What Do Electroencephalographic Microstates Have to Say About ADHD?

New research from Biological Psychiatry: Cognitive Neuroscience and Neuroimaging supports the utility of electroencephalographic (EEG) microstates (MS) D and A as functional biomarkers for attention-deficit hyperactivity disorder (ADHD).

Between 2001 and May 2018, the researchers recorded 2 minutes of resting-state EEG of 66 adult patients with ADHD (31 women, aged 34.1±11.4 years) and 66 control individuals (41 women, aged 36.5±12.4 years) in the Netherlands. A total of 40 individuals with ADHD had mixed subtype, 23 had “inattentive” subtype, and 3 had “hyperactive” subtype. The ADHD Rating Scale was selected as the best standardized clinical questionnaire to reflect current symptoms of ADHD.

In a separate dataset, researchers obtained 3 minutes of resting-state EEG recordings of 22 patients with ADHD (12 women, aged 32.3±9.2 years) and 22 healthy control individuals (14 women, aged 31.1±7.3 years) at Geneva University Hospitals. This cohort completed the Adult ADHD Self-Report Scale. Diagnosis was based on the ADHD Child Evaluation for Adults (ACE+), the Structured Clinical Interview for DSM-IV Axis II Personality Disorders, and the Diagnostic Interview for Genetic Studies. A total of 16 individuals with ADHD had mixed subtype, 5 had “inattentive” subtype, and 1 patient had “hyperactive” subtype.

The investigators utilized Koenig’s Microstate toolbox for EEGLAB to estimate a microstate map for each dataset and a k=5 global dominant map for the 2 datasets.

Analyzing the first dataset, the investigators found that the ADHD group tended to spend less time in left-right diagonal orientation (A) compared with control individuals (P ≤ .05 d = -0.43). Map D’s fronto-central topography tended to show more global variances P ≤.01, d = 0.71), increased temporal proportion (Time Coverage, P ≤.05, d = 0.59) and longer state durations (mean duration, P ≤.05, d = 0.53) among individuals with ADHD.

Map A time coverage was negatively associated with ADHD total score and ADHD hyperactivity. Map A global explained variance (Gev) and ADHD total score were negatively associated, and mean duration of map A was linked with ADHD total score and ADHD inattention. Pittsburg Sleep Quality Index among individuals with ADHD was linked with Map D global explained variance and time coverage.

Utilizing the second dataset as an out-of-sample validation, the researchers replicated the effect size and statistical significance deviations of map D between the individuals with ADHD and control individuals.

Limitations of the study included the inability to establish causation and possible differences in diagnosing ADHD.

“The combined signature of lower microstate A coverage and increased microstate D duration in our study would imply that ADHD could be characterized as a condition of ‘hyper-vigilance,’ consistent with its behavioral symptoms of physical and emotional hyperactivity,” the researchers said.

Disclosure: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

Reference

Férat V, Arns M, Deiber MP, et al. Electroencephalographic microstates as novel functional biomarkers for adult attention-deficit hyperactivity disorder. Biol PsychiatryCogn Neurosci. 2021, ISSN 2451-9022. doi:10.1016/j.bpsc.2021.11.006

This article originally appeared on Psychiatry Advisor