DBS For Depression And More: New, Non-Invasive Form Of Deep Brain Stimulation Could Be A Game-Changer For Alzheimer's Patients

Deep brain stimulation, or DBS, is used worldwide in patients with advanced or treatment resistant mental health or neurological conditions. This includes everything from treatment resistant depression to Parkinson's disease and Alzheimer's disease. The problem is that deep brain stimulation involves brain surgery and all the risks that come with it.

Non-invasive methods of deep brain stimulation-- such as electrical stimulation-- are available, but often times brain tissues outside of the targeted area are also affected by the electrical field, causing unwanted and unsafe side effects.

But now, thanks to an exciting, highly focused new technique called temporal interference, deep brain areas can be targeted non-invasively and with precision. The results of the first trial in healthy volunteers were very successful. Now it’s being tested in patients with Alzheimer's disease.

Key Takeaways

• Deep brain stimulation, or DBS, for treatment resistant depression is effective but has its risks since traditional deep brain stimulation requires brain surgery.
• New, non-invasive brain stimulation therapies-- such as temporal interference-- are showing immense promise to help treat mental health conditions and neurological disorders such as Alzheimer's disease and Parkinson's disease.
• Neurologists and other mental health experts from around the world are calling temporal interference a game changer in non-invasive brain stimulation therapies.

What is Deep Brain Stimulation Surgery?

When doctors have run out of treatment options in advanced Parkinson's disease, severe obsessive-compulsive disorder, epilepsy, and severe depression, they may offer to control symptoms using deep brain stimulation.

This surgical procedure involves making small holes in the skull and implanting electrodes in the patient’s brain to deliver an electrical current. The amount of stimulation in deep brain stimulation is controlled by a pacemaker-like device placed under the skin in the upper chest. A wire that travels under the skin connects this device to the electrodes in the brain. Several days after surgery, the neurologist programs the pulse generator. Patients are able to control the electrical impulses with an external remote control.

According to The Mayo Clinic, the electrical impulses affect cells and chemicals within the brain that cause medical conditions and improve the clinical response to illnesses and psychiatric disorders. This is why deep brain stimulation is used to treat:

• Treatment resistant depression
• Alzheimer's disease
• Parkinson's disease
• Essential tremor
• Conditions that cause dystonia, such as Meige syndrome
• Epilepsy
• Tourette syndrome
• Obsessive-compulsive disorder (OCD)

Deep brain stimulation surgery has shown a lot of promise in treating these and other mental health and neurological conditions.

Brain Stimulation Therapies: DBS for Depression (Treatment Resistant Depression)

Deep brain stimulation is used for treatment resistant depression. The deep brain stimulation device delivers electrical signals to the brain, regulating mood and blocking the impulses that cause depressive symptoms, severe depression and treatment resistant depression. In fact, research has shown that deep brain stimulation can lead to significant and sustained improvement in depressive symptoms.

In a study, participants with severe depression experienced a drop of more than half in their average depression scores, with about one-third achieving full remission of symptoms and half reporting a reduction in symptoms. The average level of functioning also improved significantly and was maintained over time.

How Does Deep Brain Stimulation Treat Depressive Symptoms

The use of deep brain stimulation for depression is a promising area of research, and recent developments have focused on a precision-medicine approach that taps into specific brain circuits involved in depression. This approach has shown success in managing treatment-resistant depression by delivering on-demand, immediate therapy tailored to the patient's unique brain and neural circuitry, alleviating symptoms almost immediately.

Deep brain stimulation has also proven to be very effective for conditions like epilepsy and Parkinson's disease.

Deep brain stimulation for severe depression is still considered an experimental procedure when it comes to mental health treatment and is appropriate only for people with severe depression whose symptoms are not adequately controlled by other treatments such as antidepressant medications.

While the U.S. Food and Drug Administration has not approved deep brain stimulation for the treatment of depression, several clinical studies have demonstrated its safety and effectiveness.

Deep Brain Stimulation Side Effects

The biggest problem with deep brain stimulation is the side effects. In addition to side effects from the two surgeries, the one on the brain and the one on the chest, people report side effects from deep brain stimulation including:

• Numbness or tingling sensations
• Muscle tightness of the face or arm
• Trouble with speech
• Trouble with balance
• Lightheadedness
• Vision changes, such as double vision
• Mood changes, such as anger, mania and depression

That's why it's not a surprise that there has been a lot of excitement over non-invasive alternatives to deep brain stimulation.

Non-Invasive Alternatives to Deep Brain Stimulation

Deep brain structures can also be stimulated non-invasively with transcranial magnetic stimulation and transcranial electrical stimulation. In this procedure, the electrodes are placed outside the body, on the scalp. But these methods are limited in their ability to reach deeper structures and to focus with precision on the targeted area.

To overcome these drawbacks, neuroscientists and engineers from the U.S. and U.K. teamed up to develop a technique based on delivering multiple electric fields to the brain at different kilohertz frequencies, thus allowing it to penetrate deeply and be highly focused.

The technology, temporal interference, was first tested in mice in 2017 and then analyzed in human volunteers in three studies published in 2022. The success of these studies led to a small, recently published human trial to test its effects on memory and cognitive function.

Non-Invasive First: Temporal Interference Deep Brain Stimulation

Before the trial began the researchers took measurements in a human cadaver to make sure electric fields could be remotely focused on the area of the brain they were interested in – the hippocampus. This curved structure lying deep in the brain plays critical roles in learning and memory and is one of the earliest affected brain regions in Alzheimer´s disease.

