title: Four-year sequential nerve conduction changes since first visit in Japanese patients with early type 2 diabetes.
abstract: OBJECTIVE
  Despite being the most common complication of diabetes, the pattern of clinical development of diabetic neuropathy is not well-known. In the present study, we retrospectively examined sequential changes in nerve conduction studies (NCS) for 4 years to characterize the way neuropathic changes develop in patients with type 2 diabetes.
  
  
  METHODS
  We randomly selected 158 patients with type 2 diabetes who newly visited Naka Memorial Clinic, Ibaraki, Japan, and underwent serial 4-year NCS. Records of clinical profile, signs and symptoms of neuropathy, and NCS data from median and tibial nerves were extracted to determine the progression of neuropathy. NCS data were represented by motor nerve conduction velocities, amplitudes of compound muscle action potentials (CMAPs) and minimal latencies of F-wave.
  
  
  RESULTS
  The prevalence of clinical neuropathy in 158 cases was 30% at baseline and 29% at the end of the study, with improvement of glycated hemoglobin (8.6-6.9%). Over 4 years, there were no changes of the signs and symptoms of neuropathy. Motor nerve conduction velocities were slightly improved or consistent at the fourth year compared with those at the beginning (+1.5% in median nerve, P < 0.05; +0.8%, not significant in the tibial nerve). The extent of the glycated hemoglobin correction correlated with the improvement of motor nerve conduction velocity. In contrast, CMAPs of both median and tibial nerves were decreased (-11.6%, P < 0.01; -3.7%, P < 0.05, respectively). For the decrease in CMAPs, no specific risk factors were identified by logistic regression analysis.
  
  
  CONCLUSIONS
  The present study showed progressive decline of CMAPs despite improved glycemic controls or the lack of NCV slowing in patients with early type 2 diabetes.
authors.affiliation: Kensei-kai Naka Memorial Clinic, Naka-city, Ibaraki, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Kobori
authors.affiliation: Kensei-kai Naka Memorial Clinic, Naka-city, Ibaraki, Japan.|Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
authors.forename: Soroku
authors.initials: S
authors.lastname: Yagihashi
authors.affiliation: Kensei-kai Naka Memorial Clinic, Naka-city, Ibaraki, Japan.
authors.forename: Norie
authors.initials: N
authors.lastname: Shiina
authors.affiliation: Kensei-kai Naka Memorial Clinic, Naka-city, Ibaraki, Japan.
authors.forename: Nana
authors.initials: N
authors.lastname: Shiozawa
authors.affiliation: Kensei-kai Naka Memorial Clinic, Naka-city, Ibaraki, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Haginoya
authors.affiliation: Kensei-kai Naka Memorial Clinic, Naka-city, Ibaraki, Japan.
authors.forename: Misato
authors.initials: M
authors.lastname: Ojima
authors.affiliation: Kensei-kai Naka Memorial Clinic, Naka-city, Ibaraki, Japan.
authors.forename: Satako
authors.initials: S
authors.lastname: Douguchi
authors.affiliation: Kensei-kai Naka Memorial Clinic, Naka-city, Ibaraki, Japan.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Tamasawa
authors.affiliation: Kensei-kai Naka Memorial Clinic, Naka-city, Ibaraki, Japan.
authors.forename: Miyoko
authors.initials: M
authors.lastname: Saitou
authors.affiliation: Department of Neurology, Aomori Prefectural Central Hospital, Aomori, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Baba
authors.affiliation: Kensei-kai Naka Memorial Clinic, Naka-city, Ibaraki, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Osonoi
mesh_terms: D044466:Asian People; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology*; D003928:Diabetic Nephropathies / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008475:Median Nerve / Q000503:physiopathology; D009431:Neural Conduction; D012189:Retrospective Studies; D013979:Tibial Nerve / Q000503:physiopathology
keywords: Diabetic neuropathy; Natural history; Nerve conduction