Abnormal auditory forward masking pattern in the brainstem response of individuals with Asperger syndrome

Abstract

Abnormal auditory information processing has been reported in individuals with autism spectrum disorders (ASD). In the present study auditory processing was investigated by recording auditory brainstem responses (ABRs) elicited by forward masking in adults diagnosed with Asperger syndrome (AS). Sixteen AS subjects were included in the forward masking experiment and compared to three control groups consisting of healthy individuals (n = 16), schizophrenic patients (n = 16) and attention deficit hyperactivity disorder patients (n = 16), respectively, of matching age and gender. The results showed that the AS subjects exhibited abnormally low activity in the early part of their ABRs that distinctly separated them from the three control groups. Specifically, wave III amplitudes were significantly lower in the AS group than for all the control groups in the forward masking condition (P < 0.005), which was not the case in the baseline condition. Thus, electrophysiological measurements of ABRs to complex sound stimuli (eg, forward masking) may lead to a better understanding of the underlying neurophysiology of AS. Future studies may further point to specific ABR characteristics in AS individuals that separate them from individuals diagnosed with other neurodevelopmental diseases.

Keywords:

• asperger syndrome
• auditory brainstem response
• forward masking
• psychoacoustics

Acknowledgements

We would like to thank Åsa Sandstedt Eriksson, Agneta Julinder and Pernilla Remsö at the NPU unit in Linköping, Sweden for their contribution to this research by performing tests and collecting data. We would also like to thank Professor Anders Forsman for valuable discussions. This research was supported by the Sjöbring foundation at the Department of Neuroscience, University of Lund.

Disclosures

Authors Johan Källstrand, Olle Olsson, and Sara Fristedt Nehlstedt are employees of, and hold stock in, SensoDe-tectAB. Author Mia Ling Sköld is an employee of Senso-Detect AB. Sören Nielzén, Assistant Professor of Psychiatry at the University of Lund, holds stock in SensoDetect AB although not employed by the company.