Sural nerve myelinated fiber density differences associated with meaningful changes in clinical and electrophysiologic measurements

James W. Russell, Jeannine L. Karnes, Peter J Dyck

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

New forms of therapy for diabetic and other neuropathies may prevent, stabilize, or ameliorate loss of nerve fibers. Clinically meaningful changes in mean Neurological Disability Score (NPS), and the associated mean change of electrophysiologic attributes have been described in diabetic polyneuropathy. It is unknown what magnitude of myelinated fiber (MF) density change is associated with these meaningful changes of clinical and electrophysiologic alterations. In 18 diabetics and 5 normal controls associations between the mean NDS, summated (ulnar, peroneal and tibial) compound muscle action potential (ΣCMAP)), summated (ulnar and sural) sensory nerve action potential (ΣSNAP), sural SNAP, and MF density in the sural nerve, were assessed using linear regression analyses. Values were corrected for age and sex. For a decrease of: 2 points in the mean NDS (minimum clinically detectable change), MF density decreased by approximately 200 fibers/mm2(p < 0.001) 1 mV in the mean ΣCMAP (sum of the ulnar, peroneal and tibial CMAP amplitudes), MF density decreased by 160 fibers/mm2 (p < 0.01) 1 μV in the mean ΣSNAP (sum of ulnar and sural SNAP amplitudes), MF density decreased by approximately 70 fibers/mm2 (p < 0.001) 1 μV in the mean sural SNAP, MF density decreased by approximately 150 fibers/mm2 (p < 0.01). Changes in sensory detection thresholds were also associated with a measurable change in the MF density. A quantifiable association exists between the magnitude of change in density of MF, and a meaningful alteration in mean NDS and various electrophysiologic parameters. Knowledge of this is needed to assess the statistical power of a clinical trial in which density of myelinated fibers is an outcome measurement.

Original languageEnglish (US)
Pages (from-to)114-117
Number of pages4
JournalJournal of the Neurological Sciences
Volume135
Issue number2
DOIs
StatePublished - Feb 1996

Fingerprint

Sural Nerve
Nerve Fibers
Action Potentials
Diabetic Neuropathies
Muscles
Sensory Thresholds
Linear Models
Regression Analysis
Clinical Trials

Keywords

  • CMAP
  • Diabetic neuropathy
  • Myelinated fiber density
  • Neurological disability
  • Sensory detection thresholds
  • SNAP

ASJC Scopus subject areas

  • Aging
  • Clinical Neurology
  • Surgery
  • Developmental Neuroscience
  • Neurology
  • Neuroscience(all)

Cite this

Sural nerve myelinated fiber density differences associated with meaningful changes in clinical and electrophysiologic measurements. / Russell, James W.; Karnes, Jeannine L.; Dyck, Peter J.

In: Journal of the Neurological Sciences, Vol. 135, No. 2, 02.1996, p. 114-117.

Research output: Contribution to journalArticle

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