In order to better understand the success of EEG biofeedback training, it is helpful to look at how the brain receives and processes information. The interaction between the plasticity and the modulation of the circuits gives us a clearer understanding of the attentional process of the brain. An understanding of the neurological problems which characterize Attention-Deficit Disorder defines where the attentional process breaks down. Dr. Andrew Abarbanel describes long-term potentiation (plasticity) and neuromodulation (the changing of brain waves) and their effect on the attentional process of the brain in his article “Gates, States, Rhythms, and Resonances: The Scientific Basis of Neurofeedback Training.” (Abarbanel, 1995)
|If the EEG biofeedback training is to make effective changes which are long term, the neuropathways must be adjustable and able to maintain the adjustments for long periods of time. The flexibility or “plasticity” of the neuropathways is referred to as long-term potentiation. This plasticity allows the brain to receive immediate feedback, process it, and learn from it.|
During an EEG biofeedback training session, the brain recieves positive feedback (usually an auditory beep and a change in the visual display) whenever the brainwaves are functioning properly. The brain processes this information–not facts or figures, just the awareness that the attentional process is working correctly–and learns from the feedback. The brain then continues to work more effectively. The neurofeedback training has established a positive feedback loop.
The plasticity of neurons allows:
- The remission of ADD to continue
- Increases the ability of the brain to respond
after the neurofeedback treatment has ended.
|The ability of the brain to retain the information it has recieved during the treatment and continue to learn from it after the treatment has ended, is the foundation which enables EEG biofeedback to be successful (1995, p.8).|
The brain receives information through a process referred to as “neuromodulation.” Dr. Andrew Abarbanel clarifies that neuromodulation does not supply information to the brain. It regulates whether or not the information is allowed to enter the brain.
Neuromodulation is the result of changes in the firing characteristics of the neurons. The firing rates of individual neurons are adjusted by ionic flow. Whether the neuron relays the information or blocks the messages depends on the amount of ion flow. In other words, are the gates opened or closed, and how fast are they opening and closing. If the gate is closed then information is blocked. The ion flow is the key to the brain’s ability to receive and process information.
|Dr. Abarbanel states that neuromodulation is central to neurofeedback training, since neuromodulation affects the changes in the “circuitry necessary to optimize attentional capacity.” (1995 p.6)|
BRAIN WAVES AND THE ATTENTIONAL PROCESS
The opening and closing of the gates and the speed at which they open and close are referred to as brain waves. Dr. Padgitt clarifies:
|When talking about brain waves, we are considering the controlled mass firing of neurons in a synchronized fashion. When a group of neurons fires in synchrony there is an electrical wavelike effect, hence the term brain wave . . . It is clear we are capable of increasing and decreasing the electrochemical activity in each clinically important range (1996g, p.1 ).|
There are two main brain wave patterns that affect Attention-Deficit Disorder. Each of the brain waves or rhythms can be connected to a particular behavior state and each of which relates to the attentional process.
- Theta waves represent rhythmic slow activity. They are usually seen when we are awake but not focusing on anything specific, such as daydreaming.
- Beta waves are fast waves. They represent active concentration and deep thinking. Dr. Abarbanel points out that “. . . the higher frequency beta components have been correlated with focused attention . . . ” (1995, p.7).
The attentional process can be monitored by evaluating the beta and theta waves. This evaluation takes place in the neurofeedback training when the electrodes are placed on specific areas of the head and a readout of the brain activity is presented on a computer screen. The amount of beta activity can then be compared to the amount of theta activity.
Since the higher frequency beta waves represent focused attention, the desire is to increase the beta waves while decreasing the theta activity.
NEUROLOGICAL PROBLEMS CONNECTED TO ATTENTION-DEFICIT DISORDER
The complicated process of attention begins when information reaches the brain. The information is processed and transmitted. The proper gates are closed, allowing the focus to be directed to one signal.
|Dr. Abarbanel explains: . . . As sensory input reaches the brainstem, it processes and transmits these signals to the . . . frontal cortex . . . then orchestrates several components of the attentional process by selectively inhibiting a number of functions at a number of centers; these include orientation, alertness, awareness, and arousal. This orchestration facilitates the focusing of attention on only one set of environmental signals . . . (1995, p.11).|
Because of the complexity of the process of attention, there are many areas where malfunctions can occur.
|“The suggestion is that in attention-disordered patients there are a number of possible imbalances between the myriad signals and counter-signals, processes and counter-processes, that amounts to a coarseness or imbalance in the “tuning” of the circuitry, this coarseness of control causes an attentional disorder marked by excessive attention to either external or internal stimuli, or both . . . A too early cut off of the . . . input makes it lock onto subsequent inputs without connecting them to prior input and trains of thought.” (Abarbanel, p.13)|
This causes an inability to filter out or to connect to previous information–or distractibility. The child is aware of every sound or movement around him and cannot focus on the task.
The reverse also occurs. The child blocks too much input. This appears as inattention, daydreaming, or “lost in or totally absorbed” by a TV show.
These imbalances directly correlate to characteristics of ADHD (attention deficit hyperactivity disorder):
The problem for ADHD children is not that they are recieving too much information, but that their brain is not recieving enough stimulation. Dr. Lubar explains,
“Attention Deficit Hyperactive children are experiencing a state of decreased sensory arousal. The visual, auditory . . . inputs were not having the impact or the reinforcement value that they should.” (Lubar, 1991, p.206)
The child has to do more and do it faster to have his brain accept that there is stimulation occurring. The brain must receive a level of sensory stimulation to “feel good” or “feel alive.” The child may feel “good” when he is getting into trouble, but becomes depressed and sad when he is being “good.” Being good usually correlates with sitting still, staying on task, and listening. These activities are all low stimulating activities. When the child is acting appropriately, the brain does not receive enough stimulation to “feel alive or good.” The child becomes hyperactive trying to send enough messages to the brain to let it know that it is working. The increased energy level attempts to get enough messages to the brain, but causes an inability to connect the messages. The brain does not receive the appropriate messages to connect “cause and effect” thinking. The child is then hyperactive and “out of control.”
Dr. Lubar goes on to explain, “When a person [with a normal brain wave] is resting, dominant EEG activity is in the alpha and theta range; but when one becomes excited, activity begins to shift toward the beta region . . . “( Lubar, 1991, p. 207). However, children with ADHD appear to be less able to produce beta activity and experience excessive slow activity primarily in the theta region. Their EEG’s show a condition more appropriate to a sleep or daydreaming state than an alert and focused state. Their hyperactivity is an attempt by the brain to “wake up.”