Crossed and uncrossed acoustic reflex growth functions in normal-hearing adults, typically developing children, and children with suspected auditory processing disorder

Abstract

Objective: Previous data suggested that children with suspected auditory processing disorders (APD) often show elevated or absent acoustic reflex thresholds, especially in crossed conditions (e.g. Allen & Allan, 2014). This study further explored these effects by measuring acoustic reflex growth functions (ARGF). Design: Crossed and uncrossed ARGF slopes were obtained by linear fits between reflex amplitudes and increases in activator level from threshold to 15 dB above it. Study sample: Normal-hearing adults, typically developing children and children with reported listening difficulties and suspected of having an APD, participated. Results: The ARGF slopes were shallower in crossed than in uncrossed conditions for all groups but the magnitude of the effect was significantly greater in the children with suspected APD. There were no differences between the typically developing children and the adults. Conclusions: The results suggest shallower ARGFs in children with suspected APD. Given the role of the acoustic reflex in facilitating hearing speech in noise these findings may begin to shed light on physiologic explanations for some of the difficulties that are reported by children with suspected APD.

Key Words::

• Auditory processing disorders
• acoustic reflexes
• children

Acknowledgements

The work was supported by grants to Prudence Allen from the Ontario Research Fund, #RE 03–009 and the Canada Foundation for Innovation, #30702. This work was presented at the 36th Midwinter Meeting of the Association for Research in Otolaryngology, Baltimore, USA, February 16–20, 2013. Saxena U., Allan C., and Allen P. Crossed and Uncrossed Acoustic Reflex Growth Functions in Normal-Hearing Children, Adults, and Children with Auditory Processing Difficulties.

Declaration of interest: The authors report no conflicts of interest.