Bilateral cochlear implantation or bimodal listening in the paediatric population : retrospective analysis of decisive criteria

Introduction: In children with bilateral severe to profound hearing loss, bilateral hearing can be achieved by either bimodal stimulation (CIHA) or bilateral cochlear implantation (BICI). The aim of this study was to analyse the audiologic test protocol that is currently applied to make decisions regarding the bilateral hearing modality in the paediatric population. Methods: Pre- and postoperative audiologic test results of 21 CIHA, 19 sequential BICI and 12 simultaneous BICI children were examined retrospectively. Results: Deciding between either simultaneous BICI or unilateral implantation was mainly based on the infant's preoperative Auditory Brainstem Response thresholds. Evolution from CIHA to sequential BICI was mainly based on the audiometric test results in the contralateral (hearing aid) ear after unilateral cochlear implantation. Preoperative audiometric thresholds in the hearing aid ear were significantly better in CIHA versus sequential BICI children (p < 0.001 and p = 0.001 in unaided and aided condition, respectively). Decisive values obtained in the hearing aid ear in favour of BICI were: An average hearing threshold measured at 0.5, 1, 2 and 4 kHz of at least 93 dB HL without, and at least 52 dB HL with hearing aid together with a 40% aided speech recognition score and a 70% aided score on the phoneme discrimination subtest of the Auditory Speech Sounds Evaluation test battery. Conclusions: Although pure tone audiometry offers no information about bimodal benefit, it remains the most obvious audiometric evaluation in the decision process on the mode of bilateral stimulation in the paediatric population. A theoretical test protocol for adequate evaluation of bimodal benefit in the paediatric population is proposed

Hearing instruments for unilateral severe-to-profound sensorineural hearing loss in adults

Objectives: A systematic review of the literature and meta-analysis was conducted to assess the nature and quality of the evidence for the use of hearing instruments in adults with a unilateral severe-to-profound sensorineural hearing loss. Design: The PubMed, EMBASE, MEDLINE, Cochrane, CINAHL and DARE databases were searched with no restrictions on language. The search included articles from the start of each database until 11th February 2015. Studies were included that: (a) assessed the impact of any form of hearing instrument, including devices that re-route signals between the ears or restore aspects of hearing to a deaf ear, in adults with a sensorineural severe-to-profound loss in one ear and normal or near-normal hearing in the other ear; (b) compared different devices or compared a device to placebo or the unaided condition; (c) measured outcomes in terms of speech perception, spatial listening, or quality of life; (d) were prospective controlled or observational studies. Studies that met prospectively-defined criteria were subjected to random-effects meta-analyses. Results: Twenty-seven studies reported in thirty articles were included. The evidence was graded as low-to-moderate quality having been obtained primarily from observational before-after comparisons. The meta-analysis identified statistically-significant benefits to speech perception in noise for devices that re-routed the speech signals of interest from the worse ear to the better ear using either air or bone conduction (mean benefit 2.5 dB). However, these devices also degraded speech understanding significantly and to a similar extent (mean deficit 3.1 dB) when noise was re-routed to the better ear. Data on the effects of cochlear implantation on speech perception could not be pooled as the prospectively-defined criteria for meta-analysis were not met. Inconsistency in the assessment of outcomes relating to sound localisation also precluded the synthesis of evidence across studies. Evidence for the relative efficacy of different devices was sparse but a statistically significant advantage was observed for re-routing speech signals using abutment-mounted bone conduction devices when compared to outcomes after pre-operative trials of air-conduction devices when speech and noise were co-located (mean benefit 1.5 dB). Patients reported significant improvements in hearing-related quality of life with both re-routing devices and following cochlear implantation. Only two studies measured health-related quality of life and findings were inconclusive. Conclusions: Devices that re-route sounds from an ear with a severe-to-profound hearing loss to an ear with minimal hearing loss may improve speech perception in noise when signals of interest are located towards the impaired ear. However, the same device may also degrade speech perception as all signals are re-routed indiscriminately, including noise. While the restoration of functional hearing in both ears through cochlear implantation could be expected to provide benefits to speech perception, the inability to synthesise evidence across existing studies means that such a conclusion cannot yet be made. For the same reason, it remains unclear whether cochlear implantation can improve the ability to localise sounds despite restoring bilateral input. Prospective controlled studies that measure outcomes consistently and control for selection and observation biases are required to improve the quality of the evidence for the provision of hearing instruments to patients with unilateral deafness and to support any future recommendations for the clinical management of these patients

The cost-effectiveness of Cochlear implants in Swedish adults.

