HHTM News Round Up: A Synopsis of Recent Hearing Research Studies

This week HHTM offers readers a synopsis of some of the latest hearing research:


Study Shows Relationship Between Early Hearing Loss and Alzheimer Disease


Columbia University researchers, using the audiogram, word recognition scores and positron emission tomography (PET) scans were able to associate hearing loss of early onset and the presence of β-amyloid, a pathologic marker found in individuals with Alzheimer’s disease. 

Ninety-eight participants with a mean age of 64.6 years of age were involved in the cross-sectional analysis of hearing sensitivity and the biomarker associated with Alzheimer’s disease.  The lead author of the paper, published online by Laryngoscope, is Justin Golub of the Department of Otolaryngology-Head and Neck Surgery at Columbia University in New York City. 

The researchers evaluated the relationship between whole brain β-amyloid standardized uptake value ratio (SUVR) on positron emission tomography (PET) and hearing, as measured by either pure-tone average or word recognition score in the better ear. Linear regression was performed to analyze the association between β-amyloid and hearing, adjusting for potentially confounding covariates. 

After adjusting for demographics, education, cardiovascular disease, and hearing aid use, whole brain β-amyloid SUVR increased by 0.029 (95% confidence interval [CI]: 0.003-0.056) for every 10 dB increase in pure-tone average (P = .030). Similarly, whole brain β-amyloid SUVR increased by 0.061 (95% CI: 0.009-0.112) for every 10% increase in word recognition score (P = .012).

Results of the study indicate that untreated hearing loss is associated with higher β-amyloid, an indicator of Alzheimer’s disease. 


Digits-in-Noise Test, Done Virtually, Detects Conductive Loss


Given the social distancing constraints associated with Covid-19, no- or low-touch audiological assessment outside a sound-booth makes it impossible to complete a comprehensive audiological assessment including bone conduction audiometry. A recent study, published in the International Journal of Audiology investigated whether conductive hearing loss (CHL) can be differentiated from sensorineural hearing loss (SNHL) using pure-tone air conduction audiometry and a digits-in-noise (DIN) test.

Data was collected from 158 adults with bilateral SNHL or CHL. Using binomial logistic regressions, the researchers determined the effects of pure tone thresholds or averages, speech recognition threshold (SRT), and age on the likelihood that participants had CHL or bilateral SNHL.

Results indicated that low frequency pure tone average, diotic digits in noise SRT and age were best able to distinguish between bilateral SNHL and CHL. Thus, in a no-touch or low-touch clinical model, according to the results of this study, conductive hearing loss can be accurately distinguished from SNHL using pure-tone air conduction audiometry and a diotic digits-in-noise score.


Researchers Develop Method of Detecting Hearing Loss via Blood Test


With what is believed to be the first test of its kind, Sunnybrook Research Institute scientists have demonstrated a way to detect hearing disorders using a simple blood test.

The research has been published in Biosensors and Bioelectronics.

“Current approaches for detecting hearing disorders are mostly based on physical examinations and cannot provide information about the exact location of the cellular damage within the inner ear. There is a need for a new more precise method to identify sites of damage,” says Dr. Alain Dabdoub, co-author of the study, senior scientist and research director of the Sonja N. Koerner Hearing Regeneration Laboratory at Sunnybrook Research Institute. .”

In their pre-clinical research, Dr. Dabdoub and Dr. Sahar Mahshid, research associate, have designed a biosensor test to detect otolin-1 and prestin, two unique proteins which can be found circulating in blood and are linked to balance and hearing disorders respectively. The test, which is patent pending, is comparable to a glucose monitor and requires only a drop of blood.

“Within 10 minutes, we’re able to detect if these proteins are in the blood sample”, says Dr. Mahshid. “The test, which relies on antibodies to detect the proteins, can be easily adapted to identify other blood-circulating proteins down the line.”

Starting with less than a finger-prick volume of blood, the novel biosensor test is capable of rapidly detecting inner ear biomarkers circulating in blood. This enables the localization of cellular damage in the inner ear and holds promise for future precision therapies. Image courtesy of Dr. Alain Dabdoub.

Dr. Mahshid cautions that the research is still in the pre-clinical stage, adding that more work is needed to improve the test before it can be used at point-of-care. “At this time, the test is able to detect the proteins in low concentrations, but still higher than what you would typically see in a patient’s blood. Our goal is to enhance our detection sensitivity, while also exploring more blood-circulating proteins reporting on hearing and balance disorders.”

The researchers note the test holds great promise for point-of-care diagnostics and will eventually allow for more precise treatments. “Being able to localize cellular damage will enable us to better personalize treatment,” says Dr. Dabdoub. “This will eventually lead to improved quality of life for patients living with hearing and balance disorders.”