Heart rate variability as an assessment of fall risk in older adults

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Lauren Quinn Higgins (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/
Louisa Raisbeck

Abstract: Falls in the older adult population are a critical public health concern, resulting in significant personal and societal financial burden, and reduced independence and quality of life. Early identification of elevated fall risk is vital for implementation of effective fall prevention strategies. However, the unidimensional nature of traditional fall risk assessments fails to accurately determine fall risk (incidence of falls) in older adults. Additionally, fall risk assessments are most often measured in the clinical setting, and consequently many injurious falls occur prior to the identification of elevated risk by a healthcare provider. Assessment of heart rate variability (HRV) in the free-living environment provides a robust solution to the limitations of traditional fall risk assessments. HRV or the fluctuations in the time intervals between adjacent heartbeats, has emerged as a valuable assessment reflecting the dynamic, non-linear autonomic nervous systems (ANS) influence on cardiac rhythm. In alignment with dynamic systems theory, previous work supports system-based overlaps of the ANS and other fall risk related physiological systems. Thus, measurement of HRV presents an opportunity to assess the interaction of multiple physiological systems that influence falls. However, the efficacy of HRV to determine fall risk in healthy, community dwelling older adults is unknown. Therefore, the purpose of this dissertation is threefold: 1) to determine if HRV indices observed over a 24-hour monitoring period differ in community dwelling older adults with a history of falls and those who have not sustained a fall, 2) to determine the discriminative validity of HRV indices observed over a 24-hour monitoring period for classifying fall risk in older adults compared to traditional fall risk assessment tools, including the Timed Up and Go (TUG), the Functional Gait Assessment (FGA), and the Activities-specific Balance Confidence Scale (ABC), 3) to examine associations between intrinsic fall risk factors [e.g., postural control, vestibular function, lower extremity muscular strength, executive function, and depression] and HRV indices observed over a 24-hour monitoring period and whether the relationships differ for those with a history of falls versus non-fallers. Forty-two healthy, community dwelling older adults (age 74.40 ± 5.46 years) participated in this study and were assigned to either the fallers group (n = 15) or non-fallers group (n = 27) based on self-reported fall history. Participants in the fallers group reported =1 fall during the 12 months prior to testing. All participants completed a demographics and health history survey, three traditional fall risk assessments (TUG, FGA, and ABC), and five measures to assess intrinsic fall risk. To measure HRV, participants wore a heart rate monitor for 24-hours in their free-living environment. Mann Whitney U tests were run to determine if HRV metrics differed between groups, and Wilcoxon effect size calculations were executed to determine the magnitude of the effect. The results reported in Manuscript I show that HRV metrics did not significantly differ between fallers and non-fallers; however, a medium effect of fall risk on the standard deviation of the normal-to-normal intervals was observed (SDNN). This suggests that SDNN may provide clinically relevant information regarding fall risk. Receiver operator characteristics (ROC) curves were run to determine the discriminative validity of HRV indices in comparison to traditional fall risk assessments. The results of Manuscript II suggest that SDNN had the greatest accuracy to differentiate fallers from non-fallers but was not significantly better than traditional fall risk assessments. Multiple regressions were completed to determine the extent to which intrinsic fall risk factors are associated with HRV indices, and whether the relationships differ for those with a history of falls versus non-fallers. The results reported in Manuscript III show that declines in postural control and vestibular function were associated with alterations in HRV non-linear parameters. These data suggest that HRV may be an effective measure of fall risk in community dwelling older adults. It is recommended that future work expand to include older adults with diagnoses of age-related diseases known to increase fall risk.

Additional Information

Language: English
Date: 2022
Fall Risk, Falls, Heart Rate Variability, Older Adults
Falls (Accidents) in old age $x Prevention
Heart beat $x Measurement

Email this document to