Thursday, May 14, 2009

Long Wave Infrared Imaging: A new detection method for ADHD?

Detecting ADHD using the long-wave infrared spectrum:

I always enjoy covering new breakthroughs in the diagnosis and treatment methods in the medical field. A new study just came out which may have a number of potential applications to aid in the diagnostic process of ADHD, which I believe is worth sharing. Called Long-Wave Infrared Imaging, this method utilizes the infrared spectrum to detect biological activity (namely bloodflow patterns) via the differences in radiation emitted by these activities. The study, titled Sensitivity and Specificity of Longwave Infrared Imaging for Attention-Deficit/Hyperactivity Disorder, found that this method may be a surprisingly powerful way of separating ADHD from other related disorders, aiding in the always-difficult process of differential diagnosis.

The basics of Long-Wave Infrared Imaging:

The term "long-wave" is a relative term, of course, referring to wavelengths of approximately 10 nanometers (or only one one-hundred millionth of a meter). Differential bloodflow patterns can result in temperature differences by a full degree (Celsius), making this technology useful in tracking bloodflow disorders. A recent publication in the Journal of Medical Physics by Bagathaviappan and coworkers suggests describes how this long-wave infrared imaging can detect areas in the circulatory system where bloodflow activity is sluggish or reduced. Typically, these areas appear "cooler" on the spectrum, due to the lack of a new, replenishing blood supply.

Applications for ADHD:

A number of studies have confirmed the hypothesis that individuals with ADHD have reduced bloodflow levels marking a recuction of activity to multiple key brain regions. Additionally, while several disorders have a number of overlapping symptoms (which can make the diagnostic process more complicated, especially if multiple comorbid disorders are present), differential blood flow patterns to the brain may be able to help make these distinctions. For example, blood flow patters to the brains of ADHD and OCD (Obsessive Compulsive Disorders) can show pronounced differences, which can aid the diagnostic process between these two disorders (while ADHD and OCD are often considered to be on "opposite" ends of the spectrum with regards to neuro-chemical signaling levels, these two disorders can often exhibit similar symptoms, such as a severe impairment in the response to verbal directions. This is especially true in younger children).

This technology may even be extended to measuring or predicting which medications may work for an individual diagnosed with ADHD, based on blood flow in specific localized brain regions. Cerebral blood flow patterns may help predict the response to common ADHD drugs such as methylphenidate (Ritalin, Concerta, Metadate, Daytrana). For example, a study by Cho and coworkers found increased blood flow in at least three different brain regions for individuals who showed poor response to methylphenidate treatment compared to their peers who did show improvements under the drug.

While the medication response study was done utilizing a different type of brain imaging device known as SPECT, which utilizes gamma rays and radioactive tracers to detect brain activity in 3-dimensional patterns. While SPECT has proven to be an extremely powerful and effectively safe method of detection (the radioactive isotope used in this method is relatively non-invasive and breaks down quickly, and the gamma rays are carefully controlled), concerned parents may still have an inherent fear of the terms "radioactivity" and "gamma rays" tend to shy away from this powerful detection method on their kids.

While this blogger personally has a very high opinion about the use of SPECT as a diagnostic tool for ADHD and related disorders, it is at least worth mentioning the possibility that long-wave infrared imaging methods may be a viable alternative method in at least some of these imaging cases (SPECT technology has been around for over 30 years, but the recent advances in computational power resurrected this technology in the very recent past, similar possibilities may abound by this infrared technology, which has been around even longer).

Keep in mind that the studies utilizing this range of infrared imaging technologies for detecting and differentiation disorders such as ADHD are still relatively scarce. Nevertheless, long-wave infrared imaging appears (at least in this blogger's personal opinion) to be a powerful diagnostic tool for ADHD and related disorders in the near future.

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