Kembara Xtra - Medicine - Presbycusis

Kembara Xtra - Medicine - Presbycusis
Presbycusis is an age-related hearing loss (HL) that occurs more frequently as people get older. It frequently manifests as trouble speaking in noisy settings.
 Causes can be categorized as central or peripheral:
Peripheral presbycusis is an age-related, bilateral sensorineural HL (SNHL) that is often symmetric. Central presbycusis is a change in the auditory sections of the central nervous system that negatively affects auditory perception, speech-communication performance, or both.
Represents a lifetime's worth of harm to the auditory system from exposure to toxic noise and aging
Presbycusis affects the "clarity" of sounds (i.e., the capacity to detect, recognize, and localize sounds), and it initially manifests as high-frequency SNHL with tinnitus (ringing). Because it is mild and progressive, amplification is sometimes used as a sole form of treatment.
 Can have negative impacts on a senior's physical, cognitive, emotional, behavioral, and social function (such as depression and social isolation), and is a factor in dementia in general.

Incidence
An ongoing community-based epidemiologic investigation indicates that the 10-year cumulative incidence rates of HL are roughly as follows:
Age 48 to 59: Men (31.7%), Women (15.6%), and all (21.8%)
60 to 69 years of age: Males (56.8%), Females (40.7%), All (45.5%).
M (87.1%), F (70.6%), and all (73.7%), aged 70 to 79 years.
Age 80 to 92 years: 100% M, 100% F; 100% all
Prevalence
10% of people acquire SNHL that is severe enough to interfere with communicating.
80% of HL cases affect elderly patients, increasing to 40% of the population over 65.
The percentage of older persons with HL who have ever worn hearing aids (HAs) is only 10–20%.
Male is more prevalent than female.
In contrast to rural or isolated civilizations, hearing levels are worse in industrialized societies.

Pathophysiology and Etiology 

The tympanic membrane receives sound energy from the external ear. Through the oval window, the middle ear ossicles amplify and transmit sound waves into the cochlea. Hair cells in the organ of Corti, which is part of the cochlea, are sensitive to these vibrations and depolarize in response, creating electrical signals that pass from the auditory nerve to the brain. Exposure to toxic noise traumatizes the hair cells, which results in cell death and HL.
Additionally, research suggests that excessive synaptic stimulation results in an increase in glutamate, another hazardous chemical.
- High-frequency HL: Sensory presbycusis is the major loss of hair cells in the cochlea's basal end.
- Spiral ganglion cells, which are nerve cells that are stimulated by hair cells to produce action potentials that pass to the brainstem, are lost in neural presbycusis.
The stria vascularis, the cochlear tissue that produces the endocochlear electrical potential, atrophys in stria (metabolic) presbycusis.
- No morphologic results for cochlear conductive (mechanical) presbycusis; basilar membrane stiffening is assumed.
- Mixed presbycusis: loss of stria vascularis, ganglion cells, and hair cells together
- No morphologic evidence in indeterminate presbycusis; inferred decreased cellular function
The cumulative effects of noise exposure, systemic illness, oxidative damage, ototoxic medications, and hereditary predisposition result in presbycusis.
Genetics
Presbycusis has a distinct familial aggregation: Heritability estimates indicate that 35–55% of the variance in sensory presbycusis originates from genetic variables, with strial presbycusis showing an even higher percentage.
Women are more prone to inheritance than men are.

Risk factors Exposure to noise (industrial, military, etc.)
 Organic solvents are ototoxic chemicals.
- Carbon monoxide - Heavy metals - Drugs
Aminoglycosides and dose-dependent Cisplatin
the salicylates
A diuretic
 Head trauma (temporal bone fractures) Alcohol abuse Lower socioeconomic status Family history of presbycusis
The labyrinthine artery is the terminal artery to the cochlea; cardiovascular illness (hypertension, atherosclerosis, hyperlipidemia).
Diabetes mellitus, obesity, autoimmunity (auto cochleitis/labyrinthitis), metabolic bone disease, aldosterone levels, Alzheimer's disease, and otologic disorders (such as Ménière disease or otosclerosis).

Prevention 
Use hearing protection, stay away from loud noises, maintain a balanced diet, and get some exercise.
Tools for patient self-screening are accessible online and via mobile apps.
- Hearing Handicap Inventory for the Elderly Screening - RCT published in 2010 on screening for HL, HA use was significantly higher in three screened groups compared to unscreened control participants (3.3%) at 1-year followup (4.1% using a questionnaire, 6.3% using handheld audiometry, and 7.4% using both modalities).
- The USPSTF states that there is inadequate information to evaluate the relative benefits and hazards of HL screening in people 50 years old based on a 2021 review.


Accompanying Conditions 
A 2018 meta-analysis revealed that dementia, cognitive impairment, and rapid multidomain cognitive decline all exhibited significant relationships with ARHL.
Depression and social withdrawal


Diagnosis: Impaired localization of sound sources and decreased hearing sensitivity in noisy/public surroundings
Increased comprehension difficulty in discussions, particularly with women, as a result of a higher frequency of spoken voice Bilateral and symmetrical presentation If unilateral HL, alternative diagnosis should be sought for.
 Additional history if HL is thought to exist or is found:
Time course of HL; tinnitus, otalgia, otorrhea, or vertigo symptoms; past exposure to loud noises; ear trauma; or head trauma
- Any neurologic deficits present Reports from the patient, family, or caregiver
- Perplexity in social settings
- Overly loud television, radio, or computer use - Social withdrawal - Group anxiety

clinical assessment 
Rinne and Weber tests are useful for distinguishing between conductive and SNHL, however they are not suggested for routine screening.
 Pneumatic otoscopy to determine whether conductive hearing loss is due to a simple middle ear effusion.

