Effect of automaticity induced by treadmill walking on prefrontal cortex activation and dual-task performance in older adults.

As individuals age, they may experience a decline in gait automaticity, which requires increased attentional resources for the control of gait. This age-related decline in gait automaticity has been shown to contribute to higher prefrontal cortex (PFC) activation and lower dual-task performance during dual-task walking in older adults. This study is to investigate the effect of treadmill walking on PFC activation and dual-task performance in older adults. A total of 20 older adults (mean age, 64.35 ± 2.74 years) and 20 younger adults (mean age, 30.00 ± 3.15 years) performed single- and dual-task walking in overground and treadmill conditions. A wearable functional near-infrared spectroscopy and gait analyzer were used to analyze PFC activation and dual-task performance, respectively. To determine the dual-task (gait and cognitive) performance, the dual-task cost (DTC) was calculated using the following formula: (single-task - dual-task)/single-task × 100. In both groups, dual-task treadmill walking led to reduced PFC activation and reduced DTC compared to dual-task overground walking. Furthermore, despite a higher DTC in gait variability, correct response, total response, response index and a higher error score in older adults than in younger adults during overground walking, there was no difference in treadmill walking. The difference in PFC activation between single- and dual-tasks was also observed only in overground walking. Performing dual-task walking on a treadmill compared to overground walking results in different levels of dual-task performance and PFC activity. Specifically, older adults are able to maintain similar levels of dual-task performance as younger adults while walking on a treadmill, with reduced PFC activation due to the automaticity induced by the treadmill. Therefore, older adults who exhibit low dual-task performance during overground walking may be able to improve their performance while walking on a treadmill with fewer attentional resources.

Change in activity patterns in the prefrontal cortex in different phases during the dual-task walking in older adults.

BACKGROUND: Studies using functional near-infrared spectroscopy (fNIRS) have shown that dual-task walking leads to greater prefrontal cortex (PFC) activation compared to the single-task walking task. However, evidence on age-related changes in PFC activity patterns is inconsistent. Therefore, this study aimed to explore the changes in the activation patterns of PFC subregions in different activation phases (early and late phases) during both single-task and dual-task walking in both older and younger adults. METHODS: Overall, 20 older and 15 younger adults performed a walking task with and without a cognitive task. The activity of the PFC subregions in different phases (early and late phases) and task performance (gait and cognitive task) were evaluated using fNIRS and a gait analyzer. RESULTS: The gait (slower speed and lower cadence) and cognitive performance (lower total response, correct response and accuracy rate, and higher error rate) of older adults was poorer during the dual task than that of younger adults. Right dorsolateral PFC activity in the early period in older adults was higher than that in younger adults, which declined precipitously during the late period. Conversely, the activity level of the right orbitofrontal cortex in the dual-task for older adults was lower than for younger adults. CONCLUSIONS: These altered PFC subregion-specific activation patterns in older adults would indicate a decline in dual-task performance with aging.

The effect of the degree of dual-task interference on gait, dual-task cost, cognitive ability, balance, and fall efficacy in people with stroke: A cross-sectional study.

ABSTRACT: This study was conducted to investigate the effects of the degree of dual-task (DT) interference on gait, dual-task cost (DTC), cognitive ability, balance, and fall efficacy in people with stroke.In this cross-sectional study, people with chronic stroke (N = 36) performed a DT gait assessment (gait and cognitive task). During the evaluation, DT interference in motor and cognition was evaluated simultaneously. Thus, the group with severe interference in both tasks (mutual interference) was compared with the group with mild interference in either.The main effects for the degree of motor interference were observed on gait performance, DTC in motor, time up and go, and trail-making test B. In the cognitive interference, the main effects were observed on correct response rate, DTC in cognition, time up and go, and trail-making test B. An interaction effect was observed in the trail-making test B.The degree of motor interference affected gait, balance ability, and executive function (EF), and the degree of cognitive interference influenced the correct response rate in the DT condition, balance ability, and EF. Furthermore, mutual interference led to a significant reduction in EF in people with stroke.

Effects of Dual-Task Gait Treadmill Training on Gait Ability, Dual-Task Interference, and Fall Efficacy in People With Stroke: A Randomized Controlled Trial.

OBJECTIVE: This study aimed to investigate the effects of dual-task gait training using a treadmill on gait ability, dual-task interference, and fall efficacy in people with stroke. METHODS: Patients with chronic stroke (N = 34) were recruited and randomly allocated to the experimental or control group. Both groups underwent gait training on a treadmill and a cognitive task. In the experimental group, gait training was conducted in conjunction with the cognitive task, whereas in the control group, the training and the cognitive task were conducted separately. Each intervention was provided for 60 minutes, twice a week, for a period of 6 weeks for both groups. The primary outcomes were as follows: gait parameters (speed, stride, variability, and cadence) under single-task and dual-task conditions, correct response rate (CRR) under single-task and dual-task conditions, and dual-task cost (DTC) in gait parameters and CRR. The secondary outcome was the Fall Efficacy Scale. RESULTS: Dual-task gait training using a treadmill improved all gait parameters in the dual-task condition, speed, stride, and variability in the single-task condition, and CRR in both conditions. A difference between the groups was observed in speed, stride, and variability in the dual-task condition. Furthermore, dual-task gait training on a treadmill improved DTC in speed, variability, and cadence along with that in CRR, indicating true improvement of DTC, which led to significant improvement in DTC in speed and variability compared with single-task training. CONCLUSIONS: Dual-task gait treadmill training was more effective in improving gait ability in dual-task training and dual-task interference than single-task training involving gait and cognitive task separately in people with chronic stroke.