Age-related hearing impairment (ARHI), or presbycusis, is the most prevalent sensory impairment in the elderly. ARHI is a complex disease caused by an interaction between environmental and genetic factors. Here we describe the results of the first whole genome association study for ARHI. The study was performed using 846 cases and 846 controls selected from 3434 individuals collected by eight centers in six European countries. DNA pools for cases and controls were allelotyped on the Affymetrix 500K GeneChip for each center separately. The 252 top-ranked single nucleotide polymorphisms (SNPs) identified in a non-Finnish European sample group (1332 samples) and the 177 top-ranked SNPs from a Finnish sample group (360 samples) were confirmed using individual genotyping. Subsequently, the 23 most interesting SNPs were individually genotyped in an independent European replication group (138 samples). This resulted in the identification of a highly significant and replicated SNP located in GRM7, the gene encoding metabotropic glutamate receptor type 7. Also in the Finnish sample group, two GRM7 SNPs were significant, albeit in a different region of the gene. As the Finnish are genetically distinct from the rest of the European population, this may be due to allelic heterogeneity. We performed histochemical studies in human and mouse and showed that mGluR7 is expressed in hair cells and in spiral ganglion cells of the inner ear. Together these data indicate that common alleles of GRM7 contribute to an individual's risk of developing ARHI, possibly through a mechanism of altered susceptibility to glutamate excitotoxicity.

Children with congenital atresia of the external auditory canal require an early assessment of hearing and a determination of the degree of atresia and associated pathology by polytomography and/or high‐resolution CT scanning. We analyzed the otologic findings in 302 ears (239 patients) with severe atresia of the external auditory canal. Eighty‐seven primary or revision surgeries were performed. Fifty‐three percent obtained a residual conductive deficit of 20 dB or less. Lateralization of the tympanic membrane graft was the primary cause of failure in obtaining good hearing results. The use of split‐thickness skin graft instead of a full‐thickness skin graft to cover the reconstructed external canal has decreased the incidence of restenosis and revision surgery.

Objective To demonstrate that sudden sensorineural hearing loss is possibly of viral origin rather than vascular. Study Design The histopathologic morphology in 7 temporal bones with known vascular impairment due to surgical interventions was compared with that of 11 bones with a history of idiopathic sudden sensorineural hearing loss (ISSNHL). Attention was paid to the spiral ligament, stria vascularis, organ of Corti hair cells, tectorial membrane, ganglion cell population, and degree of perilymph fibrosis and the auditory nerve. Setting A temporal bone laboratory that has been in operation for more than 50 years and includes a database consisting of clinical and histopathological information that facilitates quantitative and qualitative analysis. Subjects Eight hundred forty-nine individuals who pledged their temporal bones for scientific study, of which 18 were selected for this study by means of the database criteria of sudden sensorineural hearing loss and postmiddle fossa and retro sigmoid sinus tumor removal or vestibular nerve section. Results Sudden sensorineural hearing loss bones exhibited no perilymph fibrosis compared with 6 of 7 vascular cases with fibrosis (P ≤ .001), exhibited less loss of ganglion cells (P ≤ .026), exhibited greater survival of spiral ligament (P ≤ .029), and averaged twice the survival of hair cells and more widespread tectorial membrane abnormalities. Conclusion Analysis of human temporal bones from patients with a sudden sensorineural hearing loss does not support a vascular insufficiency but is more suggestive of a viral etiology.

No abstract

Objective-To demonstrate that sudden sensorineural hearing loss is possibly of viral origin rather than vascular.Study Design-The histopathologic morphology in 7 temporal bones with known vascular impairment due to surgical interventions was compared with that of 11 bones with a history of idiopathic sudden sensorineural hearing loss (ISSNHL). Attention was paid to the spiral ligament, stria vascularis, organ of Corti hair cells, tectorial membrane, ganglion cell population, and degree of perilymph fibrosis and the auditory nerve.Setting-A temporal bone laboratory that has been in operation for more than 50 years and includes a database consisting of clinical and histopathological information that facilitates quantitative and qualitative analysis.Subjects-Eight hundred forty-nine individuals who pledged their temporal bones for scientific study, of which 18 were selected for this study by means of the database criteria of sudden sensorineural hearing loss and postmiddle fossa and retro sigmoid sinus tumor removal or vestibular nerve section.Results-Sudden sensorineural hearing loss bones exhibited no perilymph fibrosis compared with 6 of 7 vascular cases with fibrosis (P ≤ .001), exhibited less loss of ganglion cells (P ≤ .026), exhibited greater survival of spiral ligament (P ≤ .029), and averaged twice the survival of hair cells and more widespread tectorial membrane abnormalities.Conclusion-Analysis of human temporal bones from patients with a sudden sensorineural hearing loss does not support a vascular insufficiency but is more suggestive of a viral etiology. Materials and MethodsThe temporal bone laboratory of our institution contains 840 pairs of temporal bones with accompanying complete clinical records. This study is in compliance with regulations of the institutional review board of St. Vincent Medical Center #06-030, October 4, 2012. Most bones are from patients in our own pledge program, but a few are from the National Temporal Bone Registry From the database containing information on these bones, a total of 7 bones from 6 patients were found that had undergone middle fossa, suboccipital, or retrolabyrinthine surgery for the removal of vestibular nerve schwannomas or vestibular nerve lysis for the relief of the vertigo of Ménière's disease. These approaches were used to preserve the patient's serviceable hearing. In all cases, the auditory nerve was left intact. The postoperative hearing loss could be attributed only to an inadvertent interruption of the blood supply. These cases were designated the postoperative vascular group. A total of 11 cases in the database were identified with ISSNHL. The bones had been fixed with buffered formalin, decalcified with ethylenediaminotetraacedic acid until shown by xray to be free of calcium, embedded in celloidin, and cut into 20-μm sections on a sliding microtome. Every 10th section was stained with hematoxylin and eosin and mounted on glass slides and cover slipped. The percentages of normal spiral ligament, stria vascularis, hair cells, and peripher...