X-linked deafness/incomplete partition type 3: Radiological evaluation of temporal bone and intracranial findings

PURPOSE:X-linked deafness (XLD) is a rare disease, characterized by typical cochlear incomplete partition type 3 anomaly (IP-III). Accompanying hypothalamic anomalies were also recently described. The purpose of this study was to document the temporal bone and intracranial imaging findings in a series of patients with XLD with a review of the literature, to better understand this anomaly.METHODS:The CT and MRI studied of 13 XLD patients were retrospectively evaluated. All structures of the otic capsule (OC) were subjectively and retrospectively assessed. The OC thickness and the size of the cochlea were measured and compared to the age-matched control group. Intracranial structures were also evaluated with specific attention to the hypothalamic region.RESULTS:All cases had bilateral IP-III anomaly, bulbous internal auditory canals (IACs), absent bony modiolus with preserved interscalar septa, intact cochleovestibular, and facial nerves. OC thickness was decreased in all cases compared to the control group (p<0.001). In XLD patients, the cochlea had decreased transverse dimension and increased height compared to the control group (p< 0.001). Five patients (38.4%) had bilateral cystic structures adjacent to the vestibule and/or semicircular canals (SCCs). Hypothalamus was thickened or had a lobular appearance in all cases (subtle in one). Additionally, hamartoma-like appearance of the hypothalamus was present in half.CONCLUSION:XLD is a rare inner ear anomaly that is frequently associated with hypothalamic malformations. The OC thickness of IP-III patients appears to be decreased with accompanying decreased transverse dimension of the cochlea which could have implications in electrode selection during cochlear implantation. Cystic /diverticular lesions surrounding the vestibule and semicircular canals are also frequently seen but a rarely reported finding

Novel domain-specific POU3F4 mutations are associated with X-linked deafness: examples from different populations

BACKGROUND: Mutations in the POU3F4 gene cause X-linked deafness type 3 (DFN3), which is characterized by inner ear anomalies. METHODS: Three Turkish, one Ecuadorian, and one Nigerian families were included based on either inner ear anomalies detected in probands or X-linked family histories. Exome sequencing and/or Sanger sequencing were performed in order to identify the causative DNA variants in these families. RESULTS: Four novel, c.707A>C (p.(Glu236Ala)), c.772delG (p.(Glu258ArgfsX30)), c.902C>T (p.(Pro301Leu)), c.987T>C (p.(Ile308Thr)), and one previously reported mutation c.346delG (p.(Ala116ProfsX26)) in POU3F4, were identified. All mutations identified are predicted to affect the POU-specific or POU homeo domains of the protein and co-segregated with deafness in all families. CONCLUSIONS: Expanding the spectrum of POU3F4 mutations in different populations along with their associated phenotypes provides better understanding of their clinical importance and will be helpful in clinical evaluation and counseling of the affected individuals. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12881-015-0149-2) contains supplementary material, which is available to authorized users

Contralateral non-auditory stimulation in auditory brainstem implantation: A case report

Auditory brainstem implants (ABIs) are neuroprosthetic devices that stimulate the cochlear nuclei without any connection between the inner ear and brainstem [1,2]. The first pediatric ABI surgery was performed in 2000 on a prelingually deafened child with common cavity and cochlear nerve aplasia [3]. More than one thousand ABIs have been placed in adults and children around the world since the late 1970sWo

Audiological And Radiological Characteristics In Incomplete Partition Malformations

OBJECTIVE: To compare the audiological and radiological findings of patients with incomplete partition malformations (IPs) and analyze the relationship between the audiological and radiological findings. MATERIALS and METHODS: The study included 84 patients (168 ears) with IPs as follows: 26 patients with Type I; IP-I (41 ears), 54 patients with Type II; IP-II (108 ears), and 4 patients with Type III; IP-III (8 ears). Remaining 11 ears were diagnosed with other inner ear malformations. Air and bone conduction thresholds were determined with pure tone audiometry, and the air bone gap was recorded in all patients with IPs. Magnetic resonance imaging studies and computerized tomography scans of the temporal bones were analyzed using the PACS system of our university. RESULTS: It was found that all the ears with IP-I were diagnosed with severe to profound hearing loss. The degree of the hearing loss varied from mild to severe/profound in patients with IP-II. Severe to profound mixed hearing loss (MHL) was determined in all ears with IP-III. The air bone gap was larger in the lower frequencies in the IP-II cases diagnosed with MHL. There was not a significant difference between the air bone gap and the size of the vestibular aqueduct in ears with IP-II (p>0.05). CONCLUSION: Each type of IP has different audiological findings. Depending on the type and degree of the hearing loss, it is possible to choose the appropriate audiological intervention. Patients with IP should be evaluated according to the type of malformation.WoSScopu

Brain stem responses evoked by stimulation with an auditory brain stem implant in children with cochlear nerve aplasia or hypoplasia

Objectives: The inclusion criteria for an auditory brain stem implant (ABI) have been extended beyond the traditional, postlingually deafened adult with Neurofibromatosis type 2, to include children who are born deaf due to cochlear nerve aplasia or hypoplasia and for whom a cochlear implant is not an option. Fitting the ABI for these new candidates presents a challenge, and intraoperative electrically evoked auditory brain stem responses (EABRs) may assist in the surgical placement of the electrode array over the dorsal and ventral cochlear nucleus in the brain stem and in the postoperative programming of the device. This study had four objectives: (1) to characterize the EABR by stimulation of the cochlear nucleus in children, (2) to establish whether there are any changes between the EABR recorded intraoperatively and again just before initial behavioral testing with the device, (3) to establish whether there is evidence of morphology changes in the EABR depending on the site of stimulation with the ABI, and (4) to investigate how the EABR relates to behavioral measurements and the presence of auditory and nonauditory sensations perceived with the ABI at initial device activation