Key Publications Öne Çıkan Yayınlar

A case report of contralateral facial nerve stimulation in a two-year-old child with pontocerebellar hypoplasia and cochlear nerve aplasia who received an ABI. The first report of contralateral non-auditory stimulation in a paediatric ABI recipient. Despite only three activated electrodes, the child demonstrated progressive improvement in auditory perception and language development at one year follow-up.

A comprehensive invited review classifying inner ear malformations (IEMs) into eight distinct groups based on cochlear anatomy. Describes radiological and audiological findings, surgical management, electrode selection, and indications for cochlear versus auditory brainstem implantation. Includes a practical classification of cochlear nerve deficiency guiding implantation decisions.

A prospective clinical study evaluating audiological and radiological findings across four subtypes of cochlear hypoplasia (CH-I to CH-IV) in 66 subjects with 112 affected ears. Cochlear hypoplasia type IV was statistically distinct from the other three groups in terms of hearing loss degree, type, and cochlear nerve/aperture status. The incidence of cochlear hypoplasia was 23.5% among all inner ear malformations in the Hacettepe IEM database.

A retrospective study of 36 children fitted with ABI between 2005 and 2013 at Hacettepe University. All children gained basic auditory perception skills by three months post-activation. Auditory functionality improved notably after four years of ABI use. Language and speech development varied considerably; additional handicaps slowed progression, and early implantation with strong family support were identified as key outcome predictors.

A comprehensive review article covering the history and development of ABI, indications (NF2, non-tumour postlingual, and prelingually deafened children with malformations), side selection criteria, surgical approaches (translabyrinthine and retrosigmoid), intraoperative monitoring, complications, and audiological outcomes. Includes detailed anatomy of the cochlear nuclei and foramen of Luschka, with management of 21 paediatric ABI cases at Hacettepe University.

The first study to assess written language skills in 15 children (grades 2–8) with ABI. All children demonstrated delayed written expression: none reached the "well writing" level, with most scoring in the "inconsiderable" range. Children using auditory-verbal communication had better scores. Written language outcomes correlated with CAP, SIR, and expressive language levels. Age at implantation, duration of ABI use, and additional handicaps were identified as key determinants of written language development.

A retrospective study of 5 paediatric nontumour ABI users who underwent revision surgery for device malfunctions at Hacettepe University (revision rate 6.45% among 155 paediatric ABI cases). MAIS and receptive/expressive language scores improved significantly after revision surgery. Aided thresholds showed no significant group-level change but individual improvements were noted. Most failures were caused by head trauma. The study demonstrates that revision surgery is worthwhile and effective in preserving or improving auditory and language outcomes in paediatric ABI users.

The first study evaluating speech-perception skills in toddlers with simultaneous bilateral cochlear implants using the Visual Reinforcement Infant Speech Discrimination (VRISD) test. Phoneme discrimination responses (/a-i/ and /ba-da/ contrasts) were similar between the cochlear implant group and normal-hearing infants. VRISD scores were highly correlated with IT-MAIS scores (r=0.822). The findings suggest that speech-perception development with CI is strongly influenced by environmental exposure and sound access, and that VRISD is an effective clinical tool for this population.

Consensus statement from the 2nd International Pediatric ABI Meeting (Kyrenia, 2013), representing 20 centres across 11 countries. Reports that ABI provides sound detection and supports language development in children with complex inner ear malformations, though outcomes generally remain below those of cochlear implant users. Covers audiological evaluation protocols, radiological indications (definite and probable), imaging (MRI and CBCT), surgical timing, intraoperative monitoring, postoperative follow-up, and management of complications including device migration and revision surgery. Recommends ABI before age 2 for optimal outcomes and emphasises multidisciplinary team involvement and appropriate family counselling.

Consensus statement from the Third International Pediatric ABI Symposium (online, September 2020), drawing on data from 41 departments across 19 countries. Reviews classification and imaging of inner ear malformations, unusual ABI indications, audiological assessment methods, decision-making between CI and ABI, surgical technique (retrosigmoid approach), complications, revision surgery, intraoperative monitoring, device programming, and outcomes from multiple international centres. Proposes standardised eligibility criteria, surgical guidelines, rehabilitation frameworks, and long-term follow-up protocols. Emphasises that early implantation (before age 3) correlates with better outcomes and that bimodal CI+ABI stimulation yields superior results in bilateral cochlear nerve deficiency.

The first study to quantify cochlear angular orientation in CHARGE syndrome. Axial CT measurements in 18 CHARGE patients and 18 age-matched controls showed that mean cochlear angulation was significantly narrower in the CHARGE group (94.49° ± 10.02°) compared with controls (114.02° ± 8.17°, p<0.001). Cochlear hypoplasia type III was the predominant inner ear finding (66.7% of ears). The altered spatial orientation — attributed to increased lateral rotation of the anterior cochlea within the petrous bone — is proposed as a key contributor to the surgical difficulties in locating the cochlea and identifying the round window during cochlear implantation in CHARGE patients. Preoperative recognition of this feature may improve surgical planning.

A case-series study comparing auditory reasoning skills in 90 prelingually deaf children aged 7–10 years, divided into early-implanted (<3 years; n=42) and late-implanted (≥3 years; n=48) groups. The early-implanted group scored significantly higher on total auditory reasoning (SIMIBT) and all six subtests (general knowledge, arithmetic, verbal absurdities, analogical completions, causal reasoning, similarities). Language performance, vocabulary knowledge, and daily communication skills (FAPCI) were also significantly better in early-implanted children. Stepwise regression showed that expressive language, receptive vocabulary, and chronological age predicted 82% of the variance in auditory reasoning. Highlights the need to explicitly target higher-order cognitive and reasoning skills in CI rehabilitation programmes.

A retrospective review of 2945 cochlear implant surgeries at Hacettepe University (1997–2023) examining outcomes in patients with otitis media with effusion (OME; n=169) versus those with a ventilation tube (VT) in situ (n=55). No significant differences were found between groups in intraoperative findings, complications, or postoperative infection rates. However, the revision rate was significantly higher in the OME group than in the VT group (10.65% vs. 0%, p=0.008), and also higher than the overall non-OME/non-VT cohort (5.29%, p=0.003). Low functional gain was the only revision reason that differed significantly between OME and the general cohort. The study concludes that VT insertion prior to CI is not mandatory for avoiding perioperative complications, but the higher revision rate in OME warrants further investigation into the role of middle ear inflammation and biofilm formation in long-term device outcomes.