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Introduction to Electroencephalography (EEG)
Electroencephalography (EEG) is a non-invasive technique that allows the record of brain activity with an EEG headset made of electrodes directly positioned on the scalp, through the hair. Among brain waves, low frequencies (from 0Hz to 12Hz) are associated with sleep or meditation, while higher frequencies (from 13Hz to 45Hz) are associated with awake functioning: alertness, concentration, action.
EEG correlates in ADHD
The record of the electric brain activity with the use of Electroencephalography (EEG) technique reveals abnormal brain rhythms in patients suffering from Attention Deficits and Hyperactivity Disorders (ADHD). First evidence of electrical brain activity abnormalities in ADHD patients were presented in 1938 by Jasper, Solomon and Bradley who reported generalized slowing of EEG activity. Ever since, it has been extensively reported that ADHD children with inattentive symptoms exhibits elevated low frequency components (responsible for the fatigue and drowsiness), and reduced high frequencies (responsible for the lake of focus and attention). Neurofeedback has been developed in the scope of these neurophysiological observations, and based on the neuronal plasticity concept according to which, training brain waves would lead to durable physiological changes and thus to long-term behavior’s improvement and symptoms’ reduction.
The introduction of neurofeedback in the treatment of ADHD
Preliminary findings have indicated that training individuals to control their electrical activity may have beneficial effects on reducing symptoms of ADHD. From 1973 to 1991, Lubar et his colleagues conducted research and neurofeedback experiment on hyperkinetic ADD-ADHD children. They showed that with SensoriMotor Rythms (SMR) and beta training at 16-20Hz, patients improved their focus and concentration. To this purpose, a variety of protocols has been developed to reduce ADHD symptoms by the modulation of cerebral activity:
- theta/beta protocols consisting on inhibiting theta activity and enhancing beta activity ratio,
- combination of both theta/beta and Slow Cortical Potentials (SCP) trainings,
- SMR training,
- beta training or,
- upper alpha enhancing.
Neurofeedback uses operant conditioning principles to train brainwaves. During training session, the patient receives a real-time feedback, either visual or audio, which reflects his/her cerebral activity. With this understandable feedback, the patient can learn to modulate his activity in a desired direction (enhancement or reduction of the activity). Also the patient is rewarded when he reaches his goal. The use of reinforcers and rewards is part of a method of learning called operant conditioning evidenced in 1938. Skinner proved that the repeated rewarding of positive responses to a given stimulus motivates the subject to repeat the positive or desired response. Over time and practice, the learned behavior can even become a second-nature.
By the mean of operant reinforcement, neurofeedback training not only shapes the brain activity, but modify durably the brainwaves, long after an operant (training) conditioning has been formed. Positive effects are often observed after 20 sessions although the number of required sessions depends on the disorder and its severity.
Benefits of neurofeedback training
Neurofeedback training is associated with a reduction of ADHD symptoms and improvement on parents and teacher’s rating scales. Significant academic performance improvement have also been detected in patient’s trained with neurofeedback.
Efficacy of neurofeedback in the reduction of ADHD symptoms have sometimes been compared with effects of medication. Many studies report positive and similar effects of neurofeedback compared to psychostimulant. These results pave the way to novel and innovative therapeutic approaches for the treatment of attention deficits.
Consult our scientific review on ADHD, EEG and neurofeedback on www.mensiatech.com/neurofeedbackinadhd/.