Gait speed will help predict dementia

Denis Strigun, Naked Science

Demographic aging of the population increases the relevance of the prevention of age-related diseases, in particular dementia. Now the main stage of her treatment is early diagnosis. However, due to the high cost and labor intensity, existing methods are not suitable for monitoring pathology at the population level. The identification of moderate cognitive disorders (MCI) according to physiological and behavioral criteria is considered more promising. So, earlier scientists proposed to evaluate the cognitive status of older people using a sense of smell test and a virtual supermarket. The authors of the new study tested the hypothesis that the risk of disease is associated with walking speed and the size of the hippocampus. Article by Rosso et al. Slowing gait and risk for cognitive impairment is published in the journal Neurology.

Numerous observations show that changes in gait, for example, its slowing down, often allow predicting dementia. Moreover, the first symptoms of MCI may appear only a few years after such signs. Until now, the neural basis of this correlation has remained unclear. To fill the gap, experts from the University of Pittsburgh and other institutions studied the cases of 193 participants in the Health ABC study, which was conducted in 1997-2012. They were involved in screening at the age of 70-79 years, then in the tenth or eleventh year of work they underwent magnetic resonance imaging (MRI) and after four to five years - a short mental status assessment scale (3MS).

The sample of scientists included only respondents who were healthy at the beginning of the study and participated in several measurements of walking speed.

At the stage of analyzing the tomograms, they described changes in gray and white matter in various areas of the brain, including the shell, posterior parietal and frontal lobes. According to the hypothesis, the most significant associations of signs should be demonstrated with the hippocampus – in neurodegenerative diseases, this structure is one of the first to be damaged. 

Drawing from the University of Pittsburgh press release The Hippocampus Underlies the Link Between Slow Walking and Mental Decline – VM.

In addition, the probability of cognitive complications was tracked by the apolipoprotein E (APOE) allele e4, a key biomarker of delayed neuron regeneration and Alzheimer's disease.

Graph of the average duration of the test with a 6-minute walk
with cognitive impairment (red line) and normal (blue line)
depending on the duration of observations (from an article in Neurology).

The results showed that the accelerated pace of gait deceleration was associated with aging, an increased risk of knee pain, as well as an increase in the volume of white and a decrease in the gray matter of the brain. Thus, long before the appearance of the first symptoms of MCI, patients had a thinning of the right hippocampus. It is noteworthy that the constructed model predicted the disorder better in the longer term: the correlation remained significant for at least 14 years, but weakened four years before cognitive decline. A decrease in the left hippocampus was practically not associated with a change in walking speed. The presence of the APOE e4 allele in the victims also contributed to the trend.

According to the authors, sociodemographic and other parameters did not explain the effect. In the future, the data obtained may help in the development of diagnostic methods for early detection of age-related cognitive disorders.

Portal "Eternal youth" http://vechnayamolodost.ru  04.07.2017