PresbyacusisDr. Vishal Sharma

Synonyms

Age-related sensori-neural hearing loss

Age-associated hearing loss (AAHL)

Presbycusis (in USA)

No official agreed age above which a person

suffers from presbyacusis & below which he/she

does not. Arbitrary agreed age is 50 years.

Definitions

Presbyacusis: B/L symmetric, progressive SNHL

due to aging, in absence of other etiologies

Socioacusis: B/L symmetric SNHL due to non-

occupational noise, fatty diet & lack of exercise

Nosoacusis: B/L symmetric SNHL due to diseases

with ototoxic effects

SNHL after 50 yrs age = presbyacusis +

nosoacusis + socioacusis + occupational NIHL

Diagnosis of exclusion

Exclude other causes of hearing loss in elderly:

Noise induced hearing loss

Atherosclerosis (hyperlipidemia), diabetes,

hypertension, myxoedema, Paget’s bone disease

CSOM, Meniere’s disease, acoustic neuroma,

cochlear otosclerosis, ear trauma & ototoxic drug

History

Toynbee (1849) first wrote about age-related

hearing loss & prescribed a treatment (application

of silver nitrate solution to external auditory canal)

Zwaardemaker (1891) gave first accurate

description of presbyacusis. He detected high

frequency involvement & origin in cochlea.

Mechanism of Presbyacusis

Age-related arteriosclerosis

hypo-perfusion & oxygenation of cochlea

formation of reactive oxygen metabolites & free

radicals

damage inner ear structures & mitochondrial

DNA of inner ear

Presbycusis

Genetic Predisposition

Genetic programming for early aging of parts of

auditory system early development of

presbycusis

Genetically programmed susceptibility to

environmental factors (noise, ototoxic drugs,

stress) may be involved

Types of Presbyacusis (Gacek & Schuknecht, 1993)

Sensory

Neural

Metabolic or strial or vascular

Mechanical or cochlear conductive

Mixed

Indeterminate or intermediate

Sensory Presbyacusis

Loss of sensory hair cells in organ of Corti due to

accumulation of lipofuscin pigment granules

Process originates in basal turn (for a length > 10

mm) & slowly progresses toward apex

Audiogram: abrupt, steep, high-frequency SNHL

Speech discrimination score: good

Sensory Presbyacusis

Neural Presbyacusis

Atrophy of spiral ganglion & cochlear neurons (>

50%) mainly in basal turn of cochlea

Slowly progressive HL (Pure Tone Average not

affected until 90% neurons are destroyed)

Audiogram: ski-slope toward high frequencies

Speech discrimination score: poor (disproportionate)

Neural Presbyacusis

Metabolic Presbyacusis

Atrophy of stria vascularis (> 30% destroyed)

Stria vascularis maintains chemical + bioelectric

balance & metabolic health of cochlea

Results in slowly progressive deafness

Audiogram: Flat (as entire cochlea is affected)

Speech discrimination score: good

Metabolic Presbyacusis

Mechanical Presbyacusis

Slowly progressive SNHL due to thickening &

stiffening of basilar membrane of cochlea

More severe in basal turn of cochlea where basilar

membrane is narrow

Audiogram: ski-slope toward high frequencies

Speech discrimination score: slightly impaired

Mechanical Presbyacusis

Other Types

Mixed Presbyacusis:

Many ears have a combination of 4 pathologies

Indeterminate or Intermediate Presbyacusis:

SNHL which progresses with age, without light

microscopic evidence of cochlear pathology

Pathology: altered cellular metabolism / ed

synapse numbers / change in endolymph

composition / central auditory pathway changes

Other age-related changes

Outer ear: ed cerumen formation, ed epithelial

migration, ed hair growth, collapse of EAC

Middle ear: stiffening of TM, Arthritis + ossicular

joints ossification, degeneration of middle

ear muscles

They do not make marked contribution in deafness

Clinical Features

Gradually progressive hearing loss

Difficulty in understanding conversation around

high level of ambient background noise

Recruitment: abnormal growth in perception of

loudness (at high intensity) in pt with hearing loss

Tinnitus (30-50%): indicate worsening of deafness

Social isolation & depression

Investigations

Pure Tone Audiometry

Speech Audiometry: diminished scores

MRI: to rule out vestibular schwannoma

Indications of MRI in presbyacusis pt:

– Asymmetry > 10 dB of PTA between both ears

– Asymmetry > 20 dB of any single frequency

– Unilateral tinnitus

Audiogram

Treatment Medical: no medical cure

Diet modification & supplementation

Psychological counseling

Amplification devices or hearing aids

Lip reading & assisted listening devices

Cochlear Implantation

Tinnitus retraining therapy

Avoidance of aggravating factors

Dietary advice

30% caloric dietary restriction

Use of antioxidant dietary supplements (vitamins

A, C, E; selenium) reduce production of reactive

oxygen metabolites that harm inner ear & lead to

age-related hearing loss

Neuro-vitamins & Gingko biloba have no role

Hearing Aids

Binaural hearing aids give more benefit

Candidacy for hearing aids:

speech reception threshold > 30 dB in better ear

hearing level > 40 dB at 3 & 4 kHz in better ear

Pt with poor speech discrimination score are poor

candidates for hearing aids

Body worn

Spectacle

Spectacle

Completely in canal

Completely in canal

Completely in canal

Behind the ear

In the ear

In the canal

Completely in canal

Lip reading or speech reading

Skill of understanding spoken message by

looking at speaker's lips, jaws, tongue, teeth,

facial expressions, gestures & body language

Lip reading is helpful in patients with diminished

speech discrimination & hearing aid users who

have hearing difficulty in noisy environments

Assisted Listening Devices

They are NOT hearing aids

They are NOT used instead of hearing aids

Help pt with hearing loss to function better in

communication situations to overcome distance,

background noise, or poor room acoustics

Can be used with or without hearing aids

Vibrating wrist watch & alarm clock

CO2 & smoke alarm with strobe light

Amplified & captioned telephone

T.V. & F.M. amplifiers

Personal & multi-user amplifier

Alerting Devices

Amplified Stethoscope

Cochlear Implantation

Patients with cochlear damage & relatively intact

spiral ganglia + central pathways are best

candidates

Cochlear implantation have been performed on

patients up to 85 years old, with good results

Pawel Jastreboff: 1990

Tinnitus Retraining Therapy (TRT)

Based on neuro-physiological model of tinnitus

Blocks tinnitus-related neuronal activity from reaching

cerebral cortex (where it is perceived) & from activating

limbic & autonomic nervous systems

Uses combination of low level, broad-band noise &

counseling to achieve habituation of tinnitus. Tinnitus

never masked in TRT. Retraining takes 12 -18 months.

Success rate = 60 - 80%

Avoidance

Avoid following aggravating factors:

Noise exposure

Ototoxic drugs

Uncontrolled diabetes mellitus

Hyperlipidemia

Future research

Gene therapy to avoid early hair cell death in

cochlea

Medications to stimulate a genetic cascade for

hair cell regeneration

Better programmed hearing aids

Alden, Alfred, Arthur, Eastman, Fletcher, Hisswald,

Luke, Matthew, Oom, Richard, Shirmer & Theodore