Age-Related Changes of Postural Control: Effect of Cognitive Tasks

Background: Postural control and falls in the elderly constitute a major health problem. The interest in balance deficits is growing, as concern about the rising costs of health care increases. This issue is particularly relevant to the elderly population in which falls occur most frequently. Postural control in the elderly was studied using a cognitive approach. Objective: The purpose of this study was to study the characteristics of central processing of postural control while performing cognitive tasks. Methods: A dual-task procedure was developed to estimate the level of automaticity of a quiet upright standing task. The effect of a concurrent attention-demanding task (modified Stroop test) on the efficiency of balance control in the elderly was determined using force platform and electromyography measurements. Results: It was found that there is an increase in postural sway in old subjects compared with young subjects when performing single tasks and dual-task tests. The results of the study demonstrate that postural adjustments require cognitive processing; young and old subjects showed similar interference effects on postural steadiness (postural sway) caused by the concurrent attention-demanding task. The results are corroborated by the hypothesis that a dual task gives information on the restoration of automaticity of postural control in old age by a central reorganization process. When performing a dual task tested on a narrow base of support, the old subjects decreased their body sway, while the younger did not. According to electromyography measurements, the older subjects increased their muscle activity in the tibialis anterior and soleus muscles, using slow-twitch motor units compared with the younger subjects. Conclusions: Both alterations (cognitive and base of support) have a substantially greater effect on the elderly than on the young. The older subjects decreased their body sway by activating a cocontraction strategy of postural control around the ankle joint, probably because of the danger to their postural stability.

[1]  C. Wickens.  Attention and skilled performance. , 1989 .

[2]  M. Woollacott,et al.  Attentional demands and postural recovery: the effects of aging. , 1999, The journals of gerontology. Series A, Biological sciences and medical sciences.

[3]  A. Salmoni.  Motor skill learning. , 1989 .

[4]  B E Maki,et al.  Preferred placement of the feet during quiet stance: development of a standardized foot placement for balance testing. , 1997, Clinical biomechanics.

[5]  G. Andersson,et al.  A dual-task study of interference between mental activity and control of balance. , 1998, The American journal of otology.

[6]  A. Jensen,et al.  The Stroop color-word test: a review. , 1966, Acta psychologica.

[7]  Odmar Neumann,et al.  Automatic Processing: A Review of Recent Findings and a Plea for an Old Theory , 1984 .

[8]  M. Woollacott,et al.  The effects of two types of cognitive tasks on postural stability in older adults with and without a history of falls. , 1997, The journals of gerontology. Series A, Biological sciences and medical sciences.

[9]  A. Geurts,et al.  Dual-task assessment of reorganization of postural control in persons with lower limb amputation. , 1991, Archives of physical medicine and rehabilitation.

[10]  Timothy D. Lee,et al.  Motor Control and Learning: A Behavioral Emphasis , 1982 .

[11]  B. Schweitz,et al.  NEUROMUSCULAR RESPONSE TESTS AS PREDICTORS OF SENSORY‐MOTOR PERFORMANCE IN AGING INDIVIDUALS , 1968, American Journal of Physical Medicine.

[12]  Age and sex dependency of the Achilles tendon reflex , 1979, The American journal of the medical sciences.

[13]  J. Ridley.  Studies of Interference in Serial Verbal Reactions , 2001 .

[14]  A M Wing,et al.  Age differences in postural stability are increased by additional cognitive demands. , 1996, The journals of gerontology. Series B, Psychological sciences and social sciences.

[15]  J. Joseph,et al.  Central determinants of age-related declines in motor function. , 1988, Annals of the New York Academy of Sciences.

[16]  N Teasdale,et al.  On the cognitive penetrability of posture control. , 1993, Experimental aging research.

[17]  F. Horak,et al.  Central programming of postural movements: adaptation to altered support-surface configurations. , 1986, Journal of neurophysiology.