Impact of age and obstacle negotiation on timing measures of gait initiation

The separate and combined impacts of age and walkway obstruction on reaction time, anticipatory postural adjustment phases of gait initiation and cognitive dual task performance are not well understood. This study aimed to a) examine the impact of age and task complexity on reaction and anticipatory postural adjustment phases separately b) examine the impact of age and walkway obstruction on cognitive task performance while walking.

Nineteen older adults (mean age± SD: 66.73 ± 3.38 years) and twelve younger adults (mean age± SD: 26.5 ± 4.37 years), participated in this study. The tests were performed in four conditions: a smooth walkway; a smooth walkway with concurrent cognitive task; an obstructed walkway; and an obstructed walkway with a concurrent cognitive task. Reaction and anticipatory postural adjustment phases were measured from the recorded center of pressure trajectory data.

Reaction time phase was significantly longer in the older group (P = 0.04), but there was no significant impact of task complexity (P = 0.95). Conversely, there was a significant impact of task complexity on anticipatory postural adjustment phase (P = 0.04), but there was no significant difference between the age groups (P = 0.38). Cognitive task response time was not significantly different between age groups or with walkway obstruction (P = 0.19 and P = 0.90 respectively).There were no significant interactions between age group and task complexity.

Reaction time phase but not anticipatory postural adjustment phase was longer in healthy older than younger adults. Anticipatory postural adjustment phase but not reaction time phase was slower for more complex gait initiation tasks. Cognitive task performance was similar across age groups and conditions.