BackgroundResearch has shown unilateral cochlear implants (CIs) significantly improve clinical outcomes and quality of life in adults. However, only 13% of eligible Swedish adults currently use a unilateral CI. The objective was to estimate the cost-effectiveness of unilateral CIs compared to a hearing aid for Swedish adults with severe to profound hearing loss.MethodsA Markov model with a lifetime horizon and six-month cycle length was developed to estimate the benefits and costs of unilateral CIs from the Swedish health system perspective. A treatment pathway was developed through consultation with clinical experts to estimate resource use and costs. Unit costs were derived from the Swedish National Board of Health and Welfare and the Swedish Association of Local Authorities and Regions. Health outcomes were reported in terms of Quality Adjusted Life Years (QALYs).ResultsUnilateral CIs for Swedish adults with severe to profound hearing loss are likely to be deemed cost-effective when compared to a hearing aid (SEK 140,474 per QALY gained). The results were most sensitive to the age when patients are implanted with a CI and the proportion of patients eligible for CIs after triage.ConclusionsAn increase in the prevalence of Swedish adults with severe to profound hearing loss is expected as the population ages. Earlier implantation of unilateral CIs improves the cost-effectiveness among people eligible for CIs. Unilateral CIs are an efficacious and cost-effective option to improve hearing and quality of life in Swedish adults with severe to profound hearing loss

Analysis of the impact of professional involvement in evidence generation for the HTA Process, subproject “Cochlear Implants”: methodology, results and recommendations

The aim of Health Technology Assessment (HTA) is to provide decision-makers, distributors and recipients with information on the effectiveness, cost and impact of health technologies. The present study constitutes a subproject within the wider project “Analysis of the impact of professional involvement in evidence generation for the HTA process”, which is part of the strategic programme “Transfer of the results of the research in clinical practice and organisation of healthcare services”, coordinated by Laziosanità – Agency of Public Healthcare of the Lazio Region and AgeNaS (National Agency for Regional Healthcare Services). The objectives of the present subproject (cochlear implants) are as follows: a) to produce a report regarding the health impact of cochlear implants (CI) on their recipients, through a systematic review of literature and extensive selection of relative studies, combining the outcomes with metanalytical techniques. Output: report on the indications of usage in the groups of population for which benefits are controversial; b) to create a registry of patients using cochlear implants. The registry should contain a selection of anagraphic and clinical information relative to patient follow-up in order to assess factors associated with safety and impact on cochlear implant users. This source of information is essential for future observational studies. This was divided into 4 phases: 1st phase: definition of key participants in the assessment process; 2nd phase: definition of methods and timing of “Aims” (definition of the objective); 3rd phase: definition of the methods and times of the “assessment process”, 4th phase: production of the final report. From the analysis of systematic reviews and italian and international guidelines, the Working Group members approved recommendations on the following topics: results after CI in children in relation to age at implantation, bilateral CI in children, CI in deaf children with associated disabilities, CI in adults with advanced age, bilateral CI in adults and CI in adults with pre-lingual deafness. These recommendations have also been evaluated by the Consulting Committee members and approved with minimal suggestions

Cochlear implant: indications, contraindications and complications

Cochlear implant (CI) is a surgically implanted electronic device that provides a sense of sound to a person who is profoundly deaf. CI represents the current treatment for patients affected by profound sensorineu- ral hearing loss (SNHL). At first times, only deaf adults were considered to be candidates for a CI; however, with the development of technology and gained experience by pshycians, indications for cochlear implan- tation have been expanded. Today, CIs are implanted also in children and broader indications are followed. There are, however, a number of patients who are potential candidates for CI but do not completely fulfill the current indications. Residual hearing and duration of deafness represent prognostic indicators for CI per- formance; however, prelingually deafened adults and children with residual hearing are still point at issue. Anatomical variations such as cochlear malformation, ossification and chronic otitis media still represent a contraindication to CI for some surgeons. Although the technology for cochlear implant surgery is advanc- ing everyday, there may be several complications related to the device or operation and some of them can be healed only with medical therapy but some are serious enough to process to reimplantation. In this arti- cle the indications and contraindications for cochlear implant candidates and complications that may occur during or after the operation were reviewed under the light of the literature

Growing up with one ear : central auditory structure and function in unilateral ear canal atresia

