Correcting for ear canal collapse during audiometry

The hearing thresholds of 20 subjects with normal hearing and normal ear canals and two subjects with collapsible ear canals were measured at octave frequencies from 250 to 8000 Hz under standard transducers (TDH-39) fitted with standard cushions (MX-41/AR) and experimental cushions (Telephonics 266CIII). When correction factors based on normal threshold differences were applied, thresholds obtained under the experimental cushion reasonably approximated the actual hearing of individuals with collapsible canals.