Familial aggregation of pure tone hearing thresholds in an aging European population.

OBJECTIVE: To investigate the familial correlations and intraclass correlation of age-related hearing impairment (ARHI) in specific frequencies. In addition, heritability estimates were calculated. STUDY DESIGN: Multicenter survey in 8 European centers. SUBJECTS: One hundred ninety-eight families consisting of 952 family members, screened by otologic examination and structured interviews. Subjects with general conditions, known to affect hearing thresholds or known otologic cause were excluded from the study. RESULTS: We detected familial correlation coefficients of 0.36, 0.37, 0.36, and 0.30 for 0.25, 0.5, 1, and 2 kHz, respectively, and correlation coefficients of 0.20 and 0.18 for 4 and 8 kHz, respectively. Variance components analyses showed that the proportion of the total variance attributable to family differences was between 0.32 and 0.40 for 0.25, 0.5, 1, and 2 kHz and below 0.20 for 4 and 8 kHz. When testing for homogeneity between sib pair types, we observed a larger familial correlation between female than male subjects. Heritability estimates ranged between 0.79 and 0.36 across the frequencies. DISCUSSION: Our results indicate that there is a substantial shared familial effect in ARHI. We found that familial aggregation of ARHI is markedly higher in the low frequencies and that there is a trend toward higher familial aggregation in female compared with male subjects.

Aggressiveness in cholesterol granuloma of the temporal bone may be determined by the vigor of its blood source.

OBJECTIVE: Recently, it has been proposed that the aggressive behavior of cholesterol granuloma (CG) of the petrous apex is explained by its proximity to the richly vascular marrow of the petroclival junction. Most CGs of the lateral temporal bone are indolent. The purpose of the present study is to examine the factors responsible for atypical aggressive behavior in mastoid CG. STUDY DESIGN: Retrospective case series. SETTING: : Tertiary academic practice. PATIENT POPULATION: Four patients with atypically aggressive CG of the mastoid. RESULTS: In each case, the CG abutted a rich blood source: the sigmoid sinus, carotid artery, a large dural vein, or a rich deposit of vascular marrow in the mastoid tip. CONCLUSION: These observations lend further support to the theory that aggressiveness of CG is sustained by a robust source of ongoing hemorrhage.