How the glossary is organised
The glossary started as a definitions sheet for the words that come up in Hermly's other pages and on prescription labels and clinic visits. It's grown to 20 entries covering five rough categories — the phases of an attack, the accompanying symptoms, related conditions, the medication classes, and the scales used to measure all of it.
Each entry is a standalone explainer with citations to a peer-reviewed source. The goal is to be the resource you actually want when you've heard a term in clinic and need a quick, accurate refresher — not a Wikipedia depth-dive, not a marketing simplification.
Phases of an attack
The structure of a migraine attack — before, during, after.
Prodrome
Prodrome is the 2–48 h warning window before a migraine. Common signs include yawning, fatigue, mood shifts, and cravings — and what Hermly forecasts.
AuraAura
Aura is a 5-to-60-minute neurological event that precedes or accompanies about 25–30% of migraine attacks. Visual disturbances are the most common form.
PostdromePostdrome
Postdrome is the 24-to-48-hour recovery phase after a migraine attack ends. Fatigue, brain fog, and mood flatness are common. Often disabling in its own right.
Symptoms & physiology
The signs that come along with migraine, and what they mean.
Photophobia
Photophobia is abnormal discomfort from light, a defining symptom of migraine attacks. The threshold drops dramatically during an attack.
PhonophobiaPhonophobia
Phonophobia is abnormal discomfort from sound, a defining ICHD-3 symptom of migraine. Often paired with photophobia during attacks.
AllodyniaAllodynia
Allodynia is pain from stimuli that shouldn't be painful — combing hair, glasses on the face. It signals central sensitisation and lower treatment response.
Estrogen withdrawalEstrogen withdrawal
Estrogen withdrawal in the late luteal phase is the leading mechanism for menstrual migraine. Stable-estrogen regimens can reduce attack frequency.
HRV (heart rate variability)HRV (heart rate variability)
Heart rate variability drops in the 24 hours before some migraine attacks. Apple Watch + iOS apps like Hermly use this as one prediction feature.
Conditions & differential diagnosis
What migraine is — and what it isn't.
ICHD-3
ICHD-3 is the international standard for diagnosing migraine, tension headache, and 200+ other headache types — used by neurologists worldwide.
Cluster headacheCluster headache
Cluster headache is a separate disorder — extremely severe, one-sided, around the eye, with autonomic symptoms. Different from migraine in every way.
Tension-type headacheTension-type headache
Tension-type headache is the most common primary headache — pressing, bilateral, not worsened by activity, lacks nausea. Often coexists with migraine.
Status migrainosusStatus migrainosus
Status migrainosus is a migraine attack lasting more than 72 hours with continuous severe pain. Treated as a medical condition needing urgent intervention.
Transformed migraineTransformed migraine
Transformed migraine — the older clinical term for episodic-to-chronic transition. Replaced by 'chronic migraine' in ICHD-3 but still useful clinically.
Medications
The drug classes used to abort attacks and prevent them.
Triptan
Triptans are 5-HT1B/1D receptor agonists used as acute migraine treatment since 1991. Seven are available — same mechanism, different onset and duration.
GepantsGepants
Gepants are oral CGRP receptor antagonists for acute and preventive migraine treatment. Class: ubrogepant, rimegepant, atogepant, zavegepant.
CGRPCGRP
CGRP is a neuropeptide central to migraine. CGRP-targeting drugs (gepants, monoclonal antibodies) are the biggest migraine treatment advance in 30 years.
Medication overuse headacheMedication overuse headache
MOH is the paradoxical condition where taking acute migraine medications too often makes migraine worse. ICHD-3 defines the overuse thresholds.
Scales & measurement
How clinicians quantify migraine impact and prediction accuracy.
MIDAS
MIDAS is a 5-question disability score used by clinicians to gauge migraine impact. It takes 90 seconds and produces a number that informs treatment decisions.
HIT-6HIT-6
HIT-6 is a 6-question scale measuring headache impact over the past month. Used to track treatment response visit-to-visit.
AUC-ROCAUC-ROC
AUC is the area under the ROC curve — standard for binary classifier discrimination. 0.5 chance; 1.0 perfect. Migraine forecasting tops out 0.65–0.70.
Suggested reading orders
If you're new to migraine vocabulary, three short paths in and out:
- The attack arc: Prodrome → Aura → Postdrome.
- The medication landscape: Triptan → CGRP → Gepants → MOH.
- The methodology side: AUC-ROC → HRV → methodology page.
Common questions
Why are these definitions different from Wikipedia?
Wikipedia is comprehensive; these entries are opinionated. Each one is written from the perspective of someone with migraine reading it — what does this term actually mean for me, what's the practical implication, what should I ask my doctor. The factual content is aligned with the medical reference (ICHD-3, peer-reviewed papers) but the framing is patient-centric.
I think a definition is wrong. What do I do?
Email [email protected] with the page URL, the specific issue, and an authoritative source for the correction. Medical accuracy matters; we update.
Will the glossary keep growing?
Yes, modestly. The goal is depth over breadth — 30 high- quality entries beat 300 thin ones. Future additions (planned: cluster headache subtypes, hemiplegic migraine, MOH transition pharmacology) will be added when we have something substantive to say.