EEG Alpha Asymmetry

Proposal details

Title: EEG Alpha Asymmetry: Healthy Normative Distribution and across Clinical Disorders
Research Area(s): ADHD and Allied Conditions
Schizophrenia and Allied Psychoses
PTSD and other Anxiety Disorders
Development and Aging
Individual Differences
Background: Lateralization of neural activity has been implicated in the neurobiology of a range of clinical disorders involving a core dysfunction in emotion-related processes, as well as aspects of emotional functioning within the healthy population. A commonly used index of functional laterality is the degree of asymmetry of EEG power within the alpha frequency band (8-13 Hz). The alpha rhythm is believed to reflect a resting or idling brain state, such that lower levels of alpha are held to reflect higher levels of cognitive activity. Given that alpha is most prominent at rest, the degree to which resting alpha is lateralized towards the right or left hemisphere is a commonly used index of basic functional brain laterality.
Aims: In the current study we aim to assess resting frontal alpha asymmetry across several clinical disorders for which deviant laterality has been implicated, encompassing schizophrenia (first episode), major depressive disorder, post-traumatic stress disorder, panic disorder, and childhood and adolescent attention-deficit/hyperactivity disorder and conduct disorder. We also aim to use a large healthy sample to determine the normative distribution of resting frontal alpha asymmetry, and to assess the influence of age and sex across the lifespan
Method: EEG alpha asymmetry for the eyes open and eyes closed conditions will be calculated using an average reference, as the natural log of Right - Left for relevant electrode pairs. In a large sample of healthy controls average alpha asymmetry will be assessed, as well as the influence of age and sex factors. Alpha asymmetry in several clinical disorders will be compared to this normative group. The clinical groups assessed will be schizophrenia, depression, PTSD, panic disorder, ADHD and conduct disorder.