Tempo-spatial gait adaptations in stroke patients when approaching and crossing an elevated surface

Premotor and Posterior Parietal Cortex Activity is Increased for Slow, as well as Fast Walking Poststroke: An fNIRS Study

Methods

Twenty individuals in the chronic stage of stroke walked: (1) at their normal pace, (2) slower than normal, and (3) as fast as possible. Functional near-infrared spectroscopy was used to assess bilateral prefrontal, premotor, sensorimotor, and posterior parietal cortices during walking.

Results

No significant differences in laterality were observed between walking speeds. The ipsilesional prefrontal cortex was overall more active than the contralesional prefrontal cortex. Premotor and posterior parietal cortex activity were larger during slow and fast walking compared to normal-paced walking with no differences between slow and fast walking. Greater increases in brain activation in the ipsilesional prefrontal cortex during fast compared to normal-paced walking related to greater gait speed modulation.

Conclusions

Brain activation is not linearly related to gait speed. Ipsilesional prefrontal cortex, bilateral premotor, and bilateral posterior parietal cortices are important areas for gait speed modulation and could be an area of interest for neurostimulation.

Walking through an aperture while penetrating from the paretic side improves safety managing the paretic side for individuals with stroke who had previous falls

BACKGROUND

Safety management of the paretic side of the body is critical for individuals with stroke. We previously reported that individuals with stroke who walk through an aperture while penetrating from the paretic side had fewer collisions with the frame of an aperture than did those penetrating from the non-paretic side. We observed spontaneous behavior of collision avoidance in our previous study; this study thus used penetration from the paretic and non-paretic sides as independent variables to confirm the usefulness of penetrating from the paretic side.

OBJECTIVE

This study aimed to (1) reconfirm whether walking through a narrow space while penetrating from the paretic side leads to reduced frequency of collision only for individuals with stroke with previous falls by manipulating the direction of penetration as independent variables and to (2) determine whether the behavioral or cognitive characteristics of passing through the aperture are observed in individuals with stroke who had previous falls.

METHODS

Individuals with stroke (12 with previous falls, 13 without) were required to walk through a narrow space while penetrating from the paretic and non-paretic sides. The collision rate and kinematic characteristics at the moment of crossing the aperture (body rotation angle, deviation of body's midpoint, and movement speed) were recorded as dependent variables. We also confirmed whether the participants expected collision after passing.

RESULTS

Individuals with stroke with previous falls were less likely to have a collision when penetrating from the paretic side. The stroke fall group was likely to experience more collisions because of deleterious changes in body rotation angle and movement speed in narrow apertures. Moreover, individuals with stroke have many unexpected collisions, but the decline in anticipatory ability was not unique to the stroke fall group.

CONCLUSIONS

Penetrating a narrow space from the paretic side improved safety management of the paretic side in patients with previous falls despite poor adjustment to narrow apertures. Penetrating a narrow space from the paretic side may make it easier to view and pay attention to the paretic side.