Critical flicker frequency in migraine. A controlled study in patients without prophylactic therapy

The critical flicker frequencies (CFF) of individuals with migraine with and without aura were determined and compared to those of normal controls. Twenty-six migraine patients, 12 with aura and 14 without aura and 30 healthy controls were included. Migraineurs were tested during a migraine-free period, through both the continuous flicker method (CFM) and the forced choice method (FCM). Migraineurs presented a mean flickering fusion threshold lower than healthy controls with the CFM (40.45 vs. 44.33, respectively; P = 0.019) and with the FCM (34.16 Hz vs. 38.5 Hz, respectively, P = 0.019). Both groups of migraineurs had significantly lower thresholds as compared to controls, migraineurs with aura presenting the lowest thresholds for the fusion of flickering (P = 0.008 and P = 0.0001 with the CFM and the FCM, respectively). Results confirmed and extended previous observations of abnormal flicker fusion thresholds in migraineurs. We hypothesize that this finding might be related to a shorter cortical stimulation silent period.