Diagnostic sensitivity of electrophysiology and ultrasonography in ulnar neuropathies of different severity

To assess the diagnostic performance of electrophysiology and nerve ultrasound in ulnar neuropathies of varying clinical severity in 135 consecutive patients.

Clinical severity of ulnar neuropathy was graded on a 4 point scale from very mild (symptoms only) to severe (marked atrophy of intrinsic hand muscles). Sensitivity and localization ability of electrophysiology and nerve ultrasound were assessed for each point of the scale.

Ultrasound had higher sensitivity than electrophysiology in clinically very mild (20% and 3% for ultrasound and electrophysiology, respectively) and mild (62% and 47% for ultrasound and electrophysiology, respectively) neuropathies, had greater localizing ability in axonal ulnar neuropathies, and identified nerve hypermobility. Ultrasound nerve cross-sectional area had strong positive correlation with both clinical and electrophysiological severity scores, but with significant overlap across the severity groups.

The diagnostic work-up of ulnar neuropathies was improved by using both electrophysiology and ultrasound at all levels of clinical severity. Ultrasound increased the diagnostic yield in very mild and mild neuropathies, localized all the ulnar neuropathies with abnormal non-localizing electrophysiology and identified nerve hypermobility.

This is the first detailed analysis of the diagnostic performance of electrophysiology and ultrasound in ulnar neuropathies of varying severity.