Changes in middle ear transmission characteristics secondary to altered bone remodelling

Disrupted harmony of the skull skeleton: Middle ear resonance in acromegaly

OBJECTIVES

This study aims to investigate whether the middle ear resonance frequency (RF) is affected in acromegaly, which causes growth in the skull bone.

METHODS

Thirty acromegaly patients and 38 volunteers were included in the study. Pure tone average scores and middle ear RF values of the groups that underwent pure tone audiometry, tympanometry, and multifrequency tympanometry tests were compared.

RESULTS

The pure tone mean was 14.95 ± 12.13 in acromegaly patients and 5.70 ± 8.52 in the control group (p:0.18). Sensorineural hearing loss(SNHL) was observed in 16.6% of the patients. The average middle ear RF was calculated as 815 ± 179.05 Hz in patients with acromegaly and 773 ± 127.15 in the control group. (p = 0.0001).

CONCLUSION

This study is the first to evaluate middle-ear RF in acromegaly patients. Acromegaly-induced changes in soft tissues and bone structures impact middle ear functions. In this patient group, we found an increase in middle ear RF without conductive-type hearing loss and a 16.6% rate of SNHL.

Association Between Early-Onset Osteoporosis With Hearing Loss and Benign Paroxysmal Positional Vertigo (BPPV): A Systematic Review and Meta-Analysis

OBJECTIVE

Osteoporosis is a chronic systemic disease characterized by low bone mass, progressive microarchitectural deterioration and increased bone fragility. Hearing loss and benign paroxysmal positional vertigo (BPPV) have been found in patients diagnosed with osteoporosis over 65 years, however, there is lack of information about these conditions in young patients. Herein, we conducted a systematic review and meta-analysis to provide evidence of the association between osteoporosis and audio-vestibular findings in young subjects.

METHODS

Systematic review and meta-analysis were performed according to PRISMA guidelines. Searches were conducted in PubMed, Embase, and Web of Science Core Collection. Mean age, proportion of patients with low mineral density, hearing loss, and BPPV were calculated for the systematic review and meta-analysis. Odds Ratio (OR) with their corresponding 95% confidence intervals (CI) were calculated.

RESULTS

A total of 26 articles were reviewed. Only 10 studies met inclusion criteria for the meta-analysis. Six were assessed pursuing the association between osteoporosis and hearing loss. Pooled evidence suggested in patients with osteoporosis, an increased risk for developing hearing loss (OR = 1.52, 95% CI 1.06-2.19; P = .02) compared to controls. Another 6 studies reported the association between osteoporosis and BPPV. A significant increased risk for BPPV was found in individuals with osteoporosis (OR = 1.58, 95% CI 1.02-2.4; P = .04). There was no publication bias.

CONCLUSION

Subjects younger than 65 years with osteoporosis have an increase odds for hearing loss and BPPV compared to controls. These conditions could be associated with early inner or middle ear bone morphologic changes.

Effects of Age and Middle Ear on the Frequency Tuning of the cVEMP and oVEMP

BACKGROUND

Upward shift in the air conducted (AC) frequency tuning of vestibular evoked myogenic potentials (VEMPs) as an effect of aging is hypothesized to be due to the microstructural stiffening changes in the inner ear. However, with an AC stimulus, it may be possible that the shift in the frequency tuning of VEMPs as an effect of aging may also be due to contributions from the middle ear.

PURPOSE

The main aim of this study was to examine the effects of age on the frequency tuning of the cervical VEMP (cVEMP) and ocular VEMP (oVEMP) and determine the role of middle ear transmission characteristics in shaping these effects.

RESEARCH DESIGN

Standard group comparison.

STUDY SAMPLE

One-hundred seven participants divided in three groups: young adult, middle-age, and older adults with "normal" middle ear and negative history of neurological or vestibular complaints.

DATA COLLECTION AND ANALYSES

Middle ear measures included static admittance and middle ear resonant frequency. cVEMP and oVEMPs were elicited with AC tone bursts at 500, 750, and 1,000 Hz.

RESULTS

No significant effect of age was observed on any of the middle ear measures. There was a significant effect of age on the amplitude of the cVEMP, but this effect was frequency specific. The age-related reduction in cVEMP corrected amplitude was only observed when the eliciting stimulus was 500 or 750 Hz, with no significant effect observed with a 1,000 Hz stimulus. For the oVEMP, the effects of age were apparent at all stimulus frequencies. We also observed a general upward shift in the frequency tuning of both the cVEMP and oVEMP for middle-age and older adults, with 750 and 1,000 Hz yielding higher response rates and larger amplitudes among middle-aged and older adults. Measurements of middle ear did not significantly contribute to the observed findings.

CONCLUSIONS

The upward shift in frequency tuning of VEMPs among middle age and older adults could be due to the changes in the vestibular system and not from the middle ear. These results support the use of different frequency stimuli (i.e., 750 or 1,000 Hz) to elicit a VEMP if a response is absent using a 500 Hz stimulus, especially in patients over the age of 40.

Low vitamin D status is associated with hearing loss in the elderly: a cross-sectional study

BACKGROUND

The elderly are at increased risk of both hearing loss (HL) and osteoporosis. Bone mineral density (BMD) has been putatively linked to HL. However, the roles of serum calcium concentrations and vitamin D status have yet to be elucidated.

OBJECTIVES

The purpose of this study was to examine the relation between vitamin D status, parathyroid hormone (PTH), total calcium, BMD, and HL in a nationally representative sample of elderly adults.

METHODS

Using the NHANES (2005-2010), audiometry and BMD data of 1123 participants aged ≥70 y were analyzed in a cross-sectional manner. HL was defined as pure tone averages >25 dB HL at 500, 1000, and 2000 Hz (low frequency); 500, 1000, 2000, and 4000 Hz (speech frequency); and 3000, 4000, 6000, and 8000 Hz (high frequency) in either ear. Multivariable logistic regression was used to examine the relation between HL and total 25-hydroxyvitamin D [25(OH)D], PTH, total calcium, and BMD, adjusting for covariates.

RESULTS

In multivariable analyses, total 25(OH)D < 20 ng/mL was found to be associated with greater odds of low-frequency HL (OR: 2.02; 95% CI: 1.28, 3.19) and speech-frequency HL (OR: 1.96; 95% CI: 1.12, 3.44). A 1-unit decrease in femoral neck BMD (OR: 4.55; 95% CI: 1.28, 16.67) and a 1-unit decrease in total spine BMD (OR: 6.25; 95% CI: 1.33, 33.33) were found to be associated with greater odds of low-frequency HL. Serum PTH and total calcium were not found to be associated with HL.

CONCLUSIONS

In the elderly, low vitamin D status was associated with low-frequency and speech-frequency HL. Low vitamin D status may be a potential risk factor for age-related HL.