Utilization of central nervous system resources for preparation and performance of complex walking tasks in older adults

Abstract

Introduction: Walking in the home and community often involves performance of complex walking tasks. Understanding the control of such tasks is crucial to preserving independence and quality of life in older adults. However, very little research has been conducted in this area. Here, we assess the extent to which two measures of central nervous system (CNS) activity are responsive to the challenges posed by preparation and performance of complex walking tasks. Prefrontal cortical activity was measured by functional near-infrared spectroscopy (fNIRS) and sympathetic nervous system arousal was measured by skin conductance level (SCL).Materials and methods: Sixteen older men and women (age: 77.2 ± 5.6 years) with mild mobility deficits participated in this study. Participants walked at their preferred speed without distractions along an unobstructed, well-lit course (control task) and also walked on the same course under five separate challenging conditions: performing a cognitive verbal fluency task (verbal task), dim lighting (dim task), carrying a tray (carry task), negotiating obstacles (obstacles task) and wearing a weighted vest (vest task). Mean prefrontal activation and SCL were calculated during the preparation and performance phases of each task. Gait spatiotemporal measurements were acquired by an instrumented gait mat.Results: Prefrontal cortical activity and SCL were elevated during the preparation phase of complex walking tasks relative to the control task. During the performance phase, prefrontal activity remained elevated to a similar level as during task preparation. In contrast, SCL continued to increase beyond the level observed during task preparation. A larger increase in prefrontal activity was found to be linked to preserved quality of gait during complex walking tasks.Discussion: These findings indicate that availability and utilization of CNS resources are important for optimizing performance of complex walking tasks in older adults.

EMG synchrony to assess impaired corticomotor control of locomotion after stroke

“…Piper band activity in the cortex has been attributed to interactions among cortical regions that are involved in movement execution under variable conditions that require attentional resources, such as to integrate visual and somatosensory information [Brown, 2000, Omlor, Patino, 2007]. This is generally consistent with the prior finding that walking adaptability tasks invoke increased cortical activity in regions important to attention and motor planning [Clark, 2015, Clark et al, 2014]. Furthermore, prior work has shown that EMG synchrony in the Piper range exhibits task-dependent changes that are consistent with the attentional and physical demands of various walking adaptability tasks [Clark, Kautz, 2013].…”

Locomotor Adaptability Task Promotes Intense and Task-Appropriate Output From the Paretic Leg During Walking

“…These findings add to other potential benefits of using adaptability tasks in rehabilitation, including more effective engagement of cerebral circuits of locomotor control 9,10 and high functional importance of adaptability tasks 4 .…”

Neural correlates of obstacle negotiation in older adults: An fNIRS study

“…Alternatively, the increased utilization of cognitive resources, operationalized using PFC HbO 2 levels, among individuals with slow gait may have contributed to their reduced gait speed costs compared to participants with normal gait. An additional study found that PFC activity was elevated during complex walking tasks relative to a control task, which the authors posited to reflect preserved quality of gait during obstacle negotiation tasks (26). …”