The effect of lamotrigine in monotherapy on photo and pattern sensitivity in people with epilepsy—a clinical study

The full effects of lamotrigine on photo and pattern sensitivity have never been fully studied, although there is some small indication in the literature of a possible beneficial effect. It is the policy of Birmingham Brainwave to substitute lamotrigine for valproate in young women who wish to become pregnant, who have primary generalized epilepsy: we use it as first-line monotherapy in young women who have developed this condition because of the known effects of vaproate on the foetus and its possible effect on ovarian function. Opportunity was therefore taken to measure the effect of lamotrigine on photo and pattern sensitivity in such patients. Pattern and photo sensitivity was measured using the standard Aston protocol in patients who were either having lamotrigine substituted and valproate withdrawn or in lamotrigine monotherapy patients, without the interpreter of the record being aware of the clinical state of the patient. In the same way the clinician responsible for adjusting the dose of lamotrigine and withdrawing valproate was unaware of the neurophysiological findings. Analysis of the data in nine patients who have completed clinical assessment shows that except in one patient lamotrigine was efficacious in controlling photo and pattern sensitivity: this effect is almost certainly dose dependent. The dose needed to produce complete control over photo and pattern sensitivity may be (as is the case with sodium valproate) slightly higher than the dose needed to obtain clinical control of seizures. We suggest that a formal trial of lamotrigine is carried out in patients with photo and pattern sensitivity, which still presents difficulties for some young people with primary generalized epilepsy.