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Re: FW: Autistic Source Localisation

Yes, I was wondering to what extent developmental issues are tangled up with the fundamental symptoms - it's a bit 'hen-and-egg'.
Also, whilst we know that there's a powerful binaural component to the separation of sources, I'm not clear that it's just that. My (admittedly limited) understanding of autism spectrum disorders is that there's a more general problem with selective attention (not just for audio). And, as Bregman and Shephard have pointed out, scene analysis isn't entirely a matter of spatial separation. Actually, thinking aloud, there seems to be something worth investigating - experimentally segregating those components that need binaural differences, and those that don't

Dr Peter Lennox

Director of Signal Processing and Applications Research Group (SPARG)
School of Technology, 
Faculty of Arts, design and Technology University of Derby, UK

(01332) 593155

-----Original Message-----
From: AUDITORY - Research in Auditory Perception [mailto:AUDITORY@xxxxxxxxxxxxxxx] On Behalf Of Daniel J. Tollin
Sent: 11 November 2008 20:11
To: AUDITORY@xxxxxxxxxxxxxxx
Subject: Re: FW: Autistic Source Localisation


        One should also consider the fact that kids with Autism have substantially higher rates of common forms of hearing loss in infancy, such as serious otitis media.  And it is known that normal-functioning (non-autistic) kids with chronic otitis media (or other forms of conductive loss) during infancty often have difficulty on 'spatial' auditory tasks such as binaural masking level differences (BMLDs) even well after the hearing loss has been corrected (clearing of the ear infection, etc).  So it is possible that some of the deficits in 'spatial' hearing in autism may be related simply to long-term maladaptive effects of the early hearing loss, as in normal kids.  Moreover, some forms of chronic ear infection are known to cause sensorineural hearing losses (passage of infection to inner ear via round window) that would, of course, persist into adulthood.  The latter might also cause 'spatial' auditory deficits.
Of course there is likely to also be interactions between these mainly auditory deficits and those due to the spectra of disorders associated with autism.

Just some thoughts.

Daniel J. Tollin, PhD
Assistant Professor

University of Colorado Health Sciences Center
Department of Physiology and Biophysics/Mail Stop 8307
Research Complex 1-N, Rm 7120
12800 East 19th Ave
PO Box 6511
Aurora, CO 80045

Tel:  303-724-0625
Fax: 303-724-4501

-----Original Message-----
From: AUDITORY - Research in Auditory Perception [mailto:AUDITORY@xxxxxxxxxxxxxxx] On Behalf Of Dan Ellis
Sent: Tuesday, November 11, 2008 12:07 PM
To: AUDITORY@xxxxxxxxxxxxxxx
Subject: Re: FW: Autistic Source Localisation

Here's a response from Rob Morris at the MIT Media Lab <rmorris@xxxxxxxxxxxxx>:

> There is a paper that addresses this exact issue. Please forward this reference along:
> Brain Res Cogn Brain Res. 2005 May;23(2-3):221-34. Epub 2005 Jan 11.
> Auditory spatial localization and attention deficits in autistic adults.
> Teder-Sälejärvi WA, Pierce KL, Courchesne E, Hillyard SA.
> Department of Neurosciences 0608, School of Medicine, 9500 Gilman Drive, University of California, San Diego, La Jolla, CA 92093-0608, USA. wat@xxxxxxxxxxxxxx
> The objective of this study was to compare autistic adults and matched control subjects in their ability to focus attention selectively on a sound source in a noisy environment. Event-related brain potentials (ERPs) were recorded while subjects attended to a fast paced sequence of brief noise bursts presented in free-field at a central or peripheral location. Competing sequences of noise bursts at adjacent locations were to be ignored. Both behavioral measures of target detection and auditory ERP amplitudes indicated that control subjects were able to focus their attention more sharply on the relevant sound source than autistic subjects. These findings point to a fundamental deficit in the spatial focusing of auditory attention in autism, which may be a factor that impedes social interactions and sensory-guided behavior, particularly in noisy environments.