Rapid Inhibition Accuracy and Leg Strength Are Required for Community-Dwelling Older People to Recover Balance From Induced Trips and Slips: An Experimental Prospective Study.

BACKGROUND AND PURPOSE: Falls can result in bone fractures and disability, presenting a serious threat to quality of life and independence in older adults. The majority of falls in community-living older adults occur while walking and are often caused by trips and slips. The study aimed to identify the specific sensorimotor and psychological factors required for older adults to recover balance from trips and slips. METHODS: Forty-one older adults aged 65 to 87 years were assessed on sensorimotor (knee extension strength, proprioception, postural sway, and edge contrast sensitivity), reaction (simple reaction time, stepping, and catching reaction inhibition), and psychological (general anxiety and concern about falling) measures. Using a harness system, participants walked at 90% of their usual pace on a 10-m walkway that could induce trips and slips in concealed and changeable locations. Post-perturbation responses resulting in more than 30% of body weight being recorded by the harness system were defined as falls. Poisson regressions were used to test associations between the sensorimotor, reaction, and psychological measures and number of falls. RESULTS: Fifty-one falls occurred in 25 of 41 participants. Poisson regression revealed body mass index, lower-limb proprioception, knee extension strength, rapid inhibition accuracy, concern about falling, and anxiety were significantly associated with the rate of falls. Other measures including postural sway were not statistically significant. Using stepwise Poisson regression analyses, normalized knee extension strength (rate ratio [RR]: 0.68, 95% confidence interval [CI]: 0.47-0.98), and rapid inhibition accuracy (RR: 0.64, 95% CI: 0.46-0.87) were independently associated with falls. CONCLUSION: Our findings suggest rapid inhibition accuracy and adequate leg strength are required for older adults to recover balance from trips and slips. The mechanisms for balance recovery during daily life activities are likely different from those for static balance, suggesting the need for task-specific assessments and interventions for fall prevention in older adults.

Effect of Reactive Balance Training Involving Repeated Slips and Trips on Balance Recovery Among Older Adults: A Blinded Randomized Controlled Trial.

BACKGROUND: This study examined whether reactive balance training (exposures to slips and trips) could improve balance recovery and reduce perturbation-induced falls among older adults. METHODS: Forty-four community-dwelling older adults participated in a parallel, blinded randomized controlled trial conducted in a research institute in Sydney, Australia in 2017-2018 (ACTRN12617000564358). The intervention group (n = 22) underwent three 40 minutes sessions (total 120 minutes) that exposed them to (1) 20 trips, (2) 20 slips, and (3) 10 trips and 10 slips in mixed order, over 2 days. The control group (n = 22) received one 40 minutes session of sham training. The primary outcome was falls (>30% body weight in harness) when exposed to trips and slips at post-assessment. RESULTS: At post-assessment, a total of 51 falls (23 and 27 falls from induced slips and trips, respectively) were recorded in the laboratory. Relative to the control group, the intervention group experienced fewer total falls (rate ratio [RR] = 0.40, 95% confidence interval [CI] = 0.22-0.76), slip falls (RR = 0.33, 95% CI = 0.12-0.90) and trip falls (RR = 0.49, 95% CI = 0.21-1.12). Eight participants reported adverse events (5 in the intervention group and 3 in the control group) which were related mainly to discomfort caused by a suboptimal harness used in the initial stages of the trial. CONCLUSIONS: The reactive balance training reduced perturbation-induced falls by 60% indicating improved balance recovery from trips and slips. A comfortable safety harness system is essential to prevent discomfort. Reactive balance training may complement traditional exercise programs in fall prevention interventions.

Catch the ruler: concurrent validity and test-retest reliability of the ReacStick measures of reaction time and inhibitory executive function in older people.

BACKGROUND: Reduced cognitive function, particularly executive function (EF), is associated with an increased risk of falling in older people. We evaluated the utility of the ReacStick test, a clinical test of reaction time, and inhibitory EF developed, for young athletes, for fall-risk assessment in older people. AIMS: To evaluate the psychometric properties of ReacStick measures of reaction time and executive functioning in healthy community-dwelling older people. METHODS: 140 participants (aged 77 ± 5 years) underwent testing. Two test conditions-simple and inhibitory go/no-go-provided measures of reaction time, recognition load (difference in reaction time between conditions), and go/no-go accuracy. Concurrent validity was evaluated against the conventional tests of reaction time and EF (simple hand reaction time, trail-making test, and Stroop colour test). Discriminant ability was determined for fall-risk factors (age, gender, physiological profile assessment, and fall history). Test-retest reliability after 1 week was evaluated in 30 participants. RESULTS: ReacStick reaction time correlated with tests of reaction time and EF, recognition load correlated with inhibitory EF, and go accuracy correlated with reaction time and inhibitory EF. No-go accuracy was not significantly correlated with any of the reaction time and EF tests. Test-retest reliability was good-to-excellent (ICC > 0.6) for all the outcomes. ReacStick reaction time discriminated between groups based on age, recognition load between genders, and no-go accuracy between retrospective fallers and non-fallers. DISCUSSION: An unavoidable time pressure may result in complementary information to the traditional measures. CONCLUSIONS: The ReacStick is a reliable test of reaction time and inhibitory EF in older people and could have value for fall-risk assessment.