After a varied clinical, but always interesting route, to clinical neurophysiology, paediatric EMG was not foremost of the speaker’s interests on arrival at GOSH. Paediatric EEG held more fascination initially but this changed rapidly. The master of paediatric EMG then was Dr Peter Payan, whose minimalistic but focused approach was to have profound influence on later practice.
Paediatric EMG is a niche speciality. Methods used in adults have limited application. Unique challenges demand novel approaches to its execution. The first challenge was people. Rather unexpectedly I found that I had a particular aptitude for dealing and reassuring both the patients and their parents. Colleagues presented a more difficult set of problems. To some Paediatric EMG was and still is perceived as a cruel and unnecessary examination.
Technique is the next challenge. Performing SPACE, a variation of stimulated single fibre EMG, successfully in almost every child was a hard-fought skill. This technique highlights the difficulties doing EMG tests on less than cooperative subjects. Every test from the simplest nerve study to identifying the lesions in obstetric brachial plexus palsy presents a challenge. If it looks easy be assured, it is not, and years of practice are required.
Clearly children suffer different illnesses from adults and need different approaches. Amongst these, obstetric brachial palsy investigation with EMG is still has no clear unifying approach. The approach to swallowing difficulty is another. Few are able to reproduce the exquisite studies perfected by Francis Renault at Hôpital Arnaud Trousseau. Surprisingly one of the most common EMG requests, does this child have a myopathy, continues to stretch us. There are many reasons for this. First and foremost, EMG is not requested when the clinician is confidant there is a myopathy. More commonly the query is whether the muscle is normal or not. EMG working at the limits of its capabilities is often wrong. MUP duration testing should help but only slightly.
Introduced to the statistical techniques used in Japanese car manufacture a realisation of the importance of variability in measurement was kindled. Its influence in EMG in general is profound. Methods to reduce its effects have informed all work in paediatric EMG. Aligned with this is the problem of normative data. An interest in databases and the perfection of one for EMG by Ralph Smith meant that when Joe Jabre’s innovative e-norm methodology came on-line we were able to produce comprehensive normal ranges for all paediatric parameters.
Dissemination of knowledge was a major challenge. The creation of the Biannual International Paediatric EMG Congresses with Royden Jones in 1997 lead to development of a global network of enthusiasts, with the 2019 meeting having attendees from over 25 countries. At the same time a continual flow of visiting fellows arrived, often self-funding and spending between a few weeks to a year in the department. Their contribution to research and perfection of techniques were significant. Publication of my textbook on Paediatric EMG was an enormous pleasure.
The final challenge is the future of paediatric EMG. Done correctly by people trained properly, it should no longer be considered too painful. Introduction of protocols for oral morphine cover should further reduce this perception. Genetics may be all conquering but still there will be the need to respond to the report of a mutation of unknown significance. Demonstration of abnormal neurophysiology may be crucial even if the diagnostic route of phenotype to genotype may have been reversed. There is still much to be done and hopefully those following will rise to the challenge of this fascinating, often challenging but always rewarding sub-speciality of EMG