Onset Of Deafness Research Articles

Etiologic Diagnosis of Nonsyndromic Genetic Hearing Loss in Adult vs Pediatric Populations

Objective: 1) Determine the diagnostic yield of a shared genetic screening algorithm in adult and pediatric populations with sensorineural hearing loss (SNHL). 2) Recommend effective testing strategies to evaluate for genetic causes of deafness in patients presenting with idiopathic sensorineural hearing loss. Method: A total of 221 adult and 163 pediatric patients with non-syndromic sensorineural hearing impairment were recruited from otology clinics between 2001 and 2011. Peripheral blood samples were screened for mutations in GJB2 and GJB6 and mitochondrial DNA mutations 1555A>G, 7444G>A, and 3243A>G. Audiometric data and family history were also collected. Results: GJB2/GJB6 related deafness was diagnosed in 23 out of 163 pediatric patients (14%) compared with only 3 out of 221 adults (1%). All 3 adults had a family history of hearing loss, and 2 patients noted deafness onset at birth. Nineteen GJB2 mutations were identified with 35delG, the most common mutation. The 35delG homozygous state was the most common pathogenic genotype (54%). Mitochondrial DNA (mtDNA) mutations were found in 6 adult probands (3%). No mtDNA mutations were found in pediatric patients. Conclusion: Testing for common GJB2/GJB6 mutations in pediatric patients has considerable value in establishing an etiologic diagnosis for SNHL. Similar testing in adults is of very low yield except perhaps in cases of early onset HL or strong family history. Mitochondrial DNA testing should be considered in adults with idiopathic SNHL.

The influence of various factors on the performance of repetition tests in adults with cochlear implants

A variety of internal and external factors influence speech perception performance following cochlear implantation (CI) in adult deaf patients. The aim of this study was to evaluate the speech perception performance during repetition testing according to various factors and to identify the predictive factors associated with postoperative speech perception. The performances on speech perception under audio-only conditions were examined over time in 61 adult patients with CI. Mono- and bi-syllable and sentence repetition testing, using both the Korean version of the Central Institute for the Deaf (K-CID) and the K-Western Aphasia Battery test (K-WAB), were performed preoperatively and at 3, 6 and 12 months postoperatively. To elucidate the effect that the etiology of deafness has on postoperative outcome, patients were divided into the following four groups: Prelingual hearing loss (HL) (n = 9), Meningitis (n = 6), Progressive HL (n = 31) and Sudden HL groups (n = 15). Moreover, the duration of HL and deafness was defined as follows: (1) "age of deafness onset: AoD", (2) "number of years between the onset of profound deafness and CI: DoD" and (3) "percentage of the patient's life with moderate-to-profound hearing loss before CI: PoL". DoD and PoL were significantly different between the four groups. Although AoD appeared to be associated with performance on the sentence repetition test before standardizing for education level and age (P = 0.015), there was no association after adjusting for these factors (P = 0.719). Only PoL showed a good correlation with performance on repetition testing after CI after adjusting for AoD and DoD. However, DoD was associated with speech perception performance on the sentence repetition test only. In addition, speech perception performance results in the Progressive and Sudden HL groups were improved over the Prelingual HL and Meningitis groups. The Meningitis group showed the poorest speech perception performance among postlingually deaf adults. Consideration of age, education level, etiology and overall time with hearing loss may be necessary for predicting speech perception outcomes in CI recipients.

Speech Intelligibility as a Predictor of Cochlear Implant Outcome in Prelingually Deafened Adults

