Reliability + validity of the CMT neuropathy score as a measure of disability

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Neurology. 2005 Apr 12;64(7):1209-14.

Reliability and validity of the CMT neuropathy score as a measure of

disability.

Shy ME, Blake J, Krajewski K, Fuerst DR, M, Hahn AF, Li J,

RA, Reilly M.

Department of Neurology, Wayne State University, Detroit, MI 48201,

USA.

OBJECTIVE: To determine the validity and reliability of the Charcot-

Marie-Tooth disease (CMT) neuropathy score (CMTNS) in patients with

inherited neuropathy.

BACKGROUND: Natural history studies and potential treatment trials

for patients with various forms of CMT are limited by the lack of

quantitative methodologies to monitor disease progression. Most cases

of CMT can be considered length-dependent axonal neuropathies because

disability for even the demyelinating forms correlates with length-

dependent axonal degeneration. The total neuropathy score (TNS) is a

validated composite measure of disability in length-dependent axonal

neuropathies but is weighted toward predominantly sensory

neuropathies. Thus, the authors have devised a CMTNS, modified from

the TNS, to provide a single measure to quantify CMT disability.

METHODS: The authors measured inter- and intrainvestigator

reliability of the CMTNS and performed a validation of the score with

the Neuropathy Impairment Score (NIS), patient self-assessment

scores, an ambulation index, and other measures of disability.

RESULTS: Inter- and intrainvestigator reliability was more than 95%

in the 60 patients evaluated. Patients could be divided into mild

(CMTNS, < or =10), moderate (CMTNS, 11 to 20), and severe (CMTNS, >

or =21) categories and demonstrated excellent correlations among all

measures of disability.

CONCLUSION: The Charcot-Marie-Tooth disease (CMT) neuropathy score is

a validated measure of length-dependent axonal and demyelinating CMT

disability and can be investigated as an end point for longitudinal

studies and clinical trials of CMT.