Cochlear Implantation in Cases of Inner Ear Malformation: A Novel and Simple Grading, Intracochlear EABR, and Outcomes of Hearing.

OBJECTIVE: To propose a simple grading of inner ear malformation (IEM) and investigate intracochlear electrical auditory brainstem response (EABR) and outcomes for hearing in terms of the novel grading system. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Sixty patients with IEMs who received cochlear implants. INTERVENTION: Grading according to observation of modiolus deficiency and/or internal auditory canal (IAC) cochlear nerve deficiency (CND). MAIN OUTCOME MEASURE: Intracochlear EABR and categories of auditory performance (CAP) scores were assessed; children in school were categorized according to the type of school attended. RESULTS: Among 60 patients, 38% were classified as Grade I (modiolus present + normal cochlear nerve), 22% as grade II (modiolus deficiency + normal cochlear nerve), 33% as grade III (modiolus present + IAC CND), and 7% as grade IV (modiolus deficiency + IAC CND). During the operation, 93% of Grade I, 36% of Grade II, 23% of Grade III, and 50% of Grade IV patients showed typical EABR waves. CAP scores of 4 or more were obtained from 91% of Grade I, 62% of Grade II, 35% of Grade III, and 25% of Grade IV. Whereas none of children in Grades III and IV entered main stream school, 55% of Grade I and 25% of Grade II entered mainstream schools. CONCLUSIONS: Outcomes of hearing with cochlear implantations in IEM children depend on the severity of IEM and IAC CND. Our novel grading of IEM is simple and can be useful for understanding the severity of IEM.

EABR measurements during cochlear implantation in one-year-old, infant, child, adult, and elderly patients.

BACKGROUND: Clinical application of electrically-evoked intracochlear auditory brainstem responses (eABRs) for evaluation of brainstem maturity or aging changes has not been well investigated. AIM/OBJECTIVE: We compare the eV latencies of intraoperative eABR measurements in one-year-olds, infants, children, adults, and the elderly, with the goal of investigating the changes in the brainstem auditory pathway due to development and aging. MATERIALS AND METHODS: We studied 58 ears of 51 patients who underwent cochlear implantation between 2013 and 2019 using MED-EL's Concerto or Synchrony implants with Flex28 or Flex soft electrodes. EABRs were recorded during cochlear implantation. The stimuli were delivered by the MED-EL Maestro to the apical, middle, and basal turn electrodes at stimulus levels 1000, 800, and 600 cu, with a pulse width of 30 µs. RESULTS: In eABRs recorded from electrodes installed at both the mastoid and nape, there was no difference in latency between age groups within each stimulus level. CONCLUSION AND SIGNIFICANCE: ABR latency was not affected by development after age one and aging of the brainstem auditory pathway. Our study will be useful as a control in identifying abnormal eABR wave configurations in patients with cochlear malformations, cochlear nerve deficiencies, or auditory neuropathy, regardless of age.

Electrically evoked ABR during cochlear implantation and postoperative development of speech and hearing abilities in infants with common cavity deformity as a type of inner ear malformation.

Background: The electrically evoked auditory brainstem response (eABR) during cochlear implantation in common cavity (CC) deformity has not been clinically well studied.Aim/Objective: To investigate the eABR wave configuration during cochlear implantation, the postoperative development of hearing, and educational settings in infants with CC deformity.Materials and Methods: Nine infants who were congenitally deaf and found to have CC deformity and suspected cochlear nerve deficiency by temporal bone CT and MRI were studied. All of them underwent sequential and unilateral cochlear implantation and their eABRs were recorded during the surgery. The postoperative development was followed up.Results: eABRs of all the nine infants with CC deformity showed that the mean peak of the evoked wave V (eV) was the same as that in controls at latencies but was twofold higher than that in controls at thresholds and their postoperative hearing thresholds improved markedly.Conclusion and Significance: The brainstem auditory pathways of the infants were considered intact on the basis of the eV peak latencies in the eABRs. The postoperative development of their speech and hearing abilities and their educational settings varied, probably because of the twofold higher thresholds of their eABRs and limited number of auditory neural units.

Elongated EABR wave latencies observed in patients with auditory neuropathy caused by OTOF mutation.

