SEARCH

SEARCH BY CITATION

Keywords:

  • migraine;
  • cortical excitability;
  • phosphene threshold;
  • transcranial magnetic stimulation

Objective.—To determine the excitability of the visual cortex by phosphene thresholds (PT) in patients with migraine using transcranial magnetic stimulation (TMS) with single- and paired-pulses.

Methods.—Nineteen patients with migraine with aura (MWA), 19 patients with migraine without aura (MWoA), and 22 control subjects were included. Patients were free from preventive anti-migraine treatment and were investigated within 3 days before or after an acute migraine attack. In each subject, PT were assessed by single-pulse and paired-pulse TMS with an interstimulus interval of 50 ms.

Results.—The main effect of diagnosis indicated that mean PT were significantly lower in migraine patients than in control subjects (P= .001). Using single-pulse TMS, mean PT tended to be lower in MWoA-patients (57.7 ± 11.8%) compared with control subjects (64.4 ± 10.5%) (P= .064). In MWA-patients, mean PT (53.1 ± 5.7%) were significantly lower compared with controls (P < .001). Using TMS with paired pulses, mean PT were significantly reduced in MWoA-patients (40.3 ± 4.9%, P= .017) as well as in MWA-patients (39.6 ± 4.2%, P= .005) compared with controls (44.6 ± 6.0%). The main effect of stimulation type indicated that mean PT were lower determined with paired-pulse stimulation than with single pulses (P < .001).

Conclusions.—PT are reduced in patients with migraine in the interictal state suggesting an increased excitability of visual cortical areas. Compared with single-pulse TMS, paired-pulse magnetic stimulation is more efficient to elicit phosphenes. This technique provides the opportunity to evaluate visual cortex excitability with lower stimulus intensities and less discomfort.