Demographic Differences in Resting State EEG in Healthy Controls and Patients with Schizophrenia
The default mode network (DMN) is composed of neural nodes that are synchronously activated when the brain is at rest and displays a decrease in activation when the brain is involved in a task. Disruptions in the DMN can potentially serve as assessment/screening for individuals with neuropsychological disorders. Many studies use electroencephalography (EEG) to study the brain at rest because of its high temporal resolution and its ability to provide a time sensitive measure of large-scale neural activity. Previous studies examining the brain at rest have found differences when comparing patients with Schizophrenia (Sz) and healthy controls (HC). While many studies have identified the impact of demographic variables on neuropsychological disorders, none of these studies have examined the impact of demographic variables on resting state EEG in either HC or Sz. The current study investigated whether demographic variables (i.e. age and sex) impacted theta (4-7 Hz), alpha (8-12Hz), beta (12-24Hz), and gamma (30-50 Hz) band power during resting state in 124 HC and 117. There were a total of 123 (38% women) HC with a mean age of 37.45 (SD = 11.12), and 117 Sz (34% women) with a mean age of 38.92 (SD = 11.13). An ANOVA revealed that patients with Sz had greater theta and gamma power at site Fz. Multiple linear regression analyses revealed that being female predicted more beta power and being older with a diagnosis of schizophrenia predicted less beta power. The importance of considering demographic variables when examining resting state EEG activity is discussed, with specific emphasis on the beta frequency band.