II. Indications
III. Preparation
- Testing environment should be quiet
- Patient should avoid loud noise exposure for 14 hours prior to testing (e.g. music via headphones, motorcycle)
IV. Technique: Pure-Tone Audiometry
- Threshold Search Audiometry (Hughson-Westlake Method)
- Start with the better Hearing ear
- Hearing is tested in each ear at frequencies between 250 Hz to 8000 Hz
- Frequencies tested at one octave intervals: 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz, 8000 Hz
- Typical sequence: 1k, 2k, 3k, 4k, 8k, 1k, 500, 250
- Each frequency is tested at volumes between 0-90 decibels (logarithmic, loudness doubles every 10 decibels)
- Start with an easily heard DB level
- Test each heard tone again at 10 DB lower until no response
- Then increase by 5 DB, testing until tone heard again
- Screening (typical handheld device)
- Hearing frequencies tested: 500 to 4000 Hz (speech spectrum)
- Loudness tested: 25-30 DB in adults (15-20 DB in children)
V. Interpretation
- Normal Hearing
- All frequencies are heard at 20 decibels or less
- Hearing Loss across all frequencies (typically 40 DB loss)
- Low frequency Hearing Loss
- Meniere's Disease (severe)
- Low to mid-frequency Hearing Loss (with bone conduction better than air conduction)
- High frequency Hearing Loss
- Noise-Induced Sensorineural Hearing Loss (4000 Hz and higher)
- Age-Related Hearing Loss - Presbycusis (2000 Hz and higher)
VI. Efficacy: Handheld Audiometry for Sensorineural Hearing Loss (over age 5 years)
- Test Sensitivity: 92%
- Test Specificity: 94%
VII. Resources
- Audiogram of normal sounds
