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Assistance Center
and Research in Neuromodulation
BRIEF HISTORY OF NON-INVASIVE NEUROMODULATION
Over the past three decades, our understanding of brain-behavior relationships has been significantly shaped by research using non-invasive brain stimulation techniques. These methods allow the safe modulation of neural processes , through the use of electrical currents or electromagnetic fields .
The therapeutic use of electrical currents has been described as a scientific activity since the end of the 18th century. Luigi Galvavani, Charles Le Roy, Duchenne de Boulogne, Beard and Rockwell, Giovanni Aldini, among many others, are prominent names in the construction of this history. In the 1960s, researchers began to experiment with the use of weak direct currents applied directly to the exposed cortex of animals, which, in recent years, has provided the basis for the use of transcranial direct current stimulation and its influence on cortical activity in humans.
Magnetic stimulation in its most primitive form was first investigated in the late 19th century by physicists studying fundamental aspects of electromagnetism and, in particular, the implications of Faraday's law. Jaques-Arsène d'Arsonval and Sylvanus P. Thompson made the first attempts at brain stimulation using magnetic fields. There are now numerous commercially available transcranial magnetic stimulation devices and the techniques are present in both research laboratories and in direct care , with an increasing volume of scientific publications on their effects on various health conditions.
WHAT IS NON-INVASIVE NEUROMODULATION?
Neuromodulation modalities include a variety of techniques designed to influence or modulate human nervous system activity. Therapeutic modalities may vary according to clinical context, location, accuracy, size of target areas and desired effect. Among noninvasive brain neuromodulation techniques, three of them have been widely studied: Transcranial Direct Current Stimulation (tDCS), Transcranial Magnetic Stimulation (TMS), and Peripheral Electric Stimulation (PES). More recently, other modalities have also been developed with promising results, such as transcranial alternating current stimulation (tACS), transcranial random noise stimulation (tRNS), transcutaneous auricular vagus nerve stimulation (taVNS), transcutaneous Spinal Direct Current Stimulation (tSDCS), among others.
APPLIED TECHNIQUES
tDCS
The tDCS is a painless noninvasive cortical modulation technique that, through the application of low intensity direct current over the skull, is able to generate a neuromodulation of cortical excitability and thus interfere with the performance of different functions. Thus, it may influence motor and sensory functions. Its effects depend mainly on the applied current polarity, its intensity, the application time, the stimulated area and the current density. It is a low cost therapy with valid results in several areas.
The technique is capable of modulating the activity of stimulated neurons and, in this way, influencing the functions of the stimulated area, whether they are sensory, motor, cognitive or emotional. The effects of tDCS depend mainly on the polarity of the current applied, its intensity, the time of application, the area stimulated and the density of the electrical current . It is a low-cost therapy with significant results in several areas of application: populations with neurological disorders (chronic pain, stroke, Parkinson's disease, etc.), psychiatric disorders (depression, anxiety, craving, etc.), and healthy individuals (improved performance in athletes, for example).
TMS
TMS is based on the principle of electromagnetic induction, discovered by Faraday in 1838. A small coil that receives an extremely powerful alternating electric current is placed over the skull. The constant change in the orientation of the electric current within the coil is capable of generating a magnetic field through the skin and bones. During TMS application, electric currents are induced in the cortical areas that can depolarize neurons and generate potential action's that promote neuromodulation. By observing and analyzing the characteristics of TMS-induced potential action's, it is possible to evaluate different aspects of neuromodulation with good temporal, spatial and functional resolution. These features make the TMS an undoubtdly useful tool for assessing brain activity, providing data on brain plasticity, muscle representation, and facilitatory or inhibitory brain functions.
Single-pulse or paired-pulse TMS techniques can be used to assess the structure and activity of central nervous system pathways. Pulses are applied to the skull and the response to these pulses is monitored and used for assessment. These techniques help determine the integrity and connectivity between brain areas.
