View Full Version : New Study Shows Promise that “Skin Tests” May Be Able to Provide a Definitive Diagnos

04-13-05, 02:02 PM
A new study provides the hope of finding a way to distinguish between what is often the subject of confusion and diagnosis: the devastating "chronic fatigue" that accompanies the baffling and disabling disease called Chronic Fatigue Syndrome and the "chronic fatigue" associated with depression.

Using tone and light stimuli, a University of Alberta study has shown that Chronic Fatigue Syndrome can be distinguished from the chronic fatigue associated with major depression by recordings of skin temperatures and electrodermal activity. In the past, numerous psychological investigations have attempted to differentiate those with the fatigue of Chronic Fatigue Syndrome and those with the fatigue associated with depression. The University of Alberta study (conducted with researchers from the University Centre for Neuroscience at the University of Alberta and from Alberta Hospital) was the first of its kind to use skin tests involving electrodermal activity; in this case, electrodes were placed on each hand to measure the differences among those diagnosed with Chronic Fatigue Syndrome, depression patients who experience chronic fatigue, and healthy controls.

These tests determined the profile of Chronic Fatigue Syndrome patients is clearly different from normal controls, offering hope of eventually being able to pinpoint the clear biological basis to the condition.

Chronic Fatigue Syndrome (CFS) is a disorder, characterized by an often debilitating host of symptoms that includes muscle weakness, myalgias, post-external malaise, and sleep and cognitive disturbances plus fever, sore throat, and headache. "The level of disability varies for people with CFS, but some individuals find they are unable to return to work or function normally on a day-to-day basis. Unfortunately, many of these symptoms are subjective in nature and are difficult to quantify or confirm," says Hannah Pazderka-Robinson, the lead author on the study and quoted in this article on medilexicon. "Not only does the stigma attached with the disorder play an emotional toll on the patient, but it has implications for insurance claims as well.

"There are a number of medical professionals who don't believe that CFS exists in the first place," said Pazderka-Robinson. "The problem is, both CFS and depression are characterized by very similar profiles. Imagine a patient who approaches a doctor and tells him they feel depressed and tired all the time.

"Because there is no objective test for chronic fatigue [syndrome], such as a blood test, the condition can be difficult for a doctor to diagnose," said Pazderka-Robinson, who has just completed a PhD in neuroscience.

Unless a patient's complete medical and psychological profile is considered, there can be confusion between whether the proper diagnosis is Chronic Fatigue Syndrome or depression. This confusion is present because those diagnosed with depression also have some symptoms associated with Chronic Fatigue Syndrome. (In strictly layman's terms, the chronic fatigue of depression is sometimes compared to inertia, while the chronic fatigue associated with Chronic Fatigue Syndrome includes muscle weakness, cognitive skills disruptions, and varying degrees of depression triggered by being so tired. In other words, in depression, the fatigue results from being depressed; in Chronic Fatigue Syndrome, the depression occurs from being so tired.)

Pazderka-Robinson was further quoted as saying that because "depression shows a high co-morbidity with CFS, some CFS patients are often given antidepressants -- that don't work or work poorly, since they do not address the underlying condition. Again, when these medications don't work, physicians sometimes jump to the conclusion that there isn't really anything, physically, wrong. Obviously, both misdiagnosis and the tendency for doctors to treat these patients as if they're not really sick can be extremely distressing. It can also undermine the patient's trust in the doctor and make them less likely to seek treatment if the condition worsens."

This University of Alberta study has verified that there is physical evidence for those who suffer from Chronic Fatigue Syndrome (CFS), giving new weight to the often stigmatized and misdiagnosed disorder. Research just published in the International Journal of Psychophysiology (Volume 53, Issue 3, August 2004, Pages 171-182; Hannah Pazderka-Robinson, James W. Morrison and Pierre Flor-Henry) determined that, using independent criteria, CFS can be distinguished from depression.

The profile of CFS patients is clearly different from normal controls, suggesting there is a clear biological basis to the condition. The study shows people with Chronic Fatigue Syndrome have higher skin temperature than people with depression or those in a control group. In addition, the skin conductivity response (the skin's capacity to conduct an electric current) of those with Chronic Fatigue Syndrome is lower.

The most significant part of the research was that there is reason to believe it can provide independent verification for CFS sufferers that will show that these CFS patients are different than normal controls and they're not "just depressed," said Pazderka-Robinson.