A functional MRI study of language disturbances in subjects with migraine headache during treatment with topiramate

Topiramate (TPM) is a new antiepileptic drug approved for the prevention of migraine headache. However its use is limited by treatment-emergent adverse events; in particular, therapy can exert profound impact on language function. In this investigation, we used functional magnetic resonance imaging (fMRI) to study the anatomofunctional correlates of language disturbances in TPM patients experiencing subjective cognitive impairment. Ten right-handed individuals receiving therapy (five with and five without language disfluency) and five matched healthy control subjects took part in this study. During fMRI subjects alternately rested and performed a word-generating task. The task comprised the silent generation of words beginning with a different input letter visually presented. The activation paradigm consisted of six activation blocks alternating with six baseline rest blocks. The main fMRI measure was the pattern activation of the prefrontal regions (Brodmann's areas 44, 45, and 46) in both left and right hemispheres. Patients receiving TPM (50-100 mg/day) significantly reduced mean monthly migraine frequency. However several differences in fMRI activation were evident in the subject group comparison. Notably, changes in brain activity were observed during the phonemic task in patients with language disturbances. It is likely that TPM therapy is associated with a "remapping" of the language cerebral network.