Békésy Audiometry – Reliability Tested
25 October 2018
There are several procedures that can be conducted in assessing if a person is suffering from noise induced hearing loss (NIHL). The Békésy test was used for many years as a tool to calculate a person’s hearing levels. However, in modern-day other, more sensitive techniques such as the pure-tone audiometry have mainly replaced it.
The Békésy test employs an automatic recording device that allows the listener to control the intensity of the stimulus by pressing a button while listening to a pure tone frequency moving through the entire audible range rather than having the audiologist to do it. As opposed to Békésy the pure-tone audiometry is where the tone is presented through earphones, and instead of discrete frequencies, the test produces a constantly increasing frequency which allows the listener to control only the attenuator and therefore the intensity of the sound evaluates the level of the person’s hearing loss in presence of a qualified specialist.
The Békésy Audiometry is an extremely demanding test which requires the subject to pay tremendous attention throughout the test. Subjects are being asked to “hit a moving target” to determine the thresholds as the sound does not become louder but the loudness goes up and down as a continuous change.
As one would expect recent studies into the reliability of Békésy, reveal that, thresholds obtained from Békésy showed greater variance, more than 15dB at all frequencies as opposed to pure tone audiogram.
In a recent unreported decision, Andrew Ransome v Secretary of State for Energy & Climate change (July 2018), Curtis Law Solicitors LLP (led by R Gregory of Ropewalk) were successful in a noise induced hearing loss matter against the NCB in establishing that a 1989 Békésy audiometry was unreliable.
HHJ Saffman, sitting at Leeds County Court, accepted the Claimant’s evidence and concluded that the claimant has established a 1989 Békésy audiogram to be unreliable for reasons and the deficiencies identified comprehensively by Mr Noweed Ahmad (FRCS ENT Consultant Surgeon). Both experts, Mr N Ahmad for the claimant and Mr Wilson for the defendant, agreed that there were many variabilities which cause concern and put to question whether the 1989 Békésy Audiogram was indeed reliable.
HHJ Saffman saw significant importance with the issue which calls into question the expertise of the tester. Was the test conducted by a person who can be expected to be a skilled operator? In this case it was not.
Defendants continue to be overwhelmed by the discovery of a Békésy Audiogram in the Claimants occupational health records but one must question how reliable is the audiogram? Defendant solicitors and insurers alike should take note and should not expect a Békésy to be easily accepted on face value. They should carefully consider each audio on its own merit and should not shy away from accepting some Békésy audiograms could be unreliable and deficient.
This case, is a significant and positive decision for Claimant’s continuing to face an unparalleled rejection in deafness claims just by finding a Békésy audiogram. Moreover, is there a strong indication that the Békésy method is questionable, can it really provide reliable, valid hearing thresholds and to what extent?
Curtis Law Solicitors LLP