Evidence for neuronal dysfunction in migraine: concurrence between specific qEEG findings and clinical drug response--a retrospective analysis-.

OBJECTIVE

The aim of this analysis was to verify objective correlates of the clinical improvement of migraine in patients by means of quantitative topographical EEG (qEEG).

METHODS

Overall 40 migraine-outpatients participated in this retrospective analysis of prophylactic migraine treatment over 3-8 months with 1600 to 2000 mg cyclandelate daily. In all patients qEEG was recorded and analysed using the Fast Fourier Transformation and the determination of the Abberation Index (AI = the statistical probability of belonging to a qEEG reference group of healthy people, n = 500).

RESULTS

A clinical response (> 50% reduction of migraine attack frequency and duration) was observed in 77.5% (n = 31). The number and duration of migraine attacks per month (median values) were reduced in a highly significant manner. In this observation 75% of all patients investigated showed a pathological positive Aberration Index at a single electrode or a cluster of neighbouring brain sites. This consisted in a power increase in theta, alpha and/or beta1 activity, and 73.3% of them had also a corresponding negative AI-focus (power decrease). In 15 patients EEG aberrations (positive AI clusters) within one frequency band were found, whereas 15 patients showed aberrations in more than one frequency. Positive AI s were mainly found in fronto-temporal and occipital brain areas with one single topographical difference between the patients with and without aura.

CONCLUSIONS

Positive AI values were the main electrophysiological findings in these migraine patients. This was supported by the highly significant decrease of the median amount of the positive AI after clinically successful treatment with cyclandelate. Twenty four out of thirty patients with positive AI foci showed concurrence between qEEG-changes and clinical response. Patients with positive AI foci involving the lower or middle frequencies (theta and/or alpha 1) seemed to show a better clinical response (84.6%) than those with AI foci with participation of only faster frequencies (alpha 2 and/or beta 1; 54.5%). A controlled study is needed to confirm these observations.