Neuromodulation: A Non-invasive Approach to Treating Chronic Pain, Movement Disorders, and Psychiatric Conditions

Neuromodulation involves the delivery of an electrical or chemical stimulus to specific neurological sites in the body to restore normal nervous system function and achieve relief for conditions like chronic pain, psychiatric disorders, movement disorders, and other medical conditions. Pain Relief

The unique benefits of this form of therapy have changed the focus of scholars in the field of neuroscience and have continued to draw interest from experts. It provides invasive and noninvasive approaches to managing chronic pain and other medical conditions. The first and most popular medical condition that has gained tremendously from the use of neuromodulation therapy is pain management. Indeed research has proven the efficacy of neuromodulation even in the management of pelvic disorders, ischemic disorders, headaches, and several other symptoms.

History of neuromodulation

The application of deep brain stimulation by clinical practitioners dates back to the 20^th century. Physicians and researchers have explored different technologies that achieve some symptomatic relief by stimulating sensory pathways or nerve fibers. In 1967, Dr.Norm Shealy demonstrated the first dorsal column stimulator for pain control at the Western Reserve Medical School.

Further research and application of neuromodulation therapies were restricted by the lack of adequate technology, high failure rates, and limited knowledge. However, this treatment method has evolved over the years and has come to include a wide range of electromagnetic stimuli and chemical agents that can be applied to modulate nervous tissue function.

As regards knowledge of this therapy, experts believe neuromodulation produces effects by inducing depolarizing blockade, axonal blockade, suppressing neural network oscillations, normalizing neural firing, and so on. Recent applications of neuromodulation in clinical medicine have explored its effectiveness in functional therapy for bladder control, bowel, and respiratory control, sensory deficits affecting hearing and vision, treatment for medication-resistant epilepsy, and the creation of technologically advanced medical devices. Less-invasive neuromodulation devices became a point of focus following the creation of a less-invasive stimulating electrode by a group of physicians in 1974 which could be implanted outside the subarachnoid space to enable stimulation with limited side effects.

How does neuromodulation therapy work?

Generally, the therapy involves the use of neurostimulation devices or pharmaceutical agents to either apply a direct stimulus to nerves and produce a natural response or deliver chemical agents to specific target areas.

Electrodes that are already connected to a power source can be placed at precise locations to deliver the necessary stimulation to the brain, peripheral nerves, or the spinal cord. The impulses generated can trigger neurological activity where absent, disrupt pain signals and relieve unpleasant sensations. They are usually safe, reversible, effective, and quick procedures that have been found to significantly improve symptoms and quality of life in patients.

Pain and neuromodulation

Chronic pain resistance to conventional therapy is the commonest indication for neuromodulation as physicians and patients continue to make efforts to avoid irreversible surgical treatments to relieve pain.

Spinal cord stimulation is one of the most common neuromodulation therapies for chronic pain management. The SCS device delivers low-voltage electrical impulses to the spine via a very thin lead placed in the epidural space. Neuromodulation was initially offered to patients who have tried other conventional therapies for chronic pain management but in recent times, these different neuromodulation therapies are suggested earlier in the treatment journey. They are cost-effective in the long run with significant improvements in the quality of life of patients.

Other neuromodulation techniques that have been used in the management of chronic pain include the use of an intrathecal pump which delivers small doses of specified pain medications into the spinal fluid. This method is also used in the administration of muscle relaxants to relieve symptoms of neurological diseases like cerebral palsy.

Focused ultrasound neuromodulation for pain management is believed to be the next revolutionary discovery. Several human trials have reported impressive results, especially in chronic back pain patients and it is still being explored as a new and effective non-invasive approach to pain management.

Neuromodulation and psychiatric disorders

People with different psychiatric disorders have been shown to demonstrate peculiar brain electrical activity that could be influenced to relieve symptoms and improve recovery. Electroconvulsive therapy was the first attempt at using neurostimulation to influence neural function. It is still believed by experts to be the most effective monotherapy for depression. Repetitive Transcranial Magnetic Stimulation and Transcranial Direct Current Stimulation is the most recent neuromodulation technology used in the management of psychiatric disorders.

The results of therapy depend on several factors which include the severity of the condition and the method of treatment used. Repetitive Transcranial Magnetic Stimulation involves the use of a magnetic coil to apply magnetic energy to the neurons in the brain and has been used to treat conditions like depression, hallucinations, post-traumatic disorder, anxiety disorder, and other mental health conditions.

Movement disorders and neuromodulation

The aims of neuromodulation in the treatment of movement disorders like dystonia and Parkinson’s disease include; reducing the need for surgery, reducing dependence on medications, and improving speed, quality, and ease of movement.

Understanding that movement is controlled and regulated by the interaction of brain structures led to the exploration of neuromodulation therapies in the treatment of movement disorders. Disruptions in the normal transmission or coordination of impulses result in significant movement disorders. These disorders may be characterized by abnormalities in the amplitude of movement, and abnormal involuntary movements and usually worsen over time.

Deep brain stimulation has become the most sought-after neuromodulation therapy for the treatment of Parkinson’s disease, dystonia, and essential tremor. This therapy targets the globus pallidus internus, subthalamic nucleus, or the ventral intermediate nucleus of the thalamus and can replace ablative surgery in certain patients.

This therapy is offered to patients with complications of Parkinson’s disease which is responsive to Levodopa but cannot be controlled only with the medications. Several studies confirm that deep brain stimulation improves the quality of life and reduces pain significantly in most patients. The mechanism of action during deep brain stimulation has not yet been fully understood but is believed to at least include silencing or inactivation of target neurons. Reported complications include hardware complications, surgical complications like intracerebral hemorrhage, and stimulation-related adverse effects like worsened speech and gait.

Advances in deep brain stimulation are opening pathways for innovations in functional imaging, treatment of tremors in conditions like multiple sclerosis, and advanced neurostimulation devices with better control and improved efficiency.

Conclusion

Neuromodulation influences neurological activity by acting on the natural response of the nerves in the body to electrical and chemical stimuli. Current technologies already in application in different fields of medicine include invasive and noninvasive modalities with varying results depending on the individual, the disease condition, and the type of treatment. Invasive neuromodulation methods include spinal cord stimulation and deep brain stimulation while non-invasive methods include; Transcranial direct current stimulation and Electroconvulsive therapy. Chemical methods include; trans thecal drug delivery systems. As research advances and more knowledge is gained in the benefits and application of these therapies, neuromodulation methods will gradually become more common in the management of several complex disease conditions.