Cochlear implant after bacterial meningitis

Cochlear Implantation in Post-Meningitis Deafness: Audiological, Imaging, and Postoperative Outcomes: A Systematic Review With Qualitative Synthesis

INTRODUCTION

Post-meningitis deafness (PMD) is a potentially devastating cause of hearing loss among pediatric and adult patients, for which hearing rehabilitation with cochlear implants (CIs) remains the standard of care. To date, there have been limited systematic studies on the impact of cochlear ossification (CO) and time-to-implantation (TTI) on audiological outcomes.

METHODS

An online database search was performed on the PubMed, Embase, and Scopus databases for articles within the past 20 years pertaining to audiological outcomes among pediatric and adult patients with PMD. Information on study characteristics, patient demographics, clinical outcomes, and postoperative complications was collected and analyzed.

RESULTS

From 8,325 articles generated in the original search, 11 were included in the final analysis, representing 376 patients in total. Of the articles discussing TTI, the majority (3 of 4) found that a shorter TTI of 6 months on average led to improved audiological outcomes compared with control groups with a longer TTI. Of the articles that discussed the impact of preoperative CO, the majority (4 of 6) found that the presence of CO had a detrimental effect on postoperative audiological outcomes after CI. Finally, of the articles that discussed long-term audiological outcomes for PMD compared with the non-PMD control group after CI, the majority (4 of 7) found that PMD patients had inferior long-term outcomes.

CONCLUSION

CI is a safe and effective treatment modality for PMD, with the majority of literature demonstrating improved long-term outcomes for patients without CO and a reduced TTI.

Bacterial Meningitis in Children: Neurological Complications, Associated Risk Factors, and Prevention

Bacterial meningitis is a devastating infection, with a case fatality rate of up to 30% and 50% of survivors developing neurological complications. These include short-term complications such as focal neurological deficit and subdural effusion, and long-term complications such as hearing loss, seizures, cognitive impairment and hydrocephalus. Complications develop due to bacterial toxin release and the host immune response, which lead to neuronal damage. Factors associated with increased risk of developing neurological complications include young age, delayed presentation and Streptococcus pneumoniae as an etiologic agent. Vaccination is the primary method of preventing bacterial meningitis and therefore its complications. There are three vaccine preventable causes: Haemophilus influenzae type b (Hib), S. pneumoniae, and Neisseria meningitidis. Starting antibiotics without delay is also critical to reduce the risk of neurological complications. Additionally, early adjuvant corticosteroid use in Hib meningitis reduces the risk of hearing loss and severe neurological complications.

Cochlear implant indications: a review of third-party payers' policies for standard and expanded indications

As cochlear implant (CI) candidacy has expanded, commercial payers in the United States have varied in their adoption of new indications, potentially confusing providers' knowledge about appropriate patients for referral. We reviewed how third-party payers classify the medical necessity of cochlear implants for a variety of indications across the lifespan.We compared policies of the six largest commercial payers in our region, focusing on clinical scenarios for which many centers experience difficulty obtaining pre-authorization. These include: (1) CI in children under 12 months, (2) audiometric and speech perception criteria in children, (3) sequential bilateral CI, (4) electro-acoustic stimulation, (5) impending cochlear ossification, and (6) single-sided deafness (SSD).Of the more notable findings for the clinical scenarios half of commercial payers have a pediatric age requirement of greater than 12 months. Generally, audiologic and speech perception criteria are more stringent for children than adults across all policies. SSD is considered investigational by most policies.Third-party payers employ variable criteria regarding the medical necessity of CI, many of which are not contemporaneous with clinical knowledge and best practices. This may impact referral patterns among audiologists. More methodologically rigorous clinical trials may help shift such restrictive policies to benefit a greater number of patients.

Outcomes of Cochlear Implantation in Patients with Post-Meningitis Deafness: A Systematic Review and Narrative Synthesis

