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Neurophysiological changes following traumatic spinal lesions in man.
Journal of Neurology, Neurosurgery, and Psychiatry
|October 1, 1984
Summary
Spinal cord injuries alter motor units below the lesion site. Neurophysiological studies reveal increased reflex pathway excitability and altered responses in spastic patients, suggesting changes in motoneurons and interneurons.
Area of Science:
- Neurophysiology
- Neurology
- Spinal Cord Injury Research
Background:
- Spinal cord injuries (SCIs) can lead to significant neurophysiological alterations below the lesion level.
- Understanding changes in motor unit function and reflex pathways is crucial for managing SCI-related spasticity.
Purpose of the Study:
- To investigate neurophysiological changes in motor units and reflex pathways in patients with spinal cord injuries.
- To characterize alterations in the H reflex and M response in relation to clinical spasticity.
Main Methods:
- Neurophysiological recordings of muscle compound action potential (M response) and H reflex from triceps surae.
- Supramaximal stimulation of the tibial nerve and tapping of the Achilles tendon.
- Assessment of H reflex modulation by vibration and conditioning stimuli in normal subjects and SCI patients.
Main Results:
- Reduced M response amplitude in SCI patients indicates changes in motor units below the spinal lesion.
- Increased H reflex activation in spastic patients suggests heightened excitability of central reflex pathways.
- Altered H reflex responses to vibration and conditioning stimuli point to modified transmission in reflex pathways.
Conclusions:
- Spinal cord injuries induce neurophysiological changes in motor units and reflex pathways distal to the lesion.
- Clinical spasticity is associated with increased central reflex pathway excitability and altered interneuronal function.
- Findings suggest potential modifications in motoneuron and interneuron excitability following spinal cord injury.