# Neurotherapy

Neurotherapy is medical treatment that implements systemic targeted delivery of an energy stimulus or chemical agents to a specific neurological zone in the body to alter neuronal activity and stimulate neuroplasticity in a way that develops (or balances) a nervous system in order to treat different diseases, restore and/or to improve patients' physical strength, cognitive functions, and overall health.

## Definition

A consensus in the academic community considers this notion within limitations of the contemporary meaning of neuromodulation, which is "the alteration of nerve activity through targeted delivery of a stimulus, such as electrical stimulation or chemical agents, to specific neurological sites in the body" (see Neuromodulation). While neurotherapy may have a broader meaning, its modern definition focuses exclusively on technological methods that exert an energy-based impact on the development of the balanced nervous system in order to address symptom control and cure several conditions. The definition of neurotherapy relies on evolving scientific concepts from different fields of knowledge, ranging from physics to neuroscience. Four central concepts that underlie the knowledge of neurotherapy are defined here:

### Energy stimulus

Energy, as the ability to do work, cannot be created or destroyed; it can only be transformed from one form to another (the law of conservation of energy). There are different form of energy. Such forms of energy as radiant energy carried by electromagnetic radiation, electrical energy and magnetic energy, are of interest to neurotherapy. Medical devices for neuromodulation exert electrical, magnetic, and/or electromagnetic energy to treat mental and physical health disorders in patients.

### Synaptic plasticity

Synaptic plasticity, a particular type of neuroplasticity is the ability of the nervous system to modify the intensity of interneuronal relationships (synapses), to establish new ones and to eliminate some. This property allows the nervous system to modify its structure and functionality in a more or less lasting way and dependent on the events that influence them such as experience or neuromodulation.

### Neuroplasticity

Brain plasticity refers to the ability of the brain to modify its structure and functionality depending on the activity of its neurons, related for example to stimuli received from the external environment, in reaction to traumatic lesions or pathological changes and in relation to the development process of the individual or neuromodulation.

### A balanced nervous system

In the balanced nervous system with required cognitive functions, the sympathetic (SNS) and parasympathetic nervous systems (PNS) operate in synergy while opposing each other. Stimulation of the SNS boosts body activity and attention: it raises heart rate and blood pressure. In contrast, stimulation of the PNS is the rest and digest state: it reduces blood pressure and heart rate. The nervous system interplays with the immune system. Through these interactions, the nervous and immune systems ensure the nervous system maintains immune homeostasis.

## Medical uses

According to the International Neuromodulation Society, neuromodulation-based therapy "addresses symptom control through nerve stimulation" in the following condition categories:
* Chronic pain
* Movement disorders
* Epilepsy
* Psychiatric disorders
* Brain injury / Stroke
* Cardiovascular disorders
* Gastrointestinal disorders
* Genitourinary and colorectal disorders
* Sensory deficits

## Types

Neurotherapy, as many medical therapy, is based on knowledge from conventional medicine, relying on scientific approach and evidence-based practice. However, some neuromodulation techniques are still attributed to alternative medicine (healthcare procedures "not readily integrated into the dominant healthcare model") because of their novelty and lack of evidence to support them. The wide range of neurotherapy techniques can be divided into three groups based on the application of energy stimulus:

### Electric energy

* Auditory brainstem implant
* Cranial electrotherapy stimulation
* Deep brain stimulation
* Electrical brain stimulation
* Electroanalgesia
* Electroconvulsive therapy (ECT)
* Functional electrical stimulation (FES)
* Hypoglossal nerve stimulation
* Neurofeedback
* Microcurrent electrical neuromuscular stimulator
* Occipital nerve stimulation (ONS)
* Percutaneous tibial nerve stimulation (PTNS)
* Peripheral nerve stimulation
* Sacral nerve stimulation (SNS) / sacral neuromodulation (SNM)
* Transcranial direct current stimulation (tDCS)
* Transcranial alternating current stimulation (tACS)
* Transcranial pulsed current stimulation (tPCS) )
* Transcranial random noise stimulation (tRNS)
* Transcutaneous electrical nerve stimulation (TENS)
* Vagus nerve stimulation

### Magnetic energy

* Magnet therapy
* Magnetic resonance therapy
* Repetitive transcranial magnetic stimulation (rTMS)
* Transcranial magnetic stimulation

### Electromagnetic radiation

* Acoustic photonic intellectual neurostimulation (APIN)
* Light therapy (phototherapy)
* Ultraviolet light therapy
* PUVA therapy
* Photodynamic therapy
* Photothermal therapy
* Pulsed electromagnetic field therapy
* Cytoluminescent therapy
* Blood irradiation therapy
* Laser therapy
* Low level laser therapy
* Transcranial pulsed electromagnetic fields (tPEMF)