Differential Diagnosis Large external ear tumors, such as polyps, exostoses, and squamous cells; complete canal obstruction (cerumen, foreign body); otitis externa; chronic otitis media or effusion;
the cholesteatoma
Otosclerosis, Osteogenesis Imperfecta, Large Middle Ear Tumors (Facial Nerve Schwannomas, Paragangliomas), Perilymph Fistula (Trauma/Iatrogenic), Ménière Disease, Acoustic Neuroma (Usually Unilateral), Vascular Anomaly, Acute Noise-Induced Traumatic Loss (Exposion), and Autoimmune HL are just a few of the conditions that can cause hearing loss.

Laboratory Results 
Peripheral: handheld audiometry; place probe in ear (sealing canal) and ask patient to indicate if tones can be heard. Central: synthetic phrase identification test with ipsilateral competing message and the dichotic sentence identification test.
Screening audiometry: - Positive likelihood ratio (LR) range: 3.1 to 5.8; negative likelihood ratio (LR) range: 0.03 to 0.40; symmetric high-frequency HL in descending slope pattern; initially, SNHL frequencies >2 KHz; crucial for determining whether the cause is conductive HL as opposed to SNHL or pseudohypacusis (conversion).


Management 
Digital HA: programmable; may reduce acoustic feedback, reduce background noise, detect and automatically accommodate different listening environments, control multiple microphones. Analog HA: picks up sound waves through a microphone; converts them into electrical signals; amplifies and sends them through the ear canal to the tympanic membrane. HAs have an average decibel gain of 16.3 dB.
- Linked to heightened sensitivity to loud noises ("loudness recruitment").
Hearing-assistive technologies (HATs) (3) - May be employed on their own or in conjunction with HAs (in circumstances that make it difficult to hear)
- Covers interpersonal contact, broadcast or other electronic media (radio, TV), telephone conversations, sensitivity to warning signals, and environmental stimuli (doorbell, baby's cries, alarm clock, etc.).
Included are alerting devices, personal FM systems, infrared systems, induction loop systems, hardwired systems, telephone amplifiers, telecoils, TDDs (telecommunication devices for the deaf), situation-specific devices (such as televisions), and infrared systems.
In addition to HAs or HATs, aural rehabilitation—also known as audiologic orientation or auditory training—involves counseling for coping mechanisms to deal with the challenges of HAs or HATs. It also includes instruction on how to use amplification devices appropriately and managing the auditory environment.

Referral 

For a formal assessment and the best fitting of HAs and/or HATs, consult an audiologist.
Post-fitting orientation/education recipients have noticeably less HA returns.
People who received >2 hours of education and counseling expressed greater pleasure.

Further Therapies 
Gene therapy: Current research focuses on a variety of transcription factors, cell cycle modulators, and cyclin-dependent kinase inhibitors, which are all connected to different facets of hair cell creation and regeneration as well as maintenance of supporting cells.
Pharmacotherapy: Cellular signaling molecules and pathways are now being researched as the most effective drug targets. Although extensively investigated and implicated in the proliferation of supporting cells, Wnt and Notch signaling cascades have only recently been linked to the slow growth of hair cells.
 Stem cell therapy: Current studies have primarily focused on the neural component of the inner ear system and hair cell-like cells derived from mouse embryonic stem cells or induced pluripotent stem cells.
Cochlear spiral ganglion neurons can be successfully revived using mesenchymal stem cells.
The most encouraging outcomes come from endogoneous stem cells.


Cochlear implants (CIs) bypass the hair cells in the cochlea and the ear canal to deliver electric stimulation to the auditory nerve. Surgical Procedures
- There are warning signs, such as the worse ear hearing no better than identifying 50% of test sentences' essential words in the best aided condition and 60% in the better ear.
- The audio processor component, which resembles a little HA, receives incoming sounds through its microphone and turns them into electrical impulses before sending them to the magnetic coil, which is situated on the skin.
Radio waves are used to convey the impulses from the implanted component (near the coil) across unbroken skin. The cochlea is stimulated at rapid rates by the pulses as they travel to its electrodes.
- The most frequent CI procedure is a unilateral one, while some patients could get bilateral CIs concurrently or sequentially. Others (bimodal fit) might wear a CI in one ear and a HA in the other ear.
- The greatest benefit comes from CI placement at a younger age.
 Active middle ear implants (AMEIs) - Suitable for elderly adults whose HL is not severe enough for a CI and whose inability to wear conventional HAs is due to medical or personal (cosmetic) reasons - Various models are available and may include implantable components Electric acoustic stimulation: use of CI and HA together in one ear - Addresses the needs of patients who present with good low-frequency hearing (a mild to moderate sensorine
 Contraindications include progressive HL, autoimmune disease, HL caused by meningitis, otosclerosis, or ossification, cochlea malformation, a difference between the air conduction and bone conduction thresholds of >15 dB, active infection in the external ear, and a refusal to use an amplification device.

Patient Follow-Up Monitoring
Check for compliance with HA use during follow-up visits because 25–40% of individuals will quit wearing them or only use them intermittently.
Assess the perceived benefit of HA and look for signs of potential surgical therapies if it is ineffective.
yearly audiograms
 If HA gets bothersome, follow up with audiologists for HA fits.
An MRI should be used to check for acoustic neuromas in asymmetric HL.
Sudden SNHL is unusual and requires immediate otolaryngologic assessment/audiometry. The American Academy of Otolaryngology's most current recommendations urge empirical use of steroids.

​Lifestyle Modification 
Formal speech reading classes may be helpful, although they may not be readily available. Should be face-to-face; delivered clearly and slowly; without competing background noise (e.g., radio, TV); and offer a confirmation that the message has been heard.

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