Chronology and Sequence of Premonitory Symptoms

Frequency of each symptom as the first premonitory symptom

Premonitory symptoms will be recorded at the beginning of each migraine attack for a maximum of 5 migraine attacks per participant. For each premonitory symptom, the percentage of recorded attacks in which it was reported as the first symptom of the premonitory phase. Symptoms are recorded at headache onset for each attack via a structured electronic diary, capturing the type, sequence, onset, and duration of symptoms preceding the pain phase. The denominator is the number of recorded attacks with a premonitory phase.

Time from onset of each premonitory symptom to headache onset (categorical intervals)

Premonitory symptoms will be recorded at the beginning of each migraine attack for a maximum of 5 migraine attacks per participant. For each premonitory symptom, the time of onset relative to headache onset, classified into predefined intervals: simultaneous with pain onset; less than 1 hour before; 1 to 2 hours before; more than 2 to 6 hours before; more than 6 to 12 hours before. Results are reported as the distribution of attacks across intervals for each symptom (percentage of recorded attacks). Onset times are recorded at headache onset for each attack via a structured electronic diary.

Time from onset of each premonitory symptom to headache onset (minutes)

Premonitory symptoms will be recorded at the beginning of each migraine attack for a maximum of 5 migraine attacks per participant. For each premonitory symptom, the time interval in minutes between its onset and headache onset, recorded for each attack via a structured electronic diary. Results are summarised per symptom (e.g., median minutes before headache onset).

Intra-subject consistency of premonitory symptoms across attacks

Premonitory symptoms will be recorded at the beginning of each migraine attack for a maximum of 5 migraine attacks per participant. The degree of within-subject agreement in the presence and chronology of premonitory symptoms across multiple attacks of the same participant, recorded via a structured electronic diary. Agreement is summarised per participant and reported across the sample (e.g., concordance in symptom presence and chronology).

Evolution and persistence of premonitory symptoms during the headache phase

Premonitory symptoms will be recorded at the beginning of each migraine attack for a maximum of 5 migraine attacks per participant. For each premonitory symptom, the evolution and persistence after headache onset, recorded via a structured electronic diary.

Patterns of premonitory symptom transition and clustering

Premonitory symptoms will be recorded at the beginning of each migraine attack for a maximum of 5 migraine attacks per participant. Identification of recurrent patterns in the transition between premonitory symptoms and in their co-occurrence (clustering), across all recorded attacks. Symptom sequences are recorded via a structured electronic diary and analysed using sequence analysis and probabilistic modelling approaches (e.g., transition probabilities between symptoms and identification of symptom clusters).