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.

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Gait disorders are more prevalent in dementia than in normal aging and are related to the severity of cognitive decline. Dementia-related gait changes (DRGC) mainly include decrease in walking speed provoked by a decrease in stride length and an increase in support phase. More recently, dual-task related changes in gait were found in Alzheimer's disease (AD) and non-Alzheimer dementia, even at an early stage. An increase in stride-to-stride variability while usual walking and dual-tasking has been shown to be more specifi c and sensitive than any change in mean value in subjects with dementia. Those data show that DRGC are not only associated to motor disorders but also to problem with central processing of information and highlight that dysfunction of temporal and frontal lobe may in part explain gait impairment among demented subjects. Gait assessment, and more particularly dual-task analysis, is therefore crucial in early diagnosis of dementia and/or related syndromes in the elderly. Moreover, dual-task disturbances could be a specifi c marker of falling at a pre-dementia stage.

Slower walking speed while counting backward was associated with recurrent falls, suggesting that changes in gait performance while dual tasking might be an inexpensive way of identifying frail older adults prone to falling.

Background: Dual-task-based assessment tests failed to establish a dependable relationship between dual-task-related gait changes and the risk of falls in the elderly. Objective: The aim of this study was to examine whether changes in gait while counting backward could be associated with the occurrence of a first fall among older adults. Methods: Walking while counting backward was investigated prospectively in a cohort of 187 older adults living independently in senior housing facilities. During enrollment, walking time, number of steps, and frequency of lateral line stepping-over and stops were measured while walking only and while walking with backward counting aloud. Information on the incident falls during the follow-up year was collected monthly. Results: Walking time and the number of steps increased significantly under the dual-task condition compared to the single-task condition among fallers and non-fallers (p < 0.001). Compared to non-fallers, fallers had significantly lower scores in the Mini-Mental State Examination (p = 0.029) and higher scores in the 15-item Geriatric Depression Scale (p = 0.003) and Timed Up & Go Test (p = 0.006) and increased walking time under both walking conditions (p = 0.030 for single-task condition and p = 0.007 for dual-task condition). After adjusting for these variables, depressive symptoms (adjusted OR = 2.6 with p = 0.041 and adjusted OR = 2.5 with p = 0.045 when walking time while walking only and walking with backward counting is considered, respectively) and walking time while walking only (OR = 2.3 with p = 0.032) were significantly associated with falls. Conclusion: Dual-task-related gait changes were poorly associated with the occurrence of a first fall and provided no additional predictive value compared to gait performance under a single task, suggesting that changes in basic clinical gait parameters while counting backward are unsuccessful to predict the first fall among older adults.