Combined nerve conduction index in diabetic polyneuropathy.

Unlabelled: Diabetic polyneuropathy can be confirmed by nerve conduction studies. The data can be analyzed in the form of a combined index instead of individual parameters.

Methods: The combined index included five parameters of nerve conduction studies commonly used for evaluation of polyneuropathies. We evaluated sensitivity in 100 diabetic patients with suspected polyneuropathy, and specificity in 200 non-diabetic patients with suspected lumbosacral radiculopathy. All results were expressed in number of standard deviations (SD).

Results: The sensitivity of the combined index was 81 or 74%, and specificity was 97 or 98%, using respectively -2.0 or -2.5 SD as cutoff. The range of sensitivity of the other parameters was 57-65% or 48-56%, and specificity range was 96-98% or 98-100%, using the same criteria.

Discussion: The combined index had higher sensitivity and equivalent specificity compared to isolated parameters.