right (RH) hemispheres during NMES-evoked and VOL wrist extension movements of the right arm. Results. NMES-evoked movements induced significantly greater activation (increase in O2Hb and concomitant decrease in HHb) in the contralateral LH than in the ipsilateral RH (O2Hb: 0˙44 ± 0˙16 $μ$M and 0˙25 ± 0˙22 $μ$M, P = 0˙017; HHb: −0˙19 ± 0˙10 $μ$M and −0˙12 ± 0˙09 $μ$M, P = 0˙036, respectively) as did VOL movements (0˙51 ± 0˙24 $μ$Μ and 0˙34 ± 0˙21 $μ$M, P = 0˙031; HHb: −0˙18 ± 0˙07 $μ$Μ and −0˙12 ± 0˙04 $μ$Μ, P = 0˙05, respectively). There was no significant difference between conditions for O2Hb (P = 0˙144) and HHb (P = 0˙958). Conclusion. fNIRS neuroimaging enables quantification of bilateral sensorimotor regional activation profiles during voluntary and NMES-evoked wrist extension movements.

Clinical Physiology and Functional Imaging