## Mechanisms

Origins behind the way that an external energy stimulus alters neuronal activity and stimulates neuroplasticity during various artificial neurostimulation techniques are still under discussion. It is important to note that electrical and magnetic energy are two forms of energy that are closely interconnected: a moving charge induces electrical and magnetic fields. Electrical current creates a magnetic field, and a magnetic field induces an electrical charge movement. Neurons are electrically active cells. Neuronal oscillations have a dual role in synapsis: they are affected by spiking inputs and, in turn, impact the timing of spike outputs. Because of the above facts, both electrical and magnetic fields may induce electrical currents in neuronal circuits. Therefore, similar mechanisms of altered neuronal activity may underlie different neuromodulation techniques that use electrical, magnetic, or electromagnetic energy in treatment.
A variety of hypotheses try to explain the mechanisms that contribute to synaptic activity during neurostimulation. According to an influential position, electrical and magnetic fields may alter Ca2+ and Na+ channel activity. The voltage-gated Ca2+ channels are the primary conduits for the Ca2+ ions that cause a confluence of neurotransmitter-containing vesicles with the presynaptic membrane. The altered activity of Ca2+ and Na+ channel changes the timing and strength of synaptic output, contributing to neuronal excitability.
Another perspective hypothesis stands that electromagnetic fields increase in adenosine receptors release that facilitates neuronal communication. Because A(2A) adenosine receptors control the release of other neurotransmitters (e.g., glutamate and dopamine), this contributes to adjusting neuronal functions.
According to the natural neurostimulation hypothesis, energy stimuli induce mitochondrial stress and micro vascular vasodilation. These promote increasing Adenosine triphosphate (ATP) protein and oxygenation, inducing synaptic strength. This position explains neuromodulation from different scale levels: from interpersonal dynamics to nonlocal neuronal coupling. According to natural neurostimulation, the innate natural mechanism of physical interactions between the mother and embryo ensures the balanced development of the embryonic nervous system. The drivers of these interactions, the electromagnetic properties of the mother's heart, enable brain waves to interact between the mother's and fetal nervous systems. The electromagnetic and acoustic oscillations of the mother's heart converge the neuronal activity of both nervous systems in an ensemble, shaping harmony from a cacophony of separate oscillations. These interactions synchronize brain oscillations, influencing neuroplasticity in the fetus. During the mother's intentional actions with her environment, these interchanges provide hints to the fetus's nervous system, binding synaptic activity with relevant stimuli. This hypothesis posits that the physiological processes of mitochondrial stress induction (affecting neuronal plasticity) and vasodilation, which cooperatively increase microvascular blood flow and tissue oxygenation, are the basis of the natural neurostimulation. It is also thought to be a foundation of many non-invasive artificial neuromodulation techniques. Because if the mother-fetus interactions allow the child's nervous system to grow with adequate biological sentience, similar (while scaling) environmental interactions can heal the damaged nervous system in adults.

## History

While neurotherapy is a relatively young medical treatment in conventional Western biomedicine (that relies on a scientific approach and evidence-based practice), different age-old cultural practices of traditional Indian, Egyptian, and Chinese medicine have been using neuromodulation elements thousands of years ago. Before the basic processes of neurotherapy were scientifically studied, humans used the electrical properties of animals for therapeutic purposes. The Egyptians used the Nile catfish (Synodontis batensoda and Malapterurus electricus) to stimulate tissue electrically, according to an interpretation of frescoes in the tomb of the architect Ti at Saqqara, Egypt. The first documented use of electrical stimulation for pain relief dates back to 46 AD when Scribonius Largus of the ancient Roman Empire used the electric properties of torpedo fish to relieve headaches.
Scientific studies of neuromodulation began in 1745, when German physician De Haen published “a number of cases of spasmodic, paralytic and other nervous affections cured by electricity”.
The first implementation of electrocutical apparatus in hospital medical treatment recorded in Middlesex Hospital of London in 1767. In 1870, German physicians Gustav Fritsch and Eduard Hitzig reported the modulation of brain activity in dogs by electrical stimulation of the motor cortex.
In 1924, the German psychiatrist Hans Berger attached electrodes to the scalp and detected small currents in the brain.
In the mid-20th century, the scientific study of neuromodulation in humans expanded significantly. Neurologist Professor Spiegel and neurosurgeon Professor Weissys of Temple University presented a stereotactic device to perform "ablation procedures" in humans; "intraoperative electrical stimulation" was introduced to test the brain's target zone before surgery in 1947. In the 1950s, Professor Heath reported about subcortical stimulation with precise descriptions of behavioral changes. In 1967, Dr. Norm Shealy from Western Reserve Medical School presented “the first dorsal column stimulator for pain control”. It was developed based on the Gate Theory of Wall and Melzack, which stated that pain transmissions from tiny nerve fibers would be blocked if competing transmissions were made along larger sensory nerve fibers.
In 1987, the team of neurosurgeons/neurologists Professor Benabid and Professor Pollak and their colleagues (Grenoble, France) published results on this topic about thalamic Deep Brain Stimulation.