title: Peripheral and central conduction abnormalities in diabetes mellitus.
abstract: OBJECTIVE
  To investigate peripheral and central somatosensory conduction in patients with diabetes.
  
  
  METHODS
  The authors recorded sensory nerve action potentials and 5-channel somatosensory evoked potentials (SEPs) with noncephalic reference after median nerve stimulation in 55 patients with diabetes and 41 age- and height-matched normal subjects. The authors determined onset or peak latencies of the Erb's potential (N9) and the spinal N13-P13 and the cortical N20-P20 components, and obtained the central conduction time (CCT) by onset-to-onset and peak-to-peak measurements.
  
  
  RESULTS
  Both onset and peak latencies of all SEP components were prolonged in patients with diabetes. The mean onset CCT in the diabetic group was 6.3 +/- 0.5 msec (mean +/- SD)-significantly longer than that in the control group (6.1 +/- 0.2 msec)-whereas no significant difference was found in the peak CCT. The amplitudes of N9 and N13-P13 components (but not N20-P20) were significantly smaller in the diabetic group. The peripheral sensory conduction velocity was also decreased in the diabetic group, but there was no significant correlation between peripheral conduction slowing and the onset of CCT prolongation.
  
  
  CONCLUSIONS
  Diabetes affects conductive function in the central as well as peripheral somatosensory pathways. The CCT abnormality does not coincide with lowering of the peripheral sensory conduction. The current results do not favor a hypothesis that a central-peripheral distal axonopathy plays an important role in development of diabetic polyneuropathy.
authors.affiliation: Third Department of Medicine, Hirosaki University School of Medicine, Hirosaki, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Suzuki
authors.forename: I
authors.initials: I
authors.lastname: Ozaki
authors.forename: M
authors.initials: M
authors.lastname: Tanosaki
authors.forename: T
authors.initials: T
authors.lastname: Suda
authors.forename: M
authors.initials: M
authors.lastname: Baba
authors.forename: M
authors.initials: M
authors.lastname: Matsunaga
mesh_terms: D000328:Adult; D000344:Afferent Pathways / Q000503:physiopathology; D000368:Aged; D003922:Diabetes Mellitus, Type 1 / Q000175:diagnosis / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis* / Q000503:physiopathology; D003929:Diabetic Neuropathies / Q000175:diagnosis* / Q000503:physiopathology; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000503:physiopathology*; D008875:Middle Aged; D011930:Reaction Time / Q000502:physiology; D013003:Somatosensory Cortex / Q000502:physiology*; D013116:Spinal Cord / Q000503:physiopathology; D009435:Synaptic Transmission / Q000502:physiology*