Alpha Auditory Entrainment for Cognitive Enhancement and Sensory Hypersensitivity in Youth With Developmental Disorders

Overview

Fragile X Syndrome (FXS) is a complex neurodevelopmental disorder caused by a mutation on the X chromosome. Scientists have investigated FXS extensively in both humans and animals. Thus far, phenotypic rescue in animal models has not resulted in treatment breakthroughs in humans, though some important discoveries have been made. Research has shown that individuals with FXS process sounds differently than those in the typical population, and they also show baseline differences in brain activity, including high gamma activity, increased theta activity, and decreased alpha activity. The investigators' central hypothesis is that these alterations in brain activity (specifically alpha and gamma activity) impair the brain's ability to process new information, thereby impeding cognitive functioning and increasing sensory sensitivity. The investigators propose that auditory entrainment, a technique that involves playing special sounds through headphones, will normalize brain activity in individuals with FXS and lead to increased cognitive function and decreased sensory hypersensitivity.

Fragile X Syndrome (FXS) is an exemplar monogenetic neurodevelopmental disorder (NDD) where a tremendous body of multi-species translational research has elucidated the underlying molecular pathophysiology, and more recently, in-depth electrophysiology of cortical function. Thus far, phenotypic rescue in animal models has not resulted in treatment breakthroughs in humans. Central to this discrepancy is a poor understanding of the constituent neurodynamics of averaged group effects and individual variability in human brain activity as related to higher-level cognitive symptomatology and clinical phenotype. The investigators' large collection of preliminary data demonstrates that individuals with FXS do not mount precise neural responses to the sensory auditory chirp and, instead, have "noisy" asynchronous gamma activity. Furthermore, a marked reduction in alpha power suggests altered thalamocortical function, reducing the ability to detect signal from noise and representing potential tractable targets for "bottom-up" entrainment. This approach involves three scientific aims, which, if addressed, would ascertain underlying mechanisms that may alleviate sensory and cognitive impairments. First, the investigators will study transient, non-continuous features (neurodynamics) of alpha and gamma oscillations in resting-state EEG and sensory auditory chirp that model patient-level heterogeneity and constitute group effects (Aim 1A), and will also identify what, if any, of these novel features are conserved in the Fmr1-/-KO using preexisting murine EEG data and represent patient subgroups (Aim 1B). Second, the research team will extend into cognition by studying neurodynamics and circuit modeling associated with statistical learning (SL), which shares similar neural mechanisms to the sensory auditory chirp (Aim 2). Third, the investigators will use individualized closed-loop alpha auditory entrainment (AAE) to attempt the normalization of neural signatures of the sensory auditory chirp and SL tasks (Aim 3). Aim 1 and 2 findings will provide critical data to optimize closed-loop parameters of AAE to serve as a "bottom- up" neural probe to understand the mechanics of disorder-relevant circuit activity through perturbation of thalamocortical drive. Ascertaining the mechanisms underlying these alterations would have a high clinical impact, especially to enhance early intervention to alter the trajectory of intellectual development in which no definitive treatments are available.