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


METHODS
Thirteen 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.


RESULTS
Dual 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.


CONCLUSIONS
The 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.
Center for Human Movement Sciences, University Medical Centre Groningen, University of Groningen, the Netherlands. c.j.c.lamoth@med.umcg.nl
Claudine J
CJ
Lamoth
Floor J
FJ
van Deudekom
Jos P
JP
van Campen
Bregje A
BA
Appels
Oscar J
OJ
de Vries
Mirjam
M
Pijnappels
D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D003072:Cognition Disorders / Q000503:physiopathology* / Q000523:psychology; D003627:Data Interpretation, Statistical; D003704:Dementia / Q000503:physiopathology / Q000523:psychology; D019277:Entropy; D005260:Female; D016330:Frail Elderly; D005684:Gait / Q000502:physiology*; D020233:Gait Disorders, Neurologic / Q000503:physiopathology* / Q000523:psychology; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000502:physiology; D016138:Walking / Q000502:physiology
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