Reto W. Kressig

Stops walking when talking: a predictor of falls in older adults?

The objective of this study was to systematically review all published articles examining the relationship between the occurrence of falls and changes in gait and attention‐demanding task performance whilst dual tasking amongst older adults. An English and French Medline and Cochrane library search ranging from 1997 to 2008 indexed under ‘accidental falls’, ‘aged OR aged, 80 and over’, ‘dual task’, ‘dual tasking’, ‘gait’, ‘walking’, ‘fall’ and ‘falling’ was performed. Of 121 selected studies, fifteen met the selection criteria and were included in the final analysis. The fall rate ranged from 11.1% to 50.0% in retrospective studies and from 21.3% to 42.3% in prospective ones. Amongst the three retrospective and eight prospective studies, two and six studies, respectively, showed a significant relationship between changes in gait performance under dual task and history of falls. The predictive value for falling was particularly efficient amongst frail older adults compared with healthy subjects. Two prospective studies challenged the usefulness of the dual‐task paradigm as a significant predictor compared to single task performance and three studies even reported that gait changes whilst dual tasking did not predict falls. The pooled odds ratio for falling was 5.3 (95% CI, 3.1–9.1) when subjects had changes in gait or attention‐demanding task performance whilst dual tasking. Despite conflicting early reports, changes in performance whilst dual tasking were significantly associated with an increased risk for falling amongst older adults and frail older adults in particular. Description of health status, standardization of test methodology, increase of sample size and longer follow‐up intervals will certainly improve the predictive value of dual‐task‐based fall risk assessment tests.

Guidelines for clinical applications of spatio-temporal gait analysis in older adults.

Quantifying spatio-temporal gait parameters in stationary and ambulatory geriatric settings may aid the early identification of potential fallers, as well as the documentation of illness-specific gait disorders and intervention-related changes in rehabilitative medicine. Bringing gait analysis out of the laboratory and into a clinical setting is the goal of the European GAITRite network group, initiated in 2003 in Geneva. To enhance reproducibility of gait measures and for better comparability of outcomes in clinical environments, a consensus on data collection was formulated and presented at the 2nd European GAITRite Meeting in Marseilles. The guidelines presented here are intended to facilitate network collaborations and to provide guidance to clinicians who wish to implement spatio-temporal gait analysis in clinical settings.

Vitamin D and cognitive performance in adults: a systematic review

Chronic low serum 25‐hydroxyvitamin D (25OHD) concentrations are common in adults and are associated with numerous non‐skeletal diseases. Vitamin D receptors (VDR) are located in the human cortex and hippocampus, which are key areas for cognition. The objective of this study was to systematically review all published data from the past 30 years which examined the association between serum 25OHD concentrations and cognitive performance in adults. An English and French Medline, PsycINFO® and Cochrane Library search ranging from 1979 to 2008 indexed under the Medical Subject Heading (MeSH) terms ‘Vitamin D’ or ‘Hydroxycholecalciferols’ combined with the terms ‘Dementia’ or ‘Cognition’ or ‘Cognition Disorders’ or ‘Delirium’ or ‘Memory’ or ‘Memory Disorders’ or ‘Orientation’ or ‘Executive Functions’ or ‘Attention’ or ‘Brain’ or ‘Neuropsychological Tests’ was performed. Of the 99 selected studies, five observational studies met the selection criteria and were included in the final analysis. No prospective cohort study was found. The number of participants ranged from 32 to 9556 community‐dwelling older adults (45–65% women). Three studies showed four significant positive associations between serum 25OHD concentrations and global cognitive functions, whereas three other studies exploring specific aspects of cognition showed 11 non‐significant associations. This systematic review shows that the association between serum 25OHD concentrations and cognitive performance is not yet clearly established. The inconclusive results of the reviewed studies could be due to methodology, types of the cognitive tasks used and/or the cellular mechanisms of vitamin D.

