Fibro Patients Challenged when Processing Words and Colors

by Kristin Thorson, Fibromyalgia Network Editor
Posted: July 31, 2008

Does your slow reading speed embarrass you, or worse yet, is it interfering with your job productivity? Or, perhaps you keep your finger near the pause button of the DVD remote control in case one of the characters in the movie speaks in a foreign language and subtitles appear across your TV screen. While you may already be frustrated with the limited speed at which you can read and fully comprehend information, the situation can be compounded when family or co-workers become annoyed with you. If you told your doctor about your memory and concentration difficulties, a simple screening test may have falsely labeled you as “normal.”

Frank Leavitt, Ph.D., and Robert Katz, M.D., of Rush Medical College in Chicago, IL, just published a study showing that the speed of information processing was significantly impaired in 50 percent of the 67 fibromyalgia patients tested.* Putting their findings into perspective, the authors state, “People with fibromyalgia are essentially doing the same job at roughly half the speed.”

If you require more time to process the same amount of stimulus information, how does this relate to the symptom of feeling like you are in a brain fog, or what is often referred to as fibro fog? According to Leavitt and Katz, “Time delays in processing information alter the timing of other cognitive operations. For example, delays in processing can affect what you remember, because time governs the decay of information.” So the quicker you can process information, the sooner it can be stored in permanent memory and the greater likelihood that the data actually gets stored. Faster processing speeds also translate into improved accuracy of the details being retained. This occurs because of the reduced odds that the information “fades” or becomes “blurred” before it has a chance to be stored in memory.

Yet, you may be wondering: If fibromyalgia patients have a reduced mental processing speed, why wasn’t this identified years ago? A person’s processing speed cannot be determined by a single test. One must measure all factors that influence the overall processing speed, which includes mental speed (i.e., how fast the brain processes info), auditory speed, quickness of pattern recognition, pace of visual scanning, speed of decision making, inspection time, and motor (muscle movement) speed. A deficit in one area could have serious ramifications, but may not be picked up unless all of the aspects that contribute to processing speed are measured.

Leavitt and Katz used a battery of ten tests to evaluate all factors that may influence a person’s processing speed. This approach is more extensive than previous studies, and it produces a complete picture of every step involved in the speed of processing all types of information. Sixty-seven fibromyalgia patients (recruited consecutively and not based on whether they complained of brain fog) were compared to 51 non-fibromyalgia subjects with memory complaints (e.g., they had a history of seizures, head trauma, stroke, etc.). The results for both groups were also compared to the standardized norms for each test.

In the reading and color naming tasks, fibromyalgia patients scored substantially poorer than the group of controls that complained of cognitive difficulties. The reading test consisted of asking subjects to read the names of colors printed in black ink (e.g., red, blue or green). The color naming test required subjects to state the color of a row of Xs printed in either red, blue or green ink. In general, people have the ability to read words automatically faster than their ability to name colors. All tests were timed.

Despite how annoyed you may be with your fibro fog, there is an upside to this finding. More than 70 percent of fibromyalgia patients scored in the normal range on at least seven of the ten tests. This means that most of the steps involved in processing information is done in a timely manner, and only the brain areas involved in reading and color naming are affected. So the processing speed deficit in fibromyalgia is selective, but the downside is that researchers do not know what is causing the dysfunction.

The findings by Leavitt and Katz are somewhat paradoxical because fibromyalgia patients performed the worst on the tests that were the easiest. “Unlike the other timed tests in the battery, naming words and colors are relatively mindless tasks that are executed with a minimum of personal effort. In tasks that require a greater demand on taxing process capabilities, the speed in fibromyalgia patients is either similar to or better than the control sample.”

While this selective glitch in mental processing speed of reading and color naming may be an oddity, this study shows that for half of the fibromyalgia patient population, fibro fog is definitely a reality! If your doctor refers you for cognitive testing, make sure that the Word and Color naming tasks of the Stroop Test are included. Inquire about the tests to be used before you even set up an appointment. Otherwise, your cognitive complaints may go undetected and your doctor will falsely assume that you are just another complainer.

The University of Washington has an Interactive Stroop Test available for you to take online.

* Leavitt F, Katz RS. J Clin Rheumatology 14(4):214-218, August 2008.

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