An electroencephalogram (EEG) is a non-invasive method for measuring the brain’s electrical activity. Small sensors placed on the scalp detect electrical signals produced by brain cells as they communicate. ADHD, or Attention-Deficit/Hyperactivity Disorder, is a neurodevelopmental condition characterized by persistent patterns of inattention, hyperactivity, and impulsivity that can affect daily functioning. EEG offers insights into these brain differences.
Understanding Brain Waves and EEG
The brain’s electrical activity manifests as rhythmic patterns known as brain waves, categorized by their frequency. Delta waves (0.5 to 4 Hz) are the slowest, associated with deep sleep. Theta waves (4 to 8 Hz) are common during drowsiness, light sleep, and states of creativity or daydreaming.
Alpha waves (8 to 14 Hz) are prominent when awake but relaxed. Beta waves (14 to 38 Hz) link to active thinking, alertness, and focused mental engagement. Gamma waves (38 to 80 Hz) are the fastest, involved in high-level cognitive processes like learning and perception. These electrical impulses are amplified and displayed as wavy lines, reflecting the brain’s continuous activity.
EEG Signatures in ADHD
Research identifies specific EEG patterns observed in individuals with ADHD. A key finding is an elevated Theta-to-Beta ratio, indicating increased slow-wave (Theta) activity or reduced fast-wave (Beta) activity in certain brain regions, particularly over the fronto-central areas. This imbalance suggests potential under-arousal or delayed cortical maturation in the ADHD brain.
This pattern may relate to challenges in attention, impulsivity, and hyperactivity. Elevated theta activity can be associated with drowsiness or under-arousal, while reduced beta activity might affect focus and sustained attention. These EEG patterns are observed correlations, but not definitive diagnostic markers on their own.
How EEG Aids ADHD Assessment
Quantitative EEG (qEEG) is an advanced EEG application that uses computer processing to analyze brain wave patterns. This method compares an individual’s brain activity to a large database of normative patterns for their age. By identifying deviations, qEEG provides objective data supporting a clinical evaluation.
qEEG serves as a supplementary tool, offering insights into specific brain dysregulation. It can highlight areas with excessive slow-wave activity or reduced fast-wave activity. This information may also guide treatment strategies like neurofeedback, where individuals learn to self-regulate their brain wave patterns through real-time feedback. Neurofeedback aims to train the brain to form healthier patterns, potentially improving ADHD symptoms.
EEG’s Place in Comprehensive Diagnosis
While EEG and qEEG offer valuable insights into brain activity, they are not standalone diagnostic tools for ADHD. An ADHD diagnosis requires a comprehensive evaluation. This evaluation includes clinical interviews, behavioral observations, and symptom checklists.
Healthcare professionals also consider ruling out other conditions with similar symptoms. EEG serves as one piece of a larger diagnostic puzzle, providing supportive evidence rather than a conclusive answer. Its use in ADHD diagnosis should always be part of a complete medical and psychological assessment.