A 77-Year-Old Man With Difficulty Hearing

Correct Answer: A. This presentation is most likely age-related hearing loss. The patient should be referred to an audiologist to confirm the diagnosis and characterize the functional implications and appropriate management strategies.

We are all going deaf over time. This is a fact of biology, aging, and life, as dramatic as that statement sounds. A recent review uses the term "every person" when discussing age-related hearing loss.¹ A compilation from recent reviews suggests that more than 50% of people older than 60 years of age have hearing loss reaching clinical recognition levels; with the incidence doubling with each decade before reaching 80% by age 85.^1,2

There are increased risk factors for hearing loss including noise exposure, drug exposure to ototoxic medicines, genetic disorders, and lesser "associations" such as cigarette smoking and diabetes, where microvascular disease is suspected.^1,2

The onset is typical such that diagnosis is essentially a clinical one. The presented patient fits the clinical situation very well. By far, the leading "symptom" in his history is a chronic (very importantly, NOT acute) and gradual bilateral hearing loss with diminished hearing particularly of conversation, specifically in the setting of background noise. Typical historical details usually include the patient's complaining about not speaking clearly and family reports of loud speech and loud TV/radio volumes.

An important part of diagnosing age-related hearing loss is what is absent from the history. Thus, no recent exposure to ototoxic medicines, no family history of genetic hearing issues, gradual rather than acute hearing loss, which is an otologic emergency,3 unilateral rather than essentially symmetrical and bilateral loss, and the absence of red flag symptoms accompanying the loss such as headache, ear pain, ear discharges, vertigo, dizziness or nystagmus all suggestive of other diagnoses. Most of the listed symptoms and signs will require a much more rapid evaluation by appropriate ancillary examination, imaging, and specialty consultation.

When one is left with a proper demographic and history for age-related hearing loss, an audiogram will confirm bilateral hearing loss most marked in the high frequency ranges using the so-called four frequency pure tone average (PTA 4) utilizing the 500, 1000, 2000, and 4000 Hz frequencies most required for understanding human speech.2 This is essentially Answer A, which is the correct answer here. Answer B refers to the sudden, sensorineural (essentially complete) hearing loss syndrome, usually unilateral, which is, indeed, an ontological emergency that requires therapy within 72 hours.³ Cochlear implantation is usually reserved for patients with severe or total sensorineural loss. The described patient is not currently at that level and should be significantly helped by hearing aids well before considering the use of cochlear implantation, which makes Answer C incorrect. Answer D refers to conditions such as acoustic neuroma of the VIII nerve which is in realm of neurosurgery or Menier syndrome with frequent vertigo accompanying the hearing loss. Both require imaging for diagnosis and are not correct here.

The pathophysiology behind age-related hearing loss resides in the inner ear; the spiral organ of Corti, to be precise. It is here that the energy of sound waves, having been transmitted from the environment through the outer ear, collecting organ and the middle ear transforming anatomy, become vibrations that stimulate the so-called "hair cells" of the organ of Corti. The hair cell movements elicited by the sound energy vibrations result in transmission to individually attached neural receptors (neuronal tissue) and further transmission via the cochlear nerve, a branch of cranial nerve VIII, to the auditory cortex of the brain which is recognized as "sounds" to us. Importantly, the organ of Corti hair cells are ectodermal ultra-differentiated epithelial cells that once lost cannot be regenerated or replaced. Further, the neural tissue derived nerve receptors synapsed to each hair cell will atrophy when their companion hair cell is lost and similarly cannot regenerate or be replaced.²

A variety of exogenous factors can damage and destroy the hair cells: ototoxic drugs, extreme loud noise exposures, for example. And it seems decades of even "routine life" results in age-related hair cell denervation and loss, which eventuate in "age-related hearing loss". A lifetime of use and exposure to loud noises thus seems adequate to, over time, result in this pathophysiology and cause the syndrome in so many of us as we age past 60 years.

Management of age-related hearing loss has two basic strategies: behavioral and technical. The loss of cochlear hair cells is not reversible. Indeed, there is no way to restore them pharmacologically with growth factors, surgery or otherwise. Thus, we depend upon maneuvers aimed to maximize whatever hearing function remains and use technology to enhance it. Regarding maximizing residual auditory function, simple household and behavioral techniques include maneuvers to protect remaining function by avoiding loud sounds and maintenance of clear auditory ear canals. Having patients learn to speak face to face (as we all read lips, to a degree) and avoiding background noise as much as possible are effective. Thus, in a household, seating arrangements and attention to background sounds and noise will be helpful.

There are two broad, technical, and advanced avenues for treatment: hearing aids and cochlear implantation. Hearing aids can perform myriad and adjustable functions including straight up sound amplification and, using physics, neutralization of background noise. They can ameliorate symptoms in 90% to 95% of impacted patients with mild to moderate (audio logically defined as PTA 4 levels less than 60 dB) hearing loss.¹ When hearing loss is very severe, PTA 4 levels greater than 60 dB, the technique of cochlear implantation, a surgical technique in which a surgically (outpatient) implanted neuro-prosthetic device that directly stimulates the cochlear nerve bypassing the hair cell mechanism, is also available.

