Table 3.
studies investigating complex walking listed by increasing walking speed
| Authors | Device [ROI]; method of placing channels |
Walking task and speed: m/s (SD) | Method of adding complexity to walking + comparator condition | Results |
|---|---|---|---|---|
| (Mitchell et al., 2018) [31] |
[18F]-FDG-PET [Whole head]; spatial resolution 4.8–5.4 mm |
Overground, comfortable pace: *Stroke: complex/comparator 0.45(0.26)/0.76(0.42) *Healthy: complex/comparator 0.81(0.14)/1.34(0.04) |
Complex: Overground obstacle course Comparator: Overground walking |
1. More asymmetric activation in superior parietal areas compared to healthy 2. More impaired showed greater activation in ipsilesional PFC and contralesional superior parietal 3. Less impaired showed greater activation in contralesional PFC and ipsilesional superior parietal 4. No subcortical differences between stroke and healthy* |
| (Al-Yahya et al., 2016) [22] |
fNIRS [PFC]; 10/20 system |
Treadmill, comfortable pace: Stroke: 0.48 (0.338) Healthy: 1.01 (0.025) |
Complex: Cognitive dual-task (serial 7 subtractions) Comparator: treadmill walking |
1. Greater PFC activation 2. No difference compared to older adults 3. No difference between hemispheres |
| (Hawkins et al., 2018) [36] |
fNIRS [PFC]; high and lateral on the forehead |
Overground, preferred speed: Stroke: 0.51 (0.27) Older: 1.07 (0.16) Younger: 1.28 (0.18) |
Complex: Motor and cognitive dual-task (obstacle stepping and verbal fluency) Comparator: Overground walking |
1. Greater increase in PFC activity with complex walking compared to young and older adults 2. Greater PFC activation in those with greater impairment (Fugl-Meyer LE), despite having similar gait speeds |
| (Hermand et al., 2019) [37] |
fNIRS [PFC]; 10/20 system |
Overground, comfortable pace: 0.52 (0.23) |
Complex: Cognitive dual-task (2 difficulties: verbal 1-back and 2-back) Comparator: Overground walking |
1. No change in PFC activation 2. Decreases in walking speed and gait variability 3. No difference in gait performance between difficulty of complex walking 4. Decrease cognitive performance with harder compared to easier complex walking 5. No significant correlations |
| (Chatterjee et al., 2019) [33] |
fNIRS [PFC]; high and lateral on forehead |
Overground, self-selected: 0.6 (0.2) |
Complex: Cognitive dual-task (serial 7 subtraction) Comparator: Overground walking |
1. Greater PFC activation, slower gait speed, shorter stride length, wider step width 2. Higher cognitive status and lower extremity impairment predicted greater PFC activation during complex walking 3. Low cognitive status subgroup: no change in PFC activation, decreased gait speed, shorter stride length 4. Greater PFC cost of complex walking correlated to greater decreased in walking speed and stride length |
| (Liu et al., 2018) [38] |
fNIRS [PFC, PMC, SMA]; no detail on head cap placement |
Overground, self-selected: 0.74–0.60 (0.16–0.18) |
Complex: Motor and cognitive dual-task (water bottle on tray, serial 3 subtraction) Comparator: Overground walking |
1. Manual dual-task: greater increase in bilateral PMC and contralesional SMA 2. Cognitive dual-task: greater increase in ipsilesional PFC, bilateral PMC, and contralesional SMA 3. Greater PMC and SMA (but not PFC) activity correlated to lower cadence, greater stride time, and slower walking speed |
| (Mori et al., 2018) [26] |
fNIRS [PFC]; landmarked to Fp1 and Fp2 |
Overground, comfortable pace: Stroke: 0.94 (0.23) Healthy: 1.24 (0.18) |
Complex: Cognitive dual-task (serial 3 subtraction) Comparator: Overground walking |
1. Less PFC activation and greater gait and cognitive costs (i.e. worse performance) in the stroke compared to healthy 2. Stroke: Greater right PFC correlated to better dual-task gait performance 3. Healthy: Greater left PFC correlated to better cognitive performance |
| (Calabro et al., 2017) [40] |
EEG [whole head]; 10/20 system and LORETA source localization |
Treadmill: 1.8 |
Complex: 8 weeks exoskeleton, non-linear force + virtual environment Comparator: 8 weeks exoskeleton linear walking, on-screen smile feedback |
1. Greater ipsilesional fronto-central, M1, S1, and visual cortex activity, gait cycle dependent changes, gait/balance performance, and hip/knee force 2. Both conditions: decreased depression, no spasticity change 3. Increased frontal and central brain activations correlated to increased gait and balance performance and hip force 4. No correlations between brain activity and age, gender, stroke duration, or number of comorbidities |
| (Chang et al., 2019) [32] |
EEG [Cz (SMC)]; not reported |
Overground, pace not reported |
Complex: Augmented reality walking with music + stepping targets Comparator: Overground walking, no music or targets |
1. Greater SMC activation 2. Greater hip and knee flexion |
All results are reports as changes in complex walking from the comparator condition
ROI region of interest, PFC prefrontal cortex, PMC premotor cortex, SMA supplementary motor area, SMC sensorimotor cortex, M1 primary motor cortex, fNIRS functional near-infrared spectroscopy, EEG electroencephalography, [18F]-FDG-PET 18F-labeled fluoro-2-deoxyglucose positron emission tomography
*Details obtained through personal communication with authors