Stephanie A. Bridenbaugh

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.

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.

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.

Laboratory review: the role of gait analysis in seniors' mobility and fall prevention

Walking is a complex motor task generally performed automatically by healthy adults. Yet, by the elderly, walking is often no longer performed automatically. Older adults require more attention for motor control while walking than younger adults. Falls, often with serious consequences, can be the result. Gait impairments are one of the biggest risk factors for falls. Several studies have identified changes in certain gait parameters as independent predictors of fall risk. Such gait changes are often too discrete to be detected by clinical observation alone. At the Basel Mobility Center, we employ the GAITRite electronic walkway system for spatial-temporal gait analysis. Although we have a large range of indications for gait analyses and several areas of clinical research, our focus is on the association between gait and cognition. Gait analysis with walking as a single-task condition alone is often insufficient to reveal underlying gait disorders present during normal, everyday activities. We use a dual-task paradigm, walking while simultaneously performing a second cognitive task, to assess the effects of divided attention on motor performance and gait control. Objective quantification of such clinically relevant gait changes is necessary to determine fall risk. Early detection of gait disorders and fall risk permits early intervention and, in the best-case scenario, fall prevention. We and others have shown that rhythmic movement training such as Jaques-Dalcroze eurhythmics, tai chi and social dancing can improve gait regularity and automaticity, thus increasing gait safety and reducing fall risk.

Imagined Timed Up & Go test: a new tool to assess higher-level gait and balance disorders in older adults?

BACKGROUND Few studies have explored motor imagery (MI) as a way of accessing the higher-level of control of complex body movements involved in gait or balance. The objective of this study was 1) to measure and compare the time needed to complete the Timed Up & Go test (TUG), the time needed to imagine performing the same test (iTUG) and to calculate the time difference between both of these conditions (delta time) in a sample of young and older adults, and 2) to examine whether there was an association between the Timed Up & Go test results (TUG, iTUG, delta time), age and cognitive decline. METHODS A total of 162 subjects (38 healthy young adults, mean age 25.7+/-2.3 years, 73.7% women and 124 older inpatients, mean age 85.3+/-6.5 years, 76.6% women) were included in this cross-sectional study. The mean+/-SD of TUG, iTUG and delta time, age and the Mini Mental State Examination (MMSE) score were used as main outcomes. RESULTS Age was associated with an increase in time of TUG (P<0.001) and of delta time (P=0.015), and with a decrease in time of iTUG (P<0.001), whereas cognitive decline was only associated with increase in delta time (P=0.030). There was an increase in time of TUG (P<0.001) and in delta time (P<0.001) for subjects who used a walking aid. The increase in delta time depended on the MMSE score when the subjects did not use a walking aid (P for trend=0.001). CONCLUSIONS iTUG is clinically feasible among frail older adults and may quickly inform any clinician about higher-level changes in control of gait and balance in older adults.

Age-Related Effects on Postural Control under Multi-Task Conditions

Background: Changes in postural sway and gait patterns due to simultaneously performed cognitive (CI) and/or motor interference (MI) tasks have previously been reported and are associated with an increased risk of falling in older adults. Objective: The objectives of this study were to investigate the effects of a CI and/or MI task on static and dynamic postural control in young and elderly subjects, and to find out whether there is an association between measures of static and dynamic postural control while concurrently performing the CI and/or MI task. Methods: A total of 36 healthy young (n = 18; age: 22.3 ± 3.0 years; BMI: 21.0 ± 1.6 kg/m2) and elderly adults (n = 18; age: 73.5 ± 5.5 years; BMI: 24.2 ± 2.9 kg/m2) participated in this study. Static postural control was measured during bipedal stance, and dynamic postural control was obtained while walking on an instrumented walkway. Results: Irrespective of the task condition, i.e. single-task or multiple tasks, elderly participants showed larger center-of-pressure displacements and greater stride-to-stride variability than younger participants. Associations between measures of static and dynamic postural control were found only under the single-task condition in the elderly. Conclusion: Age-related deficits in the postural control system seem to be primarily responsible for the observed results. The weak correlations detected between static and dynamic measures could indicate that fall-risk assessment should incorporate dynamic measures under multi-task conditions, and that skills like erect standing and walking are independent of each other and may have to be trained complementarily.

