Stress-Induced Responses in Conscious Movement Processing and Walking Behaviour in Older Adults.

We investigated how psychological and walking behaviours would respond to environmental stressor between older adults with different psychomotor tendencies. We recruited 102 community-dwelling older adults and split them into those with higher conscious movement processing tendencies (HCMP) and lower conscious movement processing tendencies (LCMP). Participants walked straight for 7.4 m in a normal environment (level-ground surface) and in a challenging environment (elevated, foam surface). Real-time conscious movement processing (indicated by T3-Fz electroencephalography coherence), walking stability (indicated by the variabilities in gait parameters and medial-lateral excursion of upper body sway), and neuromuscular efficiency (indicated by co-contraction index of lower limb muscles) were assessed. When older individuals were walking under a challenging environment, LCMP significantly increased their real-time conscious movement processing, while HCMP maintained at a consistent level compared to walking on a normal environment. Both groups significantly reduced walking stability and efficiency to the same extent under the challenging environment. LCMP appear to be susceptible to exhibiting environmentally induced conscious movement processing accompanied by less stable and efficient walking behaviour; indicating the need to investigate this cohort who are often assumed to have lower fall risk. HCMP responses seem independent of environmental stressor as a further increase in conscious involvement might be limited by overloaded working memory, leaving less capacity for adapting to additional stressors. Future research should target older adults at a higher risk of falling, as the negative impact of elevated conscious movement processing could be more pronounced in the absence of compensatory adaptations from higher physical function. CLINICAL TRIAL REGISTRATION: The trial was pre-registered in the ClinicalTrials.gov (ID: NCT05411536) prior to data collection.