ATTENTION DEMANDS IN BALANCE RECOVERY FOLLOWING LOWER-LIMB AMPUTATION

The attention demands in balance control after damage to the periphera l sensorimotor system were studied in 12 persons with a recent lower l imb amputation. The interference of an arithmetic task with two postur al tasks of different complexity (quiet standing and active weight shi fting) was examined several times during their rehabilitation while th e subjects stood on a force platform. Control data were obtained from healthy subjects. For both postural tasks, persons with amputation per formed worse than controls. Quiet standing, a relatively simple task. revealed clear dual-task interference only in the amputation group. Ev idence was found for a reduction in dual-task interference as rehabili tation progressed. In contrast, voluntary (feedback-controlled) weight shifting, a more complex task, revealed an equal amount of dual-task interference in persons with amputation and in controls, without chang es in interference over the period of rehabilitation. The results indi cate that attentional mechanisms may be involved in postural control, depending on both the novelty and complexity of the task. Moreover, a reduction in attention demands of quiet standing may reflect a central adaptation of the postural organization to the peripheral sensorimoto r impairments caused by lower limb amputation.