Transcranial Magnetic Stimulation (TMS) is a non-invasive treatment that uses magnetic fields to stimulate nerve cells in the brain and is often used to treat conditions like depression. While TMS offers a new option for those who haven’t found relief with traditional therapies, it’s important to be aware of its side effects. TMS side effects are generally mild, temporary, and manageable, but knowing what to expect can help patients feel more at ease during treatment.
Common Side Effects of TMS
Most people find TMS to be well-tolerated, but like with any medical procedure, it can come with a few side effects. The most common side effects are usually mild, and they often go away after the session or with over-the-counter treatments.
Mild to Moderate Headaches
One of the most common side effects of TMS is mild to moderate headaches. These headaches typically happen during or right after a session. They are caused by the magnetic pulses stimulating the scalp muscles, thus causing them to contact.
This muscle tension can trigger a headache similar to what you might feel with a tension-type headache. Around 10% of people experience a headache, but it usually responds well to over-the-counter pain relievers like acetaminophen.
Scalp Discomfort
Another common side effect is scalp discomfort. During TMS, the magnetic pulses can stimulate the scalp muscles and nerves, especially in certain areas of the head. This can lead to sensations of pain, irritation, or muscle twitches, which vary depending on where the magnetic coil is placed.
While parts of the scalp may experience little to no discomfort, areas like the lower frontal or temporal regions of the scalp can be more sensitive and prone to stronger reactions. The discomfort can feel like sharp pain or noticeable muscle contractions but is typically manageable and temporary.
Tingling or Spasms in Facial Muscles
Tingling or muscle spasms in the face are another possible side effect of TMS. This happens because the magnetic pulses can sometimes stimulate nearby facial muscles. It’s a fairly common experience during a TMS session. While it may feel strange, it’s usually harmless and resolves once the session ends. In most cases, the sensation is mild and doesn’t last long.
Uncommon Side Effects of TMS
While uncommon, some people may experience side effects that are a bit more unusual during or after TMS treatment. Below are a few uncommon side effects patients should be aware of.
Hearing Loss
TMS machines create a repetitive clicking sound as they deliver magnetic pulses, which can reach noise levels between 96.5 and 110 dB. This is well about the 80 dB safety threshold. Because of this, both patients and operators are encouraged to wear ear protection like earplugs during treatment.
Without proper hearing protection, there is a risk of temporary hearing loss or, in very rare cases, more serious hearing issues. Following safety guidelines, including regular screenings for hearing-related problems, helps prevent this side effect from occurring.
Increased Sensitivity to Sound
Some patients may notice they become more sensitive to sounds during or after TMS sessions. This heightened sensitivity is thought to be linked to the stimulation of brain areas responsible for auditory processing. As a result, everyday noises might seem louder or more noticeable than usual.
Fortunately, this effect is temporary, and normal hearing typically returns shortly after the session. However, in rare cases, this side effect may worsen existing tinnitus or trigger it in those not using ear protection during treatment.
Altered Taste Perception
Though rare, a small number of people report changes in their sense of taste after TMS treatment. Some patients experience an enhanced sense of taste, while others notice different taste experiences.
Research suggests that TMS may even have a positive effect on the sense of smell and taste, especially in those who have reduced sensitivity in these areas. In one study, patients with a decreased sense of taste and smell experienced significant improvements after TMS treatment. This suggests it could have therapeutic benefits for these senses.
Rare and Serious Side Effects of TMS
While TMS is generally considered safe, there are some rare but serious side effects that can occur. These side effects are very uncommon, but it’s important to be aware of them, especially for patients who might be at higher risk due to underlying health conditions or the specific type of TMS being used.
Seizures
Seizures are one of the rarest but most serious side effects of TMS. The likelihood of a seizure can depend on the type of coil used during treatment. For example, the H-coil is less precise than the traditional figure 8-coil, which can lead to a higher seizure risk.
