Discrepancies between subjective and objective acoustic thresholds.

Abstract

Three sources of error are pointed out that may cause discrepancies between the auditory acuity of a patient and his ERA threshold: 1. misinterpretation of recorded data, 2. the effects of pharmacological agents, and 3. the effects of pathological or experimentally induced metabolic disturbances of the brain on the evoked responses. To minimize the occurrence of interpretation artifacts, the authors report on inter-sensory interaction and on a multi-channel-write-out program that enables one to detect minute, but reproducable responses. Sedation was induced by intravenuous administration of valium. In human and animal experiments, DMT was used to demonstrate a temporary and reversible phenomenon: acoustically evoked potentials were being suppressed, while hearing remained unchanged. In aphasia, the AEP appeared to be normal while the CNV correlated with language comprehension.