Electrophysiological evaluation of upper motor neron diseases

Symptoms and findings such as segmental muscular atrophy, atypical recovery pattern of motor function and delaying onset of spasticity can be considered as peripheral nervous system pathology in patient with hemiplegia. But it was demonstrated in previous studies that, denervation potentials, such as positive sharp waves and fibrillations; are not distributed in segmentary or radicular order in hemiplegic patients. We evaluated 17 left, 2 right, a total of 19 hemiplegic patients (mean age: 55.2±9.6 year) at least four weeks after the cerebrovascular accident. Motor and sensory nerve conduction studies and F-responses, concentric needle electromyography, median sensory evoked potential (SEP) studies were performed at normal and paretic upper extremities and results were compared with each other. Spontaneous denervation potentials were demonstrated at distal muscles of 11 (57,9%), proximal muscles of 6 (31,6%); a total of 12 (63,2%) of hemiplegic patients. Except compound muscle action potential amplitude of distal ulnar motor nerve stimulation, no differences were found between motor and sensory nerve conduction studies. Ulnar F responses could not be recorded in three hemiplegic side. During median SEP analysis N9, N12, and N13 potentials were recorded in all patients, but cortical SEP potential were absent in four patients. We concluded that denervation potential's that can be seen at hemiplegic patients are not associated with lower motor neuron diseases. These electrophysiological findings may be due to deterioration of regulatory function of central nervous system or trans-synaptic degeneration.