However, the overall risk is still extremely low, with fewer than one seizure occurring per 60,000 sessions. Most seizures (if they do occur) happen during the first few treatments, with 62% occurring during the first exposure to TMS. Even though the risk is small, there are safety measures in place to minimize it as much as possible.
Fainting
Fainting, or transient loss of consciousness (T-LOC), is another rare side effect of TMS. In some cases, fainting can occur due to a syncope episode, which is unrelated to the TMS stimulation itself. This is often linked to anxiety or stress about the procedure rather than the treatment’s physiological effects.
For example, some people may feel nervous about the idea of stimulating their brain, which can trigger fainting. While uncommon, patients who are prone to fainting or have a history of anxiety may be at slightly higher risk of experiencing this side effect.
Mania
For patients with a history of bipolar disorder, there is a small chance that TMS could trigger a manic episode. The risk of mania occurring as a result of TMS treatment is low – around 0.84% – and is comparable to the risk of mania in patients undergoing sham-TMS treatments. Although rare, it is still important for healthcare providers to monitor patients with bipolar disorder closely for signs of mania during TMS treatment, especially if they have a history of mood instability.
How Long Do TMS Side Effects Last?
The side effects of TMS are usually mild and don’t stick around for long. Most people experience these effects during or right after their treatment sessions, and they tend to go away within a few hours.
As patients continue with their TMS treatment, any side effects they do experience often become less intense over time. It’s always a good idea for patients to let their TMS technician know if any side effects are persistent or uncomfortable. In many cases, adjustments to the treatment can help improve comfort and minimize unwanted effects.
Managing TMS Side Effects
Managing the side effects of TMS can often be done with a few simple strategies. Staying in touch with your healthcare provider and making some lifestyle changes can make a difference in how you feel during treatment. Here’s a breakdown on what you can do:
- Communicate with your healthcare provider if any side effects persist or feel uncomfortable.
- Take over-the-counter medication, like acetaminophen, to relieve mild headaches or discomfort.
- Make lifestyle changes to enhance the benefits of TMS, like staying active and eating a balanced diet.
During your TMS treatment, there are a few things you can do to support your body and minimize side effects:
- Stay hydrated
- Eat healthy meals
- Engage in physical activity
- Get enough sleep
- Remain relaxed and conscious throughout the session
TMS is a promising treatment option for many people, and while side effects can occur, they are typically mild and manageable. Understanding what to expect and how to handle any discomfort can help make the process go smoothly. If you experience any side effects that are persistent or bothersome, always reach out to your healthcare provider for guidance and support.
Sources:
- Sarah H. Lisanby: Transcranial Magnetic Stimulation Safety and Risk – National Institute of Mental Health
- Frequently Asked Questions about Non-Invasive Brain Stimulation – Perelman School of Medicine, University of Pennsylvania
- Subjective Discomfort of TMS Predicts Reaction Times Differences in Published Studies – Frontiers in Psychology
- A Study Protocol for an Open-Label Feasibility Treatment Trial of Visual Snow Syndrome With Transcranial Magnetic Stimulation – Frontiers in Neurology
- Safety Review for Clinical Application of Repetitive Transcranial Magnetic Stimulation – Brain and NeuroRehabilitation
- Effects of repetitive transcranial magnetic stimulation on chronic tinnitus: a randomised, crossover, double blind, placebo controlled study – Journal of Neurology, Neurosurgery & Psychiatry
- The Investigation of the Effects of Repetitive Transcranialmagnetic Stimulation Treatment on Taste and Smell Sensations in Depressed Patients – Archives of Neuropsychiatry
- Seizure risk with repetitive TMS: Survey results from over a half-million treatment sessions – Brain Stimulation
- Transcranial Magnetic Stimulation (TMS) Safety with Respect to Seizures: A Literature Review – Neuropsychiatric Disease and Treatment
- Witnessing loss of consciousness during TMS – Syncope in contrast to seizure – Clinical Neurophysiology Practice
- Transcranial magnetic stimulation–associated mania with psychosis: A case report – The Mental Health Clinician
