Digital Biomarkers of Cognitive Frailty: The Value of Detailed Gait Assessment Beyond Gait Speed

Abstract

<b><i>Background:</i></b> Cognitive frailty (CF), defined as the simultaneous presence of cognitive impairment and physical frailty, is a clinical symptom in early-stage dementia with promise in assessing the risk of dementia. The purpose of this study was to use wearables to determine the most sensitive digital gait biomarkers to identify CF. <b><i>Methods:</i></b> Of 121 older adults (age = 78.9 ± 8.2 years, body mass index = 26.6 ± 5.5 kg/m<sup>2</sup>) who were evaluated with a comprehensive neurological exam and the Fried frailty criteria, 41 participants (34%) were identified with CF and 80 participants (66%) were identified without CF. Gait performance of participants was assessed under single task (walking without cognitive distraction) and dual task (walking while counting backward from a random number) using a validated wearable platform. Participants walked at habitual speed over a distance of 10 m. A validated algorithm was used to determine steady-state walking. Gait parameters of interest include steady-state gait speed, stride length, gait cycle time, double support, and gait unsteadiness. In addition, speed and stride length were normalized by height. <b><i>Results:</i></b> Our results suggest that compared to the group without CF, the CF group had deteriorated gait performances in both single-task and dual-task walking (Cohen’s effect size <i>d</i> = 0.42–0.97, <i>p</i> < 0.050). The largest effect size was observed in normalized dual-task gait speed (<i>d</i> = 0.97, <i>p</i> < 0.001). The use of dual-task gait speed improved the area under the curve (AUC) to distinguish CF cases to 0.76 from 0.73 observed for the single-task gait speed. Adding both single-task and dual-task gait speeds did not noticeably change AUC. However, when additional gait parameters such as gait unsteadiness, stride length, and double support were included in the model, AUC was improved to 0.87. <b><i>Conclusions:</i></b> This study suggests that gait performances measured by wearable sensors are potential digital biomarkers of CF among older adults. Dual-task gait and other detailed gait metrics provide value for identifying CF above gait speed alone. Future studies need to examine the potential benefits of gait performances for early diagnosis of CF and/or tracking its severity over time.

Quantitative gait analysis in mild cognitive impairment, dementia, and cognitively intact individuals: a cross-sectional case–control study

“…However, there was no change in the foot rotation angle and step width. Similar to previous findings, these measures of decline in gait performance were noticeable during single-task walking but showed greater deterioration when tested under a dual-task walking condition [36,40,[65][66][67]. From our findings, there were significant differences in several gait variables between the MCI and dementia groups and between dementia and cognitively intact groups when tested under single-and dual-task walking.…”

Association between Fall History and Gait, Balance, Physical Activity, Depression, Fear of Falling, and Motor Capacity: A 6-Month Follow-Up Study

“…During all static balance tests, participants were instructed to have their feet hip-width apart and parallel, stand upright, cross their arms at their chest, keep their knees extended, and breathe normally for 30 s [ 23 ]. After the static balance test, all participants performed single-task and dual-task walking tests for 10 m with their comfortable walking speed [ 24 ]. During single-task walking tests, participants walked without any cognitive distraction, but participants walked by counting backward from a random number during dual-task walking tests.…”

The Performance of Dual-Task Tests Can Be a Combined Neuro-Psychological and Motor Marker of Mild Cognitive Impairment, Depression and Dementia in Geriatric Patients—A Cross-Sectional Study

“…A total of 155 (62%) cases TUG manual; 23 (9.2%) had cognitive and 72 (28.2%) physical problems while performing tasks. The median score was 16 (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23) seconds, stride number during the test-23 (19)(20)(21)(22)(23)(24)(25)(26)(27)(28), and while turning around-6 (5)(6)(7)(8). DTC was 11 (0-25)%.…”

“…This study aimed to evaluate changes in gait test performance in patients of different cognitive statuses. The slowness of gait speed is a well-proven factor associated with cognitive impairment and a risk factor for dementia, especially in frail patients [18]. In recent years an increasing interest in dual-task interference has been evaluated.…”

“…Depression was diagnosed in 76 (30.4%) and mild cognitive impairment in 30 (12%) of patients. Dementia was diagnosed in 38.4% of cases with median MMSE 17 (12)(13)(14)(15)(16)(17)(18)(19)(20) points and CDT 0 (0-3) points. A total of 44 (17.6%) patients were diagnosed with mild stage, 30 (12%) with moderate, and 22 (8.8%) with a severe stage of dementia.…”