The results of cortical electric response audiometry in medico-legal investigations

Abstract

Cortical ERA was conducted in a consecutive series of 118 medicolegal cases (467 threshold determination in 209 ears). In organic cases, the distribution of subjective (manual pure tone audiometry)/objective (CERA) discrepancies was normal and centred on 0 dB, with only 3.2% of the discrepancies exceeding + 15 dB. Averaged over 3 or more test frequencies in one ear, only 4.4% of the discrepancies exceeded + 7.5 dB, as compared to 95.1% exceeding + 7.5 dB in those suspected of having a non-organic overlay. The pattern of non-organic overlay superimposed on noise-induced hearing loss is expected and demonstrated to produce a flattening of the dip in the audiogram. It is argued that such flattening is very rarely the end product of noise exposure.

Detection of Pseudohypacusis: A Prospective, Randomized Study of the Use of Otoacoustic Emissions

“…Therefore, the pure-tone thresholds for each of the measured frequencies (1, 2, 3, and 4 kHz) were combined to give a mean pure-tone average (PTA) for each ear to characterize the degree of the hearing loss. In other studies (Coles & Mason, 1984); however, it has been reported that less exaggeration is expected at the higher frequencies, because of the phenomenon of recruitment, causing intensities to be perceived louder, due to the presence of hearing loss in the high frequencies in most patients. This was not observed in our study, probably because most of the patients did not suffer from severe or profound hearing loss.…”

A comparison of 40 Hz auditory steady-state response (ASSR) and cortical auditory evoked potential (CAEP) thresholds in awake adult subjects

“…The CAEP has enjoyed widespread clinical application as an objective measure of hearing sensitivity in adult subjects (Coles & Mason, 1984;Rickards et al, 1996;Hyde, 1997;Tsui et al, 2002). The CAEP is a waveform consisting of three main peaks: a positive (P1), followed by a negative (N1), and then a second positive (P2).…”

Cortical Electric Response Audiometry Hearing Threshold Estimation: Accuracy, Speed, and the Effects of Stimulus Presentation Features

“…Issues relating to neural synchrony that limits the accuracy of short latency (ABR) tests at low frequencies do not apply to the longer latency CERA tests. This excellent frequency specificity has particular advantages in noise-related compensation cases (Coles & Mason, 1984) in which audiometric notches, sometimes obscured by nonorganic overlay, may be resolved, thus addressing issues relating to diagnosis and causation (Alberti et al, 1987;Hone et al, 2003). In the United Kingdom and Ireland, CERA is the test of choice and is accepted by the courts when objective hearing assessment is required in adult medicolegal cases (King et al, 1992).…”