PEARLS 31, October 2007, written by Bruce Arroll and Brian R McAvoy
(first published New Zealand Doctor, 5 December 2007)

Clinical question
How useful are simple screening tests for diagnosing hearing impairment?

Bottom line
In symptomatic and asymptomatic patients over 16 years old, whispered voice tests and the audioscope are very accurate for ruling out hearing impairment (ie, if the person can hear whisper, they are unlikely to be deaf).

Caveat
There is no single standard method for the whispered voice test but Glasziou1 suggests the following: stand behind the patient at arm's length (hands on their shoulders), then cover one ear (by folding their tragus inward and slowly rubbing while testing). Exhale fully and whisper up to 6 letters and numbers with different types of sound (eg, b, 6, k, 2, m, 9). Ask the patient to repeat the letters/numbers after each sound. Allow 1-2 errors and repeat each sound once if necessary.

Context
Compared to the Weber and Rinne tuning fork tests the whispered voice test is the most accurate and may be better than the expensive audioscope, with pooled positive and negative likelihood ratios of 6.1 and 0.03 respectively.* A trial of 188 elderly patients randomised to a hearing aid or a waiting list showed that the hearing aid resulted in significant improvements in social and emotional function, communication, cognitive function and depression.2
* The likelihood ratio is the likelihood that a given test result would be expected in a patient with the target disorder compared to the likelihood that the same result would be expected in a patient without the target disorder.

Systematic Review
Bagai A, Thavendiranathan P, Detsky AS. Does this patient have hearing impairment? JAMA 2006;295:416-28.
Note: this review contains 24 studies involving 12,645 participants.

Further References
1. Glasziou P. EBM 2006;11:116
2. Mulrow et al. Ann Int Med 1990;113:188-194