Simultaneously Measuring Gait and Cognitive Performance in Cognitively Healthy and Cognitively Impaired Older Adults: The Basel Motor-Cognition Dual-Task Paradigm

OBJECTIVES: To investigate dual‐task performance of gait and cognition in cognitively healthy and cognitively impaired older adults using a motor–cognition dual‐task paradigm.

Effects of muscle fatigue on gait characteristics under single and dual-task conditions in young and older adults

BackgroundMuscle fatigue and dual-task walking (e.g., concurrent performance of a cognitive interference (CI) while walking) represent major fall risk factors in young and older adults. Thus, the objectives of this study were to examine the effects of muscle fatigue on gait characteristics under single and dual-task conditions in young and older adults and to determine the impact of muscle fatigue on dual-task costs while walking.MethodsThirty-two young (24.3 ± 1.4 yrs, n = 16) and old (71.9 ± 5.5 yrs, n = 16) healthy active adults participated in this study. Fatigue of the knee extensors/flexors was induced by isokinetic contractions. Subjects were tested pre and post fatigue, as well as after a 5 min rest. Tests included the assessment of gait velocity, stride length, and stride length variability during single (walking), and dual (CI+walking) task walking on an instrumented walkway. Dual-task costs while walking were additionally computed.ResultsFatigue resulted in significant decreases in single-task gait velocity and stride length in young adults, and in significant increases in dual-task gait velocity and stride length in older adults. Further, muscle fatigue did not affect dual-task costs during walking in young and older adults. Performance in the CI-task was improved in both age groups post-fatigue.ConclusionsStrategic and/or physiologic rationale may account for the observed differences in young and older adults. In terms of strategic rationale, older adults may walk faster with longer strides in order to overcome the feeling of fatigue-induced physical discomfort as quickly as possible. Alternatively, older adults may have learned how to compensate for age-related and/or fatigue-induced muscle deficits during walking by increasing muscle power of synergistic muscle groups (e.g., hip flexors). Further, a practice and/or learning effect may have occurred from pre to post testing. Physiologic rationale may comprise motor unit remodeling in old age resulting in larger proportions of type I fibres and thus higher fatigue-resistance and/or increased muscle spindle sensitivity following fatigue leading to improved forward propulsion of the body. These findings are preliminary and have to be confirmed by future studies.

Balance Training and Multi-Task Performance in Seniors

Age-related impairment in gait patterns when simultaneously performing cognitive (CI) and/or motor (MI) interference tasks are associated with an increased risk of falling in seniors. The objective of this study was to investigate the impact of balance training (BT) on walking performance with and without concurrently performing a CI and/or MI task in seniors. Twenty healthy women (n=14) and men (n=6) were assigned to either an intervention (n=11, age 71.9+/-4.8 yrs) or a control group (n=9, age 74.9+/-6.3 yrs). The intervention group conducted a six week BT (3/week). Pre and post tests included the assessment of stride-to-stride variability during single (walking), dual (CI or MI+walking), and triple (CI+MI+walking) task walking on an instrumented walkway. BT resulted in statistically significant reductions in stride time variability under single (p=0.02, Delta34.8%) but not dual or triple-task walking. Significant improvements in the MI task (p=0.05, Delta39.1%), but not in the CI task were found while walking. Findings showed that improved performance during single-task walking did not transfer to walking under dual or triple-task conditions suggesting multi-task BT as an alternative training modality. Improvement of the secondary motor but not cognitive task may indicate the need for the involvement of motor and particularly cognitive tasks during BT.

Vitamin D deficiency-related quadriceps weakness: results of the EPIdémiologie de l'OStéoporose cohort.

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