Reduced Cognitive-Motor Interference on Voluntary Balance Control in Older Tai Chi Practitioners
September 20, 2015 -
Recent dual-task studies
suggest that Tai Chi practitioners displayed better control of standing posture
and maintained a quicker response time of postural muscle activation during a
stepping down activity. Whether this effect extends to voluntary balance
control, specifically the limits of excursion of the center of pressure, remains
to be examined.
A new study by University of Illinois at Chicago
evaluated the cognitive-motor interference pattern by examining the effects of a
concurrently performed cognitive task on attention of voluntary balance control
in older adults who are long-term practitioners of Tai Chi.
Ten older Tai Chi practitioners and 10 age-matched
non-practitioners performed a voluntary balance task that required them to shift
their weight to reach a preset target in the forward and backward directions,
with (single task, ST) and without (dual task, DT) a secondary cognitive task,
which was the counting backward task. The counting backward task required the
individual to compute and verbalize a series of arithmetic differences between a
given pair of randomly generated numbers. The cognitive task was also performed
All trials were performed in a
random order. Balance outcomes included reaction time, movement velocity, and
maximal excursion of the center of pressure provided by the NeuroCom system.
Cognitive outcome was the number of correct responses generated within the
8-second trial during the ST and DT conditions. Outcome variables were analyzed
using a 2-factor, group by task, analysis of variance. DT costs for the
variables were calculated as the relative difference between ST and DT
conditions and were compared between the 2 groups using independent t tests.
Tai Chi practitioners displayed shorter reaction times
and faster movement velocities of their center of pressure than older
non-practitioners for both directions; however, no difference was found between
the maximal excursions of the 2 groups. Cost analyses revealed that reaction
time and cognitive costs were significantly lower in the Tai Chi practitioners
for both forward and backward directions; however, similar findings for movement
velocity costs were significant only in the backward direction.
The results suggest that Tai Chi practitioners expended
fewer motor and cognitive resources than older non-practitioners during a fairly
complex (dynamic) postural equilibrium task while performing a verbal working
memory task. They exhibited lesser cognitive-motor interference and thus better
allocation of attentional resources toward the voluntary balance control task.
Given that dynamic balance is a
crucial prerequisite for walking and dual-tasking ability is considered to be a
significant predictor of falls in older adults, the results might point at the
possible long-term benefits of Tai Chi practice to counteract age-related
decline in dual-tasking ability. Findings present preliminary data for further
investigation, especially related to potential benefits in fall prevention.
The findings are published in the
August 2015 issue of Journal of geriatric