Support your local paediatric neurophysiologist

Abstract

SIR–The discovery that high-dose riboflavin can treat Brown– Vialetto–Van Leare syndrome is perhaps one of the most exciting developments in paediatric neurology over recent years. This condition, like Fazio–Londe syndrome with which it shares some features, was regarded as an untreatable and relentlessly progressive condition. There have been a series of papers which suggest early treatment may reverse the deterioration although the diaphragm does seem to be stubbornly resistant. 1–3 It was therefore with interest that I read the article by Anand et al. describing a 22-month-old female who responded to high-dose riboflavin. 4 In their concluding comments the authors state that ‘… an early genetic diagnosis in patients presenting with progressive ponto-bulbar palsy with or without sensorineural deafness will enable early institution of therapy and reversal of symptom progression, leading to a better prognosis.’ I do not disagree with the sentiment, but feel that perhaps they have not emphasized the importance of clinical neurophysiology and, in particular, electromyography (EMG) in the early diagnosis of these cases. The studies done by their neurophysiologist were excellent. This neurophysiologist even succeeded with voluntary single-fibre EMG in a 22-monthold child, which is an achievement on its own. Our experience is that there are increasing numbers of referrals of children with suspected bulbar palsy and it is not at all uncommon for a discovery of neurogenic change to be made. In fact, in one of our recent cases of Brown–Vialetto–Van Laere syndrome the discovery of definite neurogenic change in the tongue antedated by several months clinical confirmation of abnormalities in that region. EMG is exquisitely sensitive to denervation and particularly chronic denervation, and it is quite feasible for these changes to be manifest on EMG before clinical appearances such as the tongue fasciculation or wasting confirm the suspicions. It is well-known that effective reinnervation may compensate for muscle fibres which lose their nerve supply with atrophy only occurring when that capacity is exhausted. We are very early on in discovering an effective treatment for this condition but there do appear to be indications that if instituted at the earliest possible point in the disease, rather like pyridoxine dependency, near normalization of the metabolic abnormality may be possible. From what has been said above, EMG of the tongue may give the first indication of abnormality and clinicians should think of this when they have a suspicion of Brown–Vialetto–Van Laere syndrome and encourage their neurophysiologist to assist them. The technique is easily within the reach of any competent clinical neurophysiologist, and if combined with screening for deafness could provide a very quick and effective way to pick up these children early. Otherwise, a great number of children are going to be screened genetically and metabolically with little benefit.