Figure 1

Example of an (n + 2)-state Markov chain representing the progression of migraine attacks. The μ represents the migraine onset probability of an attack during a given migraine free day. The δ_i’s represents the probability that a migraine attack will continue into the next day, conditional on an attack already having been ongoing on the previous i days. The complementary probabilities 1 − δ_i are the probabilities that the migraine attack ends during that day, rather than continue into the next. The state S_Q represents the first full migraine free day following a migraine day—a necessary precondition for (the model) to declare that a new migraine attack can begin assuming the Fill48 assumption.