Subclinical Diabetic Neuropathy with Normal Conventional Nerve Conduction Study

J Korean Neurol Assoc > Volume 24(6); 2006 > Article

Journal of the Korean Neurological Association 2006;24(6): 557-563.

정상 신경전도검사 소견을 보이는 무증상성 당뇨신경병증

배종석, 나성규 고석민 김성훈a 김병준b

서울의료원 신경과, 강원대학교 의과대학 신경과학교실a, 성균관대학교 의과대학 신경과학교실

Subclinical Diabetic Neuropathy with Normal Conventional Nerve Conduction Study

Jong Seok Bae

Department of Neurology Seoul Medical Center, Seoul; Department of Neurology, Kangwon National University College of Medicinea, Chunchon; Department of Neurology Sungkyunkwan University School of Medicineb, Seoul, Korea

Abstract

Background: For the early detection and prevention of diabetic neuropathy, it is important to identify subclinical diabetic neuropathies. A routine nerve conduction study often fails to detect the early stages of neuropathy. The purpose of this study is to evaluate the clinical usefulness of electrophysiological indexes including the residual latency(RL), terminal latency index (TLI) and modified F ratio (MFR) in detecting early diabetic neuropathy with no objective clinical or electrophysiological abnormalities.
Methods: A nerve conduction study of the upper/lower limbs was investigated in 38 subclinical diabetic neuropathy patients with normal nerve conduction studies (group I), 35 clinical diabetic neuropathy patients with normal nerve conduction studies (group II) and 31 normal controls. RL, TLI and MFR were calculated and compared among the groups.
Results: Compared with the control group, the MFR of the lower limbs and TLI of both the upper/lower limbs were significantly decreased in both group I and II (p<0.05). RL was increased in both groups, but the difference was not statistically significant. Comparing the indexes between group I and II, there was no significant difference.
Conclusions: RL, TLI and MFR are useful indexes for reflecting distal conduction slowing especially in slowly progressing polyneuropathies such as diabetic neuropathy. The results also suggest that electrophysiological changes veiled in a routine nerve conduction study were present before the clinical manifestations.KeyWords:Diabetic neuropathy, Terminal latency index, Residual latency, Modified F ratio