Summarise outcomes following cochlear implantation (CI) in patients with post-meningitis deafness. Systematic review and narrative synthesis. Databases searched: Medline, Pubmed, Embase, Web of Science, Cochrane Collection and ClinicalTrials.gov. No limits placed on language or year of publication. Studies with a minimum of 20 individuals with post-meningitis deafness were included. Review conducted in accordance with the PRISMA statement. Searches identified 906 abstracts and 291 full texts. Of these, 19 studies met the inclusion criteria, reporting outcomes in 610 patients with 650 implants. Audiological outcomes improved across all studies following cochlear implantation. 7 studies demonstrated a statistically significant difference between pre and post-CI outcomes. Patients with no cochlear ossification, full electrode insertion, shorter duration of deafness and no neurological sequelae generally appeared to perform best. A total of 31 minor and 19 major complications were reported, with 15 cases of reimplantation. The methodological quality of the included studies was sufficient, predominantly consisting of cohort studies. 15 studies were OCEBM grade III and 4 studies were OCEBM grade IV. All studies had a minimum of 20 individuals with post-meningitic deafness and used multi-channel cochlear implant devices. Audiological outcomes following cochlear implantation in meningitis are satisfactory, providing functional levels of speech perception and intelligibility. Improvement in hearing is dependent on the amount of cochlear ossification, duration of deafness prior to implantation, electrode insertion depth and presence of neurological sequalae. Cochlear implantation in meningitis patients can be challenging due to the presence of ossification and inaccuracies of pre-operative imaging. Therefore, early and bilateral implantation is recommended in all patients with post-meningitis hearing loss to improve the likelihood of full electrode insertion.

Facial nerve stimulation in a post-meningitic cochlear implant user: using computational modelling as a tool to probe mechanisms and progression of complications on a case-by-case basis

Facial nerve stimulation (FNS) is a side-effect of cochlear implantation that can result in severe discomfort for the user and essentially limits the optimal use of the implant. Three-dimensional cochlear implant modelling research has led to the progression from generic models to user-specific models with one of the intentions to develop model-based diagnostic tools. The objective of this study is to investigate the mechanisms that underlie the manifestation of FNS in the post-meningitic cochleae of a specific CI user through computational modelling. Bilateral models were created using a method previously developed for the construction of a three-dimensional user-specific volume conduction model of the cochlea and was expanded to include the facial nerve geometry. Reduced temporal bone density based on bone densitometry, cochlear duct ossification and degenerate auditory neural fibres were incorporated into a comprehensive FNS model. Auditory and facial nerve thresholds were predicted with the models showing good correspondence to perceptual thresholds and the user's FNS experience. Ossified cochlear ducts appear to aggravate the increase in thresholds caused by the otic capsule's decreased resistivity. This translational case study demonstrates the application of computational modelling as a clinical instrument in the assessment and management of complications with cochlear implantation.

A Comparison of Surgical Auditory Nerve Response and Speech Outcomes in Patients with Post-meningitic Deafness and Without Cochlear Osteogenesis Who Underwent Cochlear Implantation

Objective

Patients with post-meningitis deafness remain challenging candidates for cochlear implantation (CI) which can be difficult due to fibrosis or ossification of the inner ear, and their outcomes remain doubtful. We assessed the surgical and audiological outcomes of CI in patients with profound sensorineural hearing loss caused by meningitis and compared those outcomes to patients without cochlear ossification.

Methods

This retrospective cross-sectional study was carried out at King Fahad General Hospital, Jeddah, Saudi Arabia. Among 246 patients who underwent cochlear implantation, 13 patients with post-meningitic deafness were identified (Group 1). A matched control group, including patients with deafness due to other causes who did not have cochlea osteogenesis, was selected (Group 2). For all patients, data were collected from medical records, including surgical and audiological outcomes.

Results

Sclerosis of the cochlea was high in Group 1 (46.2%). There were no postoperative surgical complications in either group. Responses of the auditory nerve action potential obtained through auditory response telemetry (ART) or the neural response telemetry (NRT) were recorded. There was no significant difference between the two groups regarding the intraoperative and the postoperative ART or NRT at selected electrodes representing the entire cochlea. Likewise, no significant difference regarding the speech recognition test (SRT) was detected.

Conclusions

Cochlear implantation is a safe procedure without surgical complications in post-meningitis patients. Furthermore, early CI in children was associated with favorable outcomes in terms of preservation of the auditory nerve response, restoration of speech discrimination, and recognition to levels comparable to patients with deafness due to other causes. Early audiological assessment in meningitis patients is recommended to identify hearing loss and eventually to offer CI.

Deafness and sickle cell disease: three case reports and review of the literature

The otological complications of sickle cell disease (SCD) in general and the audiological complications in particular are not well documented and studied. Because the general management of patients with SCD has improved after the advent of newborn screening, antibiotic prophylaxis, safer blood transfusion and hydroxyurea therapy, patients with SCD are doing better in general and living longer than before. With longer longevity, the incidence of new complications of SCD became apparent and previously milder complications became more severe and more common. The dental and otological complications of SCD are examples of these changes that have become more common than before. Unfortunately with this increase, there are no guidelines or recommendations based on evidence on how to manage and treat these complications. The aim of this study was to describe three patients with SCD and deafness due to three different causes that were not adequately treated and to review the literature of deafness in SCD. We hope this may initiate more controlled trials on the incidence, prevalence and management of these complications.