A148: Motor Cortices Activation and Gait Performance of Older AdultsDuring Turning Under Motor-Cognition Dual Task

<bold>Purpose:</bold> The degeneration of neural, skeletal, and muscular systems increases the difficulty of straight walking in older adults. This challenge is further amplified when cognitive dual tasks are added. Turning is a common movement in daily life, with a higher risk of falls compared to straight walking, yet it has been under-researched. This study aimed to explore the effects of motor-cognitive dual tasks on the activation of motor-related cortices and gait performance during turning in older adults, and the correlation between brain activation and gait performance. <bold>Methods:</bold> Twenty older participants (68.8±3.3 years) were included. Participants performed two tasks at a comfortable pace: walking in an eight-shaped path (single task, ST) and performing a digit alertness cognitive task during ST (dual task, DT). Data collection was conducted using fNIRS and three-dimensional motion capture system to extract the activation of premotor cortex and supplementary motor area (PMC&amp;SMA), primary motor cortex (M1), primary somatosensory cortex (S1), and somatosensory association cortex (SAC), as well as gait parameters including step length, step width, step frequency, step speed, and their variability. Paired t-tests were used to compare the differences in test results between ST and DT, and Pearson correlation coefficients were used to analyze the correlation between brain activation and gait results. p &lt; 0.05 was considered statistically significant. <bold>Results:</bold> Compared to ST, participants under the DT condition showed decreased activation in PMC&amp;SMA, M1, and S1 (p &lt; 0.040), decreased gait speed (p = 0.048), and increased step frequency variability (p = 0.049). Under the ST condition, negative correlations were found between PMC&amp;SMA activation and gait speed (|r| = 0.519, p = 0.019), between PMC&amp;SMA, M1 activation and step frequency (|r| &gt; 0.586, p &lt; 0.01), and positive correlations between PMC&amp;SMA, S1, SAC activation and step frequency variability (|r| &gt; 0.448, p &lt; 0.05). Under the DT condition, negative correlations were observed between PMC&amp;SMA activation and step frequency (|r| = 0.481, p = 0.032), and between S1, SAC activation and step length (|r| &gt; 0.463, p &lt; 0.05). <bold>Conclusion:</bold> Compared to single task, the older adults exhibited decreased activation of motor-related cortices, poorer gait performance under motor-cognitive dual tasks. This may be related to the higher demand for brain attention resources, leaving fewer resources for the automated walking patterns that do not require as much activation in the motor areas. Regardless of single or dual tasks, the brain activation correlated negatively with gait performance.