Stride-to-stride variability while backward counting among healthy young adults

BackgroundLittle information exists about the involvement of attention in the control of gait rhythmicity. Variability of both stride time and stride length is closely related to the control of the rhythmic stepping mechanism. We sought 1) to determine whether backward counting while walking could provoke significant gait changes in mean values and coefficients of variation of stride velocity, stride time and stride length among healthy young adults; and 2) to establish whether change in stride-to-stride variability could be related to dual-task related stride velocity change, attention, or both.MethodsMean values and coefficients of variation of stride velocity, stride time and stride length were recorded using the Physilog®-system, at a self-selected walking speed in 49 healthy young adults (mean age 24.1 ± 2.8 years, women 49%) while walking alone and walking with simultaneous backward counting. Performance on backward counting was evaluated by recording the number of figures counted while sitting alone and while walking.ResultsCompared with walking alone, a significant dual-task-related decrease was found for the mean values of stride velocity (p < 0.001), along with a small but significant increase for the mean values and coefficients of variation of stride time (p < 0.001 and p = 0.015, respectively). Stride length parameters did not change significantly between both walking conditions. Dual-task-related increase of coefficient of variation of stride time was explained by changing stride velocity and variability between subjects but not by backward counting. The number of figures counted while walking decreased significantly compared to backward counting alone. Further, the dual-task related decrease of the number of enumerated figures was significantly higher than the dual-task related decrease of stride velocity (p = 0.013).ConclusionThe observed performance-changes in gait and backward counting while dual tasking confirm that certain aspects of walking are attention-demanding in young adults. In the tested group of 49 young volunteers, dual tasking caused a small decrease in stride velocity and a slight increase in the stride-to-stride variability of stride time, while stride velocity variability was not affected by the attention-demanding task. The increase in stride time variability was apparently the result of a change in gait speed, but not a result of dual tasking. This suggests that young adults require minimal attention for the control of the rhythmic stepping mechanism while walking.

Effect of Music-Based Multitask Training on Gait, Balance, and Fall Risk in Elderly People: A Randomized Controlled Trial

BACKGROUND Falls occur mainly while walking or performing concurrent tasks. We determined whether a music-based multitask exercise program improves gait and balance and reduces fall risk in elderly individuals. METHODS We conducted a 12-month randomized controlled trial involving 134 community-dwelling individuals older than 65 years, who are at increased risk of falling. They were randomly assigned to an intervention group (n = 66) or a delayed intervention control group scheduled to start the program 6 months later (n = 68). The intervention was a 6-month multitask exercise program performed to the rhythm of piano music. Change in gait variability under dual-task condition from baseline to 6 months was the primary end point. Secondary outcomes included changes in balance, functional performances, and fall risk. RESULTS At 6 months, there was a reduction in stride length variability (adjusted mean difference, -1.4%; P < .002) under dual-task condition in the intervention group, compared with the delayed intervention control group. Balance and functional tests improved compared with the control group. There were fewer falls in the intervention group (incidence rate ratio, 0.46; 95% confidence interval, 0.27-0.79) and a lower risk of falling (relative risk, 0.61; 95% confidence interval, 0.39-0.96). Similar changes occurred in the delayed intervention control group during the second 6-month period with intervention. The benefit of the intervention on gait variability persisted 6 months later. CONCLUSION In community-dwelling older people at increased risk of falling, a 6-month music-based multitask exercise program improved gait under dual-task condition, improved balance, and reduced both the rate of falls and the risk of falling. Trial Registration clinicaltrials.gov Identifier: NCT01107288.

Comparison of Traditional and Recent Approaches in the Promotion of Balance and Strength in Older Adults

Demographic change in industrialized countries produced an increase in the proportion of elderly people in our society, resulting in specific healthcare challenges. One such challenge is how to effectively deal with the increased risk of sustaining a fall and fall-related injuries in old age. Deficits in postural control and muscle strength represent important intrinsic fall risk factors. Thus, adequate training regimens need to be designed and applied that have the potential to reduce the rate of falling in older adults by countering these factors. Therefore, the purpose of this review is to compare traditional and recent approaches in the promotion of balance and strength in older adults. Traditionally, balance and resistance training programmes proved to be effective in improving balance and strength, and in reducing the number of falls. Yet, it was argued that these training protocols are not specific enough to induce adaptations in neuromuscular capacities that are specifically needed in actual balance-threatening situations (e.g. abilities to recover balance and to produce force explosively). Recent studies indicated that perturbation-based or multitask balance training and power/high-velocity resistance training have the potential to improve these specific capacities because they comply with the principle of training specificity. In fact, there is evidence that these specifically tailored training programmes are more effective in improving balance recovery mechanisms and muscle power than traditional training protocols. A few pilot studies have even shown that these recently designed training protocols have an impact on the reduction of fall incidence rate in older adults. Further research is needed to confirm these results and to elucidate the underlying mechanisms responsible for the adaptive processes.

