Topographic EEG Mapping Methods

After almost 40 years of research on EEG computer analysis, present clinical applications of this method remain limited. At the present time, EEG mapping is suited primarily for research. Despite the pitfalls of an uncritical application of EEG mapping, progress in clinical research made possible by EEG mapping techniques has been considerable. Some problems of data acquisition, display and statistical analysis are discussed in this paper. For headache research examination of the activated EEG, especially with photic stimulation, has greater diagnostic importance than mapping under resting conditions.

Computerized EEG Topography in Childhood Migraine Between and During Attacks

Topographic EEG mapping was performed in 58 migrainous children (mean age: 12.9 years; 39 without, 19 with aura) between attacks. Ten children were also recorded during an attack with visual aura. Between attacks there were no significant differences between migraineurs and age-matched controls. During visual aura a decrease in occipital alpha power contralateral to the affected hemifield was found in all patients. This was followed by a bilateral frontal increase in delta power, and, during the headache, by an increased delta activity in posterior-temporal and occipital electrode sites. The possible brain mechanisms underlying these EEG changes are discussed.

Topographic EEG Mapping in Childhood Headaches

The clinical distinction between migraine without aura and tension headache is more difficult in young children than it is in adults. The objective of this study was to examine the usefulness of topographic EEG mapping, as one method among other diagnostic techniques, for establishing a diagnosis. The clinical diagnosis of tension headache and migraine in children between 6 and 15 years of age was established according to criteria of the International Headache Society classification. Children with migraine and tension headache were examined during and between attacks. EEG mapping showed lateralized parietal diminution of alpha-power more frequently during an attack of migraine than during tension headache, which regressed between attacks. Compared to other methods, such as visual evoked potentials, EEG mapping may have the advantage of helping to diagnose each single headache, which could be useful in patients with combined headaches.