a simplified , quantitative electroencephalographic technique and apparatus for testing and assessing individuals for attention deficit hyperactivity disorder is described . the simplified procedure and apparatus is consistent with emerging neuroanatomical models of the etiology of adhd , makes the testing affordable to the public , and allows for practitioners to conduct the testing on an outpatient basis within their offices . the process comprises a new scanning method that obtains quantitative eeg data from an electrode placed at a single , active cranial site . multiple short periods of digitized eeg are obtained . the electrophysiological power in two frequency bands is examined . a computer that is programmed with the capacity to conduct a fast fourier transformation selects and statistically analyzes the power in these specific eeg frequency bands . a baseline neurometric index is obtained by calculating the ratio of the electrophysiological power recorded within the theta band by that recorded in the beta band while the individual maintains an eyes open , fixed gaze . thereafter , the individual being tested for adhd is evaluated under conditions requiring attentive behavior . a theta / beta power ratio is calculated for each of these tasks . finally , an average of the power ratios across the baseline , reading , listening and drawing tasks is calculated and an attentional index is obtained and compared to a database obtained through the evaluations of a normative sample of individuals not having adhd or any other neurological disorder . the assessment of the presence and severity of adhd is determined from this comparison .