The Affect Effect

A study by Rosello et al measured the startle eyeblink reflex, heart rate response, heart rate variability, and EEG waves in both fibromyalgia patients and a healthy control group while they looked at video clips of unpleasant, pleasant, and neutral environments, a walk in a park. They had hypothesized that fibro patients would see all three environments in a more negative light (“more unpleasant and arousing”), that the startle eyeblink reflex would be greater in the fibro patients with an increased heart rate response.  In other words, they expected a greater reaction with both physical reactions and affective (mood) reactions.

What they discovered, however, was that while fibro patients rated all the video environments as more negative than healthy subjects, their physical reactions to these stimuli weren’t as expected.  First of all, the startle eyeblink reflex was lower in fibro patients: “…patients with FM exhibited an abnormal reflex inhibition to all virtual environments…”  Fibro patients’ reactions to both pleasant and unpleasant stimuli was muted.  Not only that, their heart rate response to stimuli was also reduced.  The authors explained this by pointing out that the parts of the brain affected by fibro (the amygdala, anterior cingulate cortex, and periaqueductal gray) were also involved in the startle reflex, indicating that there could be some “functional disruption of these network circuits.”

We’re back to brain damage.  However, the authors are very careful to point out that one of the reasons that fibro patients have a lower startle reflex is because our focus is on the unpleasantness of the situation.  It’s a matter of concentration. We’re concentrating on the negative so much that we no longer react to it “normally.” This explanation falls neatly into the way fibro patients are “characterized” by the authors:

  • Abnormal affective processing including impaired affect (our moods are off kilter)
  • Increased emotional avoidance
  • Catastrophizing
  • Alexithymia (an inability to understand or recognize emotions)
  • Having an “attentional bias toward negative information”
  • Hypervigilance in our moods – how we feel
  • “An inhibition of information processing”

I’m not crazy about this list, but to complain about it is off point.  The bottom line of the authors’ discussion is that there may be “abnormal brain functioning and autonomic cardiovascular control during affective processing” as well as “peculiarities in the regulation of cortical and attentional arousal.”  Brain damage.  But has the chicken clucked or the egg cracked?  Which came first?  My biggest question, however, is:

Does the way researchers characterize fibro patients affect the way they do their research if not the outcomes of their research?

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