Phonological working memory involves temporarily storing and manipulating speech-based information. It underlies critical abilities like following instructions and sound-to-meaning mappingin reading.
Key Points
Rationale
Past research has reliably demonstrated phonological working memory deficits in children with ADHD, with meta-analyses showing moderate-to-large magnitude between-group effects (Kasper et al., 2012; Martinussen et al., 2005).
Performance accuracy serves as the predominant metric, simply quantifying the percentage of correct trials. This approach reliably indexes general working memory ability but lacks specificity regarding underlying neurocognitive processes contributing to impairment (Roberts et al., 2023).
Examining specific error types – omissions, intrusions, transpositions – can clarify which aspects of working memory are disproportionately impaired in ADHD. For example, intrusion errors implicate poor interference control, whereas transposition errors reflect difficulties manipulating information held in mind (McCormack et al., 2000).
Comprehensively analyzing multiple error types within the same phonological working memory task is the logical next step toward elucidating specific mechanisms underlying these deficits in ADHD.
Findings can guide development of better diagnostic indicators and interventions targeting the most impaired processes.
Method
Participants who were children completed a computerized phonological working memory task. The task involved remembering and manipulating a series of aurally presented numbers and letters across blocks with increasing set sizes.
Incorrect verbal recall responses were coded for errors of omission, intrusion, or transposition:
By categorizing errors into these subtypes, the researchers aimed to provide greater specificity regarding aspects of phonological working memory that are disproportionately impaired in ADHD, such as difficulties manipulating order information versus storage deficits.
Between-group differences in total errors and specific error types were analyzed using generalized estimating equations controlling for age.
Recall errors were classified as omissions, intrusions, or transpositions according to definitions established in working memory literature (McCormack et al., 2000).
Sample
The sample included 54 children diagnosed with ADHD and 65 typically developing children between ages 8-12 years. Most ADHD participants were male (83%) and White (76%).
Many had comorbid diagnoses like oppositional defiant disorder and specific learning disorders. The TD group was matched on age, sex ratio, and ethnicity.
Statistical measures
Generalized estimating equation models were used to analyze count data of recall errors, controlling for age. Negative binomial regressions specified autoregressive correlation structure to account for repeated measures over set sizes.
Between- and within-group effects were tested for significance after Bonferroni correction with adjusted alpha of .003. Cohen’s d measured effect sizes for group differences.
Results
Insight
This thorough error analysis provides compelling evidence that working memory deficits in ADHD stem from inadequate central executive processes—specifically difficulties manipulating and reordering multiple pieces of information.
Intriguingly, manipulating several numbers overtaxes central executive resources in ADHD, yet capacity remains less encumbered when simply rehearsing a single letter.
Introducing set sizes demanding substantial reordering could also help expose executive deficits for diagnostic and progress monitoring purposes beyond conventional span tasks.
Strengths
Limitations
Implications
Rather, deficits emerge distinctly when organizing thoughts and appropriately filtering irrelevant details. This executive dysfunction, especially with manipulating information, can profoundly impact a child’s ability toregulate emotions,transition flexibly, take perspectives, and solve multi-step problems.
When such mental flexibility lags, children often cannot achieve their potential academically nor develop strong social skills.
Prospective working memory training tools can also introduce set sizes with substantial reordering/updating demands, unlike traditional span tasks, to better expose and target manipulation difficulties.
Furthermore, given mounting evidence tying ADHD pathology to the central executive specifically, scientific efforts should continue confirming whether executive function deficits represent a core impaired process versus simply downstream effects.
If future work establishes central executive dysfunction as a cardinal, rather than ancillary ADHD feature, the diagnostic significance would profoundly shift clinical conceptualization of this highly prevalent, often debilitating childhood disorder.
References
Primary reference
Roberts, D. K., Alderson, R. M., & Bullard, C. C. (2023). Phonological working memory in children with and without ADHD: A systematic evaluation of recall errors.Neuropsychology.https://doi.org/10.1037/neu0000899
Other references
Baddeley, A. (2007).Working memory, thought, and action(Vol. 45). OUP Oxford.
Fosco, W. D., Kofler, M. J., Groves, N. B., Chan, E. S., & Raiker, J. S. (2020). Which ‘working’ components of working memory aren’t working in youth with ADHD?Journal of Abnormal Child Psychology,48(5), 647–660.https://doi.org/10.1007/s10802-020-00621-y
Kasper, L. J., Alderson, R. M., & Hudec, K. L. (2012). Moderators of working memory deficits in children with attention-deficit/hyperactivity disorder (ADHD): A meta-analytic review.Clinical Psychology Review, 32(7), 605–617.https://doi.org/10.1016/j.cpr.2012.07.001
Martinussen, R., Hayden, J., Hogg-Johnson, S., & Tannock, R. (2005). A meta-analysis of working memory impairments in children with attention-deficit/hyperactivity disorder.Journal of the American Academy of Child & Adolescent Psychiatry, 44(4), 377–384.https://doi.org/10.1097/01.chi.0000153228.72591.73
McCormack, T., Brown, G. D., Vousden, J. I., & Henson, R. N. (2000). Children’s serial recall errors: Implications for theories of short-term memory development.Journal of Experimental Child Psychology, 76(3), 222–252.https://doi.org/10.1006/jecp.1999.2550
Keep Learning
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Saul McLeod, PhD
BSc (Hons) Psychology, MRes, PhD, University of Manchester
Saul McLeod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.
Olivia Guy-Evans, MSc
BSc (Hons) Psychology, MSc Psychology of Education
Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.