OBJECTIVES: We sought to determine how the pathology altered electrically evoked auditory brainstem responses (EABRs) in patients with hearing loss by evaluating EABRs in auditory neuropathy patients with OTOF mutations comparing with various types of congenital deafness. METHODS: We included 15 patients with congenital hearing loss, grouped according to pathology: OTOF mutations (n = 4), GJB2 mutations (n = 4), SLC26A4 mutations (n = 4), or cytomegalovirus infections (n = 3). EABRs were recorded when patients underwent cochlear implantation surgery. We evaluated the latencies and amplitudes of the recorded EABRs and compared them statistically between four groups. RESULTS: The EABR latencies of Wave III and Wave V, and of the interval between them, were significantly longer in the OTOF mutation group than in the GJB2 and SLC26A4 mutation groups (Wave III) and in all three other groups (Wave V and Wave III-V latency); amplitudes were not significantly different between groups. CONCLUSIONS: Our results suggest OTOF mutations cause delayed (or slowed) postsynaptic neurotransmission, although the presumed mechanism involved reduced presynaptic transmission between hair cells and spiral ganglion neurons. LEVEL OF EVIDENCE: Mainly a case report.

Usefulness of measuring electrically evoked auditory brainstem responses in children with inner ear malformations during cochlear implantation.

CONCLUSIONS: EABR is a reliable and effective way of objectively confirming device function and implant-responsiveness of the peripheral auditory neurons up to the level of the brainstem in cases of inner ear malformation. OBJECTIVE: To investigate the usefulness of measuring the intra-operative electrically evoked compound action potential (ECAP) and electrically evoked auditory brainstem response (EABR) in patients with and without congenital inner ear anomalies during cochlear implantation. METHOD: Thirty-eight consecutive children (40 ears) aged 5 or younger with congenital profound hearing loss. Twenty-four (25 ears) lacked congenital inner ear anomalies. The 14 patients (15 ears) with a malformation had common cavities (four ears), incomplete partition type I (three ears), cochlea hypoplasia type III (three ears), enlarged vestibular aqueduct (four ears), and cochlear nerve canal stenosis (one ear). Main outcome measures are ECAP and EABR responses. RESULTS: Of the 25 ears lacking any malformation, 21, three, and one showed 'Good', 'Variable', and 'No' ECAP responses, respectively, and 24 and one showed 'Good' and 'Variable' intra-cochlear responses, respectively. Of the 15 ears with a malformation, two showed 'Good' ECAP responses, nine had 'Variable' ECAP responses, and four showed 'No' ECAP responses. Moreover, five showed 'Good' EABR responses and 10 showed 'Variable' EABR responses.

A case of cortical deafness and loss of vestibular and somatosensory sensations caused by cerebrovascular lesions in bilateral primary auditory cortices, auditory radiations, and postcentral gyruses - complete loss of hearing despite normal DPOAE and ABR.

CONCLUSION: A right-handed 38-year-old man's complete loss of hearing could be diagnosed as cortical deafness caused by cerebral vascular lesions in bilateral auditory cortices. OBJECTIVE: The aim of this case report was to study the pathophysiology of a particular patient who manifested deafness without residual hearing and lost somatosensory sensation, vestibular sensation, and articulation ability after a right internal carotid-posterior communicating artery (IC-PC) aneurysm and subarachnoidal hemorrhage. METHODS: MRI, aphasia and neurological tests, subjective and objective audiometry, and vestibular function tests were performed. RESULTS: The neurological test revealed system loss of somatosensory sensation with normal motor function and articulation ability. Brain imaging revealed extensive infarction in the bilateral primary auditory cortices, postcentral gyruses, and the bilateral partial third frontal gyruses. Pure-tone audiometry of both ears revealed off-the-scale results and speech audiometry demonstrated 0% maximum speech discrimination. However, objective audiometry showed normal distortion product otoacoustic emissions (DPOAE) and normal auditory brainstem response (ABR). The patient showed 0% perception of environmental, speech, and music sounds in both ears. He was unable to feel vestibular sensation despite normal caloric nystagmus. He showed no damage to his larynx or articulation organs.

Age-related hearing loss and the factors determining continued usage of hearing aids among elderly community-dwelling residents.

While hearing aids are recommended for people with age-related hearing loss, many with impaired hearing do not use them. In this study, we investigated how many elderly people in the study area needed hearing aids, and the factors that determined continued wearing of the devices. The study area was Kurabuchi Town, Japan, where 1,437 residents (those aged 65 years or over) were eligible for participation in the study; 1,414 participated, of whom, 103 (7.3%) were already using hearing aids at the start of the study. After the primary screening, hearing aids were lent to 68 participants (4.8%) who did not already have one, 38 of whom (60.3% of the borrowers, representing 2.7% of the total aged population) went on to wear the hearing aid continuously. The Hearing Handicap Inventory for the Elderly (HHIE) score was significantly elevated among these 38 participants. This study indicated that hearing aids are of potential benefit to many local residents. Multivariate logistic regression revealed that HHIE scores were associated with the extent of HA usage. The adjusted odds ratio for a 1-unit increase in HHIE score was 1.08 (95% confidence interval: 1.02-1.14). Programs like this, in which people with impaired hearing are identified at the local level and given appropriate assistance, are useful models for future use in societies with aging populations.