The neurophysiological examination provides valuable pathophysiological information for the diagnosis, prognosis, and therapy of patients with polyneuropathy (Fuglsang- Fredriksen A., Pugdahl K. Clin Neurophysilogy 122:440–455, 2011). Nerve conduction study (NCS) is the most objective and reliable measure of peripheral nerve function and is considered the gold standard for the diagnosis of most neuropathies.
Aim of the study
To evaluate the clinical usefulness of nerve conduction study (NCS) in the differentiation between axonal and demyelinating polyneuropathies.
In the present study, 125 patients with polyneuropathy were studied ranging age from 9 to 79 years. Thirty-six patients were classified as axonal polyneuropathy, 23 patients as demyelinating, and 9 as mixed, while 57 patients were classified as neuropathic. Nerve conduction study (NCS) and electromyography (EMG) were performed using Nihon Kochden electromyography machine with surface recording and stimulating electrodes.
There is statistically significant linear correlation between reduction in sensory nerve action potential (SNAP) amplitude and decrease in sensory conduction velocity (SCV) of median and ulnar nerves. Also, there is statistically significant inverse correlation between reduction in compound motor action potential (CMAP) amplitude and increase in distal motor latency (DML). There is statistically significant linear correlation between reduction in compound motor action potential (CMAP) amplitude and decrease in motor conduction velocity (MCV). There is statistically significant linear correlation between reduction in compound motor action potential (CMAP) amplitude and decreased grade of power in both axonal and demyelinating polyneuropathy; statistically significant linear correlation was found between decrease in conduction velocity and decrease in grade of power.
The present study demonstrates significant correlation between amplitude reduction and conduction slowing in demyelinating as well as axonal polyneuropathy.