Cutaneous silent period changes in Type 2 diabetes mellitus patients with small fiber neuropathy

• Published in: Clinical neurophysiology 2010-05, Vol.121 (5), p.714-718
• Main Authors: Onal, M.R, Ulas, U.H, Oz, O, Bek, V.S, Yucel, M, Taslıpınar, A, Odabası, Z
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Cranial nerves. Spinal roots. Peripheral nerves. Autonomic nervous system. Gustation. Olfaction; Cutaneous silent period; Diabetes mellitus; Diabetes Mellitus, Type 2; Diabetic Neuropathies - diagnosis; Diabetic Neuropathies - pathology; Diabetic Neuropathies - physiopathology; Electrodiagnosis. Electric activity recording; Female; Humans; Investigative techniques, diagnostic techniques (general aspects); Leg - innervation; Male; Medical sciences; Nerve Fibers - pathology; Nervous system; Nervous system (semeiology, syndromes); Neural Conduction; Neural Inhibition; Neuralgia - physiopathology; Neurology; Peripheral Nerves - physiopathology; Reaction Time; Reflex; Refractory Period, Electrophysiological; Skin - innervation; Small fiber neuropathy; Spinal Cord - physiopathology
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2009.12.024

Abstract Objective Small myelinated (A-δ) and unmyelinated (C) somatic sensory fibers are initially affected and may be the earliest exhibited sign of neuropathy in glucose dysmetabolism. Cutaneous silent period (CSP) is an inhibitory spinal reflex and its afferents consist of A-δ nerve fibers. The aim of this study was to evaluate CSP changes in Type 2 diabetic patients with small fiber neuropathy. Methods Forty-three patients and 41 healthy volunteers were included. CSP latency and duration, as well as CSP latency difference of the upper and lower extremities, were examined. Results Nerve conduction studies were within normal limits in both groups. Lower extremity CSP latency was longer (122.1 ± 15.5 vs. 96.4 ± 6.4 ms; p < 0.001), CSP duration was shorter (29.5 ± 8.9 vs. 43.1 ± 5.0 ms; p < 0.001), and latency difference was longer (48.1 ± 12.6 vs. 22.7 ± 3.7; p < 0.001) in patients than controls. The difference was more significant in patients with neuropathic pain. No significant difference existed in upper extremity on CSP evaluation. Conclusion The CSP evaluation together with nerve conduction study, has been demonstrated to be beneficial and performance of latency difference in addition to CSP latency and duration may be a valuable parameter in electrophysiological assessment of diabetic patients with small fiber neuropathy. Significance An additional CSP evaluation may be considered in cases which nerve conduction studies do not provide sufficient information.