Assessment of cognitive dysfunction during migraine attacks: a systematic review

Patients consistently report cognitive impairment during migraine attacks, yet the documentation of such dysfunction by neuropsychological evaluation has lacked similar consistency. This incongruence may be due to discrepant study designs, assessment tools and small samples sizes. To search for evidence of decline in cognitive functions during a migraine attack, compared to headache-free performance. The secondary objective was to determine if the eventual decline had a consistent neuropsychological pattern. Systematic review of the medical literature using PubMed and Cochrane library databases without limitations or restrictions from inception to March 2014, using the search terms "migraine", "cognition", "neuropsychological". We included studies in episodic migraine that had a neuropsychological evaluation performed during an attack. From 1,023 titles screened, a total of 10 articles met criteria for inclusion and were fully reviewed. Only five of these studies, comprising a total of 163 individuals, had enough data to allow an appraisal of the study question. All five studies were positive in documenting some type of reversible cognitive impairment during the migraine attack. The pattern of cognitive impairment most often documented was of executive dysfunction, but the presence of bias induced by the choice of tests and of small samples prevents this finding from being conclusive. This review supports the existence of reversible cognitive dysfunction during the migraine attack, corroborating patients' subjective descriptions. Further work is needed to establish the pattern of cognitive dysfunction, their underling pathophysiological mechanisms and the impact of these symptoms in migraine-associated disability.