How Hearing Works: Anatomy, Sound and the Audiogram

The first option is always a hearing aid. If it provides adequate, meaningful hearing, meaning the person can discriminate between words rather than just hear noise, that remains the treatment. Presbycusis, age-related hearing loss common in people 80 to 85 years old with no prior history, is a typical cause. If hearing aids only deliver noise without clarity, a cochlear implant is an option at any age.

Absolutely. Chronic myeloid leukemia and even chronic kidney disease are not contraindications, because CML is an indolent, slow-moving disease. As long as the patient is medically stable and vaccinated beforehand, implantation can significantly improve their social interaction and quality of life.

Programming is now available online because most modern devices have built-in Bluetooth. An audiologist can connect through an app on a laptop or phone and wirelessly program or calibrate the device remotely, in much the same way as this Zoom masterclass, without the patient needing to travel back.

In India, cochlear implants are not covered by insurance, and the device is expensive, so CSR funds and government programs are used to support Indian families. Nothing equivalent currently exists for international patients. Paid out of pocket, surgery including the device starts at around 14,000 US dollars and can go up to 36,000 US dollars for high-end models, with cost driven mainly by MRI-compatible magnet strength, auto-programming that adjusts to noise every few seconds, and built-in Bluetooth.

No. Implant companies design the internal device to stay compatible even as external technology advances. The first person implanted with a cochlear device, in 1984, is still using that original internal component 42 years later, having only upgraded the external processor along the way.

Sound enters through the pinna, travels down a roughly 2.5 centimetre external auditory canal, and reaches the tympanic membrane. Behind that membrane sit three small bones, the malleus, incus and stapes, and the stapes connects directly to the cochlea, where the signal is handed to the auditory nerve and sent to the brain.

Conductive hearing loss stems from problems in the outer ear or eardrum, such as a malformed pinna, a narrowed canal, wax and debris, or a perforation or infection, and is frequently temporary and treatable. Sensorineural hearing loss comes from damage inside the inner ear or cochlea, generally does not respond to medication, and requires a hearing aid or cochlear implant.

Intensity, measured in decibels, determines loudness, and frequency, measured in Hertz, determines pitch. Female voices tend to sit at a higher frequency and male voices at a lower one.

It is the shaded region where most everyday speech sounds cluster. A person with a 40 decibel loss, the level at which normal conversation happens, will miss consonant sounds like ch, sh and s, while a 60 decibel loss means missing the conversation altogether.

Normal hearing sits at 0 to 20 decibels, mild loss runs up to 40 decibels, moderate loss spans 40 to 70 decibels, severe loss spans 70 to 90 decibels, and profound loss is anything above 90 decibels. Severe and profound losses are the range where cochlear implantation typically becomes the relevant option.