Assessment scales for the diagnosis of polyneuropathy.

Epidemiological studies that investigate the occurrence and determinants of chronic length-dependent polyneuropathy are scarce. Population-based studies on polyneuropathy require a valid and reliable screening protocol with both good sensitivity and specificity. Several questionnaires and scoring scales have been developed for the detection of polyneuropathy, grading the severity of the disease, or evaluating the clinical course during follow-up. This review summarizes the aims and content of existing diagnostic polyneuropathy screening tools in order to help future studies decide which scale to use for screening in specific situations. We searched the PubMed database and identified 27 scales, 13 are based on symptoms alone, 8 on neurological signs alone, and 6 on a combination of symptoms and signs. Scales that combine questions concerning symptoms and a neurological examination with a focus on sensory alterations seem to have the best discriminatory power. However, all scoring scales were developed for and investigated in prespecified patient populations. Therefore, the generalizability of specific findings to the general population may be limited. We also discuss other limitations of existing scales. Future studies are required to determine which clinimetrically well-developed scales are preferred for use in population-based studies.