Among adult patients with prelingual deafness, interindividual variability in speech perception outcome after cochlear implantation is generally large. It was hypothesized that the intelligibility of the patient's own speech may be predictive of speech perception with a cochlear implant. The objectives were (1) to provide a validation of a new test battery as a measurement tool for intelligibility using a group of prelingually deafened patients; (2) to investigate the validity of the test battery as a predictor of postimplant speech perception, based on preliminary data with a cochlear implant from a subgroup of patients; and (3) to investigate the validity of the test battery as a predictor of postimplant health-related quality of life (HRQoL) for the same subgroup of patients. Twenty-five adult cochlear implant candidates with prelingual deafness participated in this study. Average age at onset of deafness was 8 mos (range 0 to 4 yrs). Speech samples from the participants were recorded and presented to two normal-hearing listeners. Results from the seven intelligibility tests in the battery were subjected to analyses of reliability and validity. Furthermore, the multiple test outcomes were submitted to a Principal Component Analysis to investigate the possibility of summarizing the data. Subsequently, from the group of 25 participants, 9 participants with above-average intelligibility were selected for implantation. Speech perception data with a cochlear implant from the nine implantees were collected at 12 mos postimplantation, as well as HRQoL data. Predictive validity of the intelligibility test battery was determined, using the postimplant data as the criterion. Results from the 25 participants averaged over listeners showed that all tests in the battery had good reliability and validity as measures of intelligibility. Principal Component Analysis showed that the multiple test outcomes could be summarized by a single underlying variable. Despite the early age at onset of deafness, the subgroup of nine participants who received a cochlear implant included several good performers in terms of speech perception with the implant. The intelligibility test battery summary score had good validity as a predictor of postimplant outcome: the more intelligible the participant's speech, the better his or her speech perception outcome with the cochlear implant. Availability of effective auditory input in early life may be the fundamental factor underlying the potential for speech perception with a cochlear implant in later life. The intelligibility test battery can be reduced to a single test to minimize testing time without negatively affecting its predictive validity. Predictive validity of the intelligibility test battery can be generalized to HRQoL outcomes of cochlear implantation, provided these outcomes are concerned with speech processing abilities. The new test battery (or its reduced version), used as a measure of intelligibility, is a promising tool for guiding cochlear implant candidacy decisions and counseling for individual patients with prelingual deafness. Because intelligibility has superior predictive power in comparison to age at onset of deafness, the latter should be discarded as an exclusion criterion for cochlear implantation.

Visual advantage in deaf adults linked to retinal changes.

The altered sensory experience of profound early onset deafness provokes sometimes large scale neural reorganisations. In particular, auditory-visual cross-modal plasticity occurs, wherein redundant auditory cortex becomes recruited to vision. However, the effect of human deafness on neural structures involved in visual processing prior to the visual cortex has never been investigated, either in humans or animals. We investigated neural changes at the retina and optic nerve head in profoundly deaf (N = 14) and hearing (N = 15) adults using Optical Coherence Tomography (OCT), an in-vivo light interference method of quantifying retinal micro-structure. We compared retinal changes with behavioural results from the same deaf and hearing adults, measuring sensitivity in the peripheral visual field using Goldmann perimetry. Deaf adults had significantly larger neural rim areas, within the optic nerve head in comparison to hearing controls suggesting greater retinal ganglion cell number. Deaf adults also demonstrated significantly larger visual field areas (indicating greater peripheral sensitivity) than controls. Furthermore, neural rim area was significantly correlated with visual field area in both deaf and hearing adults. Deaf adults also showed a significantly different pattern of retinal nerve fibre layer (RNFL) distribution compared to controls. Significant correlations between the depth of the RNFL at the inferior-nasal peripapillary retina and the corresponding far temporal and superior temporal visual field areas (sensitivity) were found. Our results show that cross-modal plasticity after early onset deafness may not be limited to the sensory cortices, noting specific retinal adaptations in early onset deaf adults which are significantly correlated with peripheral vision sensitivity.

Use It or Lose It? Lessons Learned from the Developing Brains of Children Who are Deaf and Use Cochlear Implants to Hear

In the present paper, we review what is currently known about the effects of deafness on the developing human auditory system and ask: Without use, does the immature auditory system lose the ability to normally function and mature? Any change to the structure or function of the auditory pathways resulting from a lack of activity will have important implications for future use through an auditory prosthesis such as a cochlear implant. Data to date show that deafness in children arrests and disrupts normal auditory development. Multiple changes to the auditory pathways occur during the period of deafness with the extent and type of change being dependent upon the age and stage of auditory development at onset of deafness, the cause or type of deafness, and the length of time the immature auditory pathways are left without significant input. Structural changes to the auditory nerve, brainstem, and cortex have been described in animal models of deafness as well in humans who are deaf. Functional changes in deaf auditory pathways have been evaluated by using a cochlear implant to stimulate the auditory nerve with electrical pulses. Studies of electrically evoked activity in the immature deaf auditory system have demonstrated that auditory brainstem development is arrested and that thalamo-cortical areas are vulnerable to being taken over by other competitive inputs (cross-modal plasticity). Indeed, enhanced peripheral sight and detection of visual movement in congenitally deaf cats and adults have been linked to activity in specific areas of what would normally be auditory cortex. Cochlear implants can stimulate developmental plasticity in the auditory brainstem even after many years of deafness in childhood but changes in the auditory cortex are limited, at least in part, by the degree of reorganization which occurred during the period of deafness. Consequently, we must identify hearing loss rapidly (i.e., at birth for congenital deficits) and provide cochlear implants to appropriate candidates as soon as possible. Doing so has facilitated auditory development in the thalamo-cortex and allowed children who are deaf to perceive and use spoken language.

