Objective: To assess the axonopathy and demyelination neuropathy according to the electrophysiologic severity in diabetic neuropathy.

Method: Electrophysiologic data of 246 patients who had been diagnosed with diabetic neuropathy was obtained and classified into suspected, possible, and definite groups by the criteria of our laboratory. Nerve conduction study was performed in the median, ulnar motor and sensory nerves, peroneal and tibial motor nerves, and sural nerve. Statistics were done with the results from the median motor and sensory, tibial motor and sural nerves. According to the severity of diabetic neuropathy, correlation and Chi-square analysis between amplitudes and latencies were performed.

Results: Frequencies of diabetic neuropathy according to

electrophysiologic severity were as follows: 24 cases of suspected, 141 cases of possible, and 81 cases of definite neuropathy. The correlation ratios between amplitude and latency were ⁣0.41∼⁣0.79 (p＜0.05) in the definite group of all the nerves examined, and below 0.3 in the suspected and possible groups. By Chi-square analysis, amplitude reduction was the predominant finding in the suspected and possible groups.

Conclusion: In the early stage of diabetic neuropathy, axonopathy might be the preceding pathogenesis, while with progression of diabetic neuropathy, axonopathy and demyelination may coexist. (J Korean Acad Rehab Med 2002; 26: 50-54)

Rett syndrome is a progressive encephalopathy in females that appears during the first 18 months of the life. A few neurophysiologic investigations of peripheral nerve and electrodiagnostic studies in Rett syndrome has proposed mild distal axonopathy. However, the electrodiagnostic study shows demyelination rather than axonopathy in presenting patient with Rett syndrome.

An 11-year-old female had normal birth history, no perinatal problems and normal development until age of 18 months. Developmental regression was recognized by her parent and slowly progressed. At physical examination at her age of 7 years, stereotypic hand movements was present and she could walk with frequent fall. Brain Computed Tomography was not specific and electrodiagnostic study revealed slow conduction velocity in all nerves tested. After follow-up for 4 years, hand wringling was remained and she became to be unable to walk alone. Electrodiagnostic study revealed as follows; 1) Compound muscle action potentials and sensory nerve action potentials in all the nerves tested revealed prolonged distal latency with normal amplitude. 2) F waves were evoked with prolonged latency in the all the nerves tested. 3) H-reflex were absent, bilaterally. 4) Facial motor conduction study and blink reflex showed normal findings. 5) Auditory evoked potential and visual evoked potential studies showed normal findings. These electrodiagnostic study indicates demyelinating neuropathy.