Neurophysiological localisation of ulnar neuropathy at the elbow: Validation of diagnostic criteria developed by a taskforce of the Danish Society of clinical neurophysiology

Objective This study validates consensus criteria for localisation of ulnar neuropathy at elbow (UNE) developed by a taskforce of the Danish Society of Clinical Neurophysiology and compares them to the existing criteria from the American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM). The Danish criteria are based on combinations of conduction slowing in the elbow and forearm segments stated in Z-scores, and difference between the segments in m/s. Examining fibres to several muscles and sensory fibres can increase the certainty of the localisation. Methods Diagnostic accuracy for UNE was evaluated on 181 neurophysiological studies of the ulnar nerve from 171 peer-reviewed patients from a mixed patient group. The diagnostic reference standard was the consensus diagnosis based on all available clinical, laboratory, and EDX information reached by a group of experienced Danish neurophysiologists. Results The Danish criteria had high specificity (98.4%) and positive predictive value (PPV) (95.2%) and fair sensitivity (76.9%). Compared to the AANEM criteria, the Danish criteria had higher specificity ( p p Discussion The difference in diagnostic performance between the two criteria sets may partly be due to different limits for conduction slowing and for difference in conduction velocity between segments, and partly due to different algorithms. Conclusions The Danish consensus criteria for UNE are very specific and have high PPV. Significance The Danish criteria for UNE are reliable and well suited for use in different centres as they are based on Z-scores.