Walking in high-risk settings: Do older adults still prioritize gait when distracted by a cognitive task?

Abstract

When a cognitive and a motor task like walking or keeping one's balance are performed concurrently, performance usually deteriorates. Older adults have often been shown to prioritize their motor performance in such dual-task situations, possibly to protect themselves from falls. The current study investigates whether these prioritization behaviors can still be observed when several challenges are combined. Younger (20-30 years old) and older adults (60-70 years old; n = 24 in each group) were asked to walk through virtual environments with and without a cognitive load (3-back task). Walking difficulty was increased by walking on an elevated surface or on a narrow as opposed to a broad track, or both. Walking instructions emphasized speed and accuracy (avoiding missteps). No instruction was given concerning which performance dimension should be prioritized during dual-task trials. Participants decreased their 3-back performance while walking. Younger adults maintained their walking speed on elevated surfaces and were able to keep the number of missteps low, even when walking on a narrow track while performing the cognitive task. Older adults increased their walking speed on elevated relative to even surfaces and committed more missteps under cognitive load. Results suggest that task prioritization might fail in healthy older adults if several challenges are combined in high-risk settings.

Effects of Physical-Cognitive Dual Task Training on Executive Function and Gait Performance in Older Adults: A Randomized Controlled Trial

“…Based on the postulate that the attentional system has a limited pool of resources [2], it is expected that the concomitant performance of different tasks competing for the same resources could be worse with respect to the independent performance of each task. Significant decrements in gait and/or cognitive performance are observed in older adults when cognitive tasks are performed while walking [3, 4]. Such performance decrements are referred to as DT interference and commonly evaluated as the difference between the single and DT performance in relation to the first (DT cost).…”

Neurological Gait Abnormalities Moderate the Functional Brain Signature of the Posture First Hypothesis

“…Findings with respect to the posture first hypothesis, however, have been mixed (Gerin-Lajoie et al 2005; Lindenberger et al 2000). It is noteworthy that failure to demonstrate this preference (Schaefer et al 2015) may be attributed to limitations of available cognitive resources in older adults (Holtzer et al 2011). Furthermore, in neurological conditions, such as Parkinson’s disease, patients are reported to use the posture second strategy where cognitive tasks are prioritized over walking, leading to an increase in falls risk (Bloem et al 2006).…”

Attentional costs of walking are not affected by variations in lateral balance demands in young and older adults

“…Table 1) for other tasks. Recent studies reported slower self-selected walking speeds in visuolocomotor situations (e.g., walking on a narrow path [26] or a sequence of stepping stones [27]) compared to unconstrained walking, for young and older adults alike. This was interpreted as an adaptive strategy to favor task performance relative to the visual context [26,27].…”

“…Recent studies reported slower self-selected walking speeds in visuolocomotor situations (e.g., walking on a narrow path [26] or a sequence of stepping stones [27]) compared to unconstrained walking, for young and older adults alike. This was interpreted as an adaptive strategy to favor task performance relative to the visual context [26,27]. Given our current results, it thus seems likely that older adults slowed down their preferred walking speed to increase the available time for visuolocomotor control [28,29].…”

“…Participants had no self-reported cardiovascular or cardiopulmonar problems, orthopedic conditions, uncorrected visual or auditory impairments, neurological disease, or other conditions limiting mobility; they did not use walking aids and the Mini Mental State Exam score for the older participants exceeded 23 (range [24][25][26][27][28][29][30]. All participants provided written informed consent before participation.…”