The aim of our study is to investigate the validity and reliability of Dutch version of the Henry Ford Hospital Headache Disability Questionnaire (HDI).

There is only a limited number of questionnaires that map headache-related disability.

To gain a better understanding of the emotional and functional effects of headaches on the patient's well-being, an English questionnaire already exists: the Henry Ford Headache Disability Index (HDI). The purpose of the HDI is to map headache related disabiltiy. This 25-item questionnaire focusses on two categories; there are 13 questions in the field of emotional effects and 12 questions on functional effects of headache complaints.

Advantage: This questionnaire can be used for all headache patients, in contrast to many questionnaires that can only be used for migraine patients. (eg MIDAS, Migraine ACT, ID Migraine...) The questionnaire contains more items than the Headache Impact Test (HIT-6), consisting of 6 items. The questions are very specifically aimed at headaches and can also be used to further inquire about the anamnesis after completing the questionnaire.

Problem statement: There is no validated Dutch version yet.

Objective: to translate and validate a Dutch version of the HDI. About 250 patients with chronic headache will be recruited to determine the validity (face validity, content validity, convergent validity with the RAND-36 and HIT-6). In addition, internal consistency and short- and long-term test and retest reliability will be evaluated using the intraclass correlation coefficient (ICC).

Inclusion Criteria:

• Patients with primary or secondary headache, diagnosed by a neurologist according to the ICHD-3 classification.
• At least 1 day of headache in the previous month.
• Native Dutch speaking participants

Exclusion Criteria:

• All other headache types not classified by the ICHD-3 as primary or secondary headache.
• Secondary headache in combination with underlying pathological situations (infection, trauma, tumors, brain haemorrhages) or severe psychotic or mental dysfunctions or substance use/withdrawal symptoms.

The study population will consist of particants with primary and secondary headaches.