X‐linked Alport syndrome in Hellenic families: Phenotypic heterogeneity and mutations near interruptions of the collagen domain in COL4A5

The X-linked Alport syndrome (ATS) is caused by mutations in COL4A5 and exhibits a widely variable expression. Usually ATS is heralded with continuous microhematuria which rapidly progresses to proteinuria, hypertension and chronic or end-stage renal disease (ESRD) by adolescence, frequently accompanied by sensorineural deafness and ocular complications. Milder forms of ATS also exist. We studied 42 patients (19M, 23F) of nine Hellenic families suspected clinically of X-linked ATS who presented with marked phenotypic heterogeneity. We identified mutations in COL4A5 in six families. Two males with nonsense mutation E228X reached ESRD by ages 14 and 18. Frameshift mutation 2946delT followed the same course with early onset renal involvement and deafness. However, two males with the milder missense mutation G624D, reached ESRD after 39 years and one patient showed thin basement membrane nephropathy (TBMN). Another 5/8 affected males with missense mutation P628L also developed ESRD between 30 and 57 years, while three exhibit only mild chronic renal failure (CRF). The data support previous findings that certain mutations are associated with milder phenotypes and confirm that mutation G624D may be expressed as TBMN with familial hematuria. Similar conclusions apply for missense mutation P628L. Interestingly, mutations G624D and P628L are near the 12th natural interruption of COL4A5 triple helical domain, which may explain the milder phenotype.

Epilogue: factors contributing to long-term outcomes of cochlear implantation in early childhood.

This report focuses on how speech perception, speech production, language, and literacy performance in adolescence are influenced by a common set of predictor variables obtained during elementary school in a large group of teenagers using cochlear implants (CIs). Time-lag analyses incorporating seven common predictor variables associated with the elementary school test period were evaluated. The elementary school-age variables included five contributors across the performance domains: gender, performance intelligence quotient, family size, socioeconomic status, and duration of deafness (operationally defined as the time period between the age of implantation and the onset of deafness). Regression analyses then examined how communication mode in early elementary grades influenced skills exhibited in high school and how this influence was mediated by information capacity of immediate memory. High correlations occurred between outcome measures collected at CI-E session and similar measures collected at CI-HS (values ranging from 0.75 to 0.83), indicating that the relative standing of individuals on these outcomes is highly stable over time. The best performers in elementary grades exhibit the best outcomes in high school, and early difficulties tend to persist throughout the elementary and high school years. The most highly related outcome areas were language and reading/literacy (values ranging from 0.74 to 0.88). These skills seem closely linked, and CI children who demonstrate the best vocabulary and syntax skills in elementary grades achieved the highest literacy performance in high school. Speech perception and speech production skills are also highly correlated with one another (r = 0.69 to 0.87), suggesting that the most direct result of improved auditory input from a CI is the child's ability to produce intelligible speech. The lowest correlations are observed between reading/literacy and speech perception (r = 0.30 to 0.54) or speech production (values ranging from 0.31 to 0.58). CI-E verbal rehearsal speed is an independent and powerful predictor of each early performance outcome, accounting for between 13% and 30% of the variance in early outcomes above and beyond that accounted for by gender, family size, socioeconomic status, performance intelligence quotient, duration of deafness, and the CI-E sign enhancement ratio. Group mean scores for language, reading, and social adjustment were generally within an SD of normative samples of typically developing age-mates with normal hearing. Use of sign to enhance spoken communication negatively influenced verbal rehearsal speed, which was a strong predictor of all early outcomes, which in turn strongly influenced later outcomes. These analyses suggest that early communication mode exerts a powerful influence on early outcomes that persist into later years. Speech perception, speech intelligibility, language, literacy, and psychosocial adjustment far exceeded that reported for similar groups before the advent of CI technology.

