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IHS President: “It is time for operationalisation of ICHD”

Presented By
Prof. Cristina Tassorelli , University of Pavia, Italy
EHC 2022

The various editions of the International Classification of Headache Disorders (ICHD) have proven to be a precise, fundamental, and an exceptional tool to classify headaches. Now, it is time to devise tools to support physicians to categorise and manage patients in daily care, argued Prof. Cristina Tassorelli (University of Pavia, Italy), who is president of the International Headache Society (IHS).

Operationalisation can be defined as a process that makes it possible to consistently and uniformly describe and measure health and disease. Prof. Tassorelli’s goal was to demonstrate why this ‘step further’ should indeed be taken [1]. “The ICHD is basically a classification of attacks (not of patients), but to what extent is it representative of the disease?” she wondered. “Because attacks are one thing, but another thing is their frequency, and also their severity, and the time they last.” She added that we need precise criteria but also the ability to apply them to clinical reality. “The reality of the migraine patient is not hieratic but dynamic.”

Prof. Tassorelli continued to discuss some of the current caveats. For example, the widely used notion of episodic migraine is an operationalisation that does not exist in the ICHD. The ‘interim’ definition of episodic migraine as ‘headache occurring on <15 days per month over the last 3 months, which on some days is migraine’ may not be accurate. A recent study suggested that the threshold should be 7–8 days.

Regarding medication overuse, Prof. Tassorelli said that acute overuse is a strong risk factor for transitioning from episodic to chronic migraine. “This type of headache is almost exclusively seen in primary headaches. My personal view to make it more operationalised in everyday practice is to consider medication overuse headache as a complication of a primary type of headache that induces a worsening of the clinical picture and is due to either inadequate management, disease severity, or both.” She suggested making medication overuse a subcategory of chronic migraine because it would give more visibility and attention to this complication.

Prof. Tassorelli also mentioned menstrual migraine, attacks of which are more severe, longer lasting, and more difficult to treat with acute medication. Yet, in the ICHD-3, menstrual migraine is only addressed in the appendix. In a recent Dutch study, ICHD-3 diagnostic criteria for menstrual migraine were found to have extremely poor accuracy [2]. Prospective headache (E-)diaries are required for menstrual migraine diagnosis, also in clinical practice.

An example of secondary headaches Prof. Tassorelli addressed was headaches secondary to psychiatric disorders. She found barely any literature on the subject, but there are tools ready for use. A suggestion for operationalisation: the SNNOOP10 algorithm, which showed a 100% sensitivity in the detection of high-risk headache disorders [3].

Overall, to support the physician in the diagnosis of aspects common to both primary and secondary headaches, informatics and machine learning can be applied. The before-mentioned SNNOOP10 list, for example, can be transformed into an application by informatics.


  1. Tassorelli C. ICHD 2022 – Is it time for operationalization? PleSe1, EHC 2022, 07–10 December, Vienna, Austria.
  2. Verhagen IE, et al. Cephalalgia. 2022;42(11-12):1184–93.
  3. García-Azorín D, et al. Cephalalgia. 2022;42(14):1521–31.


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