Irregular Movements Can Predict Risks of Frailty, Disability, and Death
Wed, April 21, 2021

Irregular Movements Can Predict Risks of Frailty, Disability, and Death

People move every day; walking to work, going for a jog, or just reaching up the cupboard. Movement is so common and natural that people rarely pay close attention to any changes / Photo by: dotshock via 123RF

 

People move every day; walking to work, going for a jog, or just reaching up the cupboard. Movement is so common and natural that people rarely pay close attention to any changes. However, these changes in daily movements could be an indicator of disease and decline, according to a new study.

Researchers from Brigham and Women's Hospital analyzed patterns of movement among elderly people and found that irregular fluctuations could predict their frailty, disability, and deaths in the future. The results of their study were published in the journal Science Translational Medicine.

Outcomes of motor activity

Using actimetry sensors, watch-like devices worn on the wrist or ankle, the researchers gathered motor activity data from 1,275 elderly participants. They then analyzed this data and looked at the participants' outcomes 13 years later using a technique called fractal physiology.

Results show that participants with more random pattern changes in their daily motor activity at time scales between 1 and 90 min had increased risk of death, disability, and frailty, according to Medical Xpress. Medical Xpress is a web-based medical and health news service that features the most comprehensive coverage in the many fields of medicine.

Researchers found that frailty increased by 31 percent while disability risks rose by 15 to 25 percent and the risk of death increased by 26 percent for a standard deviation increase in the fluctuation mean. They added that occurrences of these incidences varied on average: 4.7 years for frailty, 3 to 4.2 years for disability, and 5.8 years for death after baseline.

"These observations were independent of age, sex, education, chronic health conditions, depressive symptoms, cognition, motor function, and total daily activity," the investigators said.

"These findings indicate that spontaneous fluctuations in daily motor activity contain useful information about wellness and health, and that nonlinear dynamic analysis can serve as a powerful tool to extract such information."

Researchers from Brigham and Women's Hospital analyzed patterns of movement among elderly people and found that irregular fluctuations could predict their frailty, disability, and deaths in the future / Photo by: Cathy Yeulet via 123RF

 

Individual results

A closer look at the findings shows that the incidence of frailty, disability, and death varies. Out of the 1,275 elderly participants, 936 were not frail at the beginning of the study. The researchers followed these participants over the course of about four years and found that frailty occurred in 291 of them (31.1 percent).

The same was done with 1,073 participants who reported no disability in basic activities of daily living (ADL) and were observed for the same period. Results show that nearly 529 of them (49.3 percent) developed ADL disability.

The researchers also looked at 641 participants who said they are free from independence (ADL). After three years, 442 (70 percent) of these participants developed IADL disability. About 443 (64.8 percent) of 684 others were found to develop mobility disabilities over the same period.

Predicting increased all-cause mortality involved all 1,275 participants, who were followed for nearly six years. After that period, nearly half of the participants (42 percent) had died. The higher risk of death among the participants has been associated with older age, being a male, and fewer years of education.

Meanwhile, results for frailty and disability remained even after adjusting for the said factors.

Risk factor

The researchers said a common risk factor for frailty, disability, and death is low physical activity.

"Health benefits of physical activity have long been acknowledged, and there is indisputable evidence for the association between higher physical activity and lower risk for disability and mortality," they explained.

"Physical activity may also be beneficial for reducing the risk of frailty in the elderly, although the role of being physically active in preventing sedentary elderlies from being physically frail is still under debate."

The study showed that fractal patterns—complex patterns that are self-similar across different scales—in the random activity resulted in key insights into frailty, disability, and death among the elderly. This may not be surprising, the researchers said, since regulation of fractal motor activity "reflects the system integrity that is required for successful, repetitive execution of different motor tasks."

However, changes in the fractal fluctuations of movements may indicate subclinical information due to reasons of disruptions or physiological functions including cognition, psychiatric stability, coordination, and physical conditioning.

"This interpretation is supported by our previous findings that fractal motor activity regulation was degraded in dementia and associated with cognitive impairment," the researchers said. "Together, these findings support that fractal motor activity regulation provides additional valuable information about physiological function beyond total daily activity."

The proposed motor activity measures could help provide a possible tool for remoted medicine, said corresponding author Peng Li. He added that such a tool can also be used to facilitate mobile health care, "which is clearly important considering the challenge of population aging on health care systems all over the world."

Although they are significant, the authors noted that the results would have to be replicated in a larger sample in order to establish the current technique as a diagnostic tool. Since the participants in the study were relatively old, the researchers have yet to determine if the same method could be applied to predict the outcomes in middle-aged and younger adults.

The researchers said a common risk factor for frailty, disability, and death is low physical activity / Photo by: Fabio Formaggio via 123RF