Clinical diagnosis of distal diabetic polyneuropathy using neurological examination scores: correlation with nerve conduction studies

Abstract

The aim of this study was to diagnose diabetic sensorimotor polyneuropathy using neurological examination scores and to correlate the findings with nerve conduction studies (NCS). Thirty patients with type 2 diabetes were included in the study. Detection and grading of neuropathy were carried out based on the Diabetic Neuropathy Symptom (DNS) Score, modified Neuropathy Symptom Score (NSS), Diabetic Neuropathy Examination (DNE), and modified Neuropathy Disability Score (NDS). For the NCS, amplitudes, velocities, and latencies of seven nerves — that is, four motor (median, ulnar, tibial, and common peroneal) and three sensory (median, ulnar, and sural) nerves — were recorded. If the patient had two or more abnormal findings in any of these nerves, the patient was diagnosed as having peripheral sensorimotor neuropathy. Thereafter, the sensitivity, specificity, and diagnostic efficacy of each neurological score were recorded taking NCS as the gold standard. Diabetic sensorimotor polyneuropathy was diagnosed clinically and electrophysiologically in 17 patients (56.7%). However, there were nine cases (30%) of subclinical neuropathy. Neurological examination scores were significantly correlated with each other and with individual variables of NCS and the nerve conduction sum score. Taking the NCS as gold standard, DNS, modified NSS, DNE, and modified NDS had 65.4, 61.5, 30.8, and 61.5% sensitivity and 100, 75, 100, and 100% specificity, respectively. Their diagnostic efficacies were 70, 63.3, 40, and 66.7%, respectively. Neurological examination scores can detect and grade neuropathy in the majority of cases. However, NCS was accurate for detection of diabetic sensorimotor polyneuropathy, especially for the subclinical neuropathies.