Spinal Cord stimulation is a method to induce a contraction in the targeted muscle by the application of electrical impulses superficially, on the skin of the person under treatment. All methods of spinal cord stimulation are based on electric devices that are implanted or placed external to the body of the patient. Spinal cord stimulation makes the spinal nerves active and responsive to the environment. This is achieved by sending a controlled and timed electric current from a device into the electrodes which are then taken to the muscle in the predetermined area resulting in a contraction of the targeted muscle. The success of electrical stimulation technology requires that the embedded motor neurons of the individual be intact for an effect to be possible in the muscle being stimulated (Allen & Goodman, 2014). There are many variations of the electrical stimulation that are applicable in different situations. Some of these are the Neuromuscular Electrical Stimulation (NMES), Russian ES, Transcutaneous electric nerve stimulation (TENS) and Functional ES (FES).
Spinal cord stimulation is sometimes applied as a treatment therapy for diseases caused by protein aggregation. Protein aggregation refers to a medical condition wherein misfolded or partially folded proteins clump together in the body causing metabolic malfunction. Protein aggregation can occur within the cell or outside the cell. This condition is known to be an underlying factor for myriad of neurodegenerative diseases including Amyotrophic Lateral Sclerosis (ALS), Parkinson’s disease, Alzheimer’s disease and Huntington’s disease (Ross & Poirier, 2004). The use of electrical stimulation has been deemed as an effective mode of therapeutic treatment for these patients. Other instances where the use of electrical stimulation is known to be highly effective include cerebral palsy, injury on the spinal cord, stroke and many neurological conditions (Allen &Goodman, 2014).
There are a lot of factors to consider during the administration of electric stimulation treatment to ensure maximum results and targeted health benefits for the patients. There are many nuances and details associated with the administration of electrical stimulation. First, frequency is an important determining factor for a successful ES treatment. Frequency is defined as the amount of electrical pulses transmitted per second. In most instances, the range of the frequency used is between 30 to 50 Hertz, but 100 Hertz is also applicable in cases where neuro-rehabilitation is required (Allen &Goodman, 2014).
Second, the duration of the pulse being administered is also critically important. Normally, a pulse that lasts for about 200 to 250 milliseconds is significant to ensure rehabilitation of the neurons. Moreover, it is shown that pulses that last over short durations cause the least amount of discomfort to the patients (Allen &Goodman, 2014). Pulse durations that vary between 350 to 450 milliseconds are used to contract paretic fibers in the affected area. The neurons that play a pivotal role in pain, sensory and motor functions are affected at this level. Pulse duration above 450 milliseconds is used to stimulate the motor function (Myolyn, 2018).
The third factor that is crucial in the administering of the ES treatment is the current. The technician is trained to gradually change the rate of current flow so as to mimic the normal conditions in which the muscles being stimulated are recruited for functions in the body. Increasing the current slowly rather than instantaneously enables the nerve fibers to get stimulated for better results. The current intensity varies from 0 to 140mA. It is important to note that there is a level at which an increase in current will not result in a bigger contraction but rather cause more discomfort. The intensity required for the procedure will vary from one patient to another. This is dependent on the patient’s impedance, muscle size, electrode size and type, and sensitivity. Lastly, the duration of the session is critical. At the beginning of the therapy, shorter sessions are recommended as the patient begins to adapt to the treatment (Allen &Goodman, 2014). Typically, an ES session lasting about 5-10 minutes is enough to gain muscle activation in many neurological conditions. A session between 10 to 30 minutes is used to observe fatigue and the level of sensitivity experienced by the patient when undergoing the treatment. Furthermore, longer sessions of 30 to 45 minutes are used to stimulate the functional actions, and anything above 45 minutes would be used to promote sustained contractions (Allen &Goodman, 2014).
There are a few devices designed to administer electrical stimulation that they are available on the market. Some of these include the NESS L300 and the WalkAide system. These two gadgets are majorly used in the treatment of forefoot dropping which is caused by the paralysis of the lower leg muscles. They are designed such that the ES is delivered on the gait swing phase which then creates ankle dorsiflexing to allow leg clearance. The stance and swing phases of the individual are detected by the tilt sensor found on the cuff of the knee (Takeda, Tanino &Miyasaka, 2017). They could also be detected by the use of a pressure sensor found in the shoe so as to accurately determine the needed stimulation periods. However, the only gadget available commercially for use on the hand and upper limb is the NESS H200. Moreover, there are TENS units that are primarily designed for use in hospitals and healthcare facilities. It is mostly utilized to provide relief from nerve pain (Stubblefield, 2016). This therapy targets key areas concerned with motor activity, namely the brain and limbs. There are some research studies that show that it can also be applied to the heart (Balint, Cassidy & Cartmell, 2012).
The effectiveness of the treatment comes across in the positive results posted by the patients undergoing this form of therapy. This technique has been proven to be of significant value for the patients experiencing weakness or pain. Some of the benefits cited from the use of this therapy have been a reduction in edema, spasticity, inflammation and pain. Moreover, patients have also reported an increase in range of motions, circulation and overall bodily functions (Thomas, et al, 2016). Most patients can attest to an improvement in their health during the course of the treatment. Despite these benefits, treatment administered using NMES comes with some side effects such as lower back pain, discomfort, headaches, muscle spasms and dizziness .
The role of an electrical engineer in the administration of the electrical stimulation treatment should be acknowledged. An electrical engineer deals with electrical, components, products, applications and systems by the conduction and design of research programs thereby applying his knowledge of materials and electricity. Since the entire basis of this technique is the use of electricity and machines, the role of an electrical engineer would be to ensure that the devices created are up to the expected standards such that they would not cause bodily harm to the patient or the one administering the treatment (Kumar, 2017).
The side effects of spinal cord stimulation are rare and mostly related to the devices used rather than physical problems. Side effects related to the use of spinal cord stimulation include haemorrhage, gastrointestinal infections, constipation and intestinal pain (Allen &Goodman, 2014).
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Ross, C. A., & M., P. (2004). Protein aggregation and neurodegenerative disease. US National Library of Medicine National Institutes of Health.
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