Migraine prophylaxis with botulinum toxin A is associated with perception of headache.

The purpose of this study was to test whether the efficacy of prophylactic treatment with botulinum toxin A (BTX-A) on migraine frequency is related to the individual perception of the pain and its directionality, namely, exploding, imploding, or ocular migraine headache. Episodic and chronic migraine patients (n=82) previously treated with BTX-A were interviewed to characterize their migraine headache and its directionality. The magnitude of their response to treatment was analyzed vis-à-vis their individual type of headache. Patients showing a >67% drop in number of migraine days/month were classified as responders; those showing a drop smaller than 33% were labeled non-responders; patients showing a drop between 34% and 66% were considered questionable responders. After BTX-A treatment, the number of migraine days/month dropped 85.2+/-1.6% (from 20.1+/-1.5 to 2.8+/-0.4; p<0.0001) in 37 responders, 52.4+/-2.4% (from 16.3+/-3.5 to 7.2+/-1.5; p=0.003) in 11 questionable responders, and remained unchanged (21.2+/-1.8 vs. 21.1+/-1.7; p>0.78) in 34 non-responders. The frequency of headache types differed significantly (p<0.0001) across the 3 response sub-groups. Among non-responders, 83% described a buildup of pressure inside their head (exploding headache). Among responders and questionable responders, 84 and 64%, respectively, perceived their head to be crushed, clamped or stubbed by external forces (imploding headache) or an eye-popping pain (ocular headache). The prevalence of exploding, imploding, and ocular headache was similar between episodic and chronic migraine patients. Imploding/ocular migraine headache is more likely than exploding headache to be prevented by prophylactic BTX-A treatment. Further validation of this principle should await large-scale prospective, placebo-controlled studies.