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September 2001; Volume 4; 97-100
By Susan T. Marcolina, MD
Attention deficit/hyperactivity disorder (ADHD) is a common neurobehavioral disorder of childhood with an incidence of between 3% and 9%.1 Its primary characteristics are age-inappropriate levels of inattention, hyperactivity, and impulsivity, noted prior to age 7. Children also may experience comorbid learning disabilities and conduct disorders.2 These features often persist into adulthood with resultant negative social, academic, and vocational repercussions.3
Recognition in the medical literature dates back to 1902, when such children were labeled as "morally defective."4 Drug treatment, primarily with stimulant medications, began in 1937, has been the mainstay of therapy, and often is the only treatment for many patients.5 Although treatment with stimulant medications can result in short-term improvements in cognitive focus, the residual behavioral, social, and parenting difficulties persist and do not respond to pharmacotherapy.6 If patients discontinue their stimulant medications, the ADHD behaviors return.7
Nonpharmacologic methods, though highly effective, are under-used. Neurofeedback or electroencephalogram (EEG) biofeedback is such a modality, and has been studied over the past 25 years for ADHD. Mental health practitioners have successfully included neurofeedback in their therapeutic armamentarium for ADHD patients, and clinicians should consider it for their patients with ADHD.
The Diagnosis of ADHD
It is essential that every patient have a complete history and diagnostic evaluation to ascertain the appropriate diagnosis. Neurotherapy will not be successful in patients with mental retardation, severe depression, psychotic disorders, bipolar illness, or severe conduct/oppositional defiant disorder.8
Broad diagnostic criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) have resulted in a heterogeneous population of children diagnosed with this disorder. Diagnosis is made on the basis of history from parents and teachers, behavior rating scales such as the Connor’s Behavioral Rating Scale (teacher’s and parent’s version), and the results of a continuous performance test called TOVA (Test of Variables of Attention).
A fixed interval test that is not language-based and requires no left-right discrimination, TOVA measures inattention (errors of omission), impulsivity (errors of commission), response or processing time (usually slower than normal in individuals with ADHD), and variability (individuals with ADHD tend to be variable or inconsistent in their correct response times). TOVA has a sensitivity and specificity of 80% for the identification of attention disorders. It is a tool that must be used in conjunction with other relevant data for the diagnosis of ADHD.9,10
The American Academy of Child and Adolescent Psychiatry practice parameters do not recommend specific diagnostic testing except for rare instances of lead intoxication and generalized resistance to thyroid hormone.11
Neurofeedback is a type of operant conditioning procedure. A patient is trained to modify his or her brain waves through the use of rapid computerized technology which can provide EEG information to the patient in a variety of easily understandable formats, such as color bars, games, or audio feedback.
A typical protocol emphasizes suppression of theta brain-wave activity and augmentation of beta or sensorimotor rhythm (SMR) brain-wave activity. Table 1 summarizes the types of brain-wave activities noted on the EEG.12
|Table 1: Basic frequency bands of the EEG12|
|Delta||0.5-4 Hz||Deep sleep|
|Theta||4-8 Hz||Deep creativity; predominant frequency in day dreaming|
|Alpha||8-12 Hz||Relaxed, alert, unfocused state|
|12-14 Hz||Quiet body and active mind with external focus of attention; associated with information storage and retrieval|
|Beta 1||12-16 Hz||Higher cognitive processes; rational, analytical thinking and problem-solving|
|Beta 2||16-24 Hz||Physiological arousal and response to threat|
EEG recording of brain waves is accomplished by a specific standardized pattern of electrode placements (montages) on the scalp. EEG recordings can be analyzed quantitatively by computerized statistical tools and compared to normative EEG databases. This quantitative EEG (QEEG) can be used as measurable data for a given individual, and can provide objective, physiologically based information to supplement the subjective questionnaires, rating scales, and TOVA results currently used to identify children with ADHD.
Finally, the theta:beta ratio can be used to assess baseline and subsequent response to neurofeedback sessions. The ratio controls for the gradual EEG differences between the younger and older ADHD subjects. As individuals age, both theta and beta amplitudes decrease, but the theta:beta ratio remains relatively constant.13
EEG studies of ADHD patients have shown excessive slow-wave theta activity in the central and frontal regions of the brain.14 Together with radiographic nuclear medicine studies, EEG studies support the hypothesis that behaviors in ADHD are related to deficits in prefrontal activation.15 Since the prefrontal cortical areas are important biologic determinants of attention, disorders in these regions result in motor restlessness, inattentiveness, distractibility, and the inability to inhibit inappropriate responses.16
This reasoning may extend to adults as well. Zametkin et al performed a positron emission tomography (PET) study of 50 healthy adult controls and 25 adults with a history of ADHD as children or with offspring diagnosed with ADHD.17 These adults had no history of other psychiatric disorders or substance abuse problems and no stimulant medication history. Independent research assistants who were blinded to the identity and diagnosis of the persons in the study interpreted the scans. Four regions in the premotor and superior prefrontal cortex were shown to metabolize glucose at significantly lower rates in the subjects than the controls.
