Does Topiramate Adjust the Excitability of the Brain in Migraine Sufferers?
| Status: | Completed |
|---|---|
| Conditions: | Migraine Headaches |
| Therapuetic Areas: | Neurology |
| Healthy: | No |
| Age Range: | 18 - 55 |
| Updated: | 4/2/2016 |
| Start Date: | February 2006 |
| End Date: | August 2006 |
Modulation of the Excitability of the Occipital Cerebral Cortex Using Topiramate
The purpose of the study is to determine by the use of non-invasive magnetic stimulation if
the medication Topiramate adjusts the excitability of the migraine sufferer's brain.
Previous studies have shown the migraine sufferer's brain is more excitable. The magnetic
stimulation device has given us a way to look at excitability and to see if it changes at
the same time that a headache diary shows if the pattern or severity of headaches changes
with the administration of the drug Topiramate.
It is expected that as migraine sufferers have fewer headaches with topiramate the testing
with magnetic stimulation will show that their brains are less excitable and that if the
topiramate does not change the character of headaches then the pattern of excitabilty would
not change from the baseline test before medication is started.
the medication Topiramate adjusts the excitability of the migraine sufferer's brain.
Previous studies have shown the migraine sufferer's brain is more excitable. The magnetic
stimulation device has given us a way to look at excitability and to see if it changes at
the same time that a headache diary shows if the pattern or severity of headaches changes
with the administration of the drug Topiramate.
It is expected that as migraine sufferers have fewer headaches with topiramate the testing
with magnetic stimulation will show that their brains are less excitable and that if the
topiramate does not change the character of headaches then the pattern of excitabilty would
not change from the baseline test before medication is started.
We propose a clinic-based study to test the hypothesis that topiramate modulates the
excitability of the occipital cortex in migraine. Subjects between 18 and 55 years old, who
have migraine with aura according to IHS criteria will be recruited from the headache
clinic. All eligible subjects will have occipital cortex stimulation using the Magstim 200
apparatus. Magnetic brain stimulation will be performed using the 95 mm round coil of the
Magstim 200 stimulator. All subjects will be provided ear plugs to prevent possible noise
damage to the ear. The recordings will be conducted in a semi-darkened room. Subjects will
be asked to focus on the center of a dark screen. A 95 mm diameter circular coil will be
applied to the occipital scalp in the midline, 7 cm anterior to the inion. Stimulator
intensity will be increased in 10% increments until the subjects report seeing phosphenes
(bright scintillating scotomata in the subjects visual field generated by occipital cortical
stimulation) or until a maximum of 100% intensity is reached. generated by occipital
cortical stimulation) or until a maximum of 100% intensity is reached. Stimulation intensity
will be fine tuned to determine the threshold at which phosphenes can be barely seen. In
those subjects who do not report seeing phosphenes till 100% intensity, the stimulator will
be moved in 1 cm steps to try to define an optimum point for stimulation. No more than 20
stimulations will be given and the frequency shall be kept to less than 5/min. The threshold
at which phosphenes are generated will be recorded. To assess inhibitory function of the
occipital cortex a visual suppression method will be utilized. Timed TMS impulses usually
10% above phosphene threshold or where suppression is noted will be delivered. Subjects will
be asked to report letters projected at a fixed luminance on the screen. Visual suppression
will be calculated based on the number of errors the subjects make using an automated
analysis. The study procedure will be repeated after the patients have taken topiramate at
gradually increasing doses and have achieved stable dose for one month. Patients will be
placed on 25 mg at night for 1 week, increased to 25 mg B.I.D. for one week and then
maintained at 50 mg B.I.D.
d. There will be no placebo in the study. e. Topiramate will be used in the study.
excitability of the occipital cortex in migraine. Subjects between 18 and 55 years old, who
have migraine with aura according to IHS criteria will be recruited from the headache
clinic. All eligible subjects will have occipital cortex stimulation using the Magstim 200
apparatus. Magnetic brain stimulation will be performed using the 95 mm round coil of the
Magstim 200 stimulator. All subjects will be provided ear plugs to prevent possible noise
damage to the ear. The recordings will be conducted in a semi-darkened room. Subjects will
be asked to focus on the center of a dark screen. A 95 mm diameter circular coil will be
applied to the occipital scalp in the midline, 7 cm anterior to the inion. Stimulator
intensity will be increased in 10% increments until the subjects report seeing phosphenes
(bright scintillating scotomata in the subjects visual field generated by occipital cortical
stimulation) or until a maximum of 100% intensity is reached. generated by occipital
cortical stimulation) or until a maximum of 100% intensity is reached. Stimulation intensity
will be fine tuned to determine the threshold at which phosphenes can be barely seen. In
those subjects who do not report seeing phosphenes till 100% intensity, the stimulator will
be moved in 1 cm steps to try to define an optimum point for stimulation. No more than 20
stimulations will be given and the frequency shall be kept to less than 5/min. The threshold
at which phosphenes are generated will be recorded. To assess inhibitory function of the
occipital cortex a visual suppression method will be utilized. Timed TMS impulses usually
10% above phosphene threshold or where suppression is noted will be delivered. Subjects will
be asked to report letters projected at a fixed luminance on the screen. Visual suppression
will be calculated based on the number of errors the subjects make using an automated
analysis. The study procedure will be repeated after the patients have taken topiramate at
gradually increasing doses and have achieved stable dose for one month. Patients will be
placed on 25 mg at night for 1 week, increased to 25 mg B.I.D. for one week and then
maintained at 50 mg B.I.D.
d. There will be no placebo in the study. e. Topiramate will be used in the study.
Inclusion Criteria:
Subjects 18 to 55 years old with migraine headaches as defined by the International
Headache Society (IHS).
Subjects must be willing to take topiramate for migraine prophylaxis
Exclusion Criteria:
1. Subjects with frequent tension headaches 2. Subjects with ill-defined head pain 3.
Unable to be weaned off other headache prophylaxis. 4. Requiring daily use of
centrally-acting medications. 5. Pregnant, lactating and women not on adequate birth
control measures. 6. Subjects with a personal or family history of seizures of any type.
7. History of head injury or brain surgery. 8. Cardiac pacemakers or any other implanted
electronic device. 9. Subjects with history of headaches or with history of tension-type
headaches recurring >1/month and relieved by over the counter medications.
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