Acta Neurologica Belgica, 2026 (SCI-Expanded, Scopus)
Objective: To evaluate masseter and temporalis muscle thickness in patients with tension-type headache (TTH) using ultrasonography and to examine the associations between masticatory muscle morphology, headache severity, and temporomandibular disorder (TMD) severity. Methods: In this cross-sectional study, 54 patients with primary TTH and 40 age-matched healthy controls underwent clinical assessment, including headache and jaw pain severity (VAS-H, VAS-J) and TMD evaluation using the Fonseca Anamnestic Index (FAI). Ultrasonographic measurements of masseter and temporalis muscle thickness were obtained at rest and during maximal contraction. Results: Patients with primary TTH exhibited significantly higher VAS-H, VAS-J, and FAI scores than controls (all p < 0.001). Masseter and temporalis muscle thicknesses were greater in the patient group at rest and contraction (p < 0.05). FAI scores showed significant positive correlations with masseter and temporalis thickness measurements (r = 0.247–0.378, p ≤ 0.016). Among all ultrasonographic parameters, VAS-H was significantly associated only with MMT-C (r = 0.206, p = 0.047). Conclusion: Patients with primary TTH exhibited greater masseter and temporalis muscle thickness compared with healthy controls. The relationship between headache intensity and MMT-C suggests a possible association between masticatory muscle involvement and headache severity.