From Sensory-Perceptual Representations to Cognitive Processing in Rett Syndrome

John Foxe, PhD., University of Rochester, Albert Einstein College of Medicine | Sophie Molholm, PhD, Albert Einstein College of Medicine

$533,607 AWARDED

Most individuals with Rett Syndrome have lost the ability to speak or use their hands. It is therefore often difficult to assess just how much information is being processed and understood. Modern brain mapping techniques can be of enormous utility in these situations. The emergence of easily applied high-density electrode systems over the past decade, and the development of specialized probes of auditory and cognitive processing, allow clinical scientists to monitor the workings of the brain as children process the things they hear. That is, we no longer have to rely on a child being able to tell us what they can hear and understand; rather, we can ask their brain directly by monitoring its ongoing activity.

In the first major aim of this project, we take advantage of these cutting-edge electrical brain mapping techniques to ask some basic questions about the auditory processing abilities of individuals with Rett. We begin by assessing the building blocks of auditory perception. 1) We ask if the auditory system of Rett patients can represent a source of constant auditory input in a noisy ever-changing acoustic background. This is a crucial ability because understanding auditory inputs relies on the listener being able to segregate the most relevant input from extraneous background noise. 2) We then ask if they can represent more abstract auditory patterns (e.g. melodies). 3) Finally, we ask whether their auditory systems can adequately separate two sources of competing sound input (e.g. two different speakers).

Then, in the second major aim, we build on this work by asking whether heard information is being processed to the level of cognition. It is one thing to have a functioning auditory system that can sense and analyze the information arriving in the brain, but it is another thing altogether to ask whether this information can be acted upon and understood. Put another way, does the auditory input reach awareness? Again here, we can use brain mapping to objectively ask whether the brains of Rett children register surprise when unpredictable auditory events occur.

In summary, using these brain mapping techniques, we intend to build a much better understanding of the fundamental auditory processing abilities of individual with Rett syndrome. In doing so, we will also establish a set of biomarkers that will have potential utility as outcome measures in clinical trials.

Fifty non-ambulatory and fifty ambulatory individuals with Rett will be tested as well as fifty age-matched controls. The individuals with Rett will be grouped into two age groups, 7 to 12 and 13 to 18. Patients will be recruited from the Rett Syndrome Clinic in the Bronx run by Dr. Sasha Djukic.

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