Detection of ADHD more accurately: Study

A new study has identified a new neurological marker for attention deficit disorder with or without hyperactivity. The research has been published in the ‘Biological Psychiatry Cognitive Neuroscience and Neuroimaging Journal’. Supported by the national research centre Synapsy, neuroscientists from the University of Geneva (UNIGE), the Centre for Biomedical Imaging (CIBM), and the University Hospital of Geneva (HUG) focused their attention on a new electroencephalographic approach called microstates to identify ADHD’s neurological signatures.

The microstates technique is used to look at the combined spatial and temporal aspects of cerebral activity. Using this technique, the research team discovered that a certain cerebral activity state associated with sleep and attention lasted longer among people with ADHD. The results provided evidence of a more robust ADHD biomarker and thus contributed towards helping psychiatry become a more precise medical discipline.

ADHD affects five per cent of adults, making it one of the most common psychological disorders. Current clinical diagnosis is based only on questionnaires that focus mainly on the inattention and impulsivity symptoms. However, neuroscientists speculate that ADHD’s causes, while still not well known, have a biological and genetic basis, suggesting that there may exist biomarkers that could help in its diagnosis. This was the scope of this new study supported by Synapsy, a research centre that has combined psychiatry and the neurosciences over the past twelve years to understand the neural basis of different psychological disorders in the hope of creating better means for diagnosing and treating them.

The study of the human brain is a difficult endeavour because we cannot directly access the brain to look at its cellular and molecular mechanisms. Hence, non-invasive investigative methods such as brain scans or electroencephalograms (EEG) are used. The latter test uses a network of electrode sensors placed on the subject’s scalp to measure the electrical fields generated by large-scale neural networks.

Recent studies have revealed abnormal EEG activity among patients affected by ADHD, suggesting that abnormal cerebral development may be the cause of ADHD. Unfortunately, the data vary too much from one study to another, making them unreliable markers for ADHD. “These variations are due either to the wide heterogeneity of ADHD’s causes or to the fact that traditional EEG analyses are not a good tool for looking into the matter because they do not take into account the Spatio-temporal aspects of cerebral states,” said Tomas Ros, a researcher at the Department of Psychiatry and Neuroscience at the UNIGE Faculty of Medicine.

Brain activity fluctuated successively from one state to another while at rest, manifesting different spatial configurations in the EEG’s electrical field. Neuroscientists speak most often of five “micro” states or main configurations, lettered from A to E.