Presbycusis

Presbycusis refers to age-related hearing loss. Once again it is a sensorineural form of hearing loss.

Pathophysiology

The normal perceivable sound range is between 20Hz - 20,000Hz. However, as we tend to lose the ability to perceive high-pitched sounds (and later on the lower-pitched sounds). Young adults may find it difficult to detect sounds above the 15-16kHz range even.

Presbycusis is characterized by bilateral hearing loss above 2000Hz. On a standard audiogram, presbycusis appears as an overall down-sloping line that represents impaired hearing at higher frequency sounds.

There are several causes of presbycusis including:

Sensory presbycusis - loss of hair cells at the base of the cochlea (base corresponds to high frequency transmission).
Neural presbycusis - loss of cochlear nerve fibres and spiral ganglion neurons.
Strial presbycusis - degeneration of stria vascularis epithelial cells and thus decreased endolymph and endocochlear potential.
Mechanical presbycusis - physical changes to cochlear duct .

Other factors include genetics, ototoxic drugs and potentially even hormonal factors.

⚠️ Risk factors

Age
Male gender
Family history
Exposure to loud noises

Diabetes
Hypertension and arteriosclerosis
Ototoxic medication
Smoking

😷 Presentation

⭐️ Hearing loss that is gradual. Patients may have difficulty hearing in loud environments, trouble with female voices (as they tend to be higher-pitched than male voices). They may sometimes seem as if they are not paying attention. They may also have difficulty on the cell phone. They may increase the volume on the TV and phone.
Tinnitus may be associated.

🔍 Investigations

🧏🏼

Audiometry 🏆 Pure-tone audiometry is the gold standard investigation. It will indicate a sensorineural pattern of hearing loss (worsening hearing loss at higher frequencies). It is similar to noise-related hearing loss.

🧰 Management

At this stage, presbycusis is irreversible. However it is important to aid the patient in hearing better by offering:

Hearing aids - these are essentially amplifiers for the ear to allow us to hear sounds better.
Cochlear implants - these electronically stimulate the cochlea nerve. There is an internal part that is placed under the post-auricular skin and there is an external part with a microphone that sits behind the ear.