PROJECT SUMMARY The majority of older adult patients who seek physical therapy have pain. Physical rehabilitation for many painful orthopedic and neurologic conditions often involves the use of motor learning strategies, in which new movement patterns are taught using repeated trial-and-error practice. However, preliminary data from our lab suggests that pain may negatively affect the retention of newly learned motor patterns. If correct, this would suggest that the presence of pain may limit rehabilitation outcomes sought through motor learning-based interventions. To date, the effects of acute or chronic pain on motor learning have not been thoroughly investigated in clinical populations. Further, it is not known how pain affects motor learning in older adults specifically, despite the fact that cognitive declines, which are well-documented in the elderly, could also negatively affect learning and motor memory. Broadly, the purpose of this research is to investigate the impact of both acute and chronic pain on locomotor learning and its retention in young and older adults as well as older adults with chronic low back pain. Our central hypothesis is that both acute and chronic pain impair retention of locomotor learning and that in older adults, these deficits are worsened and are related to the degree of cognitive decline. We will investigate this hypothesis with three aims: (1) using our experimental pain paradigm, to compare effects of acute pain on retention of locomotor learning in healthy young and healthy older adults; (2) to determine whether older adults with chronic low back pain have impaired retention of locomotor learning; and (3) to assess relationships between chronic pain, cognition, and motor learning retention capacity in older adults. Motor learning and its retention will be assessed using our novel visually- driven locomotor learning paradigm. Several aspects of cognition will be quantified with a cognitive battery, with special focus on attention and working memory. Finally, pain will be quantified with assessments of intensity, interference and sensitivity. Results from this work will provide much needed data concerning the relationship between pain and motor learning in older adult clinical populations. Given that many rehabilitation interventions utilize motor learning-based strategies to recover normal movement patterns, gaining this new knowledge is likely to fundamentally improve delivery of rehabilitation in multiple patient populations that experience pain.