Control of compensatory stepping reactions: Age-related impairment and the potential for remedial intervention

Abstract

Stepping is a prevalent and functional reaction to loss of balance, yet this element of postural control has only recently begun to receive due attention. It is likely that the impaired ability to execute compensatory stepping reactions is an important contributor to the unsteadiness, loss of balance confidence, and risk of falling that is associated with aging and age-related pathology. Even healthy, active older adults appear to experience difficulty in controlling stepping reactions, as evidenced by a tendency to require multiple steps to recover equilibrium. There seems to be a particular problem in controlling lateral stability. When stepping in response to forward or backward loss of balance, older adults often experience difficulty in countering the tendency of the body to fall laterally during the step. When stepping in response to lateral loss of balance, they often have problems controlling movement of the swing foot so as to avoid collision with the stance limb. The problems in controlling lateral stability may be particularly relevant given the prevalence of lateral falls in older adults and the links to risk of hip fracture. With regard to mechanisms, early findings implicate age-related loss of cutaneous sensation from the plantar surface of the foot as an important contributing factor. Loss of strength may also play a role. Neural lesions, due to stroke or Parkinson' s disease, can result in profound difficulties in controlling the reactions. It is expected that studies of compensatory stepping will lead to development of new and improved diagnostic and therapeutic approaches for detecting and treating specific causes of imbalance and falling. Potential areas for remedial intervention include sensory aids, footwear, strength training, and balance training. Such interventions, if proven effective, may have a significant impact on the ability of clinicians to help older adults maintain as active and independent a lifestyle as possible, without undue fear or risk of falling.