RESPONSE TO LETTER TO THE EDITOR "AUDITORY DYSFUNCTION IN FACIOSCAPULOHUMERAL MUSCULAR DYSTROPHY TYPE 1: BEYOND THE INNER EAR INVOLVEMENT" BY GHELLER ET AL.

Abstract

In Reply: We read with interest the Letter to the Editor entitled “Auditory dysfunction in Facioscapulohumeral Muscular Dystrophy Type 1: beyond the inner ear involvement” by Gheller et al. (1), reporting further evidence of an auditory impairment in patients affected by Facioscapulohumeral Muscular Dystrophy Type 1 (FSHD1). In particular, Gheller et al. performed various audiological examinations, including speech evaluation tests, frequency discrimination and event related potential (P300) latency analysis, highlighting the presence of a hearing impairment in a population of 13 patients affected by FSHD1, for frequencies higher than 2 kHz. In our recent study on 26 FSHD1 patients, we reported a general alteration of otoacoustic emissions (OAEs) analysis, irrespective of the degree of muscular involvement, suggesting a primary cochlear dysfunction as a typical feature of this disease (2). Altogether, these findings further indicate the existence of a complex involvement of the auditory pathways in FSHD1. Based on our findings, we suggest to maintain strict exclusion criteria when recruiting patients for such studies to avoid a possible bias of patient's selection and considering not only those subjects who complain about hearing problems, but all FSHD1 subjects. This approach may reveal a possible subclinical hearing dysfunction still unrecognized by the patient. Further studies are needed to evaluate hearing outcomes in the light of the progression of the disease and to better understand possible correlations between auditory impairment, muscular balance and genetic features. As to the absence of acoustic stapedial reflexes reported by Gheller et al. in their patients’ group, which we did not observe in our cohort, we can hypothesize this inconsistency is probably related to the small samples of both studies. It would be interesting to assess this issue in larger patients’ populations. In conclusion, our study (1) is supported by the evidence obtained, with other methods, by Gheller et al., in highlighting the importance of an early and comprehensive evaluation of auditory function in FSHD1 patients.