Sphenopalatine ganglion stimulation induces changes in cardiac autonomic regulation in cluster headache.

In cluster headache patients subjected to low-frequency and sham stimulation of the sphenopalatine ganglion, we found changes indicating higher sympathetic tone during low-frequency stimulation preceding cranial autonomic symptoms or cluster pain. During cluster pain, regardless of stimulation parameters, we saw increased parasympathetic activity, congruent with previous reports. The results indicate involvement of cardiac autonomic regulation before and during cluster headache attacks.