Our Gait May Give Clues to Early Alzheimer’s
Barely perceptible changes in the way a person walks may well be the first physical warning signs of the onset of Alzheimer’s disease and dementia. This is the surprising news coming out of the Alzheimer’s Association international conference in Vancouver.
Up until now, doctors have only been able to diagnose Alzheimer’s disease when cognitive function is clearly impaired and protracted neurological tests have confirmed irreversible changes to a person’s mental capacities. The idea that there may be an early observable symptom, even in advance of cognitive changes, will be a major boon to doctors and the federal government. It launched a program in May for better dementia training of doctors, and that it will find a cure by 2025.
The Chief Medical Officer of the Alzheimer’s Society points out the benefits of this new research, “Monitoring deterioration and other changes in a person’s gait is ideal because it doesn’t require any expensive technology or take a lot of time to assess.” There close on five and a half-million Alzheimer’s sufferers currently in America and the number is set to triple in the next four decades as the ‘baby boomer’ generation enters the third age.
What seems to healthy people like the simple act of walking is, in fact, a highly complex integrated function of many brain areas. Alzheimer’s disease disrupts the links between these areas as soon as it appears. Parkinson’s disease and arthritis do not do this.
The Mayo clinic in Minnesota analysed and measured the walking performance of 1,341 volunteers. They recorded the size of each stride, the gait cadence and the pace using a computerized ‘gait instrument’. They did this on at least two clinical visits over a year apart for each participant in the study. The patients with lesser cadence, slower pace and shorter stride saw a significant loss of overall cognitive function, deteriorated memory and poorer executive functioning. This deterioration indicates a possible part played by gait changes as an early precursor of brain deterioration.
In a different study with over 1100 subjects aged on average seventy-eight, scientists the in Basel Mobility Center, Switzerland found people suffering with early Alzheimer’s developed a slower and more variable walk as cognitive ability declined. The patients were categorized according to their cognitive state from OK through ‘mild cognitive impairment’ to full Alzheimer’s dementia. Their gait was again scrutinized using a walkway containing 30,000 computer linked sensors.
The healthy group walked normally but the pace steadily slowed as cognitive impairment went up. But it can be difficult to spot in the clinic because patients focus on the task when asked rather than walking unconsciously. Also a researcher measured gait speed during MRI scans and at home and found that patients were slower at home. The connection is clear between a smaller overall brain size and a slackening of walking pace. Brain shrinkage is one of the symptoms of Alzheimer’s.