As many as 30 million older adults in the US have walking limitations which could impact community mobility. Restriction in community mobility contribute to disability, institutionalization, and poor quality of life. Compared to walking in clinical settings, community mobility requires rapid negotiation of complex, multi-sensorial, and often variable and unpredictable environments. Successful community mobility requires rapid integration of information both external (e.g. surface quality, distances) and internal (e.g. fatigue, pain) to the individual. Integration of these inputs primarily occurs at the level of the central nervous system. Under normal conditions, this integration favors automatic motor control with few demands on attention-related networks, primarily located in the prefrontal cortex (PFC). As automatic motor control diminishes in older adults, activation of the PFC during walking tasks increases. Age-related impairments in body systems (e.g. musculoskeletal, cardiopulmonary) increase the demands of walking while concurrent impairments in the brain can reduce capacity for motor control. The mismatch in demands and capacity can be magnified when walking occurs in the context of complex community environments (e.g. uneven surfaces, attentional demands); therefore, automatic motor control is likely a critical component of community mobility. Motor skill training (MST) is an integrated intervention approach developed to improve walking. The goal of MST is restoration of automatic motor control and behavioral flexibility during walking, which are needed for addressing environmental challenges during community mobility. The MST approach may restore automatic motor control and provide older individuals with the capacity to address environmental challenges and maintain community mobility. We propose to test the effects of MST on community mobility and motor control. Community mobility will be quantified by state of the art, objective measures from global position system (GPS) tracking, including activity space (the area travelled by an individual in daily activities) and time away from home. Central motor control will be assessed by wireless functional near-infrared spectroscopy (fNIRS) at the PFC during dual-task walking. Further, we will assess the influence of individuals? cognitive function and neighborhood environments by neighborhood socioeconomic status and walkability audits on changes in community mobility. We will leverage an ongoing randomized, 12-week efficacy trial of standard therapy compared to standard plus MST (R01 AG045252; PI: Jennifer Brach) that is enrolling individuals aged 65 years and older with gait speeds 0.6- 1.2 m/s (n=248). The primary outcome of the parent trial is gait speed; our proposal will extend the outcome from clinic-based measures to real world community mobility at baseline and 12, 24, and 36 week follow-up visits. Results will provide evidence for intervention approaches to improve community mobility of older adults.
Motor skill training therapy aims to improve the brain?s control of walking and can improve clinic-based measures of walking in older adults. However, it is unknown whether the benefits of motor skill training extend to real world mobility measures. We will test the effects of motor skill training on measures of community mobility of older adults and assess the mechanisms through improved motor control at the level of the brain. These results will inform intervention approaches to maintain community mobility of older adults and prevent disability and institutionalization.
