Changes in cognitive-motor interference during rehabilitation of cane walking in patients with subacute stroke: A pilot study.

No previous research has examined cognitive-motor interference (CMI) repeatedly in patients with subacute stroke. This pilot study aimed to report on the changes over time in CMI in patients with stroke who have recently learned to walk with a cane. The assessment started as soon as the participants could walk independently with a quad cane, and was repeated up to six sessions as long as the cane was still used. The dual-tasking paradigm required participants to walk and perform continuous subtractions by 3s. Data were analyzed for 9 participants 33-127 days post-stroke. All 9 participants showed CMI in walking velocity at baseline and 8 of these showed improvement over time (Z = -2.547; p = 0.011). The improvement in CMI was associated with baseline dual-tasking performance (ρ = 0.600; p = 0.044), motor control ability (ρ = -0.695; p = 0.019), walking velocity (ρ = -0.767; p = 0.008), and functional mobility (ρ = 0.817; p = 0.004). All participants showed decrements in both tasks (mutual interference) at baseline, 1 evolved to decrements in walking velocity (cognitive-related motor interference), and 3 finally evolved to decrements in cognitive performance but increments in walking velocity (motor-priority tradeoff). In conclusion, during rehabilitation with cane walking in patients with subacute stroke, the dual-tasking paradigm revealed CMI and its improvements in the majority of participants. Greater improvement in CMI was moderately to strongly associated with worse baseline performance of many variables. The evolution of the CMI pattern over time provides novel information relevant to neurological recovery.

Attentional demands of cane-free walking and cane walking in subacute stroke patients who have just learned to walk without a cane.

This study compared the attentional demands between cane-free walking and cane walking in patients with stroke during the transitional period of cane weaning. Patients with stroke who had just learned to walk cane-free were recruited. Cross-sectional measurement was scheduled within 30 days since the patients were able to walk independently without a quad cane. The dual-tasking paradigm required participants to walk with and without a cane, as well as perform continuous subtractions by 1 s (low-demand) or 3 s (high-demand). The cognitive-motor interference (CMI) of walking velocity was calculated as [(low-demand - high-demand)/low-demand] × 100%. Nine participants (average age, 53.4 ± 6.4 years; stroke onset, 38-131 days) were recruited, and eight showed positive CMI. The paired t-test confirmed a significantly smaller CMI during cane-free walking than during cane walking [t (8) = -3.168; P = 0.013]. The Pearson correlation tests revealed associations between age and CMI of cane walking (r = 0.751; P = 0.010) and CMI of cane-free walking (r = 0.584; P = 0.050). The time since independent cane-free walking was associated with CMI of cane walking (r = 0.699; P = 0.018). In conclusion, experience with cane-free walking leads to increased attentional demand for cane walking. In subacute stroke patients weaning use of a cane, the attentional demand for cane-free walking decreases to less than that of cane walking. During both cane and cane-free walking, the older the participant, the more the walking performance deteriorated due to dual-tasking.

Age-related differences in alpha and beta band activity in sensory association brain areas during challenging sensory tasks.

Sensory challenges to postural balance are daily threats for elderly individuals. This study examined electroencephalography (EEG) in alpha and beta bands in sensory association areas during the Sensory Organization Test, involving withdrawal of visual or presenting misleading somatosensory inputs, in twelve young and twelve elderly participants. The results showed stepwise deterioration in behavioral performance in four conditions, with group effects that were amplified with combined sensory challenges. With eye closure, alpha and beta activities increased in all sensory association areas. Fast beta activity increased in the bilateral parietal-temporal-occipital areas. Misleading somatosensory information effects on EEG activity were of smaller amplitude than eye closure effects and in a different direction. Decreased alpha activity in left parietal-temporal-occipital areas and decreased beta and fast beta activities in bilateral parietal-temporal-occipital areas were significant. Elderly participants had increased fast beta activity in the left temporal-occipital and bilateral occipital areas, indicative of sustained efforts that they made in all sensory conditions. Similar to the young participants, elderly participants with eyes closed showed increased alpha activity, although to a smaller degree, in bilateral temporal-occipital and left occipital areas. This might indicate a lack of efficacy in redistributing relative sensory weights when elderly participants dealt with eye closure. In summary, EEG power changes did not match the stepwise deterioration in behavioral data, but reflected different sensory strategies adopted by young and elderly participants to cope with eye closure or misleading somatosensory information based on the efficacy of these different strategies.