This study of sleep changes in patients with cluster headache (CH) was conducted in view of the nocturnal predominance of this condition, the efficacy of oxygen and the fact that the attacks follow oxygen desaturation. Proposed mechanisms include impairment of carotid body activity secondary to hypothalamic vasomotor regulatory dysfunction. Sixteen patients with episodic CH and 29 healthy volunteers underwent nocturnal polysomnography. Five (31.3%) patients with episodic CH were found to have sleep apnoea (SA). Two patients with SA experienced two attacks during the study period. The attacks followed episodes of oxygen desaturation and were associated with REM sleep. In two patients with SA and CH, treatment with continuous positive airway pressure abolished their oxygen desaturation, sleep apnoeas and headaches. Our study confirmed the high percentage of CH associated with SA. We suggest that oxygen desaturation may be a trigger factor in some patients and play a role in the pathogenesis of CH.

Chronic migraine is a condition with significant prevalence all around the world and high socioeconomic impact, and its handling has been challenging neurologists. Developments for understanding its mechanisms and associated conditions, as well as that of new therapies, have been quick and important, a fact which has motivated the Latin American and Brazilian Headache Societies to prepare the present consensus. The treatment of chronic migraine should always be preceded by a careful diagnosis review; the detection of possible worsening factors and associated conditions; the stratification of seriousness/impossibility to treat; and monitoring establishment, with a pain diary. The present consensus deals with pharmacological and nonpharmacological forms of treatment to be used in chronic migraine.

Headache is a major worldwide health problem and the second most common type is migraine, with a global prevalence among adults greater than 10%. Migraine mainly affects adults between 25 and 55 years, during the most productive years of life 1 . In Brazil, the prevalence of migraine is estimated to be 15.2% 2 .Lipton et al. 3 demonstrated that migraine is still underdiagnosed and inappropriately treated. They evaluated 4,376 individuals with headache through a computer-assisted telephone interview survey and 536 individuals had migraine, as defined by the International Classification of Headache Disorders -2nd edition 4 (ICHD-2). They found that 48% of migraine sufferers had seen a doctor for headache within the last year and 73% of these reported a physician-made diagnosis of migraine. Of all migraine sufferers, 49% were treated with over-the-counter medications, 23% with prescription medication, 23% with both, and 5% with no medications at all 3 .A study by Bigal et al. 5 with 6,006 participants, conducted in the State of São Paulo, Brazil revealed that migraine was the most prevalent primary headache, accounting for 45.1% of patients reporting headache as their only symptom. In another Brazilian study, the correct diagnosis of migraine by non-specialists was made in only 44.9% of migraine sufferers, The diagnosis of headache was made according to the ICHD-2 criteria. Results: Of the 232 patients, 86% had migraine. The questionnaire showed a sensitivity of 92% (95%CI, 88% to 95%), specificity of 60% (95%CI, 43% to 77%) and a positive predictive value of 93% (95%CI, 89% to 96%). Discussion: Our results were similar to other international studies of the ID-Migraine TM application. The Portuguese version is considered easy to use, and an appropriate screening tool for migraine diagnosis in our sample. Conclusion: Considering the characteristics of our health system, we can infer that this questionnaire would be beneficial in a Brazilian primary care setting; however, more studies are necessary.Keywords: migraine disorders; surveys and questionnaires; headache. O questionário apresentou sensibilidade de 92% (IC de 95% 88% a 95%), especificidade de 60% (IC de 95% 43% a 77%) e valor positivo preditivo positivo de 93% (IC 95 89% a 96%). Discussão: Nossos resultados foram similares a outros estudos mundiais de aplicação do ID-Migraine TM . A versão em Português é considerada de fácil utilização, sendo uma ferramenta adequada para triagem diagnóstica de migrânea em nossa amostra. Conclusão: Considerando as características do nosso sistema de saúde, podemos inferir que este questionário seria útil nos serviços primários de saúde brasileiros, porém mais estudos são necessários.Palavras-chave: transtornos de enxaqueca; inquéritos e questionários; cefaleia.

Our findings suggest that decreased values of ABI are more common in migraineurs than in controls. Although causality was not assessed by us, the relationship is of importance per se. Doctors should measure the ABI in individuals with migraine as an easy way to screen for cardiovascular risk.