Adult ADHD
Visual Abstract
Alpha modulation during working memory encoding predicts neurocognitive impairment in ADHD.
ADHD: Working Memory and Alpha Waves
A. Lenartowicz,, H. Truong,, G.C. Salgari,, R. M. Bilder,, J. McGough,, J.T. McCracken,, and S.K. Loo,
Summarized by:
August 31, 2023
study source
J Child Psychol Psychiatry
Aug 2020
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What they studied
What is the biological basis and mechanism of working memory difficulties in ADHD?
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What they found
Those with ADHD tended to have weaker alpha waves, which are responsible for filtering out distracting sensory information.
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What this means
This provides a potential mechanism for some ADHD symptoms. This mechanism was shown to be linked with some key effects of ADHD.
Alpha modulation during working memory encoding predicts neurocognitive impairment in ADHD.
Objectives
Working memory refers to the small amount of temporary and retrievable memory we use when performing tasks.
What is working memory?
Previous studies have linked ADHD with difficulties in working memory:
The study wanted to understand further the mechanisms behind the effect of ADHD on working memory.
Study Quote
Attention-deficit/hyperactivity disorder (ADHD) is associated with working memory (WM) deficits. However, WM is a multi-process construct that can be impaired through several pathways, leaving the source of WM impairments in ADHD unresolved. In this study, we aim to replicate, in an inde...
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Methods
Researchers conducted EEGs, a test that measures brain waves, on children with and without ADHD.
They examined and compared specific signals that are potentially significant in ADHD and working memory.
Study Quote
In 119 children (7–14 years old, 85 with ADHD), we used electroencephalography measures to quantify component processes during performance of a spatial working memory task. We quantified stimulus encoding using alpha range (8–12Hz) power; vigilance by the P2 event-related potential to cu...
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Results
The results showed that those with ADHD had weaker alpha waves. These waves help block sensory distractions when we are trying to focus. For example, these would help us ignore the squirrel outside the window when trying to take a test.
These results are consistent with our understanding of ADHD and difficulties with distraction.
When researchers look further into the data, they found significant links between weaker alpha waves and ADHD symptoms. Those with weaker alpha waves struggled more with reading, math, visuospatial accuracy, and executive function.
Study found that those with ADHD had weaker alpha waves on EEG. This was associated with more academic difficulties, less accuracy on visual spatial tasks, worse, ADHD symptoms, and difficulties with executive function.
Study Quote
Encoding alpha-power decreases and cue P2 amplitude were attenuated in ADHD, whereas occipital-alpha power during maintenance was significantly greater in ADHD, consistent with a compensatory response to weak encoding. Weak alpha modulation during encoding was associated with poorer read...
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Conclusions
These results suggest that alpha waves and working memory are a key part of ADHD.
Working memory is a known component of executive function, and this research suggests a potential biological mechanism for these deficits.
Study Quote
Stimulus encoding, a component process of WM coupled to alpha modulation, is impaired in ADHD, and, unlike WM maintenance or vigilance processes, has implications outside of the laboratory via a relationship with executive function, and, to a weaker extent, reading comprehension.