Véronique Dubost

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.

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.

Gait analysis in demented subjects: Interests and perspectives

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 specific 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 specific marker of falling at a pre-dementia stage.

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.

Walking speed-related changes in stride time variability: effects of decreased speed

BackgroundConflicting results have been reported regarding the relationship between stride time variability (STV) and walking speed. While some studies failed to establish any relationship, others reported either a linear or a non-linear relationship. We therefore sought to determine the extent to which decrease in self-selected walking speed influenced STV among healthy young adults.MethodsThe mean value, the standard deviation and the coefficient of variation of stride time, as well as the mean value of stride velocity were recorded while steady-state walking using the GAITRite® system in 29 healthy young adults who walked consecutively at 88%, 79%, 71%, 64%, 58%, 53%, 46% and 39% of their preferred walking speed.ResultsThe decrease in stride velocity increased significantly mean values, SD and CoV of stride time (p < 0.001), whereas the repetition of trials (p = 0.534, p = 0.177 and p = 0.691 respectively for mean, SD, CoV); and step asymmetry (p = 0.971, p = 0.150 and p = 0.288 for mean, SD and CoV) had no significant effect. Additionally, the subjects effect was significant for all stride parameters (p < 0.001). The relationship between a decrease in walking speed and all stride parameters (i.e., mean values, SD and CoV of stride time) was significantly quadratic and showed higher STV at a slow speed (p < 0.001).ConclusionThe results support the assumption that gait variability increases while walking speed decreases and, thus, gait might be more unstable when healthy subjects walk slower compared with their preferred walking speed. Furthermore, these results highlight that a decrease in walking speed can be a potential confounder while evaluating STV.

Impact of impaired executive function on gait stability

Background: Executive dysfunction contributes to gait changes, but the precise mechanisms are still poorly understood. Dual-task-related gait changes depend in part on the capacity to appropriately allocate attention between tasks performed simultaneously and are mainly related to executive deficits. This study aimed to describe the impact of dysexecutive function on gait stability in subjects with dementia using dual tasking. Methods: Mean values and coefficients of variation of stride time while only walking and while walking and backward counting (dual tasking) were measured using the GAITRite® System in 18 subjects with dementia and impaired executive function (IEF), in 16 subjects with dementia and intact executive function, and in 22 nondemented subjects as controls. Results: Stride time, and particularly its variability, significantly increased while performing dual tasking (p < 0.05). IEF was related to both stride time and stride time variability during walking only and to even more gait changes, while dual tasking compared to nondemented subjects and demented subjects without IEF. Conclusions: These findings confirm the role of executive function in dual tasking, but also strongly suggest their importance for gait stability.

Relationship between dual-task related gait changes and intrinsic risk factors for falls among transitional frail older adults

Background and aims: Gait changes in dual-task conditions have been associated with an increased risk of falling in older adults, and become more important in increasingly frail older adults. We studied the relationship between commonly known intrinsic risk factors for falls and dual-task related gait changes among transitional frail older adults. Methods: Walking time and number of steps were measured while walking alone and while walking with counting backward on a 10-m walkway in 66 transitional frail older adults (mean age 83.6±6.1, 84.9% women). Uni- and multiple linear regression analyses were performed to explore the relationship between dual-task related gait changes (walking time and number of steps) and age over 85 years, polymedication, psychoactive drugs, poor distance vision, abnormal mobility and cognitive impairment. Results: Compared with walking alone, both walking time and number of steps increased significantly while counting backward (p<0.001). Polymedication and abnormal mobility were associated with a significant increase of walking time and number of steps (p<0.01 for unadjusted change, p<0.05 for adjusted change). Conclusions: Dual-task related gait changes were closely correlated with polymedication and impaired mobility in our sample of transitional frail older adults. These findings give some insight into the complexity of performing attention-demanding tasks while walking and accentuate the need for multi-factorial, personalized intervention strategies, to prevent decline in dual-task performance in this fall-prone population.

Does Change in Gait while Counting Backward Predict the Occurrence of a First Fall in Older Adults

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.

Analysis of postural control in elderly subjects suffering from Psychomotor Disadaptation Syndrome (PDS)

PDS is a geriatric affliction, described in 1999, characterized by postural impairments, including backward disequilibrium, freezing, a deterioration in the ability to anticipate postural adjustments, anxiety and fear of falling, inducing loss of autonomy. This study compared 10 subjects suffering from PDS, aged 87.3+/-4.9 years, with 10 control subjects, aged 85.4+/-7.9 years concerning postural control (body sway amplitude). In all participants, postural control was assessed using the SwayStar system in natural (spontaneous) and standardized stances, eyes open and eyes closed over a period of 40 s. It was found that: (1) with eyes open, subjects with PDS showed greater body sway amplitude than did controls whatever the position (natural or standardized) and the plane (sagittal or frontal) considered (F(1,16)=6.05; p=0.026), (2) with eyes closed, subjects with PDS showed greater body sway amplitude than did controls in the natural stance whatever the plane (F(1,18)=7.65; p=0.013). In conclusion, PDS has a negative effect on postural control. This data must be taken into account during the rehabilitation of patients with this syndrome.

Médicaments et chute de la personne âgée

The use of curative support for the treatment of the pressure sores, simple to handle, compatible with ambulatory care, is a goal important to reach to reduce the durations of hospitalization and to support the maintenance in residence. We led an exploratory study with an alternate pressure air support. 14 patients carrying 22 pressure sores of stage 2 or more (7 had several pressure sores), of average age 68 years, analyzed in 4 hospital sites (2 of physical therapy, 2 of geriatrics), were followed according to 3 methods: healing, improvement, aggravation or appearance. The surface, depth and speed of healing, were systematically measured. In parallel, thanks to a scale of Likert on 4 levels, comfort was described by the patient thanks to 7 items (felt comfort, pain, maceration, facility of reversal, passage in sitting position, noise, impact on the sleep). According to same methodology, the conditions of use of the mattress were analyzed by 7 items (facilitated of operation, installation with the daily newspaper, technical facility of use, maintainability, facilitated for the care, safety, solidity and reliability). 13 pressure sores out of 22 evolved to the healing with an average reduction of similar surface of 4,2 cm 2 according to localizations. The average duration of healing was longer on the level of the heel than on the level of the sacrum (33 versus 18 days) and according to the initial stage (stage 3: 45 days versus 25 days for stage 2). 9 pressure sores out of 12 evolved/moved in the direction of the improvement (they were more severe forms). No pressure sores worsened. The mean velocity of healing was 0,21 cm2/day. On 79 evaluations of comfort made by the patients, the majority brought back very satisfactory appreciations. The most appreciated elements were the effect on the pain, the noise level and felt comfort. In parallel, the personnel considered to be very satisfactory the items quality of the support, facility of cleaning and facility of use at the time of the care. This prospective clinical trial multicentric, even among patients carrying pressure sores of stage 2 or more and high-risk, showed the clinical effectiveness, comfort, the handiness of mattress Barmat 2 Modena ® which is a support with alternated low air pressure likely to be used for continuous ambulatory care.