title: Assessment of symptomatic diabetic patients with normal nerve conduction studies: utility of cutaneous silent periods and autonomic tests.
abstract: Established electrophysiological methods have limited clinical utility in the diagnosis of small-fiber neuropathy (SFN). In this study, diabetic patients with clinically diagnosed SFN were evaluated with autonomic tests and cutaneous silent periods (CSPs). Thirty-one diabetic patients with clinically suspected SFN and normal nerve conduction studies were compared with 30 controls. In the upper extremities (UE), the CSP parameters did not differ statistically between the patient and control groups, whereas, in the lower extremities (LE), patients had prolonged CSP latencies (P = 0.018) and shortened CSP durations (P < 0.001). The sensitivity of the CSP duration was 32.6%, and the specificity was 96.7%. The expiration-to-inspiration ratios and amplitudes of the sympathetic skin responses in the lower extremities were also reduced. Our findings indicate that the diagnostic utility of CSPs was higher than that of the autonomic tests to support the clinically suspected diagnosis of SFN.
authors.affiliation: Department of Neurology, Marmara University Hospital, Tophanelioglu Cad. 13/15, Istanbul, Turkey. pinarkahraman@yahoo.com
authors.forename: Pinar Kahraman
authors.initials: PK
authors.lastname: Koytak
authors.forename: Baris
authors.initials: B
authors.lastname: Isak
authors.forename: Deniz
authors.initials: D
authors.lastname: Borucu
authors.forename: Kayihan
authors.initials: K
authors.lastname: Uluc
authors.forename: Tulin
authors.initials: T
authors.lastname: Tanridag
authors.forename: Onder
authors.initials: O
authors.lastname: Us
mesh_terms: D000328:Adult; D003920:Diabetes Mellitus / Q000175:diagnosis / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000175:diagnosis* / Q000503:physiopathology*; D042241:Early Diagnosis; D004576:Electromyography / Q000379:methods; D005260:Female; D005712:Galvanic Skin Response / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D012867:Skin / Q000503:physiopathology*