Objective: To determine the validity and reliability of the total neuropathy score (TNS) in normal subjects and in subjects with diabetic polyneuropathy.
Background: Clinical research in peripheral neuropathy requires validated outcome measures. Multiple outcome measures have been used in clinical trials, including symptom measures, functional scales, quantitative clinical examinations, nerve conduction studies, computerized sensory examinations, and nerve biopsy. Each of these measures has its strengths and weaknesses. In two previous studies of toxic neuropathy from chemotherapeutic agents, the authors used the TNS as the outcome measure. The TNS combines information obtained from grading of symptoms, signs, nerve conduction studies, and quantitative sensory tests, and provides a single measure to quantify neuropathy.
Methods: The authors measured the inter- and intrarater reliability of the TNS and preformed a cross-sectional validation study of the TNS and its subscales with the Mayo Clinic measures of neuropathy, neuropathy symptom score (NSS), and the neurologic impairment score (NIS) in five healthy control subjects and 30 individuals with varying severities of diabetic polyneuropathy.
Results: Inter- and intrarater reliability of the TNS was excellent (0.966 and 0.986 respectively). The cross-sectional validation study showed excellent correlations among all measures of neuropathy.
Conclusions: The total neuropathy score is a validated measure of peripheral nerve function and could be used as an end point for clinical trials of peripheral neuropathy.