Motoric cognitive risk syndrome Multicountry prevalence and dementia risk

Objectives: Our objective is to report prevalence of motoric cognitive risk syndrome (MCR), a newly described predementia syndrome characterized by slow gait and cognitive complaints, in multiple countries, and its association with dementia risk. Methods: Pooled MCR prevalence analysis of individual data from 26,802 adults without dementia and disability aged 60 years and older from 22 cohorts from 17 countries. We also examined risk of incident cognitive impairment (Mini-Mental State Examination decline ≥4 points) and dementia associated with MCR in 4,812 individuals without dementia with baseline Mini-Mental State Examination scores ≥25 from 4 prospective cohort studies using Cox models adjusted for potential confounders. Results: At baseline, 2,808 of the 26,802 participants met MCR criteria. Pooled MCR prevalence was 9.7% (95% confidence interval [CI] 8.2%–11.2%). MCR prevalence was higher with older age but there were no sex differences. MCR predicted risk of developing incident cognitive impairment in the pooled sample (adjusted hazard ratio [aHR] 2.0, 95% CI 1.7–2.4); aHRs were 1.5 to 2.7 in the individual cohorts. MCR also predicted dementia in the pooled sample (aHR 1.9, 95% CI 1.5–2.3). The results persisted even after excluding participants with possible cognitive impairment, accounting for early dementia, and diagnostic overlap with other predementia syndromes. Conclusion: MCR is common in older adults, and is a strong and early risk factor for cognitive decline. This clinical approach can be easily applied to identify high-risk seniors in a wide variety of settings.

Age-related decline of gait control under a dual-task condition

High stride-to stride variability and the inability to walk and talk at the same time have been associated with an increased risk of falling (1;2). The aim of this study was to compare stride-to-stride variation in stride length and velocity beween community dwelling older and young adults under dual-task condition

Dual-task-related gait changes in transitionally frail older adults: the type of the walking-associated cognitive task matters.

Background: Changes in gait patterns due to a simultaneously performed cognitive task have been reported previously and associated with an increased falling risk among older adults. Little is known whether the type of cognitive task performed while walking is important concerning possible gait interference in older fall-prone individuals. Objective: To quantify and compare the effects of two different cognitive tasks on gait in transitionally frail older adults. Measurements: Gait was tested in 30 transitionally frail older adults (mean age 82.6 ± 7.1 years, 90% female) while either walking alone, performing a simple arithmetic task, or performing a task of verbal fluency. Walking time in seconds, number of steps, frequency of lateral line stepping-over, and stops were recorded. Health status was assessed using standard instruments of geriatric assessment. The classification of Speechley and Tinetti was used to define the participants’ degree of frailty. Results: Walking time and number of steps increased significantly under both dual-task conditions compared to walking alone (p < 0.001) without reaching a significant difference between the two dual-task conditions (respectively, p = 0.131 and p = 0.407), whereas lateral gait instability (frequency of lateral line stepping-over) increased significantly in association with counting backward (p = 0.006) but not with the verbal fluency task (p = 1). Conclusion: Among the studied sample of transitional older adults, a walking- associated arithmetic task significantly interfered with lateral gait stability, whereas no lateral gait deviations were seen in association with a verbal fluency task. We, therefore, suggest that the choice of the attention-splitting task in dual-task gait assessment among older adults must be made carefully.

Gait variability among healthy adults : low and high stride-to-stride variability are both a reflection of gait stability

Background: It has been suggested that high stride-to-stride variability (STV) is a reflection of gait instability. However, both low and high STV has been shown in fallers and in nonfallers; therefore, the interpretation of STV of spatiotemporal gait parameters remains difficult. Thus, we sought to characterize and compare STV of spatial and temporal stride parameters among young and older healthy adults, and to determine the extent to which opposite results in STV could provide similar implications in terms of gait stability. Methods: Mean values of coefficients of variation of spatiotemporal gait parameters were collected from 30 young adults (14 men and 16 women; mean age 28.1 ± 6.0 years) and 33 older adults (2 men and 31 women; mean age 74.4 ± 7.1 years) walking at self-chosen normal walking speed over a GAITRite® System. Results: An age-related increase in STV was only observed with stride width (p = 0.012), whereas increased stride length and stance time variability in older adults were related to decreased walking speed (p = 0.006 and p = 0.018). In addition, both low and high STV was found in both groups of subjects and the highest value was observed for stride width (p < 0.001). Conclusion: The two main implications of the present results are that decreased walking speed should be taken into account when exploring age-related effects on gait variability, and that both low and high spatiotemporal STV may reflect gait stability in healthy adults.