The purpose of this non interventional research is to set up a French database, initially for 3 years, of patients suffering from refractory chronic headache disorders (chronic migraine, cluster headache, chronic paroxysmal hemicranias, SUNCT syndrome, hemicrania continua, cervicogenic headache disorders), and treated by occipital nerves stimulation.

Every team using this neuromodulation approach in France is likely to participate in the network.

Fifty patients a year are expected. They will be informed about data which are collected and why they are collected.

The data will come from medical files and questionnaires filling out by the patients. The data will be collected on a case report form adapted to each refractory chronic headache disorder. The case report form pages will be faxed to the coordinating team who will enter the data in the database and analyse the data in a descriptive manner.

These data are social and demographic data, medical data (headache features, headache functional and emotional impact, medications, and concomitant medical conditions), technical data (kind of electrodes and implantable pulse generator used, stimulation parameters chosen), and safety data.

This research should provide an update on practices, an evaluation of the efficacy and long term safety of occipital nerves stimulation, and perhaps help in identifying response predictive factors to this neuromodulation approach.

Inclusion Criteria:

• patients suffering from refractory chronic headache disorders and treated by occipital nerves stimulation

Exclusion Criteria:

• patients who don't agree with participating in the study because the ending of professional confidentiality is required for setting up the database

Patients suffering from refractory chronic headache disorders (chronic migraine, cluster headache, chronic paroxysmal hemicranias, SUNCT syndrome (Short-lasting Unilateral Neuralgiform headache attacks with Conjunctival injection and Tearing), hemicrania continua, cervicogenic headache disorders) according to ICHD-II