Overview

Innovations in brain stimulation techniques for dementia patients represent a significant advancement in the quest to improve the lives of those affected by cognitive decline. With the global prevalence of dementia on the rise, innovative approaches are urgently needed to address the multifaceted challenges posed by this complex syndrome. From electrical currents to focused ultrasound, these techniques offer targeted interventions to modulate brain activity and potentially alleviate cognitive symptoms. While challenges persist, including the need for further research and validation, these innovations promise to reshape the landscape of dementia care. This article explores research and developments in brain stimulation techniques, offering hope for enhanced treatment options and improved outcomes for individuals living with dementia and their families.

Understanding dementia and its challenges

As we are starting to live longer and the global lifespan increases, dementia is becoming an incredibly relevant health problem, affecting more than 55 million people worldwide. Dementia is a general term that describes a collection of symptoms one may experience when living with certain diseases that cause abnormal brain changes and damage to brain cells. The connections between brain cells are essential for any cognitive function. Any damage to these cells leads to a loss of connections, with a loss of cognitive function. 

Alzheimer's disease accounts for 60%-80% of dementia cases, with the second most common cause being vascular dementia, where there’s microscopic bleeding and blood vessel blockages in the brain. Dementia is characterised by a progressive cognitive impairment that interferes with daily life and activities. Common symptoms include loss of cognitive abilities, such as memory loss and difficulty communicating. Dementia can also affect a person’s behaviours and feelings and can impact their relationships. 

Due to the complexity of dementia and its diagnosis, drug development for managing dementia has been incredibly challenging, with 99% of drug candidates failing after showing no improvement.¹ The need for the drug to pass the blood-brain barrier, a tightly controlled membrane protecting the brain from substances in the blood, also poses a severe challenge. The difficulties with pharmacological approaches to the treatment of dementia necessitate the development of a non-pharmacological approach.

Innovations in brain stimulation techniques

Deep brain stimulation

Deep brain stimulation (DBS) is a neurosurgical approach to brain stimulation. This technique was developed in the 1990s and is now commonly used for treating various neurodegenerative diseases. It is currently utilised in the treatment of movement disorders such as Parkinson’s disease, but it shows great promise in addressing the cognitive symptoms of dementia.² 

In DBS, small electrodes are placed within the brain to help regulate brain activity. These electrodes then send controlled electrical signals to specific areas of the brain, aiming to “reset” abnormal brain circuits associated with dementia and improve cognitive function.² DBS may not be ideal for many people as it is considered an invasive procedure, which is why multiple new non-invasive brain stimulation techniques are in development

Transcranial magnetic stimulation

Within the family of non-invasive brain stimulation techniques, transcranial magnetic stimulation, or TMS, has generated considerable interest as a preventative strategy or disease-modifying treatment in dementia. TMS has shown potential therapeutic efficacy in a clinical setting and is considered both safe and affordable.² 

TMS produces a magnetic field to stimulate nerve cells in the brain. In many clinical trials of repeated TMS treatment in Alzheimer’s Disease, patients showed improved cognition or, at the very least, stable maintenance in language and memory. In various trials, TMS gave hope for improvements in language deficits in patients with Alzheimer’s, and the cognitive improvements achieved were shown to last for up to four months.³ Although there is still debate regarding the long-term benefits of TMS, there is no question that it is an up-and-coming technique with significant future potential to improve the symptoms of dementia.

Transcranial electric stimulation

Transcranial direct current stimulation (tDCS) is a technique that delivers a sustained, low-intensity current to neurones in the cerebral cortex. This is the region of the brain that controls the many cognitive processes mentioned earlier, such as:

• Language
• Memory
• Reasoning
• Emotion

tDCS uses scalp electrodes in an attempt to regulate brain plasticity and excitability (how the brain responds to stimuli and rewires and adapts to them).⁴

Clinical trials of tDCS have shown positive results, with short-term improvement in overall cognitive function.² tDCS is particularly popular because, like TMS, it is considered safe and affordable. It is also portable and ergonomic, making it a popular choice for hospitals and bedridden patients at home. The cognitive improvements seen with the use of tDCS, combined with its accessibility, make it an excellent choice for patients with dementia, and future trials are looking to combine tDCS with cognitive training for more efficient results.²

Temporal interference

One of the more recent innovations in brain stimulation techniques is temporal interference (TI). TI is a noninvasive approach to DBS involving the use of multiple electric fields that are applied to the brain at different frequencies. These frequencies intersect in a way that creates a new pattern of electrical stimulation (known as interference patterns) within specific brain regions.⁵ TI has been groundbreaking as it allows for specificity, even with great depths into the brain, without affecting any other tissues or areas of the brain while being completely non-invasive. In a study using TI, stimulation of the hippocampi of healthy participants led to significant improvements in memory.⁶ Although research on TI is currently limited, the results seen in tDCS, which also uses electricity, provide much hope for the future of TI.

Transcranial ultrasound stimulation

Ultrasound is well known to many people due to its common use in healthcare. The use of focused ultrasound (FUS) for brain stimulation is a novel approach that transmits thermal and mechanical energy to a specific brain region. The primary interest in the therapeutic use of FUS is its ability to produce neurobiological effects without the need for surgical operations or any other invasive technique.

FUS can be divided into high, medium, and low intensity. High intensity isn’t used in the treatment of dementia; however, research into the use of medium and low-intensity FUS in this respect has shown incredible progressions.

Medium-intensity FUS has a unique approach compared to other methods of brain stimulation. As previously mentioned, developing drugs for the treatment of dementia symptoms has been a challenge, especially because the blood-brain barrier presents an obstacle to delivering drugs to the brain. Researchers have found that medium-intensity FUS creates openings in the blood-brain barrier, thereby increasing its permeability. In the context of dementia, researchers found that medium-intensity FUS increased permeability in brain regions related to Alzheimer's Disease.²

In recent years, low-intensity FUS has garnered interest as a therapeutic intervention by modulating neural activity. In a pilot study, patients demonstrated mild improvements in overall cognitive function, including memory and executive function. In studies using mice models of Alzheimer's disease, low-intensity FUS showed significant improvements in learning and memory functions.⁷ However, the research is quite limited, with few research trials conducted in humans. Further research is also required to ensure the safety of increasing the permeability of the blood-brain barrier for drug delivery using medium-intensity FUS, as well as ensuring the general safety of low-intensity FUS.

Summary

The landscape of dementia care is undergoing a transformative shift with the emergence of innovative brain stimulation techniques. From both invasive and non-invasive Deep Brain Stimulation to Transcranial Ultrasound Stimulation, these advancements hold promise for addressing the cognitive symptoms of dementia and reshaping the future of neurological treatment. 

It should be noted that although some of these techniques are available to the public in the treatment of certain conditions (for example, tDCS), they are still not available for the treatment of dementia symptoms. These innovations are relatively new in the field and require further research before they are available as treatment. While challenges remain, including the need for further research and clinical validation, the potential of these techniques to improve cognitive function and quality of life for dementia patients is undeniable. As research continues to progress, the horizon shines brighter with hope for a future where effective treatments for dementia are within reach.