Table 1.

Summary of studies of NIRS in motor recovery.

Study	# of patients	Patients character	Etiology	Target area	Measurement	Method	Clinical applications
UPPER LIMB RECOVERY
Kato et al. (24)	6	4 men,2 women; 59–79 years old	Cerebral infarction of the middle cerebral artery territory	MCA	Δ[Oxy-Hb] and Δ[Deoxy-Hb].	Multi-channel NIRS	Evaluate the compensatory motor activation of cortical region
Takeda et al. (25)	5	one man, four women, 52–67 years old	Ischemic stroke	Bilateral SM1	Δ[Oxy-Hb] and Δ[Deoxy-Hb].	44-channel NIRS	Monitor cerebral activation and investigate the longitudinal change
Hara et al. et al. (26)	16	14 men, 2 women	Chronic stroke patients with residual hemiparesis	SMC	Δ[Oxy-Hb] and Δ[Deoxy-Hb].	24-channel NIRS	Investigate relationship between hemiparetic arm function improvement and brain cortical perfusion change during different tasks
Gobbo et al. (27)	23	13 males; 10 females, aged 60.4 ± 13.2) years (range: 40–84 years	Subacute or chronic stroke	Flexor muscles of the forearm	Δ[Oxy-Hb] and Δ[Deoxy-Hb].	fNIRS	Evaluate the acute effects induced by a single session of robot-assisted passive hand mobilization on local perfusion and upper limb function
Brunetti et al. (28)	11	Six female, seven male	Subacute stroke with severe upper limb paresis	Primary motor cortex and precuneus	Δ[Oxy-Hb] and Δ[Deoxy-Hb].	fNIRS	Investigate determinants of efficacy of mirror therapy
LOWER LIMB RECOVERY
Miyai et al. (29)	6	Four men, two women; 57 years old	Stroke with hemiplegia	Bilateral frontoparietal cortices covering SMCs, PMCs, SMAs, pre-SMAs, part of prefrontal cortices, and the superior parietal lobes	Δ[Oxy-Hb] and Δ[Deoxy-Hb].	Multi-channel NIRS	Investigate motor cortices activation
Miyai et al. (30)	8	5 men, 3 women; 4 with right and 4 with left hemiparesis; aged 57 years;	Stroke	Bilateral frontoparietal cortices covering the primary SMC, PMC, SMA, pre-SMA, part of PFC, and the superior parietal lobes	Oxy-Hb, deoxy-Hb, and total-Hb levels	Multi-channel NIRS	Illuminate the mechanism of gait recovery
Mihara et al. (31)	12	11 men,1 woman;age range: 12–74 years, mean ± S.D.: 52.7 ± 16.9 years	Infratentorial stroke	Frontoparietal region covering bilateral PFC,the medial PFC,SMA and medial SMC	Δ[Oxy-Hb] and Δ[Deoxy-Hb].	42-channel NIRS	Investigate the difference of cortical activation between patients and controls
Lin et al. (32)	17	16 men, 1 woman; age 55.53 ± 12.06	Subcortical stroke with hemiparesis	Frontoparietal region covering SMC;bilateral SMA and PMC	Δ[Oxy-Hb] and Δ[Deoxy-Hb].	Multichannel frequency domain NIRS	Measure the cortical activation patterns during active cycling with and without speed feedback
Rea et al. (33)	7	6 men, 1 woman	Chronic stroke	Frontal regions, bilateral PMC, SMA, primary and secondary motor areas, and somatosensory areas	Δ[Oxy-Hb] and Δ[Deoxy-Hb].	fNIRS	Assess the reliability and feasibility of NIRS in clinical usability in lower limb movement preparation
Holtzer et al. (34)	236	age ≥ 65 years	167 normal,40 peripheral NGA,29 central NGA	Forehead	Δ[Oxy-Hb] and Δ[Deoxy-Hb].	fNIRS	Confirm the posture first hypothesis
BALANCE CONTROL
Mihara et al. (35)	20	15 men and five women; mean (SD) age 61.6 (11.9) years	Stroke	Frontoparietal region	Δ[Oxy-Hb] and Δ[Deoxy-Hb].	fNIRS	Evaluate cortical activation associated with external postural perturbation
Fujimoto et al. (36)	20	17 men and 3 women; mean (± SD) age 60.2 (± 9.5) years	Subcortical stroke	Frontoparietal region	Δ[Oxy-Hb] and Δ[Deoxy-Hb].	Single-channel NIRS	Evaluate cortical activation associated with external postural perturbation
MOTOR LEARNING
Hatakenaka et al. (37)	12	10 men and 2 women; mean (± SD) age 56 (± 16) years	Ataxia resulting from infratentorial stroke	Forehead, including SMC, SMA, pre-SMA, dorsal PMC, and dorsolateral PFC	Δ[Oxy-Hb] and Δ[Deoxy-Hb].	42-channel NIRS	Investigate impact of the capacity for motor learning on motor recovery

MCA, middle cerebral artery; SMC, sensorimotor cortex; PMC, premotor cortex; SMA, supplementary motor area; PFC, prefrontal cortex.