Pure-Tone Audiometry in Hearing Evaluation

Intensity (Loudness)

• Loudness is measured in decibels (dB), reflecting the pressure exerted by sound.
• Sounds exceeding 80 dB are often harsh and can cause inner ear damage.

Tympanogram (Impedance Audiometry)

• Evaluates middle ear muscle reflexes and tympanic membrane compliance through air pressure changes in a sealed ear canal.
• Compliance impairment indicates possible middle ear disease.

Electronystagmography (ENG) and Video Nystagmography (VNG)

• Tests for vestibular function by detecting eye movements in response to head position changes or balance sensor stimulation.
• Assesses the interaction between the oculomotor and vestibular systems.
• Useful for diagnosing unknown causes of unilateral hearing loss, vertigo, or tinnitus.

Hearing Loss

• Deafness encompasses partial to complete hearing loss due to genetic or acquired factors.
• Classified into:
  • Conductive hearing loss: Results from disorders affecting the external or middle ear; sound transmission to the inner ear is interrupted.
  • Sensorineural hearing loss: Involves damage to the cochlea or vestibulocochlear nerve (e.g., presbycusis).
  • Mixed hearing loss: Combination of conductive and sensorineural loss due to dysfunction in sound conduction.

Risk Factors for Hearing Loss

• Cerumen impaction, head or ear trauma, exposure to loud noises.
• Use of ototoxic medications or chemicals, nutritional deficiencies, viral infections.
• Delayed onset or progressive genetic hearing loss may occur.

Clinical Manifestations

• Symptoms can include tinnitus, otalgia (earache), and difficulty hearing.
• Individuals may need to turn up volume, respond inappropriately, show irritability, and ask others to repeat.

Severity of Hearing Loss

• Categorized by decibel loss:
  • Normal: -10 to 15 dB
  • Slight: 16 to 25 dB
  • Mild: 26 to 40 dB
  • Moderate: 41 to 55 dB
  • Moderately severe: 56 to 70 dB
  • Severe: 71 to 90 dB
  • Profound: 91 dB +

Investigations for Hearing Loss

• Audiometry assesses the type and pattern of hearing loss.
• Speech audiometry evaluates the minimum intensity for speech comprehension.
• Tympanometry measures compliance and impedance in the middle ear.

Management of Hearing Loss

• Prevention includes using ear protection to avoid noise-induced hearing loss and reducing acoustic trauma risks.
• Surgical options enhance conductive hearing loss by addressing underlying causes.
• Hearing aids amplify sounds by converting them to electrical signals before reconverting to acoustic signals.
• Implanted devices provide assistance for those with severe hearing loss.

Types of Audiometry

• Pure-tone audiometry uses musical tones to assess hearing; louder tones indicate greater hearing loss.
• Speech audiometry tests the ability to hear and differentiate sounds and words.

Frequency Considerations

• Frequency refers to the number of sound wave cycles per second, measured in Hertz (Hz).
• The human ear perceives sounds between 20 Hz and 20,000 Hz; the speech range is particularly between 500 Hz and 2000 Hz for everyday communication.

Explore the role of pure-tone audiometry in assessing hearing capabilities. This quiz covers the essential frequencies needed for understanding everyday speech and evaluates your knowledge on hearing evaluation methods.