Conventional and Quantitative EEG Use in the Psychiatric Medicine

Hughes, J.R. and John, E.R., Conventional and Quantitative Electro-encephalography in Psychiatry. Journal of Neuropsychiatry and Clinical Neurosciences, 1999; 11 (2), 190-208

New brain imaging technologies, such as the electroencephalogram
(EEG) and quantitative electroencephalogram (QEEG) are providing valuable information about structural and/or functional abnormalities
in individuals suffering from various psychiatric disorders, such as Anxiety Disorder, Depression, Dementia, Obsessive-Compulsive
Disorder (OCD), Learning Disabilities, Attention Deficit Disorder with and without Hyperactivity (ADD, AD/HD), and Schizophrenia.
It is now understood that such disorders involve the interaction between brain dysfunctions and/or altered neuroanatomical structure and environmental influences.
Biological assessment methods, such as the EEG and QEEG provide an invaluable manner for the diagnosis of disorders, selection and evaluation of treatment, decrease of severity and shortening symptom duration, minimization of false starts, and marked reduction in
treatment cost.

Dementias

Use of conventional EEG and QEEGs complement each other, both providing valuable information for clinicians. Conventional EEGs provide reliable diagnostic information and are especially sensitive to "organic" or neurological disorders, while QEEGs enable precise comparison of an individual's record with normative and psychopathologic patient databases. EEG and QEEG analysis allow accurate early detection of Alzheimer's Disease, AIDS-Related Dementia, decreased regional cerebral blood flow or metabolism due to stroke, even when a CAT scan is still normal or the degree of ischemia is mild enough to cause dysfunction without infarction. QEEGs are also useful in distinguishing Alzheimer's from Pick's Disease, Multi-Infarct Dementia (MID), Depression and normal aging in the elderly.

Mood Disorders: Uni-polar and Bi-polar Depression

QEEGs also prove a useful tool in differentiating between Uni-polar and Bi-polar depression in individuals presenting in a state of depression without prior history of mania. This is achieved through the examining of alpha and beta wave levels in the individual. In Bi-polar illness, alpha wave activity is reduced and beta wave activity is increased. As Bi-polar disorder is currently treated with anticonvulsant medications, the use of EEG studies to rule out convulsive illness prior to initiation of anticonvulsant treatment in Bi-polar individuals may be wise. Increases in alpha or theta wave levels, as well as asymmetry in anterior brain regions most often appear in Uni-polar depressed patients.

Developmental Learning Disorders and Attention Deficit Disorders

An estimated 4% to 6% of all school-age children are affected by Specific Developmental Learning Disorders (SDLD); 6% to 9% of all school-age children are affected by Attention Deficit Disorder with or without Hyperactivity (ADD or AD/HD). Precise and accurate determination of the presence of ADD, ADHD, or SDLD is of critical importance in avoiding the potentially devastating impact of these disorders on children and their families. EEG and QEEG contribute successfully to this distinction as well as separation of children with social or motivational factors underlying school problems from those with organic dysfunction. A high incidence of excess theta or decreased alpha and/or beta wave activity has been reported in SDLD children, with theta or alpha wave excess of ten seen in children with ADD or ADHD. Using QEEG measures, it is possible to discriminate between children suffering from ADD, ADHD, and SDLD. 

Alcohol and Substance Abuse

Both EEG and QEEG reveal marked anomalies in individuals with a history of substance abuse; the effects visible with the EEG and QEEG varying upon the drug abused. In individuals suffering from Alcoholism an increase in theta and beta activity and a decrease in alpha frequency and abundance is noted; while increased alpha has been noted during Alcohol Withdrawal Syndrome, as well as after acute exposure to Cannabis. Increased levels of alpha waves and decreased delta and theta waves have been coupled with Crack-Cocaine Withdrawal Syndrome.

Mild Head Injury or Post concussion Syndrome

Often individuals will present for psychiatric evaluation for worker's compensation and disability benefits with complaints of Attention Deficit or Cognitive Memory Impairment after mild head trauma without loss of consciousness. In such cases, EEG/QEEG evidence of brain dysfunction can be vital in separating dysfunctional individuals from malingerers. EEG or QEEG abnormalities persisting following mild or moderate cranial trauma are similar in type to those found following severe head injury; increase in theta waves, decrease in alpha waves, increased asymmetry and low coherence namely.