Luís F. Silva

DFNB1-associated deafness in Portuguese cochlear implant users: prevalence and impact on oral outcome.

OBJECTIVES Hearing loss is a condition that interferes with the development of the child at a cognitive and language level. Therefore, early diagnosis of deafness is important for (re)habilitation, namely through the use of cochlear implant (CI). The present study aimed at screening CI Portuguese individuals for the presence of mutations in the genes GJB2 and GJB6 (DFNB1 locus), and searching a possible correlation between the genotype and the oral habilitation outcome following implantation. METHODS Our sample included 117 CI individuals implanted longer than 5 years. Sequencing of GJB2 entire coding region was first performed. The presence of deletions del(GJB6-D13S1830) and del(GJB6-D13S1854) was subsequently tested by multiplex PCR. To assess the oral outcome of these individuals, a global score is calculated through a formula that integrates the results of a battery of speech and audiological tests routinely used in ORL services. This global oral performance score was used to test whether individuals with DFNB1-associated deafness perform significantly better than individuals without DFNB1-associated deafness. RESULTS In 35% of the cases, deafness was clearly associated to DFNB1. The most common mutated allele was c.35delG (85%). Other variants have also been found, namely p.Gly130Ala, p.Asn206Ser, p.Val37Ile, p.Glu47X, p.Arg184Trp, p.Trp24X and the two common GJB6 deletions, del(GJB6-D13S1854) and del(GJB6-D13S1830), the last one identified for the first time in our population. Regarding the oral outcome, after testing the homogeneity of the two groups it could be observed that, in mean, the individuals with DFNB1-associated deafness perform significantly better (p=0.012) than the individuals without DFNB1-associated deafness. DISCUSSION AND CONCLUSION This first screening of DFNB1 genes in the Portuguese CI population provides clear evidence of the high proportion of DFNB1-associated deafness amongst the Portuguese implanted individuals. DFNB1 status is significantly associated to higher oral performance scores, with DFNB1 individuals performing, on average, 6% better than the individuals without DFNB1-associated deafness.

Cochlear implant rehabilitation outcomes in Waardenburg syndrome children

OBJECTIVES The purpose of this study was to review the outcomes of children with documented Waardenburg syndrome implanted in the ENT Department of Centro Hospitalar de Coimbra, concerning postoperative speech perception and production, in comparison to the rest of non-syndromic implanted children. METHODS A retrospective chart review was performed for children congenitally deaf who had undergone cochlear implantation with multichannel implants, diagnosed as having Waardenburg syndrome, between 1992 and 2011. Postoperative performance outcomes were assessed and confronted with results obtained by children with non-syndromic congenital deafness also implanted in our department. Open-set auditory perception skills were evaluated by using European Portuguese speech discrimination tests (vowels test, monosyllabic word test, number word test and words in sentence test). Meaningful auditory integration scales (MAIS) and categories of auditory performance (CAP) were also measured. Speech production was further assessed and included results on meaningful use of speech Scale (MUSS) and speech intelligibility rating (SIR). RESULTS To date, 6 implanted children were clinically identified as having WS type I, and one met the diagnosis of type II. All WS children received multichannel cochlear implants, with a mean age at implantation of 30.6±9.7months (ranging from 19 to 42months). Postoperative outcomes in WS children were similar to other nonsyndromic children. In addition, in number word and vowels discrimination test WS group showed slightly better performances, as well as in MUSS and MAIS assessment. CONCLUSIONS Our study has shown that cochlear implantation should be considered a rehabilitative option for Waardenburg syndrome children with profound deafness, enabling the development and improvement of speech perception and production abilities in this group of patients, reinforcing their candidacy for this audio-oral rehabilitation method.

Facial nerve stimulation after cochlear implantation: Our experience in 448 adult patients

Facial nerve stimulation (FNS) after cochlear implant activation is a well-known side effect, with an incidence rate raging between 1% and 14.9%. Some causes of deafness have been associated with a higher incidence of this entity, however, there is still no consensus regarding its pathophysiological mechanisms. Although FNS can be solved with changes in speech processor programming, in some cases this can lead to a decrease in performance. The aim of this work was to review the epidemiologic, clinical aspects, and performance results in a group of FNS after cochlear implantation. It was conducted a retrospective chart review of 448 adult patients, all implanted between 1985 and 2016. Speech perception tests results were statistically analysed, using non-parametric tests. We registered a group of 13 patients with FNS, contributing to a prevalence of 2.9%. The causes of hearing loss in this group varied between otosclerosis, Menière’s disease, head trauma, and idiopathic cause. Six cases were managed by changing the programming strategy and the other seven required the deactivation of the affected electrodes. Statistical evaluation showed no statistically significant difference between the performance results of the groups with and without FNS. In this series, the overall incidence of FNS was consistent with the literature. Our study supports the current idea that FNS can frequently be eliminated by changing programming strategies or deactivating the involved electrodes, without affecting the implant’s performance.

Switching off Electrodes in Cochlear Implants - Causes and Consequences

The evolution of the CI has been notable in the development of the external component microphone, speech processor, transmitter with a constant evolution over the years. This same evolution allows us to have speech processors miniaturized and increasingly effective in auditory processing. The inner component is formed by the receiver and the electrode array. The receptor has remained similar over the years, but the electrode array has evolved considerably and we now have several types of electrode bundles available for cochlear implantation [2].