From an anatomical perspective, hearing loss can occur in the ear canal, inner ear, or middle ear. The degree of hearing loss is expressed in decibels, a unit of measurement for sound intensity or volume. Depending on the degree of hearing loss, there are categories of deafness and hard of hearing. People who are hard of hearing experience hearing loss in the range of 20-90 dB, while those who are deaf have hearing loss greater than 90 dB.

According to the degree of hearing loss, the classification is as follows:

• Mild hearing loss: 25 – 40 dB
• Moderate hearing loss: 40 – 55 dB
• Moderately severe hearing loss: 55 – 70 dB
• Severe hearing loss: 70 – 90 dB
• Profound hearing loss: over 91 dB

The functional difference between deaf and hard of hearing individuals is that hard of hearing people primarily rely on hearing to understand speech, while deaf individuals mainly use their vision, such as reading lips, and may use hearing aids.

Hearing loss can be classified as conductive, sensorineural, or mixed. Conductive hearing loss is often caused by infections or issues in the middle or outer ear, and it involves a problem with the transmission of sound from the outer ear to the inner ear. Sensorineural hearing loss occurs when nerve structures disrupt or prevent the perception of sound, often due to damage to the cochlea, auditory nerve, or auditory centers in the brain. Mixed hearing loss involves a combination of both conductive and sensorineural hearing loss.

Hearing loss can occur before birth, during delivery, or after birth. In addition to this classification based on when the hearing loss occurs, there is also a distinction based on whether the hearing loss happened before or after the acquisition of speech and language.

Today, newborns have their hearing tested before being discharged from the hospital. Early detection of hearing loss is crucial for ensuring timely and appropriate rehabilitation, which helps reduce the impact of the impairment and improves the individual’s quality of life.

Symptoms that may indicate hearing loss include:

• Frequently asking people to repeat themselves
• Often misunderstanding what others are saying
• Frequently needing to increase the volume on the TV or phone
• Hearing sounds as if people around them are speaking very softly or mumbling
• Experiencing tinnitus often – a condition associated with hearing loss, characterized by a ringing or buzzing in the ears

Symptoms that may indicate a baby or child has hearing loss include:

• Not reacting to loud noises
• Not responding when their name is called
• Not turning towards the source of a sound
• Not speaking simple words like “mama” or “dada” by their first birthday
• Speech development not meeting age-appropriate expectations
• Increasing the volume on the TV or phone