A total of 250 adult patients presenting with sudden unilateral sensorineural hearing loss had their hearing evaluated with the Weber test using a 512Hz tuning fork at screening. Audiometric evaluation was performed afterwards, with frequency thresholds and pure tone average for each ear recorded. The results of the Weber test were then compared with those of the audiogram to allow calculation of the sensitivity of the Weber test.
The Weber test had an overall sensitivity of 78% – the sound of the tuning fork correctly lateralised to the ear opposite the hearing loss in 78% of patients. One per cent incorrectly lateralised to the wrong ear, giving a false diagnosis of middle ear conductive hearing loss, while 15% were heard in the midline and 6% were not heard at all. The Weber test had an overall agreement coefficient with audiometry of 0.82 in the entire cohort, but better agreement among the subset in which the test lateralised, with a coefficient of 0.98.
What does it mean for GPs?
The US researchers warned that ‘clinicians should be alert to the possibility of sudden sensorineural hearing loss being overlooked in patients without the expected tuning fork findings’, but confirmed that ‘lateralisation of the Weber test to the contralateral ear very reliably predicts a sensorineural etiology and patients should be promptly referred and treated accordingly’.
Mr John Graham, consultant ENT surgeon at the Royal National Throat, Nose and Ear Hospital in London: ‘The paper seems very sensible. Nobody would claim that tuning fork tests are a true substitute for proper audiometry. It shows that they certainly have the potential to be useful if no more accurate tests of hearing are available – when the Weber test is heard louder in the non-deafened ear, as it was in nearly 80% of the patients studied, it does mean that the patient is likely to have a sensorineural deafness and needs proper assessment. It detects eight out of ten cases, which is likely to be seriously better than guesswork, which often seems to be the alternative.’