Cognitive impairment in chronic migraine: a cross-sectional study in a clinic-based sample

Cognitive impairment has been described in all phases of a migraine attack and interictally. However, the prevalence and phenotype of such impairment in chronic migraine (CM) have not yet been studied. Objectives: The aim of this study was to evaluate both the prevalence of the objective cognitive deficit in patients with CM and the factors underlying its etiology. Methods: 144 patients with CM and 44 age-matched patients with low-frequency episodic migraine (EM) (a maximum of 4 headache days per month) participated in this study. Neu ropsychiatric characteristics were measured with the HADS Hospital Anxiety and Depression Scale. Cognitive function was assessed with the Montreal Cognitive Assessment (MoCA), Digit Symbol Substitution Test (DSST), Rey Auditory Verbal Learning Test (RAVLT), and the Perceived Deficits Questionnaire (PDQ-20). Results: Compared to EM, CM subjects demonstrated higher subjective and objective cognitive impairment across all tests. CM patients had 4 times higher odds of achieving a RAVLT score in the lower quartile range compared to EM (Odds Ratio [OR] 3.8; 95% confidence interval [95%CI] 1.5-9.6; p=0.005). In the MoCA, CM patients demonstrated the most striking impairment in memory/delayed recall (65.3%), attention (46.5%), abstraction (30.6%), and language (27.1%). Chronic headache and level of education, but not gender, depression or anxiety, were independent predictors of cognitive impairment. Conclusions: Cognitive impairment is prevalent in the CM population during their mildest possible pain and may be caused by a central sensitization. Timely preventive treatment of EM is warranted.