The repetitive transcranial magnetic stimulation (rTMS) technique is capable of generating a magnetic field that passes through the skin and bones and modulates the activity of the stimulated neurons, increasing or decreasing their activity. The effects of rTMS depend mainly on the intensity , number of pulses and frequency used. It can be used to regulate the sensory, motor, cognitive or emotional function related to the stimulated region. Therefore, it is indicated for clinical application in populations with neurological disorders (chronic pain, stroke, Parkinson's disease, etc.) and psychiatric disorders (depression, anxiety, craving, etc.).
taVNS
Transcutaneous auricular vagus nerve stimulation (taVNS) is a relatively recent form of non-invasive stimulation that consists of electrical stimulation to the auricular branch of the vagus nerve, an easily accessible target that innervates the human ear. The main areas of stimulation are: tragus and concha cimba. In the last decade, several groups have demonstrated the safety and tolerability of this method that can be applied in a clinical setting. taVNS has been studied in neuropsychiatric populations with promising effects on cognitive domains, on social functioning, addiction, inflammation, and tinnitus. Stimulation parameters may vary between groups and which have minimal side effects.
As principais áreas de estimulação são tragus e concha cimba, na região da orelha. Na última década, vários grupos demonstraram a segurança e a tolerabilidade deste método que pode ser aplicado em ambiente clínico com mínimos efeitos colaterais. A taVNS vem sendo estudada em populações neuropsiquiátricas com efeitos promissores nos domínios cognitivos, no funcionamento social, na função sensório-motora, nas compulsões, no controle da dor, inflamação e zumbido.
PES
The Peripheral Stimulation has been used for a long time, however only recently its effects on brain behavior and neural plasticity have been unveiled. The application of this technique cause muscle contractions and it can increase cortical excitability, similarly to the response of anodic tDCS or high frequency rTMS. This stimulation possibly promotes selective plasticity in the representation of muscles in the cerebral cortex, inhibiting or facilitating its activity. It can be especially helpful in the treatment of movement disorders in which there is hyperactivity of some muscles while hypoactivity of others.
The PES technique, although applied directly to nerve regions of the peripheral nervous system, is capable of indirectly altering the behavior of neurons in the central nervous system in the brain and spinal cord. Thus, it can be considered a non-invasive neuromodulation technique for brain regions. Depending on the type of parameter chosen, the effects of PES on the behavior of the central nervous system can be facilitatory or inhibitory . In this regard, the scientific literature has shown that PES parameters that cause slight muscle contraction for approximately 45 minutes produce facilitatory effects in the motor cortical region (primary motor cortex) . On the other hand, PES parameters that only cause a tingling sensation or painful discomfort for approximately 30 minutes cause inhibitory effects in the motor cortical regions. Currently, PES can be indicated for several clinical conditions, such as chronic pain, motor sequelae after stroke and movement disorders, among others.
Spinal cord stimulation
The Peripheral Stimulation has been used for a long time, however only recently its effects on brain behavior and neural plasticity have been unveiled. The application of this technique cause muscle contractions and it can increase cortical excitability, similarly to the response of anodic tDCS or high frequency rTMS. This stimulation possibly promotes selective plasticity in the representation of muscles in the cerebral cortex, inhibiting or facilitating its activity. It can be especially helpful in the treatment of movement disorders in which there is hyperactivity of some muscles while hypoactivity of others.
Noninvasive spinal cord stimulation has attracted much attention due to its ability to modulate motor and sensory pathways in a painless manner and with no reported adverse effects to date. It can be applied through transspinal magnetic stimulation (tsMS) or transspinal direct current stimulation (tsDCS). Both have shown therapeutic potential in modulating chronic pain and in recovering sensorimotor function in individuals after spinal cord injury and stroke.
rPMS
The Peripheral Stimulation has been used for a long time, however only recently its effects on brain behavior and neural plasticity have been unveiled. The application of this technique cause muscle contractions and it can increase cortical excitability, similarly to the response of anodic tDCS or high frequency rTMS. This stimulation possibly promotes selective plasticity in the representation of muscles in the cerebral cortex, inhibiting or facilitating its activity. It can be especially helpful in the treatment of movement disorders in which there is hyperactivity of some muscles while hypoactivity of others.
