Preface

In spite of the fact that, in clinical practice, neurophysiological investigations are still carried out in primary headaches, there is little evidence that they are useful as a diagnostic tool. Recently, a task force of the European Federation of Neurological Societies examined the literature concerning this issue, and came to the conclusion, according to the Evidence Based Medicine criteria, that neurophysiological tests are of little or no value in the clinical setting.

On the contrary, the contribution of neurophysiological studies to our understanding of the pathophysiology of primary headaches appears to be very important, and a large number of investigations have been carried out in this field, particularly over the last 10 years. Members of the above task force were asked to contribute to this Supplement. A chapter on the role of experimental animal models in inspiring studies of headache patients has been included, and the Supplement also covers the main methods employed in the neurophysiological study of headache. It is important to underline that some functional abnormalities, such as cortical dysexcitability and impairment of the habituation phenomena, have been documented mainly through neurophysiological studies, evoked potentials in particular.

Recently, taking both experimental models and clinical and neuroimaging studies as a starting point, an impairment of the trigeminal pain control system has been put forward as a crucial factor in the pathogenesis of so-called vascular headache, and sensitization phenomena seem to play an important role during the attack and in the interictal phase, as confirmed by neurophysiological investigations. Other contributions relate to two important aspects of the pathogenesis of primary headache: the role of the autonomic nervous system and the relevance of peripheral mechanisms in tension-type headache. This Supplement sets out to provide an interesting update to this complex chapter.

The authors would like to thank Catherine Wrenn for her valuable editing of some manuscripts. Finally, we acknowledge the support of the C. Mondino Foundation of Pavia, the University Centre for Adaptive Disorders and Headache, and the Italian Ministry of Universities, which sponsored this Supplement.