The present project focuses on age-related degradation in coordination of movements at multiple joints of the limbs. Studying these deficits is of considerable importance, because movements performed in everyday life (reaching, grasping, pointing, lifting, etc) are essentially multijoint and decreases in coordination is one of the most debilitating aspects of motor performance in the elderly. Our studies of control of multijoint movements in young adults suggest a general direction of research that would investigate reasons for age-related deficits in joint coordination. Namely, recent findings indicate that the biomechanical structure of multijoint limbs imposes constraints on coordination patterns among the joints. The biomechanical constraints are represented by interactive (motion-dependent) torques at the joints. Young subjects are able to overcome the biomechanical constraints and regulate influence of interactive torques with the muscle torques at normal speed movements. However, interactive torques become too influential at high movement speed. Inability of subjects to cope with high amplitudes of these torques and adjust to their fast changes results in movement discoordination. Due to deficits in force control, processing of afferent information, and other age-related deficits in motor performance, we predict that elderly adults have a decreased ability to regulate interactive torques and this is the primary reason for discoordination of multijoint movements in this age group. The present project is designed as a pilot study. Its purpose is to investigate (1) if elderly adults demonstrate inability to regulate interactive torques at tower speed levels than young adults, (2) whether elderly adults are more deficient in movements that require more complicated interactive torque regulation, and (3) if absence of visual information laffects regulation of interactive torques in elderly adults more than in young adults. The obtained data will create a basis for a more detailed and comprehensive research of age-related degradation Iof multijoint movements and mechanisms underlying this degradation.
| Lee, Gyusung; Fradet, Laetitia; Ketcham, Caroline J et al. (2007) Efficient control of arm movements in advanced age. Exp Brain Res 177:78-94 |
| Ketcham, Caroline J; Dounskaia, Natalia V; Stelmach, George E (2004) Age-related differences in the control of multijoint movements. Motor Control 8:422-36 |
