Our long-term objective is to characterize the physiological processes that underlie involuntary muscle contractions, weakness and fatigability, major problems encountered in skeletal muscles paralyzed by injury or disease. In individuals with skeletal muscles paralyzed (not under voluntary control) by spinal cord injury, our Specific Aims are: 1) to quantify involuntary activity (spasms) from surface electromyographic signals (EMG) recorded from 8 leg, arm and hand muscles over 24 hours. EMG data from spinal cord injured people who take no medication to control spasms (non-users) will be compared to their activity log and to voluntary EMG recorded from able-bodied subjects. Whole muscle contractile properties will be measured to assess whether these involuntary contractions counter the effects of muscle disuse. Repeat experiments will be used to establish the validity of the 24-hr EMG recording technique;2) to evaluate whether single interventions (exercise, baclofen) and combined interventions (exercise and baclofen) alter the number, duration and intensity of spasms. 24-hr EMG recordings will be made in non-users and chronic baclofen users who stop this drug. Analysis of spasms before and after each intervention will show the acute extent (within 24 hrs) to which exercise (baclofen;exercise and baclofen) changes spasms in the same subject. Comparison of spasms across experiments involving different interventions will reveal the effectiveness of exercise versus baclofen or the combined intervention as a treatment to reduce involuntary muscle contractions;3) to examine whether exercise (baclofen, exercise and baclofen) alters muscle spasms by changing inhibitory processes, motoneuron excitability, and/or muscle responses. Quantifying spasms during natural unconstrained behaviors over an entire day will improve our understanding of muscle spasms, the most debilitating aspect of the spasticity that is so prevalent after spinal cord injury and other neuromuscular disorders. These studies will also determine the effectiveness of therapies used to control involuntary muscle activity after spinal cord injury. If muscle spasms prevent deterioration, the widespread use of medication should be re-evaluated.

Public Health Relevance

. Muscle spasms often interfere with care and mobility after spinal cord injury. Documenting muscle activity over 24 hours in relation to the activity log of the person with spinal cord injury will show what features of these contractions disrupt daily activities. Analysis of whether exercise and/or anti-spasm medication reduces involuntary contractions will clarify whether the treatments currently used to control unwanted muscle contractions need revision.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS030226-15
Application #
7876637
Study Section
Musculoskeletal Rehabilitation Sciences Study Section (MRS)
Program Officer
Kleitman, Naomi
Project Start
1994-01-01
Project End
2012-06-30
Budget Start
2010-07-01
Budget End
2012-06-30
Support Year
15
Fiscal Year
2010
Total Cost
$301,681
Indirect Cost
Name
University of Miami School of Medicine
Department
Neurosurgery
Type
Schools of Medicine
DUNS #
052780918
City
Coral Gables
State
FL
Country
United States
Zip Code
33146
Winslow, Jeffrey; Martinez, Adriana; Thomas, Christine K (2015) Automatic identification and classification of muscle spasms in long-term EMG recordings. IEEE J Biomed Health Inform 19:464-70
Thomas, C K; Dididze, M; Martinez, A et al. (2014) Identification and classification of involuntary leg muscle contractions in electromyographic records from individuals with spinal cord injury. J Electromyogr Kinesiol 24:747-54
Mummidisetty, Chaithanya K; Bohórquez, Jorge; Thomas, Christine K (2012) Automatic analysis of EMG during clonus. J Neurosci Methods 204:35-43
Wallace, Douglas M; Ross, Bruce H; Thomas, Christine K (2012) Characteristics of lower extremity clonus after human cervical spinal cord injury. J Neurotrauma 29:915-24
Zijdewind, Inge; Thomas, Christine K (2012) Firing patterns of spontaneously active motor units in spinal cord-injured subjects. J Physiol 590:1683-97
Klein, Cliff S; Peterson, Lillian B; Ferrell, Sean et al. (2010) Sensitivity of 24-h EMG duration and intensity in the human vastus lateralis muscle to threshold changes. J Appl Physiol 108:655-61
Thomas, Christine K; Hager-Ross, Charlotte K; Klein, Cliff S (2010) Effects of baclofen on motor units paralysed by chronic cervical spinal cord injury. Brain 133:117-25
Winslow, Jeffrey; Dididze, Marine; Thomas, Christine K (2009) Automatic classification of motor unit potentials in surface EMG recorded from thenar muscles paralyzed by spinal cord injury. J Neurosci Methods 185:165-77
Klein, C S; Hager-Ross, C K; Thomas, C K (2006) Fatigue properties of human thenar motor units paralysed by chronic spinal cord injury. J Physiol 573:161-71
Thomas, C K; Johansson, R S; Bigland-Ritchie, B (2006) EMG changes in human thenar motor units with force potentiation and fatigue. J Neurophysiol 95:1518-26

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