Prevalence and anatomical localization of muscle referred pain from active trigger points in head and neck musculature in adults and children with chronic tension-type headache.

OBJECTIVE To compare differences in the prevalence and the anatomical localization of the referred pain areas of active trigger points (TrPs) in head and neck musculature between adults and children with chronic tension-type headache (CTTH). DESIGN A cross-sectional study. SETTING Some studies had found that referred pain from active TrPs reproduce the head pain pattern in adults. No study has compared clinical differences between referred pain patterns elicited by active TrPs between adults and children with CTTH. PATIENTS Twenty adults (10 men, 10 women, mean age: 41 ± 11 years) and 20 children (10 boys, 10 girls, mean age: 8 ± 2 years) with CTTH were included. OUTCOME MEASURES Bilateral temporalis, sternocleidomastoid, upper trapezius, and suboccipital muscles were examined for TrPs. TrPs were identified by palpation and considered active when local and referred pains reproduce the headache pain attacks. The referred pain areas were drawn on anatomical maps, digitalized, and also measured. An analysis technique based on a center of gravity (COG) method was used to provide a quantitative estimate of the localization of the TrP referred pain areas. RESULTS Adults with CTTH exhibited a greater years with headache, higher intensity, and longer headache duration (P < 0.05) compared with children. The COG coordinates of the spontaneous pain on the dominant side were located more anterior (higher X-value), and spontaneous pain in the frontal and posterior areas was located more inferior (lower Y-value) in adults than in children. The number of active muscle TrPs was significantly higher (P = 0.001) in adults with CTTH (mean ± standard deviation [SD]: 4 ± 0.8) as compared with children (mean ± SD: 3 ± 0.7). Children with CTTH had larger referred pain areas than adults for upper trapezius, sternocleidomastoid, and temporalis (P < 0.001) muscles. The COG coordinates of the referred pain areas of temporalis and sternocleidomastoid muscle TrPs were more inferior (lower Y-values) in adults than in children with CTTH. CONCLUSIONS This study showed that the referred pain elicited from active TrPs shared similar pain patterns as spontaneous CTTH in adults and children. Differences in TrP prevalence and location of the referred pain areas can be observed between adults and children with CTTH.