AQP4 and Headache: There was a significantly higher frequency of seizures and psychosis (P = 0.032 and 0.009, respectively) and a trend (approach significant) towards a higher frequency of headache, anxiety, and cranial neuropathy in the AQP4-IgG Ab-positive subgroup than in the AQP4-IgG Ab-negative subgroup (P = 0.065, 0.065, and 0.08, respectively).