A hearing evaluation is a comprehensive set of non-invasive, painless diagnostic procedures performed by an audiologist. These tests determine the frequencies and sound intensities a person can detect, identify the type and degree of hearing loss (if present), and pinpoint the location of the issue along the auditory pathway.

When is a hearing evaluation recommended?

• Difficulty understanding speech: Feeling that sounds are muffled or unclear, frequently asking others to repeat themselves (“What?”), or needing to turn up the TV or device volume.
• Medical warning signs: Tinnitus (ringing in the ears), a sudden feeling of ear fullness, dizziness, or sudden sensorineural hearing loss, which requires urgent evaluation.
• Noise exposure: Prolonged exposure to noisy workplaces, heavy machinery, or loud music.
• Monitoring ototoxic medications: Undergoing medical treatments that may damage the hair cells in the inner ear.
• Age-related monitoring: Routine hearing checks for people aged 50 and older.
• Hearing aid selection and follow-up: Taking precise measurements for fitting hearing aids and optimizing their performance.
• Pediatric needs: Newborn hearing screening, speech and language delays, lack of response to sounds, or recurrent middle ear infections.

Pure Tone Audiometry (PTA) is the gold-standard diagnostic test for determining hearing sensitivity. The patient sits in a soundproof booth wearing headphones. Pure tones are presented at different frequencies (approximately 250 Hz to 8,000 Hz) and sound levels. The patient responds whenever a tone is heard, by pressing a button or raising a hand. The test usually takes 15 to 30 minutes.

Two main testing methods:

• Air Conduction (AC): Sounds are delivered through headphones and travel through the entire auditory pathway: the outer ear canal, eardrum, middle ear bones, and inner ear.
• Bone Conduction (BC): A small oscillator is placed behind the ear, on the mastoid bone, to create vibrations. These vibrations travel directly to the cochlea through the skull bones, bypassing the outer and middle ear.

By comparing air-conduction and bone-conduction thresholds (the “air-bone gap”), specialists can determine whether hearing loss is conductive, sensorineural, or mixed.

What is a hearing threshold?

The hearing threshold is the lowest sound intensity, measured in decibels hearing level (dB HL), at which a person can reliably hear a sound at least 50% of the time at specific test frequencies.

What is an audiogram?

An audiogram is a standardized clinical graph showing hearing thresholds for each ear separately:

• Horizontal axis (X-axis): Frequency or pitch in hertz (Hz), from low-pitched sounds (250 Hz) to high-pitched sounds (8,000 Hz).
• Vertical axis (Y-axis): Hearing level in decibels (dB HL), from very quiet (-10 dB) at the top to very loud (120 dB) at the bottom.

Clinical note: Lower points on the graph indicate reduced hearing sensitivity. Thresholds at or below 25 dB are considered within the normal clinical hearing range.

Tympanometry is an objective diagnostic test that evaluates middle ear function and eardrum mobility. A soft probe creates a seal at the entrance of the ear canal, introduces gentle changes in air pressure, and measures eardrum movement.

• Procedure: It takes about one minute per ear, is completely painless, and does not require an active behavioral response, making it suitable for infants and young children.
• Results: The test produces a diagnostic graph called a tympanogram, which can help identify conditions such as middle ear fluid (effusion), eardrum perforation, ossicle fixation, or Eustachian tube dysfunction.
• Acoustic reflex test: Often measured alongside tympanometry, it evaluates contraction of the stapedius muscle in response to loud sounds, providing information about middle ear mechanics and auditory pathways in the brainstem.

While pure-tone tests reveal which sounds a person can hear, speech audiometry measures how well they understand and distinguish speech in everyday communication. The audiologist presents standardized spoken words through headphones, and the patient repeats them. Key measures include:

• Speech Recognition Threshold (SRT): The lowest sound level at which the patient can correctly repeat at least 50% of two-syllable words. It serves as a cross-check of the accuracy of pure-tone results.
• Word Recognition Score (WRS): Standardized lists of phonetically balanced, single-syllable words are presented at a comfortable, clearly audible level. Results are calculated as a percentage:
  • Close to 100%: Excellent word recognition and healthy auditory processing.
  • Low percentage: May indicate distorted speech perception due to cochlear damage or neural problems.

Speech audiometry is essential for selecting suitable hearing aid technology and estimating the real-world benefits of amplification.

A comprehensive hearing report combines pure-tone thresholds, speech recognition, and middle ear assessment results. Together, these measures provide a complete picture of hearing health:

• Degree and configuration: Determines the severity of hearing loss (mild, moderate, severe, or profound) and the pattern of hearing decline across frequencies.
• Type and site of the problem: Distinguishes between outer or middle ear problems (conductive) and inner ear or neural system problems (sensorineural).
• Interaural asymmetry: Any difference in hearing thresholds between the ears (for example, greater than 15 dB at certain frequencies) may warrant prompt medical referral to rule out retrocochlear conditions.
• Treatment planning: Helps determine whether medical or surgical intervention is needed, whether hearing aids or cochlear implants are recommended, and which device settings are appropriate.

Clinical note: An audiogram should always be interpreted by a licensed audiologist alongside an otoscopic examination and the patient’s medical history, since the graph alone cannot identify the underlying medical cause.