title: Pericranial tenderness in chronic tension-type headache: the Akershus population-based study of chronic headache.
abstract: BACKGROUND
  Most knowledge on chronic tension-type headache (CTTH) is based on data from selected clinic populations, while data from the general population is sparse. Since pericranial tenderness is found to be the most prominent finding in CTTH, we wanted to explore the relationship between CTTH and pericranial muscle tenderness in a population-based sample.
  
  
  METHODS
  An age- and gender-stratified random sample of 30,000 persons aged 30-44 years from the general population received a mailed questionnaire. Those with a self-reported chronic headache were interviewed and examined by neurological residents. The questionnaire response rate was 71% and the interview participation rate was 74%. The International Classification of Headache Disorders II was used. Pericranial muscle tenderness was assessed by a total tenderness score (TTS) involving 8 pairs of muscles and tendon insertions. Cross-sectional data from the Danish general population using the same scoring system were used for comparison.
  
  
  RESULTS
  The tenderness scores were significantly higher in women than men in all muscle groups. The TTS was significantly higher in those with co-occurrence of migraine compared with those without; 19.3 vs. 16.8, p = 0.02. Those with bilateral CTTH had a significantly higher TTS than those with unilateral CTTH. The TTS decreased significantly with age. People with CTTH had a significantly higher TTS compared to the general population.
  
  
  CONCLUSIONS
  People with CTTH have increased pericranial tenderness. Elevated tenderness scores are associated with co-occurrence of migraine, bilateral headache and low age.Whether the increased muscle tenderness is primary or secondary to the headache should be addressed by future studies.
authors.affiliation: Head and Neck Research Group, Research Centre, Akershus University Hospital, 1478 Lørenskog, Norway. kjersti.aaseth@ahus.no.
authors.forename: Kjersti
authors.initials: K
authors.lastname: Aaseth
authors.forename: Ragnhild Berling
authors.initials: RB
authors.lastname: Grande
authors.forename: Christofer
authors.initials: C
authors.lastname: Lundqvist
authors.forename: Michael Bjørn
authors.initials: MB
authors.lastname: Russell
mesh_terms: D000328:Adult; D000367:Age Factors; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008881:Migraine Disorders / Q000453:epidemiology / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000503:physiopathology*; D063806:Myalgia / Q000503:physiopathology*; D009664:Norway / Q000453:epidemiology; D010147:Pain Measurement; D012737:Sex Factors; D018781:Tension-Type Headache / Q000453:epidemiology / Q000503:physiopathology*