Short-lasting unilateral neuralgiform headache attacks: where is the headache generator?

Abstract

This scientific commentary refers to ‘Ventral tegmental area deep brain stimulation in refractory short-lasting unilateral neuralgiform headache attacks’, by Miller et al. (doi:10.1093/brain/aww204) . Short-lasting unilateral neuralgiform headache attacks last seconds to minutes, occur up to hundreds of times a day and are usually associated with prominent lacrimation and redness of the ipsilateral eye. The condition is classified in the headache group known as the trigeminal autonomic cephalalgias, together with cluster headache, paroxysmal hemicrania and hemicrania continua, all of them characterized by strictly unilateral headaches associated with prominent craniofacial autonomic phenomena, usually involving the eye and the nostril (Headache Classification Committee of the International Headache Society, 2013). Activation of the posterior hypothalamic region during the pain has been shown in short-lasting unilateral neuralgiform headache attacks (May et al. , 1999) as well in other trigeminal autonomic cephalalgias (for review see May, 2009), leading to the suggestion that this is the location of the headache generator. Hypothalamic involvement was first proposed in cluster headache, based on the assumption that involvement of the biological clock in the hypothalamus could explain the clockwork regularity of single headache attacks and the typical seasonal recurrence of bouts, thereafter reinforced by altered hypothalamo-pituitary axis responses and abnormal circadian production of certain hormones. The hypothalamic hypothesis led to the successful use of deep brain stimulation (DBS) of the posterior hypothalamus to treat otherwise intractable chronic cluster headache (Leone et al. , 2001). Hypothalamic DBS was subsequently also used successfully to treat intractable short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) (Leone et al. , 2005). In this issue of Brain , Miller et al. present the results from the largest group of patients suffering from intractable short-lasting unilateral neuralgiform headache attacks to be successfully treated with DBS (Miller et al. , …