Frequency of premonitory symptoms, shown as percentage of each of the three groups (all migraine patients, MwA, MwoA). Symptoms were only counted as real premonitory symptoms, if patients reported an onset of 2 or more hours before the headache. Asterisks indicate significant differences between MwA and MwoA patients. *p < 0.05, **p < 0.01, ***p < 0.001. MwA = Migraine with Aura, MwoA = Migraine without Aura.