Often, a patient presents to the physician complaining of transient neurological symptoms, but the examination is now normal and one must interpret the history to make a judgement on what happened. Transient ischemic attack, partial seizure, and migraine aura aren’t always easy to distinguish but here are a few suggestions:
TIAs typically come on rapidly over seconds or a couple of minutes and are often maximal at onset. Migraine aura typically occurs gradually and may progress over 20 minutes or more, often marching across vascular territories — for example, from occipital visual symptoms to more anterior language, sensory, or even motor symptoms. Partial seizures are generally intermediate in time course and also may progress along the body.
TIAs typically cause negative symptoms such as weakness, loss of sensation, or hemianopia. Seizures usually cause positive symptomatology such as tingling or jerking. Migraines can cause either type of symptoms but most typically produce positive symptoms such as visual scintillations.
Migraine aura is often followed by headache — but so are the other two conditions.
Psychic symptoms or altered consciousness are more typical of seizures.
Patients with TIA are typically older or have vascular risk factors whereas those with migraine tend to be younger. Seizures can occur at any age.
None of these distinguishing characteristics is foolproof and it’s important to consider each patient’s situation individually. It’s often worth asking oneself, “What’s the worst thing this could be and how am I going to rule that out?”