Benjamin C Ringger and Dr. Donovan Fleming, Psychology and Neuroscience

The p300 event related potential is a particular wave of the measured electrical activity of the brain. This wave may be evoked by a visual stimulus presented to the subject and occurs approximately 300 msec. following presentation of the stimulus. In previous studies, it has been suggested that a processing continuum exists between serial and parallel processing at opposite ends of the continuum. Serial processing, which involves attending to only one object, is generally associated with a slower reaction time, while parallel processing, which attends to two objects, is usually accompanied by a quicker response. Depending on various characteristics of the EEG, the P300 in particular, and the reaction time, it may be determined which of these two types of visual processing is used by the subject.

The purpose of this study was to gather data on the effects of migraine headaches on visual perception. I evaluated the differences in reaction time and characteristics of the p300 wave to determine if visual processing differs between migraine sufferers (migraneurs) and a control group. The data collected was applied to the serial to parallel continuum in hopes of determining if migraine headaches had a significant effect on visual processing in the subject.

I originally intended to find a large group of subjects (20) and subdivide them into two groups of ten. The first group would be taken from non-migraine sufferers with no history of headaches. The second group would be taken from migraine sufferers chosen after diagnosis by physicians from the BYU student health center. The visual perception of the migraneurs was to be evaluated three times. The first evaluation would occur in the interictal or non-migraine period. Of the two remaining evaluations, one was to be conducted on the migraine group during a migraine headache or within 48 hours of a migraine attack. The second measurement was also to be conducted on the migraine group during a migraine headache or within 48 hours of a migraine attack. This measurement, however, was to be taken while under the influence of pharmaceuticals. Unfortunately, I overestimated the potential pool of migraneurs who would be willing to participate in this study. Despite offered incentives such as gift certificates, a very limited number of subjects chose to participate. This was a valuable lesson in research study design. I learned that one must prepare for circumstances that may be out of his control and prepare and plan accordingly. Notwithstanding these complications, I attempted to make do with the subjects available and narrowed the scope of the research to include interictal versus migraine periods in migraneurs and non-migraneurs.

I expected to find a slower reaction time and a resulting shift toward serial processing in the migraine group. Slower reaction times are also inversely related to p300 wave amplitude. For example, as reaction time increases wave amplitude decreases. Thus with the expected slower reaction time due to the severe pain and (I presumed) resulting decrease in perceptual ability associated with migraine headaches, I also expected to see an increase in p300 amplitude in migraneurs with respect to the control.

Following data collection and evaluation, I found that the actual results in general differed from my prediction. Reaction time actually decreased in the migraine group when compared to the control. This was further supported by the corresponding negative correlation between reaction time and p300 amplitude. That is, with the decrease in reaction time, the expected corresponding increase in p300 amplitude generally was present. This tendency toward faster or parallel processing even occurred with stimuli that normally would be expected to elicit reaction times and wave characteristics generally associated with serial or slower processing.

This data and the resulting conclusions that migraine pain may actually enhance visual perception lead one to ask some intriguing questions. For example, are there potentially helpful treatments that could target this connection between perception and migraine pain? Can such findings elucidate our “perceptual pathways” and lead to a better understanding of the connection between what we see and how we actually perceive it? In any case, more complete and comprehensive studies must be performed before one may unequivocally determine that migraine pain enhances perception. It is my hope that these questions and possibilities will be further researched and lead to an alleviation of pain in those who suffer from migraines.