Scientists believe that low levels of a brain chemical calledserotonin may make people susceptible to developing migraineheadaches. Many people with migraine also have a problem withmotion sickness, but it is not clear why this might be. We knowthat many drugs to treat motion sickness increase brain levelsof serotonin, an important brain chemical. It is possible thatlow brain levels of serotonin may also be responsible for motionsickness. In this issue of Neurology,1 Drummond reports on astudy that evaluated whether low brain levels of serotonin triggermotion sickness in people with and without migraine. More informationabout migraine can be found on the next page.
Motion sickness occurs when messages from two motion detectorsto the brain conflict. One of these detectors is the inner earand another is the eyes. If the inner ear and the eyes detectmotion even slightly differently, motion sickness can occur.Motion sickness is usually caused by riding in a car, boat,or airplane. Motion sickness can also be caused by motion inthe visual surroundings while standing still. This is the techniquethat the researchers used in the study described in this PatientPage.
The investigators studied the effect of tryptophan on motionsickness in two groups of people: 39 people with migraine headachesand 37 people of similar age and gender without migraine. Tryptophanis a key ingredient used by the brain to make serotonin. Wetake in the tryptophan needed by the brain through our diet.The investigators gave half of study participants in each groupcapsules and a protein drink that did not have any of the aminoacid tryptophan in it. The other half of each group got capsulesand a balanced protein drink containing tryptophan. The researchersthen tried to make the study participants motion sick. Theydid this by having them sit in a chair with their head insidea rotating drum painted with 24 pairs of vertical black andwhite stripes. When this drum was rotated, it created an opticalillusion that made the subjects feel as though they were spinning.The drum rotated 10 times per minute for 15 minutes or untilthe subject felt as though he or she were going to vomit andasked to stop. Study subjects were asked to rate the intensityof nausea, dizziness, and headache on a scale of 1 to 10 (with10 being the most severe) before the drum started rotating andevery 3 minutes after the drum started rotating.
The people with migraine who got the balanced protein drink(containing tryptophan) asked to stop the experiment earlierthan people without migraine who got this drink (11 vs 14 minutes).People in the group without migraine who got the tryptophan-freedrink asked to stop the experiment earlier than those who gotthe balanced protein drink (12 vs 14 minutes). People with andwithout migraine who got the tryptophan-free drink asked tostop the experiment at about the same time (12 minutes for eachgroup).
People without migraine who got the tryptophan-free drink hadan increase in nausea, dizziness, and a feeling of spinningwhile the drum was rotating. People with migraine had higherratings of nausea, dizziness, and headache than those withoutmigraine both before and during the experiment regardless ofwhich drink they got. The tryptophan-free drink had no effecton headache at the time or for 24 hours after the experimentin any of the study subjects.
The tryptophan-free drink caused the same degree of motion sicknessinduced by the rotating drum in people without migraine thatwas experienced by people with migraine. Because tryptophanis required by the brain to make serotonin, this suggests thata lack of serotonin may increase the symptoms of motion sickness.It is interesting that the tryptophan-free drink did not havethis effect on people with migraine. This suggests that peoplewith migraine may have abnormally low brain levels of serotonin,and lowering them further had no effect. These low brain serotoninlevels could be responsible for both headache and motion sicknessin people with migraine.
A migraine is a recurring, throbbing headache. It usually occurson one side of the head. While it is much more common in youngwomen, it can strike anyone, at any age. It often runs in families.
The exact cause of migraine is unknown, but may be related tolow brain levels of an important chemical called serotonin.During an attack, changes in brain activity may cause bloodvessels and nerves around the brain to become inflamed. Manywomen have attacks linked to their menstrual cycles.
People with migraines may have very varying symptoms, whichcan include the following:
Moderate to severe headache that lasts 4 to 72 hours
Throbbingpain, often on one side of the head
Increased pain after exerciseor movement
Sensitivity to bright light, sound, or odors
Nauseaor vomiting with the headache
One in five people with migraine have a warning before the headache.This is called an aura. You may see flashing lights, temporarilylose your sight, or go numb on one side of your body.
No medical test can tell you if you have migraine. You willneed to provide details about your headache to your neurologist.Your doctor will also do a neurologic examination. Often, nofurther testing is needed.
Although there is no cure, migraine is treatable with medications,stress management techniques, and a healthy lifestyle. Mostpeople with migraine can find relief using some of the treatmentapproaches described below. Talk to your doctor about whichtreatment is best for you. Keeping a headache diary is a valuabletool for treating migraine. It will help you work with yourneurologist to identify triggers and track how medical and nonmedicalinterventions are working.
What are some of the things I can do other than taking medicine to treat my migraine?
Diet: Missed meals, alcohol (especially red wine), foods withmonosodium glutamate (MSG), excessive caffeine, and preservedmeats with nitrates and nitrites
Sleep: Too much or too littlesleep
Stress: Stress and release from stress
Environmentalfactors: Weather change, glaring or fluorescentlights, strongodors, and high altitude
Research has shown that some cognitive and behavioral treatmentscan help prevent migraine:
Relaxation training
Thermal biofeedback with relaxation training
Electromyographic biofeedback
Cognitive-behavioral therapy(also called stress managementtraining)
Medicines to treat the headache right after it has started
Acute, or immediate, treatments are used to stop an attack whenit occurs or to treat its symptoms. These are listed below.Overuse of acute drugs can lead to a daily migraine-like headachecalled rebound headache.
Nonprescription (over-the-counter) medications, such as aspirin,ibuprofen, or acetaminophen combined with aspirin and caffeine
Prescription nonsteroidal anti-inflammatory drugs and analgesics
Specific drugs used to stop migraine attacks such as triptansand ergot alkaloids
Drummond PD. The effect of tryptophan depletion on symptoms of motion sickness in migraineurs. Neurology 2005;65:620–622.[Abstract/Free Full Text]
This article has been cited by other articles:
Y. Sakai, C. Dobson, M. Diksic, M. Aube, and E. Hamel Sumatriptan normalizes the migraine attack-related increase in brain serotonin synthesis
Neurology,
February 5, 2008;
70(6):
431 - 439.
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What is motion sickness?
