Cognitive dysfunction during migraine attacks: a study on migraine without aura.

Background: Cognitive difficulties contribute to patients' disability during migraine attacks and have been overlooked in migraine research. Neuropsychological studies performed during attacks have produced inconsistent findings due to design differences and limitations. Objective: Our objective is to document changes in cognitive performance of migraine patients during migraine attacks with a comprehensive battery of cognitive/behavioral tests, while controlling for potential confounders. Method: A prospective two-period, randomized, cross-over study compared within-subject neuropsychological evaluation in two conditions - during a naturally occurring untreated migraine attack and a headache-free period. Results: Thirty-nine patients with episodic migraine (37 females, average 38 years old) were included and 24 completed the study. Participants performed worse during the attack in the majority of cognitive tests, compared to the headachefree status, and significantly so in word reading speed (p = 0.013), verbal learning (p = 0.01), short-term verbal recall with (p = 0.01) and without (p = 0.013) semantic cueing and delayed recall with (p = 0.003) and without (p = 0.05) semantic cues. Differences found were unrelated to age, gender, literacy, condition order, interval between evaluations, anxiety, pain intensity or duration of the attack. Discussion: Cognitive performance decreases during migraine attacks, especially in reading and processing speed, verbal memory and learning, supporting patients' subjective complaints. These findings suggest the existence of a reversible brain dysfunction during attacks of migraine without aura, which can relate specifically to migraine or be a consequence of acute pain processing by the brain.