Monday, November 24, 2008
At one point many of us in ADHD World were very interested in electrical activity in the brain. There were dramatic demonstrations around, such as using electrical output of the brain to control a toy train set. There seemed to be a nice set of brain rhythms in separate categories, going from very slow during sleep phases, to very fast during active thinking and cognition. Measurement was easy. There seemed to be correlations with mental state, as when the large-amplitude waves between 8 and 12 Hz were accompanied by a state of alert relaxation. I became entranced with the idea that one could use those rhythms to alter mental states. I was convinced that all the benefits of meditation could be created by finding the key electrical signatures for meditation, and using those outputs (easily obtained with simple amplifiers and filters), to achieve the Nirvana-like states attributed to meditation. In my naive and excited optimism I carried a portable EEG machine to Nepal to measure the brain activity of highly practiced monks during meditation, (After all, attaching electrodes to the scalp of bald monks beats the messy efforts with long-haired practitioners at home.) The kindly head of the Buddhist order in Nepal, the Bikku Sumangala, made arrangements for me to obtain my data. He laughed at the idea that I would "find" attention through those little wires attached to the head. Instead he said he could show me how to do it very easily without the wires. So he gave me instruction in meditation of the "mindfulness" variety, and I abandoned my silly escapade in favor of studying the readily observable processes in my own mind. As he said, "Simple, but not easy!) However, when I returned to my laboratory, then at the University of Pittsburgh, I continued to use biofeedback with a variety of patients, particularly those with anxiety and various kinds of muscle pain and headache. I gradually learned that the biofeedback instruments could mostly be replaced by simple relaxation instructions and practice. I had one instructive patient, a middle-aged woman who suffered from recurrent tension headaches, whom I treated with simple relaxation patter, with great success in the lab, where I could see in the sessions how well her frontalis muscles relaxed when I gave her the verbal relaxing patter. I gave her a tape with my voice giving the relaxation instructions, to play as homework. After a couple of weeks she returned saying that this cognitive approach was working very well; headaches were gone! I commended her for doing her homework and listening to the tape, whereupon she said, "Oh I found I didn't have to actually listen to it; I just carry the tape around in my purse and it works just as well as listening." Well, we might call this "cue-induced relaxation" in which a visible object has become a cue for the verbal material previously learned. But even this bit of technology can be supplanted rather easily. But the fact that the EEG machine could readily differentiate the different levels of electrical activity available at the scalp, and that the different rhythms could be used to trigger events that could reward or increase some rhythms and decrease others, as for example, increasing alpha or beta rhythms while decreasing Theta or Delta rhythms, led many others to the idea that it might be possible to permanently change the resting states of the brain, or to give the practitioner a tool for correcting undesired mental states (like the sluggish or sleepy brain which is often associated with conduct problems). Thus was born a rapidly expanding movement called Neurofeedback, where practitioners charge substantial fees over many sessions to alter the brain states and to give some self-control over those brain states to the clients. In ADHD and conduct disorders, it was in fact well-known that they tended to have more slowing of occipital waves on average, and less of the faster rhythms associated with higher order mentation. By sounding a simple tone or giving some visual feedback when the desired rhythms occur, it turns out to be quite true that for most people they will be able to alter their own brain rhythms! But now comes the crucial question: How well does that self-alteration of brain wave control translate into improved behavior? Do the symptoms of ADHD or conduct disturbances, --or anxiety or whatever--stay improved over time? How does one find out? The obvious answer is, you ask the client. But here is a problem, doesn't the mere expensive exercise itself create a large placebo effect? Well, yes. The fancier the machine, the more convincing the therapist, the more that plain old placebo effect takes over. Okay then, it seems obvious that practitioners can simply do some controlled studies in which one group gets real feedback, one group gets false feedback, and perhaps one group gets no feedback. Sounds easy, but in practice there are significant problems. How does one give false feedback that seems real and does not discourage the client because nothing is happening? Remember that the client begins to shape their EEG when the feedback tells them what to increase or disregard. False feedback would be discouraging since no changes in brain output would be there to reward changing in the right direction. Another problem is that clients might well be on some medications to improve their behavior. Many of the so-called supported trials reported in the literature ignore the fact that many of the biofeedback patients were also getting treated with a stimulant drug or other drug. If so, this could likely confound the results or wash out any changes due to the feedback. Sure, one could pick unmedicated patients, though this creates a problem in how representative the ADHD sample would be. Having clients evaluate their treatment has a serious flaw as well. The client is not "blind" to the treatment conditions, and typically wants to follow the doctor's expectations and improve according to the prescribed outcome. This is called the "demand characteristics" of the experiment, and is often the main thing causing the treatment to "work." So to counter this problem one can have independent evaluators: not the doctor giving the treatment and aware of the side effects, but truly independent observers, perhaps teachers or parents, who can evaluate the behavioral changes without knowing which treatment was being given. Surprisingly, there are no controlled evaluations of Neurofeedback that deal with the various threats to experimental validity. The main clue here is that most Neurofeedback specialists are "true believers" who don't need evidence to bolster their belief in the programs. They charge a lot of money and show little interest in the scientific support for treatment effects for tracking the followup status of their clients. The key is that the practitioners do not publish controlled outcome studies in reputable peer-reviewed scientific journals. Until they do, clients are advised to ignore the blandishments of the seductive machines and pretty blinking lights. But they may want to look into mindfulness meditation as a potential avenue for the simple, but not easy approach. In future posts we will look at the evidence for the value of mindfulness meditation or other attention-training approaches.