Hearing History Influences Voice Gender Perceptual Performance in Cochlear Implant Users

The study was carried out to assess the role that five hearing history variables (chronological age, age at onset of deafness, age of first cochlear implant [CI] activation, duration of CI use, and duration of known deafness) play in the ability of CI users to identify speaker gender. Forty-one juvenile CI users participated in two voice gender identification tasks. In a fixed, single-interval task, subjects listened to a single speech item from one of 20 adult male or 20 adult female speakers and had to identify speaker gender. In an adaptive speech-based voice gender discrimination task with the fundamental frequency difference between the voices as the adaptive parameter, subjects listened to a pair of speech items presented in sequential order, one of which was always spoken by an adult female and the other by an adult male. Subjects had to identify the speech item spoken by the female voice. Correlation and regression analyses between perceptual scores in the two tasks and the hearing history variables were performed. Subjects fell into three performance groups: (1) those who could distinguish voice gender in both tasks, (2) those who could distinguish voice gender in the adaptive but not the fixed task, and (3) those who could not distinguish voice gender in either task. Gender identification performance for single voices in the fixed task was significantly and negatively related to the duration of deafness before cochlear implantation (shorter deafness yielded better performance), whereas performance in the adaptive task was weakly but significantly related to age at first activation of the CI device, with earlier activations yielding better scores. The existence of a group of subjects able to perform adaptive discrimination but unable to identify the gender of singly presented voices demonstrates the potential dissociability of the skills required for these two tasks, suggesting that duration of deafness and age of cochlear implantation could have dissociable effects on the development of different skills required by CI users to identify speaker gender.

Multiple effects of childhood deafness on cortical activity in children receiving bilateral cochlear implants simultaneously

Objective Auditory development is disrupted without normal hearing but might proceed to some extent depending on the type and onset of deafness. We therefore hypothesized that activity in the auditory cortex would be highly variable in children who are deaf. Methods To answer this, activity in the deaf brain was evoked by electrical pulses from newly provided bilateral cochlear implants (CIs) in 72 children ( n = 144 responses). Results Responses were categorized by visual inspection into 3 main types which were validated by principal component cluster analyses; 49% had a negative amplitude wave similar to that previously reported in pre-term infants, 26% were dominated by a positive peak typical of responses in young normal hearing children and experienced paediatric CI users, 25% were novel multi-peaked responses. No significant demographic differences, including duration and onset of deafness, were found between response types. However, children with severe biallelic mutations of GJB-2 showed predominately negative peak type responses (79%) as compared with their peers without these mutations who had a more equal distribution between cortical response types. Conclusion Cortical development in children who are deaf is heterogeneous but can be better predicted when the genotype is known to be a GJB-2 mutation. Significance Remediation of childhood deafness seeks to restore normal development and function of central auditory functions and thus may need to be tailored to account for effects specific to the aetiology of deafness.

Identifying deafness in early childhood: requirements after the newborn hearing screen

BackgroundNewborn hearing screening has been nationally implemented, but longitudinal cohort follow-up is required to inform Children's Hearing Services of the requirements for postneonatal care pathways.MethodsA 10-year cohort of 35 668...

Sudden bilateral sensorineural hearing loss as the presenting symptom of meningeal carcinomatosis of gastric cancer: Report of a case

Meningeal carcinomatosis is the diffuse infiltration of the meninges by metastatic carcinoma. A 62-year-old man presented with a sudden onset of profound hearing loss affecting both ears. Brain magnetic resonance imaging showed increased signal intensity on T1-weighted images of both vestibulocochlear nerves. Upper gastrointestinal endoscopy revealed a large type 3 gastric cancer, and the pathological diagnosis was poorly differentiated adenocarcinoma. Although combination chemotherapy with oral S-1 and weekly paclitaxel and radiation therapy were performed, the patient's condition gradually worsened, and he eventually died 12 weeks after the onset of deafness. Isolated bilateral hearing loss is therefore considered to be a rare first manifestation of meningeal carcinomatosis.

Prevalence and Etiology of Hearing Loss in Primary and Middle School Students in the Hubei Province of China

The purpose of this study was to investigate the prevalence and etiology of hearing loss in primary and middle school students in the Hubei province of China. During a 2-year period, 504348 students were examined by a speech audiometry test, and 813 deaf students were detected. Among the 813 deaf students, 232 cases were diagnosed with congenital deafness and 560 cases had acquired deafness, among which 276 cases had aminoglycoside-antibiotic-induced deafness. The severity of deafness could be further ascertained in 804 other students, with 402 profound, 363 severe, 21 moderate and 18 mild deafness cases. The age at deafness onset of most students was under 3 years. The prevalence of congenital and acquired deafness was 0.046% (232/504348) and 0.111% (560/504348), respectively, much lower than previously reported in other regions of China. Furthermore, the genetic factor was identified as one of the principal causes of deafness by pedigree analysis.

