Turning Mobility and its Association to Falls and Cognitive Function

Recently published in by the Gerontological Society of America in the Journals of Gerontology: Medical Sciences – “Continuous Monitoring of Turning Mobility and Its Association to Falls and Cognitive Function: A Pilot Study” by Martina Mancini, Heather Schlueter, Mahmoud El-Gohary, Nora Mattek, Colette Duncan, Jeffrey Kaye, and APDM Chief Scientist Fay B. Horak.

This pilot study showed interesting results – The team found that the quality of turning was significantly compromised in recurrent fallers compared with nonfallers. The activity rate and mean number of turns per hour remained relatively similar in compared groups, and future falls were related to an increased variability of number of steps in turn. The team also concluded that continuous monitoring of turning characteristics, while walking during daily activities, is feasible in older people. Turning in real life is more sensitive to fall risk than prescribed turning tasks.

Turning is a dynamic activity that requires balance control, which worsens with age. Previous studies have shown relations between difficulty turning and an increase or contribution to disability, falls, and reduced quality of life. However, no study had quantified the quality and quantity of turning during normal daily activities in older people. The team set out to determine if the quality of turning in this population is related to falls and cognitive function.

The study was performed on 35 elderly participants (85 ± 8 years) who wore three APDM Opal sensors on the lumbar, and one on each foot. Based on retrospective falls, participants were grouped into nonfallers (17), single fallers (12) and recurrent fallers (7). The participants engaged in an at-home protocol to follow during the study, all of which complied. Their turning and activity rates were measured and data was recorded on the internal memory of each Opal for 7 days. The team then uploaded the data to a laptop for analysis.

From the lumbar sensor, the team was able to define gait bouts as walking periods of 10 seconds or longer. These bouts were then used by an algorithm to look for potential turns using a horizontal rotational rate. A turn was defined as a trunk rotation about the horizontal plane with a minimum of 45º, accompanied with at least one right and one left foot stepping. The team went on to look at turn angles, and also remarked on the validity of the APDM Opal sensors compared to Motion Analysis in a lab. Metrics computed included number of turns per hour, turn angle amplitude, turn duration, turn peak velocity, and number of steps to complete a turn.

Results showed that the quality of turning, quantified by the mean turn duration, mean peak speed of turning, and mean number of steps to complete a turn were significantly compromised in recurrent fallers compared with nonfallers. Recurrent fallers showed a longer turn duration, slower peak speed, and more steps per turn. The mean turn angle was similar across all groups, however, the recurrent fallers showed a lower CV of turn angle. Unlike the quality of turning, the quantity (percent of time participant is walking or turning compared with full time monitoring during the day) and the mean number of turns per hour were similar across all three groups.

Findings of this study demonstrated the following:

• Quality of turning is impaired in recurrent fallers

• Continuous monitoring of turns, but not prescribed turns, differentiate between fallers and nonfallers

• Turning mobility may be associated with visuospatial and memory function

• Variability of steps during a turn may predict prospective falls

For more information on the study, click here. 

For more information on long-duration mobility recording, click here.