This year, 2017, marks the peak number of baby-boomers reaching the age of 60. So it’s no coincidence that researchers and public health officials have turned their attention to the plethora of chronic conditions, including hearing loss, that are linked to aging. The Journal of the American Medical Association, one of the most widely circulated peer-reviewed journals in the world, appears to be a hub for much of this information.
Last week, HHTM reported on public policies experts advocating for the inclusion of hearing aid coverage by Medicare. The first week of July saw two more noteworthy articles – both directly related to hearing healthcare and the pending changes to its provision published in JAMA.
On July 4th, in a JAMA research letter, Nicholas Reed and colleagues at Towson University and Johns Hopkins published data comparing personal sound amplification products (PSAPs) to a conventional hearing aid. In their study design, Reed and colleagues used the AZBio speech-in-noise test to measure and compare the performance of five PSAPs and one conventional hearing aid to the unaided condition. The laboratory task was completed at a signal-to-noise ratio of +5 dB with the speech presented directly in front of the study participants at 35dB HL and the noise directly behind them at 30dB HL. The devices were fitted unilaterally to the better hearing ear. Forty-two adults, aged 60 to 85, with mild to moderate hearing loss and no prior experience with amplification participated in the study.
Conventional Hearing Aid vs. PSAP
Results indicated that the conventional hearing aid (Oticon Nera 2), listed by the study authors having a consumer price of $1910, provided the best improvement relative to the unaided condition with a mean score on the test of 88.4%. Three of the five PSAPs, at costs ranging between $349 to $299, came within five percentage points of the conventional hearing aids score. Specifically, the Sound World Solutions CS50+ (mean score of 87.4%), the Soundhawk (mean score of 86.7%), and the Etymotic Bean (mean score of 84.1%) had scores on the AX Bio speech-in-noise task approaching that of the conventional device. Additionally, a fourth PSAP, the Tweak Focus (retail cost $269), was not far behind with a mean score on the AZ Bio task of 81.4%. A fifth PSAP, the MSA 30 Sound Amplifier, listed at a retail cost of $29.99, performed more poorly that the unaided condition with a mean score of 65.3%. Note the mean score in the unaided condition was 76.5%.
Considering the change from the unaided condition for all of the devices studies, this data would suggest that PSAPs above the $250 price point perform similarly to a conventional hearing in this test condition.
Given the improvement in speech-in-noise recognition scores as it relates to the retail cost of each device, this study provides evidence that some PSAPs may be a cost-effective option for individuals who cannot afford a conventional hearing aid.
Further, the study suggests that the unregulated PSAP market leads to uneven performance, as one of the five PSAPs used in this study actually made speech understanding in noise worse for all the study participants. (The MSA 30X PSAP had a mean change from the unaided condition of -11.2%). Given the abundance of unregulated PSAPs on the market today, individuals thinking about a direct-to-consumer amplification device must proceed with caution when considering the use of PSAPs.
Hearing Restoration: Closer Than We Think?
A July 7th article by JAMA senior staff writer Jeff Lyon provided an update on the latest breakthroughs on the science of hearing restoration. The report focused on recent advances at Harvard University, led by stem cell biologist Albert Edge, PhD. Their recent work in this area indicates that certain support cells in the organ of Corti express a marker protein called LGR5 (leucine-rich repeat-containing G protein-coupled receptor 5) – the same marker expressed in the stem cells of the intestinal epithelium . The same stem cells that allow the gut lining to completely renew itself every week. Edge and his colleagues found that the LGR5-positive support cells in the inner ear can be coaxed to perform a similar feat.
In February, the researchers reported they could regenerate these cells in great abundance, as they reported a 2000-fold or more increase in LGR5-positive support cells that resulted in more than 11 500 fully functional hair cells. This dramatic increase in hair cell growth is a cornerstone of hearing restoration as a clinical intervention.
Mr. Lyon reports in his article that the Boston-area research team is now moving into human trials. A Connecticut-based company called Frequency Therapeutics, has been licensed to use the technology in the United States and raised $32 million in research money. The company aims to begin human testing within 18 months. Two other companies, the Dutch company Audion Therapeutics, partnering with Eli Lilly, expect to be involved in human trials within the next 3 to 5 years.
The ability to generate quantities of new hair cells is a promising new avenue for hearing loss treatment, but some experts remain skeptical that hearing restoration will be a clinical reality in the near future.
Otolaryngologist Richard Chole of the Washington University School of Medicine expressed caution in the article, explaining that the intricacies of the neuro-auditory are extremely complex and clinical utilization of hearing restoration techniques– although exciting and viable – is still several years away.
In addition to the two articles mentioned here, over the past few months, JAMA has also published commentary on the pending OTC device category and a University of Michigan study examining the delivery of hearing aids at a free subspecialty clinic.
This is fabricated research up to a point. The issue is not a simple one as explained. The speech score is dependent on codification of speech signals to allow relevant passage of impulses through the hippocampal tract of CA 1. This is the key processing entrance that separates the speech codes from noise as the first step in fine tuning. What happens next is a comparison with the incoming codes with long term memory . This is definitely affected by distortions in the speech codes that occurs (not due to external noise dummy!) due to neural pathologies, and physiologic changes as a further effect of damage to the cochlea.
The research may be deliberately falsified, or the researchers do not much about neuropsychology.
OK fixed directivity works fine for PSAP devices.
But what about speech in noise in real condition ? When there are several sources of speech and noise.