Technological advances have enabled the ability of a smartphone to test and quantify hearing function. And, as with so many things technical and electronic, the costs of hearing aids have been reduced akin to costs of LED lights and TV screens. Excellent quality devices are available now in the $100-$300 range.⁴ Now, imagine the cost-adjusted benefits of this. And remember, age-related hearing loss is recognized as the most modifiable risk factor for dementia prevention,^1,2 compared with the very modest, if any, effects of amyloid plaque shrinkage as a dementia maneuver with current costs in the range of $250,000 per patient per year. That works out to one patient receiving drug for one year costing an amount equivalent to 1000 patients receiving hearing aids that last for many years. In addition, hearing aids can now be obtained totally outside the hospital, and yet only 14.2% of adults in the United States with hearing loss have hearing aids.⁵

Patient Follow Up. The patient was seen by an otolaryngologist who confirmed the history of present illness (e.g. chronic onset, essentially bilateral and symmetrical, normal external and middle ear conduction/anatomy and absence of ototoxic medicines or red flag symptoms). An audiologist then confirmed bilateral hearing loss with thresholds for hearing increased, most marked at the higher frequencies, all consistent with age-related hearing loss. The PTA-4 pure tone averages were 60 dB (R) and 70 dB (L) consistent with moderate-to-severe hearing loss. Discussion options indicated the patient was borderline for use of over-the-counter hearing aids. For now, behavioral household maneuvers regarding background noise, placement of TV/radio and human speakers and use of everyday hearing technologies such as face time will be tried. If, however, these do not result in improved communication function he is ready to use over the counter hearing aids. Or, if communication function in daily life worsens despite these maneuvers, again hearing aids will be used.

What’s The Take Home? Age-related hearing loss is a ubiquitous condition that indeed effects essentially everyone who lives long enough. The condition usually appears after age 60 with the key symptoms at onset being decreased appreciation of speech in the setting of background noise. The incidence doubles with each decade of life after 60 years. The pathophysiology of this form of hearing loss is the progressive loss of sensory hair cells within the cochlea of the inner ear.¹ These sensory hair cells cannot regenerate once lost. Diagnosis is usually somewhat obvious in a good history of chronicity of onset, bilaterality and absence of dangerous other sign and symptoms such as vertigo, dizziness, nystagmus, ear pain/discharge, acute onset or unilaterality. Diagnosis is confirmed via audiology testing, which is also quantifiable as to degree of loss and involvement of important human speech frequencies.

There is no restorative means to correct the sensory hair losses in the cochlea. However, there are excellent modalities of improving symptoms via hearing technologies, namely hearing aids and in very severe cases cochlear implantation. Of significant importance is the condition of hearing loss in adults having connections to several very important medical issues of our times.

First its universality in that essentially all will experience it as we get older, and the age expectancy of humans continues to lengthen.  In addition, it is known and accepted that age related hearing loss is the single largest, potentially modifiable risk factor for dementia, responsible for 8% of cases.¹ Yet as of 2021 the US Preventative Task Force determined "There is insufficient evidence to assess the benefits and harms for hearing impairment in asymptomatic adults 50 years or older".⁶

Finally, the advent of over-the-counter devices, at home smartphone techniques to test hearing, place greater control into the hands of patients with spectacular cost savings.

AUTHOR
Ronald N. Rubin MD^1,2

AFFILIATIONS
¹Lewis Katz School of Medicine at Temple University, Philadelphia, PA
²Department of Medicine, Temple University Hospital, Philadelphia, PA

CITATION
Rubin RN. A 77-year-old man with difficulty hearing. Consultant. 2024;64(12):eXX. doi: 10.25270/con.2024.12.000004

DISCLOSURES
The author reports no relevant financial relationships.

CORRESPONDENCE:
Ronald N. Rubin, MD, Temple University Hospital, 3401 N. Broad Street, Philadelphia, PA 19140 (blooddocrnr@yahoo.com)

References

1. Lin FR Age related hearing loss. N Eng J Med. 2024;1505-1512
2. Cunningham LL, Tucci DL. Hearing loss in adults. N Eng J Med. 2017;377:2465-2473
3. Rauch SD . Idiopathic sudden sensorineural hearing loss. N Eng J Med. 2008;359:833-840
4. Lin Fr, Chadha S. Over the counter hearing aids using - using regulatory policy to improve public health. N Eng J Med. 2023;388:217-219
5. Chien W, Lin FR. Prevalence of hearing aid use among older adults in the United States. Arch Intern Med. 2012;172:292-293
6. Krist AH, Davidson KW, Mangione CM, et al. Screening for hearing loss in older adults: US preventive Services Task Force Recommendation Statement. JAMA. 2021;325:1196-1201