Recent PCHT PubMed Articles

1. The association between fall frequency, injury risk and characteristics of falls in older residents of long-term care: do recurrent fallers fall more safely?

van Schooten KS, Yang Y, Feldman F, Leung M, McKay H, Sims-Gould J, Robinovitch SN.


Background: Although a fall is a necessary prerequisite to a fall-related injury, previous studies suggest that frequent fallers are at lower injury risk for a given fall. We tested the hypotheses that differences in protective responses or the circumstances of falls underlie differences in injury risk with fall frequency.

Methods: We analyzed video footage of 897 falls experienced by 220 long-term care residents (mean age 82±9 yrs) to identify the cause of imbalance, activity leading to falling, direction of fall initiation, balance recovery and fall protective responses, and occurrence of impact to the head or hip. We further obtained injury information from the facilities' fall registration. We used generalized estimating equation models to examine the association between quartiles of fall frequency, injury risk, and fall characteristics.

Results: Residents with the highest fall frequency group (Q4; ≥5.6 falls/year) were less likely to sustain an injury per fall. They were less likely to fall during walking and more likely to fall during stand-to-sit transfers. Residents in the lowest fall frequency group (Q1; <1.15 falls/year) were more likely to fall during walking, and walking was associated with an increased risk for injury.

2. Surveying predictors of late-life longitudinal change in daily activity energy expenditure.

Valiani V, Sourdet S, Schoeller DA, Mackey DC, Bauer DC, Glynn NW, Yamada Y, Harris TB, Manini TM; Health, Aging and Body Composition Study.


Background: Total daily energy expenditure (TEE) is composed of resting metabolic rate (RMR), post-prandial thermogenesis and activity energy expenditure (AEE). Higher AEE is strongly associated with lower mortality and physical limitations among older adults, but factors that predict changes in AEE in septu and octogenarians are not clearly understood.

Objectives: To identify factors associated with late-life longitudinal change in AEE.

Design: Energy expenditure was re-assessed in 83 participants (average age at baseline, 74.4±3.2 years)-an average of 7.5±0.54 years since the baseline measure. RMR was measured using indirect calorimetry and the thermic effect of meals was estimated at 10% of TEE. AEE was calculated as: TEE(0.9)-RMR. Participants were categorized into two groups according to the estimated day-to-day precision of the doubly-labeled water technique. Those who were within 10% or increased relative to their initial AEE measurement were categorized as having preserved AEE. Participants who declined greater than 10% of their initial measurement were categorized as having reduced AEE. A variety of socio-demographic, functional and mental factors, body composition, community and personal behaviors, blood measurements and health conditions were evaluated between groups at baseline and changes during follow-up.

3.Validation of accuracy of SVM-based fall detection system using real-world fall and non-fall datasets.

Aziz O, Klenk J, Schwickert L, Chiari L, Becker C, Park EJ, Mori G, Robinovitch SN.


Falls are a major cause of injuries and deaths in older adults. Even when no injury occurs, about half of all older adults who fall are unable to get up without assistance. The extended period of lying on the floor often leads to medical complications, including muscle damage, dehydration, anxiety and fear of falling. Wearable sensor systems incorporating accelerometers and/or gyroscopes are designed to prevent long lies by automatically detecting and alerting care providers to the occurrence of a fall. Research groups have reported up to 100% accuracy in detecting falls in experimental settings. However, there is a lack of studies examining accuracy in the real-world setting. In this study, we examined the accuracy of a fall detection system based on real-world fall and non-fall data sets. Five young adults and 19 older adults went about their daily activities while wearing tri-axial accelerometers. Older adults experienced 10 unanticipated falls during the data collection. Approximately 400 hours of activities of daily living were recorded. We employed a machine learning algorithm, Support Vector Machine (SVM) classifier, to identify falls and non-fall events. We found that our system was able to detect 8 out of the 10 falls in older adults using signals from a single accelerometer (waist or sternum). Furthermore, our system did not report any false alarm during approximately 28.5 hours of recorded data from young adults. However, with older adults, the false positive rate among individuals ranged from 0 to 0.3 false alarms per hour. While our system showed higher fall detection and substantially lower false positive rate than the existing fall detection systems, there is a need for continuous efforts to collect real-world data within the target population to perform fall validation studies for fall detection systems on bigger real-world fall and non-fall datasets

4. Waist circumference is correlated with poorer cognition in elderly type 2 diabetes women.

West RK, Ravona-Springer R, Heymann A, Schmeidler J, Leroith D, Koifman K, D'Arcy RC, Song X, Guerrero-Berroa E, Preiss R, Hoffman H, Sano M, Silverman JM, Schnaider-Beeri M.


Introduction: Waist circumference is associated with type 2 diabetes (T2D) and cognition, yet the relationship between waist circumference and cognition in individuals with T2D is not well understood.

Methods: We studied the relationship of waist circumference with five cognitive outcomes (executive functioning, language/semantic categorization, attention/working memory, episodic memory, and an overall cognition measure) in 845 cognitively normal elderly with type 2 diabetes (T2D).

Results: In women, waist circumference was correlated with significantly lower language and/or semantic categorization performance (P < .0001), executive functioning (P = .026), and overall cognition (P = .003) after controlling for age, education, BMI, and cardiovascular, diabetes-related, APOE ε4, and inflammatory potential confounders. Attention/working memory (P = .532) and episodic memory (P = .144) were not associated with waist circumference. These correlations were not found in men.

Discussion: These results suggest that central adiposity in elderly women with T2D may increase their risk for dementia.

5. Behavioral and Electrophysiological Differences in Executive Control Between Monolingual and Bilingual Children.

Barac R, Moreno S, Bialystok E.


This study examined executive control in sixty-two 5-year-old children who were monolingual or bilingual using behavioral and event-related potentials (ERPs) measures. All children performed equivalently on simple response inhibition (gift delay), but bilingual children outperformed monolinguals on interference suppression and complex response inhibition (go/no-go task). On the go/no-go task, ERPs showed larger P3 amplitudes and shorter N2 and P3 latencies for bilingual children than for monolinguals. These latency and amplitude data were associated with better behavioral performance and better discrimination between stimuli for bilingual children but not for monolingual children. These results clarify the conditions that lead to advantages for bilingual children in executive control and provide the first evidence linking those performance differences to electrophysiological brain differences in children.