From Tics to Stabs: Renaming Cluster Tics in Cluster Headache-A Cross-Sectional Study

BACKGROUND: Short-lasting paroxysms of facial pain in patients with cluster headache have traditionally been called "cluster tics." Mostly described as co-occurring trigeminal neuralgia, they remain to be explored as an independent phenomenon. We investigated the prevalence of cluster tics in cluster headache, the clinical differentiation from trigeminal neuralgia, and propose a distinct definition and renaming of cluster tics.

METHODS: We conducted a retrospective, controlled, cross-sectional study using semi-structured interviews of patients with cluster headache at the Danish Headache Center. A comparator cohort of patients with trigeminal neuralgia was included from a previous study. We investigated the lifetime prevalence of cluster tics in the cluster headache group and characterized them according to duration, location, pain-intensity, triggerability, and serial occurrence.

RESULTS: We included 424 participants with cluster headache (median age 52 years (IQR: 32-72), male-female ratio 3:2) and 576 participants with trigeminal neuralgia (median age 72 years (IQR: 50-94), male-female ratio 1:3). Cluster tics were reported by 200 (47%) cluster headache participants with higher odds for participants of female sex (OR: 1.94, 95% CI: 1.27-2.96, p = 0.002) and participants with chronic cluster headache (OR: 1.74, 95% CI: 1.15-2.63, p = 0.008). Unlike trigeminal neuralgia, cluster tics were not triggerable (OR: 0.02, 95% CI: 0.01-0.04, p < 2e-16) and presented with pain restricted to the first trigeminal division.

CONCLUSIONS: Cluster tics are prevalent in nearly half of patients with cluster headache, associated to female sex and chronic phenotype. Unlike trigeminal neuralgia, cluster tics occur in the orbital region and are largely non-triggerable. To improve terminology, we propose renaming cluster tics to "cluster stabs."