Through rPMS, it is possible to perform sensory and motor stimulations throughout the body, seeking localized muscle contractions, and can be used for evaluative or therapeutic purposes. rPMS has been studied for the reduction of spasticity, pain reduction, modulation of the sensory cortex, functional recovery after injury to the central and peripheral nervous system, prevention of muscle atrophy, among others.
Cerebellar stimulations
The Peripheral Stimulation has been used for a long time, however only recently its effects on brain behavior and neural plasticity have been unveiled. The application of this technique cause muscle contractions and it can increase cortical excitability, similarly to the response of anodic tDCS or high frequency rTMS. This stimulation possibly promotes selective plasticity in the representation of muscles in the cerebral cortex, inhibiting or facilitating its activity. It can be especially helpful in the treatment of movement disorders in which there is hyperactivity of some muscles while hypoactivity of others.
APPLICATIONS
The use of noninvasive clinical neuromodulation was initially developed to the treatment of pain, movement disorders, psychiatric disorders, epilepsy, tinnitus, and post-stroke rehabilitation. Recently, neuromodulation techniques has been used in association to active therapy-associated and have presented enhanced effects; examples combining such stimulation with occupational therapy, with assisted robotic training for the upper limb, cognitive behavioral therapy for depression, language therapy for aphasia, among others have been published. tDCS has been pointed out as one of the seven most promising technologies for the future of stroke rehabilitation.
LEGAL INFORMATION
MEDICINE
The use of rTMS or sp-TMS for therapeutic and/or diagnostic purposes in the medical profession was approved by the Federal Council of Medicine in 2011 (CFM consultation process no. 7,435/08 – CFM Opinion no. 37/11). The summary specifies the use of TMS with indications for the treatment of depression, auditory hallucinations and neurosurgery planning. Furthermore, the summary emphasizes that in addition to having the technical and scientific knowledge to apply TMS, the physician must adapt the therapeutic environment and have emergency support equipment to provide first aid – including cases of seizures.
PHYSIOTHERAPY
The Federal Council of Physiotherapy and Occupational Therapy regulates the use of non-invasive neuromodulation for physiotherapists, through resolution 434/2013 and ruling 378/2014, and its updates through Resolution 554/2022, as follows:
Resolution No. 434, of September 27, 2013 - Recognizes the use of transcranial stimulation physiotherapeutic techniques by physiotherapists;
Ruling No. 378, of August 29, 2014 - Regulates the use of Transcranial Magnetic Stimulation (TMS) and Transcranial Direct Current Stimulation (tDCS) in the exercise of physiotherapy;
Training: To be qualified to apply non-invasive neuromodulation techniques, theoretical and practical training is required with a minimum workload of: tDCS - 30h; TMS physiotherapeutic diagnosis - 60h; and TMS treatment - 60h; 60% of the workload being practical training. Alternatively, training may be obtained through a master's or doctoral course, whose dissertation/thesis was carried out with the application, in human beings, of the non-invasive stimulation technique(s) of the nervous system, with which the person intends to work.
Apostille (COFFITO, 2013; COFFITO, 2014; FREGNI et al, 2014)
NURSING
COREN-SP Opinion 025/2019 Summary: Performance of transcranial electrostimulation by direct current and transcranial magnetic stimulation by the nurse
Technical Opinions Coren-ES No. 001/2019 and Technical Opinion Coren-DF No. 10/2018 are in favor of nurses performing transcranial direct current electrostimulation (tDCS) and transcranial magnetic stimulation (TMS).
SPEECH THERAPY
Resolution No. 650, of March 3, 2022 - Provides for the use of non-invasive neuromodulation as a therapeutic resource in speech therapy.
Resolution No. 662, of March 30, 2022 - Provides for the amendment of § 2 of art. 1 and art. 4 of CFFa Resolution No. 650, of March 3, 2022. Non-invasive neuromodulation (NmNI) as a therapeutic modality includes Transcranial Magnetic Stimulation (TMS), Repetitive Transcranial Magnetic Stimulation (rTMS), Peripheral Electrical Stimulation (PES) and Transcranial Direct Current Stimulation (tDCS), which comprise magnetic and electrical modalities.
Minimum time of 30 hours of course in tDCS and 90 hours of course in tDCS and TMS, with a mandatory practical workload of 50% of the training.