October 23, 2014

Dr Wilner: Welcome to Medscape. Today I am with Dr Selim Benbadis, professor of neurology at the University of South Florida and Tampa General Hospital.

Dr Benbadis has made something of a side career of looking at the electroencephalogram (EEG)—not only how it is used but how it is misused. When I saw the publication of the US Food and Drug Administration approval of an EEG device that assists in the diagnosis of attention-deficit/hyperactivity disorder (ADHD), I thought of Dr Benbadis. This device was approved in July 2013, and I thought it would be worthwhile to ask Dr Benbadis what he thinks of such a device. How is it possible that one can learn about ADHD with EEG?

Dr Benbadis: Thank you for having me, Andrew. Personally, I do not believe that it is possible to diagnose ADHD with EEG. I believe it will result in many errors in diagnosis in both directions—overdiagnosing and underdiagnosing. EEG is a wonderful test for certain things, but as you know, it has a lot of variability, a lot of normal variant fluctuations even among normal people. I believe that we have better ways to diagnose ADHD than relying on an EEG. The culture in medicine, and particularly American medicine, is to over-rely on the test as if it were automatically superior to clinical judgment. I am very concerned that it will not be a reliable tool.

Dr Wilner:, The patient comes in, has the EEG, and the results are sent to the company. Then the company sends back a report saying, “Yes, the patient has ADHD,” or “No, the patient does not have ADHD.” It relies on the ratio of theta to beta waves.

Dr Benbadis: Yes, it is a quantitative analysis.

Dr Wilner: It is an analysis based on the frequency of slow waves to fast waves, but it seems to me that there can be so many variables. You know—when patients are drowsy they have theta waves; when they wrinkle their foreheads they have beta waves

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Dr Benbadis: Yes, we can see a lot of confounding information.

Dr Wilner: It is very hard to understand how it could possibly work.

Dr Benbadis: I believe that it probably does not work. As you know, with quantitative EEG we have had similar experience with attempts at diagnosing traumatic brain injury, which of course plays a role in litigation. But none of us in the EEG field believe that this test is reliable for ADHD diagnosis. You can make the quantitative EEG say many things. We are very concerned that for a diagnosis such as ADHD, which is an important diagnosis and a real diagnosis, it is much better made by an experienced clinician than by brainwaves, particularly quantitative analysis of brainwaves. Again, laypeople tend to have more faith in the test than in an experienced clinician’s examination. I believe that is a mistake.

Dr Wilner: Dr Benbadis, thank you very much for your insights into the use of EEG for the diagnosis of ADHD. I look forward to speaking with you again soon.

Dr Benbadis: My pleasure.


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