[Lateralization phenomena and headache]

Ipsilateral carotid and vertebral vasomotor phenomena are marked components of a unilateral cluster headache crisis. Investigation of lateralisation at the height of a crisis has shown that Doppler findings supplement Heick's observation of the reversible opening of both intra and extracranial arteriovenous shunts. This observation is in line with personal thermographic evidence and that of Lance indicating local hypothermia, and with Wolff's demonstration of dilatation and congestion associated with the superficial temporal artery. Personal dynamographic findings now point to a local extra-intracranial artery pressure gradient as the cause of the peripheral component of lateralisation in cluster headache.