The following thesis aims to give more insight into the functional and structural response of the central auditory system to congenital unilateral ear canal atresia (UCA) and the accompanying asymmetric hearing with conductive hearing loss on the atretic side. There is clear evidence that unilateral hearing loss, including UCA, has a negative impact on sound localization ability and perception of speech in noise. There is a spread in performance within the group, and the reason for this is not well known. In paper I of this thesis we examined sound localization with eye tracking and perception of speech in a cocktail party setting, in participants with congenital unilateral ear canal atresia, who had no hearing aids before age 12 (n=12) and compared to normal hearing references. Results show that the level of hearing loss on the atretic ear was associated with sound localization ability but not to speech perception. In the second study, participants with UCA (n=17) underwent MRI-scanning of the brain with diffusion weighted imaging (DWI). A method is described how to segment the white matter bundle between the medial geniculate body of the thalamus and the primary auditory cortex, the acoustic radiation (AR). Methods to define the AR are previously described in high resolution diffusion weighted imaging (DWI) scans but is very time consuming or has problems with including more structures around the primary auditory cortex (PAC). An algorithm was trained to quickly segment the core of the AR in individual clinical scans. The white matter tract was also assessed with measurements of fractional anisotropy (FA), but no differences were found between UCA and normal hearing (NH) controls. The third study describes the measurements of the grey matter of the primary auditory cortex of the Heschl’s gyrus in the same participants as in paper II. Thickness and volume of the Heschl’s gyrus were compared within the groups of UCA and controls, and between the groups. A difference in thickness was found between the left and right side (right thicker than left, corrected p=0.0012) in UCA, whereas controls had symmetric thickness. Volumes and total thickness were not different compared to controls. Rat brains from 12 months old rats with a surgically constructed left-sided ear canal atresia were examined in study IV. DWI was acquired in a research camera for rodents, 9.4 T magnetic field and a prolonged scanning time. Tractography and FA measurements were obtained both from whole brains and from tracts between auditory regions of interest (ROIs) using two different software. FA was generally higher in UCA rats than in controls. The AR was asymmetric in FA (left<right) in UCA, whereas FA was symmetric in controls. The FA was found to be lower at the left connection (same side as hearing loss) cochlear nucleus -inferior colliculus compared to the right side in UCA, while it was symmetric in controls. This finding (CN-IC) aligns with previous histology findings in ferrets with unilateral conductive hearing loss

Incorporating Over-the-Counter Hearing Aids into Private Audiology Practice

Over-the-counter (OTC) hearing aids are a new category of hearing aid devices designed to help adults with mild to moderate sensorineural hearing loss. This new category of devices was created with the aim to provide increased access to hearing aids for millions of Americans. Their advent has created significant change for hearing healthcare within the United States as they can be purchased without consulting an audiologist or medical professional. As a result of these changes, private audiology practice owners must choose how they will react. Moving forward they must decide if they will integrate OTC hearing aids into their practices, and if they do, how that integration would work for both the practice owner/audiologist and the consumer/patient. The advantages and disadvantages of incorporating OTC hearing aids into private audiology practice are discussed along with three different models of integration that could be utilized. The hybrid model is proposed as the most advantageous option. Little to no scholarly research on OTC hearing aids currently exists. As such, directions for future research and other needs are considered to better understand the impact that these devices will certainly have

Comparisons of unilateral and bilateral cochlear implantation for children: spatial listening skills and quality of life

Recently, controversy in the care of severely-profoundly deaf children has centred on whether they should be provided with bilateral cochlear implants (two implants, one in each ear) rather than a unilateral cochlear implant (one implant in one ear). Potentially, implanting both ears rather than one could improve children’s spatial listening skills, meaning the ability to localise sources of sound (by comparing the intensity and timing of sounds arriving at the two ears) and to perceive speech in noise (by attending to whichever ear gives the better signal-to-noise ratio). The overall aim of the studies reported in this thesis was to assess whether bilateral implantation for children is more effective than unilateral implantation in improving spatial listening skills and quality of life. The first study measured the relationship between spatial listening skills and age in normally-hearing children. The second study compared the spatial listening skills of unilaterally- and bilaterally-implanted children. Whilst controlling for confounds, the bilateral group performed significantly better than the unilateral group on tests of sound-source localisation. Moreover, the bilateral group, but not the unilateral group, displayed improved speech perception when the source of a masking noise was moved from the front to either side of the head. Neither group of implanted children performed as well as normally-hearing children on tests of the ability to localise sources of sound and to perceive speech in noise. The third study measured the spatial listening skills of normally-hearing adults when listening to simulations of unilateral or bilateral implants. The differences in performance between simulations were similar to the differences in performance between groups of implanted children, which provides further evidence that the children's performance was primarily influenced by the number of implants they used rather than by confounds. The fourth study found that there was no significant difference between bilaterally- and unilaterally-implanted children in parental estimates of quality of life. The fifth study presented informants, who were not the parents of hearing-impaired children, with descriptions of a hypothetical child with unilateral or bilateral implants. The informants judged that the bilaterally-implanted child had a higher quality of life than the unilaterally-implanted child. These studies indicate that bilateral implantation for children is more effective than unilateral implantation in enabling spatial listening skills, but the extent of any gain in quality of life remains uncertain