Placement of reference electrode position in motor nerve conduction study of ulnar nerve while recording from FDI

Background: Ulnar nerve is the second most common entrapment neuropathy in the hand at the wrist and at across elbow. There are various techniques have been developed to diagnosed the entrapment. Ulnar nerve supply to wrist at the two main muscles First Dorsal Interosseous (FDI) and Abductor Digiti Minimi (ADM). Many research shows that FDI muscle is use to diagnose an early entrapment across elbow. Recording from FDI muscles, there is an issue in placing the reference electrode placement due to its positive deflection.

The aim of this research to identify which is the best position to place the reference electrode in FDI muscles.

Method: A total of 46 hands were included in this study.  Data was collected based on the extensive and detailed description mentioned in different research papers. The tests were performed by a qualified clinical physiologist (Neurophysiology) using a Keypoint 9033A07 machine, used in line with departmental protocol (Ulnar nerve screening protocol1.1, 2020). All data was recorded numerically to ensure methodological reliability.

Result: Out of 46 hands tested for the nerve conduction study (NCS) by placing reference electrode in five different places i.e. tendon of the FDI muscles at the base of digit II, over the thumb, tendon of ADM muscles at the base of digit V, At the radial pathway of the wrist and other hand at the FDI tendon. Tendon of the FDI muscles at the base of digit II shows positive deflection in all hands with amplitude rage between 6-15 mV. Over the thumb show the baseline slightly elevated to get accurate distal motor latency with amplitude between 5-8mV. And tendon of ADM muscles at the base of digit V shows correct baseline for accurate distal motor latency with the amplitude rage 10-18mV.

Conclusion: This study shows that to record the best and clear response by placing the reference electrode at the tendon of ADM muscles at the base of digit V is more reliable as compare to other two areas.

What will audience learn from your presentation?

It is crucial to place the reference electrode in proper place with the normative data should be collected.

He is Salim Hirani and he studied BSc in Karachi University, Pakistan in 1990. He is Reg. Technologist from ECNE board UK in 1999. He has completed my on-the-job training in the field of Physiological Measurement services of one year 6 months from The Aga Khan University Hospital, Karachi Pakistan in 1989. He is registered with RCCP. He is almost 28 years’ experience in Neurophysiology and 5 years in Cardiopulmonary field. He worked in three different countries in the field of Neurophysiology. He established a new Neurophysiology department in Torbay Hospital.  His paper on Refine grading of CTS published in MBC open access journal which achieve great welcome. Few other research papers has been published on ulnar nerves study in different stages, across wrist and across elbow and double crush syndrome which are available on google website as open access.