Visual cortex excitability in migraine before and after valproate prophylaxis: a pilot study using TMS.
Article first published online: 26 FEB 2003
Headache: The Journal of Head and Face Pain
Volume 43, Issue 3, page 304, March 2003
How to Cite
Mulleners, W., Chronicle, E., Vredeveld, J. and Koehler, P. (2003), Visual cortex excitability in migraine before and after valproate prophylaxis: a pilot study using TMS. Headache: The Journal of Head and Face Pain, 43: 304. doi: 10.1046/j.1526-4610.2003.03062_12.x
- Issue published online: 26 FEB 2003
- Article first published online: 26 FEB 2003
- Cited By
Eur J Neurol. 2002 Jan;9(1):35-40
We examined the effect of standard migraine prophylaxis with sodium valproate on repeated measures of occipital excitability using transcranial magnetic stimulation (TMS). We predicted that, comparing pre- and post-treatment assessments, a reduction in clinical migraine parameters would be paralleled by a decrease in excitability measurements.A total of 31 migraine patients enrolled in the study, for assessment prior to and 1 month after commencement of sodium valproate prophylaxis. At each assessment, we used a standardized protocol to stimulate the occipital cortex with a 90-mm circular (coil A) and 70 mm figure-of-eight (coil B) coil. We recorded the threshold stimulation intensity at which subjects just perceived phosphenes. Subjects kept detailed records of headache parameters 1 month before and also during the study period.Valproate therapy significantly improved headache indexes, as expected. In MA subjects assessed with coil B, phosphene thresholds were significantly higher post-treatment than pre-treatment, but those for MO did not change. Modest correlations were observed in MA patients between increase in phosphene threshold and decrease in headache index. Although preliminary, the findings with coil B lend some support to the notion that effective migraine prophylaxis may be achieved through lowering cortical excitability by gamma-aminobutyric acid (GABA)-ergic intervention. Further investigation of the effect of sodium valproate or other similarly acting substances on cortical excitability in migraine is warranted.
Comment: This paper provides a useful noninvasive human model in which to study the potential development of prophylactic treatments for migraine with aura. It will be important to standardize experimental conditions and to establish a rigorous experimental protocol for simulation parameters. However, this promises to be an important technique for use in future drug development. DSM