One controversy surrounding ADHD has been the lack of a definitive, objective medical test to diagnose ADHD. Illnesses such as diabetes are definitely diagnosed with a blood test but a diagnosis of ADHD relies on subjective evaluations by medical professionals. But a new brain wave test has been approved by the U.S. Food and Drug Administration (FDA) to aid in diagnosing ADHD . While this still isn't the definitive test many are waiting for, it has been shown to provide for more accurate diagnosis.
The NEBA device is already in operation for diagnosis of other conditions, such as sleep disorders and brain injuries and is also use to measure unconsciousness and to monitor the brain during surgery.  It is manufactured by NEBA Health of Augusta, GA.
The new device, a Neuropsychiatric EEG-Based Assessment Aid (NEBA) uses an electroencephalogram (EEG) test to measure two types of brain waves, theta and beta, and the ratio between the two. The ratio between these brain waves has been found to be higher in children and adolescents with ADHD according to previous research.
The FDA approved the device based on a company study of 275 children between the ages of 6 and 17. All of the children were given the 15 to 20 minute NEBA test as well as other standard diagnostic evaluation tools, such as behavioral questionnaires, IQ testing, comparing behaviors to the current DSM IV-TR criteria and physical exams. The information from the testing was shared with an independent group of ADHD experts who provided consensus diagnosis of ADHD or other conditions. The results showed "the use of the NEBA system aided clinicians in making a more accurate diagnosis of ADHD when used in conjunction with a clinical assessment for ADHD, compared with doing the clinical assessment alone." 
Some experts are dubious about the role this device will play in the diagnostic process. In an article on Medicinenet.com, Dr. Andrew Adesman, chief of developmental and behavioral pediatrics at Steven & Alexandra Cohen Children's Medical Center, stated, "It is doubful that this EEG test...will be as accurate and reliable as clinicians and families would ideally want...although this new EEG test may prove helpful... neither parents nor professionals will be able to rely upon it as a standalone 'litmus test' for whether a child has ADHD." 
FDA Approval Letter, Addressed to NEBA Health, LLC, Dated 2013, July 15
 "FDA Approves Brain Wave Test for ADHD," 2013, July 16, Robert Preidt, MedicineNet.com, HealthDay
 FDA Permits Marketing of First Brain Wave Test to Help Assess Children and Teens for ADHD," 2013, July 15, U.S. Food and Drug Administration
 "First ADHD Brain Wave Test Approved by FDA," 2013, July 15, Ryan Jaslow, CBS News