Headache, epilepsy and photosensitivity: how are they connected?

Abstract

Although headache and epilepsy have often been associated, the precise electroclinical and pathophysiological interaction between these disorders and in particular its relations with photosensitivity is as yet to be fully understood in adults or children. The association between headache and epilepsy commonly occurs in all types of epilepsy and not only in occipital epilepsy. Generally, peri-ictal headache is often neglected, regardless of its severity, because patients are more concerned about their seizures. Altered cerebral cortex excitability may be the link between these two conditions and photosensitivity shows this. The physician should bear this association in mind when dealing with epileptic and migraine patients so as to be able to offer such patients an accurate diagnosis and appropriate treatment; this should be borne in mind when declaring epileptic patients ‘seizure free’. To date neither the International Headache Society nor the International League against Epilepsy mention that headache/migraine may, on occasion, be the sole ictal epileptic manifestation. Lastly, studies designed to investigate the triggering role of photosensitivity in both headache and epilepsy are warranted.

The crossover between headache and epilepsy

“…With regards to the epidemiological literature findings on comorbidity between headache and epilepsy, the major discrepancies and conflicting data are due to: the confusion and mixture of epidemiological data between adults and children across studies, and the significant underestimation of headache when it is comorbid in populations with epilepsy; in addition, it is likely that the comorbidity is higher in children than in adults, as is the case for all other ictal autonomic manifestations [10][11][12]14]. Indeed, the conflicting literature data on this topic can be explained by the co-occurrence (synergistic and/or divergent) of confounding variables according to the different sampling and study design.…”

“…Recently, we have studied this aspect in depth and, due to lack of space, here we refer to the recently published [6][7][8][9][10][11][12]. In this respect, we consider of particular interest the patients reported by Fabricius et al, "…whose seizure activity spread from electrode to electrode at the same slow speed as CSD…" [13].…”

“…However, when headache and epilepsy overlap as a result of the crossing of the cascade of events at the cortical level, in both of the events (CSD and epileptic focus), their onset and propagation are triggered when these events reach a certain threshold, which is lower for CSD than for seizure [6][7][8][9][10][11][12]. These two phenomena may be triggered by more than one pathway converging (at cortical level) upon the same destination: depolarization and hypersynchronization.…”

“…In this regard, we have recently suggested to include 'ictal headache' among the ictal autonomic manifestations in both headache and epilepsy international classifications, which until now have always ignored each other [1,[6][7][8][10][11][12]16]. In particular, we have proposed new criteria for the event termed 'ictal epileptic headache' (IEH) in which "headache is the sole ictal epileptic manifestation" [1,2].…”

The Prevalence of Migraine and Tension Type Headaches among Epileptic Patients

“…In addition Clarke et al reported that the increased prevalence of migraine in children with rolandic epilepsy was 15% (20). Several studies have shown that there is an association between occipital lobe epilepsy, especially with photosensitivity, and migraine (21)(22)(23)(24)(25)(26). These findings and close relationship of epilepsy with familial hemiplegic migraine may be explained with possible common genetic mechanisms of the migraine and epilepsy (27).…”