New borders in deep brain stimulation include neurosurgery and ultrasound

There are several forms of proof (ECP) stimulation. The surgical technique, which uses the implementation of intracerebral electrodes, is the oldest. Deep transcranial magnetic stimulation (EMTP) is a more recent alternative, and low-intensity-focused pulsed ultrasound stimulation (Lifus) is currently undergoing research in some excellence centers. We will start presenting the neurosurgical technique of ECP, followed by non -invasive approaches, such as Lifus, ending with a note on EMTP.

How Surgical ECP works

Surgical ECP consists of the implementation of electrodes in specific regions, functioning as a pacemaker, linked to a generator (small subcutaneous battery). Through electrical stimuli, ECP promotes the normalization of hypo or hyperactive activities in certain brain areas (LOZANO et al., 2008), in addition to altering neuroplasticity (neural path adaptations) (Kringelbach et al., 2007) and regular neurotransmitters such as glutamate and dopamine. This technique has been routinely used in Parkinson’s disease and essential tremor. More recently, it was applied in some specific cases within psychiatry (Mayberg et al., 2005).

Psychiatry uses

Surgical ECP has been studied in various psychiatric disorders, achieving different therapeutic targets and presenting good results in:

• Refractory depression (Holtzheimer et al., 2017);
• Obsessive-compulsive refractory disorder (DENYS et al., 2010);
• Resistant schizophrenia;
• Severe chemical dependencies.

As an invasive procedure, surgical ECP is only used in psychiatry in rare and extremely serious cases. With advances in the future, associated with better patient selection criteria (genetic studies and biomarkers), the technique tends to have more specific indications.

How lifus works

Lifus uses focused and low intensity ultrasound pulses. It is a noninvasive, painless and extremely promising method in the modulation of neural activity, providing very high accuracy. Ultrasonic waves generate pressure changes that modulate ion channel activity (Tyler et al., 2008), promoting synaptogenesis and the release of neurotrophic factors such as BDNF (Folloni et al., 2019), as well as acting in the modulation of neural networks (Dalla Piazza et al., 2018).

Lifus potential in psychiatry encompasses paintings such as resistant depression, OCD, schizophrenia and Tourette syndrome, among other disorders. In neurology, there are also possible applications in neurodegenerative diseases (Alzheimer’s and Parkinson), chronic pain, epilepsy, among other paintings.

Advantages of lifus in relation to other techniques

Method Invasivity Precision Side Effects

Lifus noninvasive minimum high (light headache)

Invasive ECP (surgery) high risk of bleeding, infection

Non -invasive average headache, rare risk of seizure

Lifus challenges include the precise location of deep brain regions, individual variability and proof of long -term effects. Our group, in the Department of Neurology of HCFMUSP, has been researching these techniques for some years, with encouraging results in intractable central pain based on a pilot study; The full study is now in statistical analysis. Several studies are underway in the area of movement disorders. We currently have a depression protocol and we are elaborating a research protocol for Tourette syndrome.

Future Applications

There is great potential for Lifus application in various psychiatric disorders, such as ADH, ADHD, OCD, resistant depression, schizophrenia, Tourette, among others. In addition, with Lifus, it is possible to temporarily open the hematoencephalic barrier, allowing certain medications to penetrate the central nervous system. These medications could be inactive (as in an enclosure) and would be activated when they reach the desired place.

Deep transcranial magnetic stimulation

Our group has been researching this theme for decades, with a wide production of publications in the area. In the previous item (Lifus), only one comparative table was presented between different forms of deep brain stimulation.

Conclusion

ECP techniques are becoming increasingly promising, and Lifus, in particular, represents a revolution in brain neuromodulation, as not invasive, safe and highly effective for both psychiatric disorders and neurological conditions.

*Por Marco Antonio Marcolin – CRM 38301
Psychiatrist, PhD University of Illinois, Chicago Researcher, Department of Neurology, HCFMUSP