Faster Walking Speeds Require Greater Activity from the Primary Motor Cortex in Older Adults Compared to Younger Adults

Sensors (Basel). 2023 Aug 3;23(15):6921. doi: 10.3390/s23156921.

Abstract

Gait speed declines with age and slower walking speeds are associated with poor health outcomes. Understanding why we do not walk faster as we age, despite being able to, has implications for rehabilitation. Changes in regional oxygenated haemoglobin (HbO2) across the frontal lobe were monitored using functional near infrared spectroscopy in 17 young and 18 older adults while they walked on a treadmill for 5 min, alternating between 30 s of walking at a preferred and fast (120% preferred) speed. Gait was quantified using a triaxial accelerometer (lower back). Differences between task (preferred/fast) and group (young/old) and associations between regional HbO2 and gait were evaluated. Paired tests indicated increased HbO2 in the supplementary motor area (right) and primary motor cortex (left and right) in older adults when walking fast (p < 0.006). HbO2 did not significantly change in the young when walking fast, despite both groups modulating gait. When evaluating the effect of age (linear mixed effects model), greater increases in HbO2 were observed for older adults when walking fast (prefrontal cortex, premotor cortex, supplementary motor area and primary motor cortex) compared to young adults. In older adults, increased step length and reduced step length variability were associated with larger increases in HbO2 across multiple regions when walking fast. Walking fast required increased activation of motor regions in older adults, which may serve as a therapeutic target for rehabilitation. Widespread increases in HbO2 across the frontal cortex highlight that walking fast represents a resource-intensive task as we age.

Keywords: cortex; fast gait velocity; frontal lobe; functional near infrared spectroscopy; oxygenated haemoglobin; preferred gait velocity.

Publication types

  • Comparative Study

MeSH terms

  • Aged
  • Gait / physiology
  • Humans
  • Motor Cortex*
  • Oxyhemoglobins
  • Spectroscopy, Near-Infrared / methods
  • Walking / physiology
  • Walking Speed* / physiology
  • Young Adult

Substances

  • Oxyhemoglobins

Grants and funding

This work was supported by the National Institute for Health Research (NIHR) Newcastle Biomedical Research Unit (BRU) and Centre (BRC) based at Newcastle upon Tyne Hospitals NHS Foundation Trust and Newcastle University. The research was also supported by NIHR Newcastle CRF Infrastructure funding and Sao Paulo Research Foundation (FAPESP 2016/00518-8; postdoctoral fellowship to Rodrigo Vitório).