Once satisfied it could be targeted successfully, they recruited 20 healthy volunteers with an average age of 27. The research team gave them temporal interference for a very short period while they memorized pairs of faces and names – a process heavily dependent on the hippocampus. At the same time, they were given brain scans to confirm the stimulus was confined to the hippocampus and not to surrounding areas.

Targets The Hippocampus and Improves Memory

Researchers took various measurements during the test which included sham procedures where no electrical stimulus was provided. The results showed that temporal interference targeted the hippocampus and improved memory for the face-name task.

To confirm the results, another 21 volunteers completed the same task, but this time for a much longer period of 30 minutes. Compared to sham procedures, temporal interference was shown to improve memory for the task and improve other aspects of memory reliant on the hippocampus.

Overall, the procedure was well tolerated, no adverse effects were recorded, and side effects were mild.

A delighted Nir Grossman, who led the work, said “we have shown for the first time that it is possible to remotely stimulate specific regions deep within the human brain without the need for surgery. This opens up an entirely new avenue of treatment for brain diseases like Alzheimer’s which affect deep brain structures.”

His colleague, Ines Violante, added that this approach is “very exciting as…the combination of non-invasive imaging and brain stimulation will help us unravel the processes that support our cognitive functions, such as memory and learning.”

Safe and Tolerable

Research has shown the safety and tolerability of temporal interference deep brain stimulation in humans, as well as the ability to focally target the stimulation locus to specific brain regions such as the hippocampus.

This suggests that temporal interference stimulation holds promise as a safe and feasible non-invasive neurostimulation technique and an alternative to side-effect riddled deep brain stimulation.

Experts Give It The Thumbs Up

Neurologists and other medical professionals are excited about this new class of brain stimulation therapies to improve mental health and psychiatric disorders, not to mention neurological conditions like Alzheimer's disease and Parkinson's disease.

Dr. Richard Oakley, associate director of research at the Alzheimer’s Society, was enthusiastic about this new kind of deep brain stimulation, saying, “This is incredible technology. It really is exciting to see research opening up whole new areas for future treatment.”

Dr. Joanna Latimer, Head of Neuroscience at the U.K. Medical Research Council, was equally excited about this deep brain stimulation, saying “the results from the next stage of this highly promising treatment cannot come fast enough.”

Dr. Leah Mursaleen, Head of Research at Alzheimer’s Research UK described temporal interference deep brain stimulation as an “exciting technique”.

Dr. Julian Mutz from Kings College London said this deep brain stimulation “could be a game-changer”.

Richard Morris, Professor of Neuroscience at the University of Edinburgh, believes this deep brain stimulation technology is “potentially an astonishing step forward [and] a very welcome development”.

Temporal interference is now being tested in people in the early stages of Alzheimer’s to see if it can restore normal brain activity and improve memory. We’ll keep you posted.

Summary

Deep brain stimulation (DBS) is a treatment that uses implanted electrodes to deliver electrical current to specific areas of the brain. It's used to treat a variety of neurological and psychiatric disorders, including Parkinson's disease, Alzheimer's disease, and severe depression. However, deep brain stimulation is a surgical procedure that carries risks, such as infection and bleeding.

Non-invasive brain stimulation therapies are being developed as an alternative to deep brain stimulation. These therapies use methods such as magnetic fields or electrical currents to stimulate the brain without surgery. One promising non-invasive brain stimulation therapy is temporal interference, which is showing promise in the treatment of Alzheimer's disease.

Frequently Asked Questions

Can DBS (deep brain stimulation) be used for depression treatment or treatment resistant depression?

Deep brain stimulation is used for treatment resistant depression. The deep brain stimulation device delivers electrical signals to the brain, regulating mood and blocking the impulses that cause depressive symptoms, severe depression and treatment resistant depression.

What is the success rate of DBS (deep brain stimulation) for depression?

Research has shown that deep brain stimulation can lead to significant and sustained improvement in depressive symptoms, especially in treatment resistant depression. In a study, participants with severe depression experienced a drop of more than half in their average depression scores, with about one-third achieving full remission of symptoms and half reporting a reduction in symptoms. The average level of functioning also improved significantly and was maintained over time.

Does DBS (deep brain stimulation) work for Alzheimer's disease?

Deep brain stimulation has been investigated in the treatment of Alzheimer's. The new, non-invasive deep brain stimulation in particular is showing promise. Temporal interference was shown to improve memory for the task and improve other aspects of memory reliant on the hippocampus. Overall, the procedure was well tolerated, no adverse effects were recorded, and side effects were mild.

A delighted Nir Grossman, who led the work, said “we have shown for the first time that it is possible to remotely stimulate specific regions deep within the human brain without the need for surgery. This opens up an entirely new avenue of treatment for brain diseases like Alzheimer’s which affect deep brain structures.”

What are the downsides of DBS (deep brain stimulation)?

Traditional deep brain stimulation surgery is rife with side effects. In addition to the healing required from the two surgeries, the one on the brain and the one on the chest, people report an array of side effects.

• Numbness or tingling sensations
• Muscle tightness of the face or arm
• Trouble with speech
• Trouble with balance
• Lightheadedness
• Vision changes, such as double vision
• Mood changes, such as anger, mania and depression

However, the new non-invasive therapy, temporal interference, was well tolerated in research and did not result in any adverse side effects.