Identifying Chinese Medicine patterns of Tension-type Headache (TTH) and its implication on understanding TTH subgroups

Abstract Background Acupuncture is commonly used to relieve tension-type of headache (TTH), however, there is a lack of consistent approach of devising acupuncture interventions for TTH due to limited evidence for symptom patterns according to Chinese medicine. This study aimed to identity common Chinese medicine symptom patterns of TTH.Methods We applied a validated Chinese Medicine Headache Questionnaire to a group of headache sufferers. The questionnaire consisted of information about headache, aggravating and relieving factors and accompanying symptoms. The Migraine Disability Assessment Test (MIDAS) was used to assess disability and the Perceived Stress Scale (PSS) for the level of stress. Information about comorbidities was collected. The modified International Headache Society TTH diagnostic criteria (ICHD-II) were used to screen the participants. Principal component analysis was used for factor extraction and Two-Step cluster analyses for clustering. One-way analysis of variance (ANOVA) was used to compare cluster groups in disability and stress.Results In total 170 participants, including 114 females and 56 males, met the selection criteria. The commonest headache features were continuous pain (64%) and fixed location (74%). Headache was aggravated by overwork (74%), stress (74%), and mental strain (70%) and relieved by sleeping (78%). The commonest accompanied symptoms were fatigue (71%) and neck stiffness (70%). Four clusters were identified with 46, 34, 46 and 44 participants in Clusters 1-4, respectively. Assessed by experts, the four clusters could be assigned to three different patterns, including Ascendant hyperactivity of Liver-Yang (Cluster 1), Dual Qi and Blood deficiency (Cluster 2), Liver depression forming Fire (Cluster 3), and an Un-labelled group (Cluster 4). The four clusters differed in their key signs and symptoms. Additionally, over 75% participants in clusters 1 and 2 were episodic TTH, over one third in Cluster 3 having chronic TTH, and the majority in Cluster 4 were in-frequent TTH. The three patterns identified also differed in levels of disability and some elements of coping as measured with PSS.Conclusion The three symptom patterns identified are common clinical presentations of TTH. The new information will contribute to further understanding of the subtypes of TTH and guide the development of targeted interventions, including acupuncture, for clinical practice and research.