ACC: An objective test for DLI (Kumar et al., 2020)

Purpose: This study aimed to investigate usefulness of acoustic change complex (ACC) as an objective measure of difference limen for intensity (DLI) in auditory neuropathy spectrum disorders (ANSD) and cochlear hearing loss (CHL).
Method: The study used a multiple static group comparison research design. Twenty normal-hearing individuals (NH), 19 individuals with ANSD, and 23 individuals with CHL underwent DLI measurement using behavioral (psychoacoustic) techniques and ACC. For eliciting ACC, a 500-ms, 1,000-Hz pure tone was presented at 80 dB SPL. Additionally, six variants of this stimulus with intensity increments of 1, 3, 4, 5, 10, and 20 dB starting 250 ms after stimulus onset were used to elicit the ACC.
Results: The lowest intensity change that produced replicable and clearly identifiable ACC was referred as objective DLI. In comparison to NH and CHL, the behavioral as well as the objective DLI were significantly larger (poorer) in ANSD (p < .05). Significantly strong positive correlation existed between DLI obtained using behavioral and objective measures (p < .05).
Conclusions: ACC could be a useful objective tool to measure DLI in the clinical population, provided the individuals of the clinical population fulfill the prerequisite of the presence of Auditory Long Latency Responses.

Supplemental Material S1. Individual overlapping waveforms and grand averaged waveforms.

Kumar, P., Sanju, H. K., Hussain, R. O., Ganapathy, M. K., & Singh, N. K. (2020). Utility of acoustic change complex as an objective tool to evaluate difference limen for intensity in cochlear hearing loss and auditory neuropathy spectrum disorder. American Journal of Audiology. Advance online publication.