Sural and radial sensory responses in healthy adults: Diagnostic implications for polyneuropathy

Authors

  • Gregory J. Esper MD,

    Corresponding author
    1. Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, TCC 810, Boston, Massachusetts 02215, USA
    • Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, TCC 810, Boston, Massachusetts 02215, USA
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  • Rachel A. Nardin MD,

    1. Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, TCC 810, Boston, Massachusetts 02215, USA
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  • Michael Benatar MB, ChB, DPhil,

    1. Department of Neurology, Emory University, Atlanta, Georgia, USA
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  • Tracy W. Sax MD,

    1. Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, TCC 810, Boston, Massachusetts 02215, USA
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  • Juan A. Acosta MD,

    1. Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, TCC 810, Boston, Massachusetts 02215, USA
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  • Elizabeth M. Raynor MD

    1. Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, TCC 810, Boston, Massachusetts 02215, USA
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Abstract

We prospectively performed sural and radial sensory nerve conduction studies in 92 healthy subjects, aged between 21 and 88 years, both to determine the lower limits of normal (LLN) and to assess the effects of age and body mass index (BMI) on the sural and radial sensory nerve action potential (SNAP) amplitudes and on the sural/radial amplitude ratio (SRAR). Using the nonparametric bootstrap method to calculate 95% confidence intervals, we found that the 5% LLN values for sural and radial SNAPs were 14 μV and 25.5 μV in subjects aged ≤39 years, 7 μV and 17.4 μV in subjects aged 40–59 years, and 3 μV and 12 μV in subjects aged ≥60 years. The 5% LLN for SRAR for all patients was 0.21. Sural and radial SNAP amplitudes but not SRAR were strongly and inversely correlated with age and BMI. These age-adjusted normal values and revised SRAR will aid in the electrodiagnosis of polyneuropathy. Muscle Nerve, 2005

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