Types of Hearing Loss
Hearing loss can vary in degree—ranging from mild to profound—and may affect specific pitches or frequencies. Comprehensive hearing tests help identify the severity of hearing loss by comparing your hearing ability to that of individuals with normal hearing.
How Hearing Is Measured
- Volume (Decibels, dB): Sounds range from 15-20 dB (a soft whisper) to 120 dB (a jet engine). The softest sounds you can hear are called thresholds.
- Normal Hearing: For adults, thresholds between 0-25 dB across tested frequencies are considered normal.
- Speech Testing: Evaluates how well you can hear and understand specific words, helping diagnose the type of hearing loss.
Hearing loss is typically categorized into three types: conductive, sensorineural, and mixed.
Conductive Hearing Loss
Overview
Conductive hearing loss occurs when sound is not conducted properly to the inner ear. The issue may be in the ear canal, eardrum, or middle ear (ossicles and Eustachian tube). The inner ear and auditory nerve remain unaffected.
Symptoms
- Sounds may seem muffled or unusually quiet.
Causes
- Outer or middle ear infections
- Complete earwax blockage
- Damage or deterioration of the middle ear bones (ossicles)
- Otosclerosis: Fixation of the ossicles
- Perforated eardrum (hole in the tympanic membrane)
- Absence of outer or middle ear structures
Treatment
Conductive hearing loss can be temporary or permanent, depending on the cause.
- Medical management: May correct reversible cases, such as infections or blockages.
- Hearing aids: Recommended for long-term or permanent cases.
Sensorineural Hearing Loss
Overview
This type of hearing loss results from issues with the sensory receptors in the cochlea (inner ear) or the auditory nerve. Damage to the hair cells in the cochlea prevents proper sound transmission to the brain.
Symptoms
- Muffled speech
- Difficulty hearing in noisy environments
- Tinnitus (ringing in the ears)
- Reduced clarity of speech
Causes
- Congenital: Abnormal hair cells present since birth.
- Acquired damage: Results from genetics, infections, ototoxic drugs, trauma, or noise exposure.
- Presbycusis: Age-related hearing loss.
Treatment
Sensorineural hearing loss is typically permanent and may worsen over time.
- Hearing aids: The most effective treatment, allowing adjustments as needs change.
- Routine monitoring: Regular hearing tests help track changes.
Mixed Hearing Loss
Overview
Mixed hearing loss is a combination of sensorineural and conductive hearing loss. It involves problems in the inner ear as well as the outer and/or middle ear.
Treatment
- Medical management: May address the conductive component.
- Hearing aids: Often recommended for managing the sensorineural aspect.
