天美传媒

By Naveed Khokhar, M.D., Department of Psychiatry

Brain imaging – taking pictures of brain tissue – was invented in the 1890s. Imaging technology started becoming readily available to clinicians and researchers in the 1970s. With the ability to better visualize the brain, doctors began using imaging methods to study chronic mental health conditions such as  (major depressive disorder, or MDD), bipolar affective disorder, schizophrenia, and cognitive disorders.

Since then, a brain imaging revolution has swept the field of psychiatry, steering away from solely observation-based diagnoses and toward imaging-guided treatment plans. Sophisticated magnetic resonance imaging (MRI) and computed tomography (CT) imaging helped us better understand brain anatomy. Further advances in brain imaging, such as functional MRI, positron emission tomography (PET) scans, and single-photon emission computerized tomography (SPECT) scans, have helped us understand the etiology of psychiatric illnesses better, leading to novel, noninvasive interventions in psychiatry.

These evolving interventions are rapidly becoming the standard of care for treatment-resistant depression – when antidepressants don’t adequately control symptoms – which affects about 30%-40% of people with depression. In addition, neuromodulation is being used with targeted stimulation, such as electric or magnetic pulses, to modify the activity of specific neurons (nerve cells) that are interconnected in the brain’s complex circuits. Modifying activity in certain circuits allows normalization of activities in other brain regions, leading to improvement in mood, anxiety, and thinking.

One of the latest neuromodulation therapies available at UTSW’s  is  (TMS). This therapy uses external magnets and coils to depolarize affected neurons, “resetting” the connected networks to restore normal function.

TMS was approved by the Food and Drug Administration in 2008 for MDD, and subsequently for other conditions including obsessive-compulsive disorder, addiction, and . It is currently under study for post-traumatic stress disorder. It is safe and painless, with no need for anesthesia or activity restrictions like with . TMS does not cause side effects common with antidepressant medication, such as upset stomach, appetite changes, and sexual problems.

Over half of patients with unipolar depression get a measurable response from TMS, and most see significant improvement within two to three weeks of starting treatment.

TMS can be effective as a standalone treatment or in combination with cognitive behavioral therapy and/or medication. For a growing number of patients, it can effectively “reset” the brain and relieve debilitating symptoms of depression that don’t respond to medication.

How TMS works

There are many hypotheses for depression, including neurochemical imbalance, altered regional brain activity, inflammation, nutritional, and endocrinal reasons. Evolving concepts about depression emphasize altered activity in different brain circuits and regions. For purposes of depression, certain brain circuits – default, salience, negative and positive affect, cognitive control, and attention circuits – are important.

Elevated activity in default brain circuits and altered activity in regions constituting salience brain circuits are commonly observed. Altered and abnormal activity in different brain areas that are associated with self-referential thinking, emotional control, behavioral activation, concentration, and focus results in life-disrupting symptoms observed in clinical depression.

TMS is an outpatient, noninvasive treatment. No anesthesia, additional medications, or incisions are needed. Treatment is applied using a magnetic coil shaped like a flattened figure eight with a handle that is attached to a powering station. The coil is positioned on top of the hair on the left side of the head. Magnetic pulses travel through the coil, past the scalp and skull, and into the areas of the brain associated with mood regulation. The dorsolateral prefrontal cortex is a commonly stimulated area of the brain. This area is connected to other deeper areas and helps normalize brain activity in depression.

Each patient is given a personalized care plan with the appropriate calculation of magnetic charge delivered, depending on his or her skull measurements, condition, and severity of symptoms. In general, smaller coils provide more focused magnetic fields and are often used for superficial stimulation, and larger coils reach wider treatment areas and are used for deeper stimulation.

Stimulation depolarizes the neurons, resetting the brain circuits to process signals and information (internal and external) normally. That kicks off a wave of neural reconnections over time that restore healthier cognitive processing and mood regulation.

Who is eligible for TMS?

A psychiatrist might recommend TMS if you’ve been diagnosed with severe depression and you haven’t seen any improvement with at least one medication and psychotherapy.

Patients with a history of seizures are not eligible due to the small risk of medical complications involving seizure exacerbation. Because TMS uses magnetic fields, it is not an option if you have metal devices in or near your skull, such as aneurysm clips, cochlear implants, or surgical hardware in the head and neck region. This does not apply to common dental work such as fillings or braces.

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What to expect during TMS treatment

During your first treatment, your provider will take precise measurements of your skull to determine the exact placement of the coil. They also will test the amount of magnetic charge needed by stimulating a painless twitch in your thumb. Your initial visit takes about an hour. After this setup visit, the typical TMS therapy plan for depression includes 15-20 minutes of daily treatment for about six weeks. Modern and improved protocols have decreased the duration of daily treatment to approximately three minutes.

When the magnetic pulses are delivered, you will feel no pain. Some patients may feel pressure or a clicking sound near the coil, and some may have minor, temporary side effects such as headache, scalp discomfort, lightheadedness, or facial twitches. There is only one known risk of medical complication – a less than 1% (0.01% per session and 0.3 per 10,000 sessions) chance of seizures during the procedure. Less than 5% of patients discontinue TMS due to side effects or medical concerns.

Because TMS is painless and performed in your provider’s office, there is no need for anesthesia. After your visit, you can resume your regular daily routine with no activity restrictions, including driving.

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How effective is TMS?

Decades of research show how effective TMS can be for unipolar depression:

• About 50% of patients have a measurable response to the treatment.
• Most see significant improvement in symptoms within two to three weeks of beginning treatment.
• About 30%-40% report complete remission of symptoms.

Most of our patients continue doing well four to six weeks after treatment ends and about two-thirds report continued success after three months.

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The future of TMS in psychiatric care

The success of using TMS for severe depression gives us hope for treating other psychiatric conditions. We recently began a unique  for accelerated TMS therapy that delivers 10 treatments a day. This means a full course of treatment can be completed in just five days.

Clinical trials are showing promising outcomes for TMS in patients with psychiatric conditions that are difficult to treat with medication, such as , drug addiction, and bipolar disorder. Ongoing research is showing benefits for neurological conditions such as early dementia, , , and Tourette syndrome. Consider  through UTSW’s Center for Depression Research and Clinical Care.

UTSW is dedicated to connecting patients with effective, lasting depression treatments. Our longitudinal research has led to comprehensive, anonymized data collection that spans a decade. We are using the data to search for biomarkers – cell-level signs of disease, such as changes in blood or brain cells – that correlate with specific conditions. In doing so, we are continuously refining our understanding of neurological diseases and developing more effective and personalized treatment strategies.

If you live with treatment-resistant clinical depression, talk with a health care provider about TMS. It is safe, effective, and low-risk. Together, you and your care team can decide if this noninvasive and targeted treatment is right for you.