Classification and diagnostic criteria for primary headache disorders (Ad Hoc Committee IHS, 1988).

Clinical features and pathophysiological mechanisms of primary (idiopathic) headaches are revisited in the light of the new classification of headache, recently proposed by the Ad Hoc Committee of the International Headache Society. This computer-based classification is hierarchically constructed and offers operational diagnostic criteria for all headache disorders. However, further investigations are required in some cases (e.g. in case of tension-type headache) to better define the clinical form