Effect of auditory deprivation on binaural sensitivity in bilateral cochlear implant users.

Increasing numbers of cochlear implant (CI) users receive Implants in both ears in an effort to restore spatial hearing abilities. A known limitation of commercial CI devices is lack of synchrony to the signal fine timing cues arriving at the two ears. In addition to these hardware limitations, which may contribute in substantial ways to the gap in performance typically seen between bilateral CI users and normal-hearing people, there are considerable inter-subject differences in the type and history of hearing loss. We use a research processor which enables inter-aurally coordinated pulsatile stimulation of selected pairs of electrodes in the right and left ears. This project is concerned with the effects of the age at onset of deafness, and place of stimulation, on binaural sensitivity. Thresholds for discrimination of inter-aural time difference (ITD) and inter-aural level difference(ILD) and pointer-identification for perceived intracranial position were measured. Prelingually deafened subjects had no sensitivity to ITD but retained ILD sensitivity. People with childhood- or adult-onset of deafness retained sensitivity to both ITD and ILD, some within normal-hearing level of performance on some conditions. The role of auditory deprivation in the emergence and preservation of binaural sensitivity will be discussed. [Work supported by NIH-NIDCD.]

Investigation of the child with permanent hearing impairment

In England the birth prevalence of bilateral per manent childhood hearing impairment (PCHI) of >40 dB HL is approximately 1:1000 live births but almost doubles up to the age of...

Effect of age at onset of deafness on binaural sensitivity in electric hearing in humans

Sensitivity to binaural cues was studied in 11 bilateral cochlear implant users, all of whom received both of their cochlear implants as adults, but who varied in the age at onset of deafness, from pre-lingual to childhood-onset to adult-onset. Sensitivity to interaural timing difference (ITD) and interaural level difference (ILD) cues was measured at basal, middle, and apical pitch-matched places of stimulation along the cochlear arrays, using a stimulation rate of 100 Hz. Results show that there is a trend for people whose onset of deafness occurred during adult life or late childhood to retain at least some sensitivity to ITDs, whereas people with onset of deafness earlier in life were insensitive to ITDs. In contrast, ILD cue sensitivity was present in all subjects. There were no effects of place of stimulation on binaural sensitivity, suggesting that there is no indication of a dependence of ITD sensitivity on apical vs basal electrode location.

Phenotypic and Expression Analysis of a Novel Spontaneous Myosin VI Null Mutant Mouse

In humans, hearing is a major factor in quality of life. Mouse models are important tools for the discovery of genes responsible for genetic hearing loss, often enabling analysis of the processes that regulate the onset of deafness in humans. Thus far, at least 400 deafness mutants have been discovered in laboratory mouse populations and used in the study of deafness. Here we report the discovery of a new spontaneous recessive Rinshoken shaker/waltzer (rsv) mutant derived from our in-house C57BL/6J stock, which exhibits circling and/or head-tossing behaviour and complete lack of auditory brain response to any sound pressure. The hearing and balance phenotypes are associated with structural defects, in particular, disorganisation and fusion of stereocilia in the inner ear hair cells. Two sets of intersubspecific N(2) mice were generated for the positional cloning of the rsv mutation. The mutant locus was mapped to a 4.8-Mb region of chromosome 9, which contains myosin VI (Myo6), a gene responsible for deafness in humans and Snell's waltzer mutation in mice. The rsv mutant showed reduced expressions of Myo6 mRNA and MYO6 protein in the inner ear. Moreover, no immunoreactivity was observed in the cochlear and vestibular hair cells in the rsv mutant mice. We sequenced the genomic region (30,154 bp) of Myo6, including all coding exons, a non-coding exon, UTRs and the Myo6 promoter; however, no mutation was discovered in these regions. We therefore speculate that loss of MYO6 expression might cause shaker/waltzer behaviour and deafness in the rsv mutant; also, loss of MYO6 expression might be the result of mutations in an unidentified regulatory region(s) of the gene.