Linden et al performed a randomized, controlled study of 18 children diagnosed with ADHD.13 Nine subjects were randomly assigned to an experimental group, which underwent 40 sessions of the EEG biofeedback treatment over six months. Experimental subjects underwent standard neurofeedback with visual and auditory feedback. The biofeedback training was performed to suppress the theta bands and enhance the beta bands of the EEG. Nine were assigned to a waiting list group, which did not undergo EEG biofeedback during the same time period. IQ testing and parent behavior rating scales were collected prior to and after six months of treatment. The research assistants scoring the rating scales and the IQ examiners were blinded to the subjects’ group assignments.
Experimental subjects showed significantly enhanced IQ scores at post treatment; the average IQ increase in the experimental group was 9 points greater than that of the waiting list control group (P = 0.023). Additionally, inattentive behaviors were significantly reduced in the experimental group (P = 0.04).
A retrospective study performed by Thompson and Thompson examined the results of neurofeedback training and metacognitive teaching strategies in 111 (98 children and 13 adults) subjects with ADHD.18 Thirty percent of the children took stimulants at the beginning of the study. Each subject received twice weekly neurofeedback sessions (a total of 50 sessions). The feedback training was aimed at decreasing slow-wave activity (defined as 4-7 Hz, but occasionally 9-11 Hz) and increasing fast-wave activity (15-18 Hz for most subjects, but initially 13-15 Hz for those with impulsivity and hyperactivity). Metacognitive strategies were used to teach academic tasks when the feedback indicated patient focus. Some clients received peripheral biofeedback modalities during some of the sessions.
Pre- and post-test results of TOVA, Wechsler Intelligence Scales (WISCs), Wide Range Achievement Tests (WRATs), and the theta:beta ratio on QEEGs were available for 68%, 62%, 89%, and 59% of subjects, respectively. Significant improvements (P < 0.001) were found in ADHD symptoms (with regard to inattention, impulsivity, and variability of response times on the TOVA), on the WISCs, and on the WRATs. The average gain for full-scale IQ scores was 12 points. A decrease in the theta:beta ratio on the QEEG was observed as well as the number of children taking stimulants decreased by 24%. One- to 10-year follow-up of successfully treated patients suggests that EEG biofeedback leads to long-term ADHD symptom reduction.19
Neurofeedback and QEEG equipment are classified by the Food and Drug Administration as Class 2 prescriptive devices and, as such, should be sold only to professionals licensed in a health care field. The currently available QEEG equipment has not been approved for diagnostic purposes. Legally approved purposes for obtaining a QEEG include its use before patient training as a baseline and for comparison to normative databases.12
The Biofeedback Certification Institute of America (BCIA) manages and administers a formal certification program in EEG biofeedback. The certification requirements are listed on the BCIA web site (www.bcia.org), which also contains a registry of BCIA-certified practitioners.
Occasionally patients report headaches, the etiology of which is likely muscle tension during training, as it disappears rapidly once muscles are relaxed. Patients may experience fatigue from the training of the initial sessions but generally are more alert and awake after neurotherapy. There can be some minor discomfort as the electrodes are applied and removed from the scalp surface.
Neurofeedback can be useful as an adjunctive therapy for the multidisciplinary treatment of ADHD. With the proper guidance of a competent practitioner, patients can learn physiologic regulation skills necessary to cope with the challenges of ADHD. Progress and response toneurotherapy can be quantitatively measured by continuous performance testing (TOVA), IQ, achievement testing, and QEEG. Success, however, requires a long-term time and financial commitment on the part of the patient, the patient’s family, and the practitioner. A total of 20-40 sessions, performed twice weekly over several months in conjunction with other forms of therapy, maybe required. The practitioner performing the neurofeedback should have experience in the diagnosis and treatment of ADHD and be certified by the Biofeedback Certification Institutes of America in neurotherapy.
EEG Biofeedback performed by a competent practitioner can be a powerful addition to the armamentarium of ADHD treatment regimens. There are good data to show that particular training protocols can affect improvements in behavior, IQ scores, and aptitude testing for individuals with ADHD.
Dr. Marcolina is a board-certified internist and geriatrician in Issaquah, WA.
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