Effect of 12-week Oral Treatment with alpha-lipoic acid on the Nerve Conduction in Symptomatic Diabetic Neuropathy

Sohn, Tae Seo; Lee, Jung Min; Chang, Sang Ah; Son, Hyun Shik; Cha, Bong Youn; Son, Ho Young; Lee, Kwang Woo; Kang, Sung Ku

Abstract

BACKGROUND: Diabetic peripheral neuropathy is multifactorial disorder arising from hyperglycemia and insulin deficiency. It has been suggested that oxidative stress resulting from enhanced free-radical formation and defects in antioxidant defence plays a major role among the putative pathogenic mechanisms of diabetic neuropathy. As alpha-lipoic acid, a natural antioxidant, has been suggested to improve symptoms of diabetic neuropathy, we assessed the efficacy of alpha-lipoic acid on neuropathic symptoms and peripheral nerve conduction in patients with type 2 diabetes mellitus with symptomatic polyneuropathy.
METHODS
A cohort of 30 type 2 diabetic patients with symptomatic polyneuropathy received a daily dose of 600 mg alpha-lipoic acid, and was followed for 3 months. Neuropathic symptoms (pain, burning, paraesthesiae, and numbness) of the feet were scored at monthly interval and summarized as a Total Symptom Score (TSS). Nerve conduction study was done before and after 3 month treatment of alpha-lipoic acid.
RESULTS
Treatment of alpha-lipoic acid given 600 mg per oral for 12 weeks improved the symptoms of diabetic polyneuropathy. Effects of alpha-lipoic acid on nerve conduction study were that in the motor nerve, the amplitudes of median nerve and tibial nerve and the conduction velocity of tibial nerve improved after 12 weeks treatment. In the sensory nerve, the conduction velocities of median nerve, ulnar nerve, and sural nerve improved after 12 weeks.
CONCLUSION
alpha-Lipoic acid was effective in the treatment of diabetic peripheral polyneuropathy improving both clinical manifestations and nerve conduction. The improvement of clinical manifestations may be due to improved conduction velocity of sensory fibers.