How to prepare for a transcranial magnetic stimulation (TMS) visit
Transcranial magnetic stimulation (TMS) is a safe and noninvasive technique for brain stimulation used for clinical and research purposes in thousands of centers worldwide. Currently, the Food and Drug Administration (FDA) has approved TMS applications for treatment of depression and migraine; other therapeutic applications are being investigated. TMS also has a unique role in understanding how the normal brain works, because it can be used to either disengage or activate a brain area for a fraction of a second, allowing scientists to understand its functional role.
To prepare for a TMS scan, make sure to have a good night's sleep before the scan. Do not use any alcoholic beverages for at least 24 hours before the scan. You may be asked to remove your make-up before TMS. The investigators may give you additional instructions. If you were unable to follow any of these instructions, let the investigators know. The purpose of these instructions is to make the TMS scan as safe as possible for you.
The TMS procedure consists of changing into hospital clothes in the laboratory, filling a safety screening form, and sitting in a chair or lying on a bed while one or several TMS coils are placed over your head. The coils send brief magnetic field pulses that induce weak electric currents in the brain. The coils make a clicking sound associated with their operation - you will wear ear plugs so the clicks should not be bothersome. You will wear frames fitted on your head that allow us to localize the stimulated areas in your brain.
Subjects and patients that consider participating in a TMS study should know that TMS is not suitable for everyone. To see a list of our TMS screening questions, click here. People who have electrically, magnetically, or mechanically activated implants (such as cardiac pacemakers or deep brain stimulation devices) should not have TMS because these devices may malfunction as a result of the TMS pulses. Also, those with metal or magnetic pieces in their head (such as clips on blood vessels in the brain or other metal fragments) should not have TMS because the magnetic pulses may cause the metal to move and/or heat up. However, persons with metal dental fillings may have TMS. It is recommended that women who are pregnant do not participate in TMS research, unless there is potential for direct clinical benefit to the participant.
As an extremely rare side effect (less than 1 in 10,000 sessions) even healthy individuals can experience a seizure during TMS. This likelihood is somewhat elevated in subjects with epilepsy and some other clinical conditions. When TMS has been operated within the international safety guidelines, there have not been seizures in healthy subjects. In the unlikely event that a seizure would occur we are prepared to manage the situation. All subjects that have experienced a seizure during TMS have recovered fully. Personnel trained in managing any potential problems will be present throughout the experiment to make sure that you are feeling fine.
You will be required to keep your head still during TMS for up to 30 minutes at a time. After TMS, some subjects have experienced a headache that may be related to keeping the head still and/or stimulation of the scalp muscles and nerves. If present, this headache it is typically mild and resolves by itself in a few hours, and if needed, responds well to over-the-counter mild analgesics. The study staff will help you find a comfortable head position to make it less likely that you will experience any headache.
You will not be able to wear your own eyeglasses during TMS. If the study requires that you read or view images and you require vision correction, you should inform the investigator when you sign up for the study, and you may be fitted with special eye glasses. It is OK to wear contact lenses during TMS, but if you tend to have dry eyes and/or blink a lot, then the provided special glasses may be more comfortable. Generally, if EEG is recorded with TMS, we ask our subjects to blink as little as possible, because blinking disturbs the EEG recordings.
Since the TMS magnetic fields are strong, you should not bring any electrical devices or credit/debit cards near the TMS equipment. You may be asked to remove metal jewelry or makeup. We will provide a secure place to store your clothes and valuables during the scan.
We will try to make you feel comfortable during TMS. If you feel pain or become uncomfortable at any point during the visit, let the investigators know. They will try to make you more comfortable, and if that does not succeed, they will stop stimulation. You may ask to stop the session at any time for any reason.
If you have any questions or concerns about participating in an a TMS experiment, please do not hesitate to ask the study investigators or staff, or contact the CBS Director Tommi Raij.