brain wave [AS, bragen + wafian] , any of a number of patterns of rhythmic electric impulses produced in different parts of the brain. Most patterns, identified by the Greek letters alpha, beta, delta, gamma, kappa, and theta, are similar for all normal persons and are relatively stable for each individual. Brain waves help in the diagnosis of certain neurological disorders, such as epilepsy or brain tumors. See also alpha wave, beta wave, delta wave, theta wave.
