Navigating the world, a bustling city like Chicago nonetheless, as an individual with Attentional-Deficit/Hyperactivity Disorder (ADHD) is not an easy task, since almost every moment is filled with a variety of overlapping sounds. Amidst this noise, the neurotypical brain is able to hone in their attentional focus to certain targets and disregard the interrupters surrounding it. Unfortunately, according to a study done by Kwasa et al. titled Top-down attention modulates auditory-evoked neural responses in neurotypical, but not ADHD, young adults, the ADHD brain does not possess the same attentional modulation abilities as the neurotypical brain, and has a harder time filtering out the extra noise. Kwasa and her team explored the “attentional contest” and effect of the “push-and-pull” in noisy environments on the brain, and the strength of “top-down” voluntary control of attention compared to the “bottom-up” attentional capture, or in other words, susceptibility to distraction (Kwasa et al., 2). The study performed by Kwasa et al. seeks to draw electrophysiological correlates between “top-down” and “bottom-up” attention, and how cognitive control over auditory selective attention varies within a neurodiverse population, more specifically, exploring neurotypical and ADHD brains within this study.
Kwasa et al.’s paper titled, Top-down attention modulates auditory-evoked neural responses in neurotypical, but not ADHD, young adults, studies the neural and electrophysiological correlates of the “push-and-pull” dynamic between “top-down” and “bottom-up” attentional modes, specifically in young adults that are neurotypical or have ADHD. They hypothesized that people with ADHD would display weaker neural signatures overall and perform poorly compared to neurotypical individuals on an auditory task that requires strong “top-down” attentional control. The study consisted of neurotypical adults and adults with ADHD, who have normal hearing, listening to one of three speech streams and then having to report the order of the syllables. Kwasa et al. were using this auditory control task as a way to test the ability of participants to maintain attentional focus on one “target” stream, as well as one’s capacity to flexibly switch one’s attention to an unpredictable, “interrupter” stream. Furthermore, throughout the duration of this task, the neural and electrophysiological responses of participants were being measured via electroencephalography (EEG). In the end, Kwasa et al. concluded that the interrupter elicited a larger neural response in both groups compared to when participants were focusing on a single “target” stream. Along with that, attentional modulation was found to be weaker in participants with ADHD although their behavioral performance was the same, thus the stimulus structure and demands of the task itself affected behavioral performance while ADHD status did not. These results display that task goals cause variance in a listener’s ability to modulate and selectively attend to sound, and young adults with ADHD were found to have weaker controls over their attentional processes overall compared to neurotypical, young adults. In addition, weaker neural responses were elicited when the “interrupter” sounds were ignored versus when they were attended to which demonstrates the brain’s incredible, selective attentional abilities. Furthermore, the results of this experiment illustrate a stunning contrast between the attentional capabilities of the neurotypical brain and the ADHD brain, specifically, how ADHD subjects demonstrate weaker attentional focus and filtration of “competing sounds” (Kwasa et al., 2-3).
In a similar, recent, 2021 study titled Closed-Loop Neurofeedback of ɑ Synchrony during Goal-Directed Attention, Mishra et al. studied alpha oscillations in the sensory cortex and how they desynchronize during attentional preparatory stages. In particular, this study hones in on selective attentional abilities and the neural correlates that impact task performance overall. Similarly to Kwasa et al.’s study on “top-down” attentional control, Mishra et al. utilizes Electroencephalography (EEG) to demonstrate how lessened alpha synchronization between the dorsal attention network and the ventral visual sensory cortex leads to greater task performance. When humans are preparing themselves to attend to sensory information or stimuli, neural oscillations take place in the alpha band, specifically at 8-14 Hz, and desynchronization occurs under control of the prefrontal cortex (Mishra et al., 2021). Mishra and their team sought to mechanize repetitive attentional modulation in order to see if a closed-loop, NF structure could improve an individual’s ability to attend to stimuli over time. Thus, this experiment consists of a double-blind, closed-loop neurofeedback (NF) of the alpha frontal-sensory synchrony, or FSS, where participants were alerted to get ready for a visual stimulus during each trial and had to report if the stimulus was a target or a non-target stimuli by pressing a button (Mishra et al., 2021). With each trial, response times from participants were measured and the response window itself increased and decreased throughout the experiment for each participant depending on their response times and accuracy. At the beginning of the experiment, the stimulus was displayed for participants, a specific shape and orientation combination, and participants were instructed that all other targets would be considered non-target stimuli (Mishra et al., 2021). The cognitive, closed-loop neurofeedback task, or cNF, was done on both adults and children with Attention Deficit/Hyperactivity Disorder (ADHD), and demonstrates how continuous modulation, trial-by-trial, in a closed-loop neurofeedback circuit brought about significant improvement of sustained attention response times for the participants (Mishra et al., 2021). Furthermore, this task-design was able to give rise to plasticity of responses to stimuli, and via rapid cognitive NF (cNF), improve performance of participants on a sustained attention task. Thus, this experiment demonstrates the possible capability of rapid cognitive NF, or cNF, as a way to significantly improve sustained attention in individuals with ADHD via measurement of the alpha FSS signal through EEG (Mishra et al., 2021).
Mishra et al.’s study particularly stood out to me since it proposed a possible treatment path for individuals with ADHD to improve their sustained attention, or in other words, increased frontal-sensory synchrony (FSS) of alpha oscillations during preparatory stage of attention. I picked this study as well since I believe it aligns with Kwasa et al.’s study of selective attention and sound filtration in individuals with ADHD compared to neurotypical brain attentional capacities. As an individual who has ADHD and intends on pursuing research in attentional modulation for neurodiverse populations, these journals stood out to me and provide a lot of promise for the field and for making the world an easier place for individuals with attentional deficits to navigate.
Citations:
Kwasa, Jasmine A., et al. “Top-down Attention Modulates Auditory-Evoked Neural Responses in Neurotypical, but Not ADHD, Young Adults.” 2021, https://doi.org/10.1101/2021.02.11.430824.
No comments:
Post a Comment