Speech Perception after Cochlear Implantation in 53 Patients with Otosclerosis: Multicentre Results

Objectives: To analyse the speech perception performance of 53 cochlear implant recipients with otosclerosis and to evaluate which factors influenced patient performance in this group. The factors included disease-related data such as demographics, pre-operative audiological characteristics, the results of CT scanning and device-related factors. Methods: Data were reviewed on 53 patients with otosclerosis from 4 cochlear implant centres in the United Kingdom and the Netherlands. Comparison of demographics, pre-operative CT scans and audiological data revealed that the patients from the 4 different centres could be considered as one group. Speech perception scores had been obtained with the English AB monosyllable tests and Dutch NVA monosyllable tests. Based on the speech perception scores, the patients were classified as poor or good performers. The characteristics of these subgroups were compared. Results: There was wide variability in the speech perception results. Similar patterns were seen in the phoneme scores and BKB sentence scores between the poor and good performers. The two groups did not differ in age at onset of hearing loss, duration of hearing loss, progression, age at onset of deafness, or duration of deafness. Conclusions: The clinical presentation of the otosclerosis (rapid or slow progression) did not influence speech perception. Better performance was related to less severe signs of otosclerosis on CT scan, full insertion of the electrode array, little or no facial nerve stimulation and little or no need to switch off electrodes.

Self-Reported Listening Habits and Enjoyment of Music among Adult Cochlear Implant Recipients

We sought to assess the associations between self-reported listening habits and enjoyment of music, and the following variables: age at implantation, gender, prelingual versus postlingual deafness, duration of deafness, duration of cochlear implant (CI) use, type of CI, speech coding strategy, and speech perception abilities. A questionnaire on listening habits and enjoyment of music before the onset of deafness and after implantation was sent to 85 adult CI recipients who had been using the devices for at least 6 months. Of the 53 responders, 39 (73.6%) listened to music after implantation. Listening to music was not significantly related to age at implantation, gender, duration of deafness, duration of CI use, type of CI device, speech coding strategy, or open-set speech perception abilities. The 14 nonlisteners were postlingually deafened. The ratings of enjoyment were the same for 22.6% of patients, improved for 26.4%, and worse for 50.9%. Only 2 of 13 patients who played a musical instrument and 14 of 24 patients who sang before the onset of deafness resumed their musical activities. Despite the decline in listening habits and in the enjoyment of music after cochlear implantation, most patients do listen to music. The changes in listening habits and enjoyment were not related to the selected background variables.

Subacute onset of deafness and vertigo in a patient with leptomeningeal metastasis from ovarian cancer

Ovarian carcinoma is a common gynecological malignancy. Distant metastases usually involve the liver and lung while neurological complications are rare. We describe the case of a 63-year-old woman diagnosed from an ovarian carcinoma with peritoneal seed, which was treated surgically and with chemotherapy. After 4 years she was admitted to our Department for the development of subacute right deafness, vertigo and imbalance. MRI revealed the presence of leptomeningeal carcinomatosis and an expansive formation in the right pontocerebellar angle, suggesting involvement of the right VIII cranial nerve. Examination of the cerebrospinal fluid disclosed the presence of neoplastic cells. Subsequently the patient rapidly deteriorated and eventually died. Involvement of VIII cranial nerve as the presentation of leptomeningeal carcinomatosis in ovarian carcinoma is rare. In the literature at least two other cases presented with deafness, suggesting that leptomeningeal carcinomatosis should be considered in the differential diagnosis when deafness appears in a cancer patient.

The association of codeine, macrocytosis and bilateral sudden or rapidly progressive profound sensorineural deafness

Conclusions. Codeine shows a similar association with profound deafness to other opiates. Good cochlear implant outcomes suggest a sensory disorder. Although macrocytosis could be due to confounding factors, the lack of other consistent findings may signify a vascular pathology. Objectives. To describe a series of patients identified as codeine users after referral for cochlear implantation. Patients and methods. This was a retrospective case series review. Patients were identified by the senior audiologist. Information regarding mode of onset of deafness, past medical history, drug and alcohol history, investigations and audiological outcomes following cochlear implantation was collected from hospital records and patient questionnaires. Results. Ten patients were included in the study. All patients had taken codeine phosphate and paracetamol in combination for several years, usually at greater than recommended daily dose. All patients presented with sudden or rapidly progressive bilateral deafness. All patients had a significant macrocytosis at the time of deafness (mean cell volume (MCV): mean 115 fL; range 105–132 fL). No other investigation was consistently abnormal. Four patients had a history of alcoholism. Seven patients had abnormal liver function tests. Patients usually performed well with cochlear implants (CUNY sentence scores without lip reading >90% in 9 of 10 patients).