Walking the walk: using gait to gauge dementia
Monash University Central and Peninsula Clinical School researchers have shown that a person’s gait can predict whether they are headed for dementias such as Alzheimer’s disease, and which specific brain functions are involved in this cognitive decline.
Associate Professor Michele Callisaya and Professor Velandai Srikanth, supervising first author PhD student Ms Oshadi Jayakody from the University of Tasmania, investigated whether variability from one step to the next during walking, and gait speed, were related to cognitive decline over time. Their study was published in the Journal of Alzheimer’s Disease.
Gait is increasingly being recognised as an early indicator of dementia, however few studies have previously examined whether gait predicts decline in specific cognitive domains.
Associate Professor Callisaya and Professor Srikanth are considered leaders in the field.
Collaborating with the Menzies Research Institute, they conducted a study that tested the gait of 410 elderly people (over 60 years, average age 72 years) randomly selected from the electoral roll. They measured the participants’ gait at baseline and used neuropsychological tests to assess processing speed, memory, executive (mental processes needed for planning and managing tasks) and visuospatial function at baseline, 2.6 and 4.6 years.
The participants were asked to walk on a computerised mat that measured gait speed and step to step variability.
The study found that higher variability in double support time (DST) – the amount of time a person spends with both feet on the ground during one gait cycle – was associated with greater decline in memory. It found that slow gait speed predicted decline in processing speed and visuospatial function. Interestingly, in people carrying the ApoE4 gene – which is associated with Alzheimer’s disease – gait speed also predicted decline in memory.
“We think there might be walking patterns which might be an early indicator that a person may suffer decline in specific cognitive functions,” Associate Professor Callisaya said.
Gait measures combined with usual risk assessments could be used to help better predict risk of future cognitive decline, potentially helping in planning future care, and gait could be objectively measured as a proxy to study the effectiveness of interventions to slow the progression of dementia, she said.
Professor Srikanth said the study highlighted that there is far more to gait than thought.
“Walking is usually taken for granted as a simple daily function – whereas we have demonstrated in our studies that it is dependent on several brain networks functioning effectively together,” he said.
“Hence, we and others have begun to take the view that it may actually be a ‘super cognitive function’ itself. The simplicity with which we can measure gait and balance makes them easily applicable to a wide variety of settings as a future biomarker of dementia.”
Associate Professor Callisaya, a physiotherapist, and Professor Srikanth, a geriatrician in the Department of Medicine at Peninsula Health, will see if they can translate the work for use in cognitive disorder and memory clinics.
“We think gait is a really good marker of somebody’s overall health status,” Associate Professor Callisaya said. “It has been shown to not only predict falls but also hospitalisation, mortality, and now even cognitive decline in specific domains.”
Professor Srikanth is a NHMRC Practitioner Fellow and Associate Professor Callisaya a NHMRC Boosting Dementia Leadership Fellow.
Jayakody O, Breslin M, Srikanth V, Callisaya M. Gait Characteristics and Cognitive Decline: A Longitudinal Population-Based Study.J Alzheimers Dis. 2019 Apr 1. doi: 10.3233/JAD-181157. [Epub ahead of print]