[Influence of a specific cognitive task on spatial-temporal walking parameters in elderly frail individuals].
OBJECTIVE
Walking is a complex voluntary rhythmic motor behaviour. Its implicit nature suggests that reduced attention resources are required for its execution. The aim of this study was to demonstrate that, to perform a mental calculation while walking, might modify the spatial-temporal parameters of walking in fragile elderly patients.


METHODS
We compared the walking, in a straight line over a distance of 10 meters, of 30 fragile elderly subjects (mean age 82.6 +/- 7.1 years) with that of 30 healthy controls (mean age 37.5 +/- 11.5 years). Two walking conditions were studied: with and without a counting task. The time, number of steps, lateral deviations and stops were recorded on a video camera.


RESULTS
The condition of a double-task provoked three types of effects on walking: an increase in time and the number of steps in both groups, but significantly greater in the elderly patients than in the control group of patients (6.4 s and 4.6 steps in the elderly versus 0.5 s and 0.4 steps in the controls); a reduction in the cadence and length of the step, only significant in the elderly patients, and a significant increase in the number of lateral deviations and stops in the double-task condition in the elderly patients.


CONCLUSIONS
Globally, these results indicate that walking requires more attention resources in the elderly than in the middle-aged. The loss of the implicit character of walking to the benefit of cognitive attention resources may partly explain the high risk of falling in fragile elderly subjects.
Beauchet
O
O
Département de gériatrie, Hôpitaux universitaires de Genève, ch. du Pont-Bochet, 3, route de Mon Idée, 1226 Genève-Thônex, Suisse. Olivier.Beauchet@hcuge.ch
Dubost
V
V
Stierlam
F
F
Blanchon
M A
MA
Mourey
F
F
Pfitzenmeyer
P
P
Gonthier
R
R
Kressig
R W
RW
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003071:Cognition; D005260:Female; D016330:Frail Elderly; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D013647:Task Performance and Analysis; D013997:Time Factors