Gait stability and variability measures show effects of impaired cognition and dual tasking in frail people

Abstract

BackgroundFalls in frail elderly are a common problem with a rising incidence. Gait and postural instability are major risk factors for falling, particularly in geriatric patients. As walking requires attention, cognitive impairments are likely to contribute to an increased fall risk. An objective quantification of gait and balance ability is required to identify persons with a high tendency to fall. Recent studies have shown that stride variability is increased in elderly and under dual task condition and might be more sensitive to detect fall risk than walking speed. In the present study we complemented stride related measures with measures that quantify trunk movement patterns as indicators of dynamic balance ability during walking. The aim of the study was to quantify the effect of impaired cognition and dual tasking on gait variability and stability in geriatric patients.MethodsThirteen elderly with dementia (mean age: 82.6 ± 4.3 years) and thirteen without dementia (79.4 ± 5.55) recruited from a geriatric day clinic, walked at self-selected speed with and without performing a verbal dual task. The Mini Mental State Examination and the Seven Minute Screen were administered. Trunk accelerations were measured with an accelerometer. In addition to walking speed, mean, and variability of stride times, gait stability was quantified using stochastic dynamical measures, namely regularity (sample entropy, long range correlations) and local stability exponents of trunk accelerations.ResultsDual tasking significantly (p < 0.05) decreased walking speed, while stride time variability increased, and stability and regularity of lateral trunk accelerations decreased. Cognitively impaired elderly showed significantly (p < 0.05) more changes in gait variability than cognitive intact elderly. Differences in dynamic parameters between groups were more discerned under dual task conditions.ConclusionsThe observed trunk adaptations were a consistent instability factor. These results support the concept that changes in cognitive functions contribute to changes in the variability and stability of the gait pattern. Walking under dual task conditions and quantifying gait using dynamical parameters can improve detecting walking disorders and might help to identify those elderly who are able to adapt walking ability and those who are not and thus are at greater risk for falling.

Comparação dos parâmetros espaçotemporais da marcha durante a execução do TUG associado à dupla tarefa em adultos jovens

“…Levantar hipóteses sobre o porquê das diferenças entre a execução da marcha isolada e da agregada a uma tarefa cognitiva nos remete a demais estudos nos quais é mostrado que esta associação acarreta alterações no desenvolvimento das atividades 5,7,12 . Em seus contextos, as explicações propostas nesses trabalhos se baseiam na degradação da função relativa à divisão da atenção entre as tarefas a serem executadas e ao potencial limitado de atuação da função executiva 22 .…”

“…A deambulação, assim como a manutenção do equilíbrio durante este processo, são atividades que demandam um complexo planejamento, monitoramento e coordenação adequada de uma se quência de padrões de ativação muscular, alinhamentos articulares e controle dos graus de liberdade do movimento pelo sistema nervoso central [1][2][3][4][5] . Associar à marcha tarefas cognitivas, como falar com outra pessoa, fazer cálculos ou escrever pequenas mensagens, podem alterar o controle postural e provocar declínio funcional em ambas as atividades devido à necessidade de dividir a atenção entre coordenação postural e execução da função cognitiva 6,7 .…”

Wireless slips and falls prediction system

“…The wireless sensor is light weight, compact, and low power so that it can be comfortably worn all day on the patient's hip while it acquires accelerometer and gyroscope data that will be used to assess patient stability via Lyapunov approaches [4][5][6][7][8][9]. The largest Lyapunov exponents (LLEs) can indicate system stability.…”

Hilbert Transform and Gait Analysis: A New Method to Evaluate Gait Variability

“…Many studies tested gait variability under different conditions, such as different walk speeds or age groups [3], [4], or to evaluate the impacts of impairments [5], [6], [7], [8], injuries or diseases in human gait [9], [10].…”