Audiometry Special Tests

AUDIOMETRY GUIDES

ABLB

The perceived growth of loudness of a suprathreshold tone in an impaired ear may differ from the compared growth of loudness of a tone of identical frequency in the normal ear. Recruitment, if present, may be found.

Short Increment Sensitivity Index (SISI)

SISI stands for Short Increment Sensitivity Index. This is a legacy test in audiometry that determines site of lesion. Patients with cochlear hearing loss are able to detect very small changes of loudness when compared to patients with normal hearing or retrocochlear pathology.

Stenger Test

The Stenger is an audiometric test that is used quite frequently when patients are giving inconsistent responses and malingering is suspected. The Brain is an amazing tool. If two stimuli identical in all ways except loudness are introduced simultaneously to both ears, only the louder tone will be perceived. It is possible to use either Tone or Speech stimuli to find malingerers with the Stenger test.

Masking

Masking is a technique to isolate the test ear when there is suspected crossover in an asymmetric loss. Narrow band noise or speech noise is introduced to the non-test ear to ensure that the response is from the test ear. Masking is a fun challenge because you have to consider the transducers, the interaural attenuation, and the thresholds to make sure you have an effective masking level.

Pediatric Noise

Pediatric hearing testing requires fast thinking and lots of variation of stimuli to get results. Historically, audiologists have used narrow band noise as an additional stimulus to create interest and keep attention of their little patients. NBN is definitely frequency specific, but it is calibrated as effective masking and has a wider spectral envelope - which could lead to false thresholds. Pediatric noise is a super steep narrow band noise that is calibrated to the pure tone standards. it's easy to access and gives the audiologist a unique stimulus that they can trust to elicit accurate responses.