Reduced Frontal P3a Amplitude in Migraine Patients during the Pain-Free Period

Abstract

Background and purpose: Neuropsychological and neuroimaging studies both suggest that frontal lobe dysfunction is present in migraineurs. Since P3a abnormalities manifest in other diseases associated with attention problems, such as attention deficit hyperactivity disorder, we hypothesized that migraine patients have P3a abnormalities, particularly in the frontal region.

Methods: Event-related potentials were measured using a passive auditory oddball paradigm in 16 female migraineurs (aged 22.9±2.0 years, mean±SD) during the interictal period and in 16 age-matched healthy females (22.6±2.0 years). The amplitudes and latencies were analyzed independently using repeated-measures analysis of variance. Nonparametric statistical testing using a cluster-level randomization method was performed to localize the abnormalities.

Results: The mean P3a amplitude at frontal areas during the third trials was significantly lower in migraineurs (1.06 µV) than in controls (1.69 µV, p=0.026). P3a amplitudes were negatively correlated with the duration of the migraine history (r=-0.618, p=0.014). Cluster-based nonparametric statistical analysis showed that the amplitudes over left frontal areas were significantly lower in migraine patients than in controls.

Conclusions: A reduced P3a amplitude of migraineurs reflects attentional deficits and frontal dysfunction. The negative correlation between P3a amplitude and the duration of the migraine history suggests that attentional deficits and frontal dysfunction are either the cause or the result of headache.

Keywords: P3a; attention; cognitive function; event-related potentials; frontal; migraine.

Fig. 1

Grand average event-related potential responses to standard and deviant auditory stimuli recorded from 21 electrodes. Red lines represent plots from migraineurs, and blue lines plots from controls. Solid lines represent plots for deviant tones, and dotted lines those for standard tones.

Fig. 2

Voltage topographic scalp maps of the P3a component (B) and of event-related potential (ERP) differences between patients and normal controls at 260-280 ms after deviant tones (C). Red denotes a positive and blue a negative potential. Significant electrodes are highlighted, shown by cluster-based nonparametric statistical analysis (p<0.05). The P3a component is indicated by a rectangle on the grand average ERP plot at the Fz electrode (A).

Fig. 3

P3a amplitudes of successive blocks at frontal areas (F3, Fz, and F4 electrodes). Mean P3a amplitudes only significantly differed between controls and migraineurs during the third block (p=0.026).

Fig. 4

Correlation between frontal P3a amplitude and migraine duration.