Muscle activation patterns in point-to-point and reversal movements in healthy, older subjects and in subjects with Parkinson's disease

K. D. Pfann*, J. A. Robichaud, G. L. Gottlieb, C. L. Comella, M. Brandabur, D. M. Corcos

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

When young, healthy subjects perform rapid point-to-point and reversal movements over a range of distances, the patterns of muscle activation associated with accelerating the limb toward the target are modulated in the same way for both movement tasks. Differences in patterns of muscle activation for these two movement types are not observed until the deceleration phase of the movements. In this study, we first test the hypothesis that healthy, older subjects and subjects with Parkinson's disease will modulate the pattern of muscle activation in the same way during the acceleration phase of point-to-point and reversal elbow movements. Second, we test the hypothesis that healthy, older subjects and subjects with Parkinson's disease exhibit the same relationship in muscle activation patterns between the two movement types that have been observed for the young in the deceleration phase of the movements. Subjects performed point-to-point and reversal movements initiated in the direction of flexion over three distances (36, 54 and 72 degrees) "as fast as possible". Angle, velocity, acceleration and surface EMGs from biceps and triceps were recorded. With respect to the first hypothesis, the EMG, kinetic, and kinematic measures related to the acceleration phase of the movements were modulated in the same way for both movement types in the healthy older subjects. In the Parkinson's disease group, the kinematic and kinetic measures during the acceleration phase of the movements were the same in both movement types; however, the flexor and extensor EMG activation was smaller during reversal movements than during point-to-point movements. With respect to the second hypothesis, in contrast to that found in young subjects, in healthy older subjects, there was no significant difference between the movement types in the flexor EMG activity immediately after the time of peak velocity. This difference between younger and older subjects may be attributed to the fact that older subjects perform both movement types more slowly than do younger subjects. Although subjects with Parkinson's disease also move slowly, the flexor EMG shuts off more abruptly and more completely just after the time of peak velocity during reversal movements than during point-to-point movements. These results show that (1) for healthy subjects, when the task requirements are the same for the two movement types (acceleration phase), muscle activation patterns are modulated in the same way, and (2) both age and disease alter the relationship of muscle activation, kinetics and kinematics between point-to-point and reversal movements.

Original languageEnglish (US)
Pages (from-to)67-78
Number of pages12
JournalExperimental Brain Research
Volume157
Issue number1
DOIs
StatePublished - Jul 2004

Funding

Acknowledgements This study was supported, in part, by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (RO1-AR 33189), the National Institute of Neurological and Communicative Disorders and Stroke (RO1-NS 28127 and RO1-NS 40902), and by the National Institute on Disability and Rehabilitation Research (H133P000005). We would like to thank Steve Cranstoun for developing our systems for data acquisition and data analysis and Charity Moore for her continued help with our statistical analyses. We would also like to thank Vanessa Portra for help in editing the manuscript and Serge Roy for his support.

Keywords

  • EMG
  • Motor control
  • PD
  • Upper limb
  • Voluntary movement

ASJC Scopus subject areas

  • General Neuroscience

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