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Parkinson’s disease is a neurodegenerative disease of the central nervous system and is primarily characterized by cardinal motor symptoms such as tremor, bradykinesia (slowness of movement), and rigidity. Lower extremity symptoms such as gait and balance disturbances (initiating movement, freezing of movement, improper movement form), especially in advanced patients, can be very debilitating, leading to decreased mobility and independence, decreased quality of life, and an increased falling/hip fracture risk ^[1]. A positive PD diagnosis occurs when a minimum of two cardinal symptoms present themselves. However, less attention is given to gait and balance abnormality as it typically develops in the advanced stages of PD.

Standard clinical assessment of gait and balance based on a 0 (no severity) – 4 (high severity) scale is performed using a subset of the Unified Parkinson’s Disease Rating Scale (UPDRS) motor section. Tasks typically consist of foot stomping while seated, gait assessment while walking, arising from chair with arms crossed over the chest, and balance assessment while being pulled backwards. As gait is particularly sensitive to ON-OFF therapy state changes in PD and incorporates upper extremity function such as arm swing as well as rigidity and bradykinesia in lower extremities, gait analysis may be a reliable method of assessing overall motor function over time in PD ^[2].

When diagnosed with PD, the first line of treatment typically consists of L-Dopa medication to alleviate motor symptoms. However over time, drug effectiveness decreases, requiring the patient to increase dosage. Frequent and stronger side effects such as dyskinesias (uncontrolled arm movement) and unpredictable “on”/”off” episodes are cause for more invasive therapeutic intervention. Deep brain stimulation (DBS) has been widely recognized as an appropriate treatment option when medication no longer adequately alleviates motor symptom severity. Several therapy targets have been established for PD. Subthalamic nucleus (STN) and Globus Pallidus Interna (GPi) stimulation are recognized treatments for sustained improvement in tremor, rigidity, and bradykinesia ^{[3, 4]}. However the effects on gait disturbance are less understood. During DBS lead placement and post-evaluation, neurologists adjust several settings: electrode contact configuration and stimulation parameters (frequency, pulse width, and amplitude). Studies show that while high-frequency/high voltage stimulation improves cardinal symptoms, patients exhibit increased frequency of freezing episodes. However, stimulation at lower frequencies has demonstrated improved gait ^[5].

New PD gait therapies are being researched and developed and existing interventions further established. Another DBS target, the pedunculopontine nucleus (PPN), located near the brain stem plays an important role in locomotion function in animal models, specifically initiation and modulation of gait ^[6-8]. Patients with advanced stages of PD only exhibit mild improvement of freezing with standard medication such as L-Dopa ^{[9, 10]}. Preliminary studies of PPN surgeries off-medication marked a significant improvement of the UPDRS motor exam section III, specifically gait and postural qualities. In addition, the combination of STN and PPN DBS resulted in a further significant improvement. Despite promising results, PPN surgical intervention is currently in its infancy as little is known about the nucleus’ function in humans and how well animal model testing translates to human clinical trials ^[7].

CleveMed is currently working with the Center for Neurological Restoration at the Cleveland Clinic to monitor motor symptoms during and after Deep Brain Stimulation surgery. To learn more about DBS, click here. Currently, motor symptoms are evaluated during multiple times during DBS surgery to determine if the optimal electrode placement has been determined. Kinesia is being used to evaluate if better methods are available for measuring these symptoms to decrease the duration of the surgery, which can last for hours while the patient is fully conscious, and increase patient comfort. One potential application is to have the patient wear the device while their motor symptoms are being evaluated. The output of Kinesia could then be used as an objective measure from which to base the movement of the electrode.

In addition to the evaluations performed during the surgery, patients need to return to the clinic post surgery to optimize the stimulator settings once the surgical location is completely healed. Here, a nurse or clinician will evaluate the motor symptoms and adjust parameters of the stimulator such as frequency, amplitude and pulse width. As the settings are adjusted, the patient completes an upper extremity evaluation and this is sometimes completed multiple times, which can result in fatigue and therefore, not the most appropriate settings. Here, Kinesia can be worn by the patient while they complete these exams and the output of the device can be correlated to the most optimal stimulator settings. This can decrease the length of time of the visit, as well as increase patient comfort. If the device is able to suggest actual setting parameters, stimulator tuning can be completed in a typical clinician’s office instead of having the patient go to specialty movement disorder centers.

Parkinson’s disease (PD) is a neurodegenerative disorder that is caused by the death of dopamine producing neurons in the brain. Primary motor symptoms of PD include tremor, rigidity, bradykinesia (slowed movements or hesitations) and gait and balance issues. Since there is currently no cure for PD, the symptoms are treated typically with pharmaceutical interventions.

One of the more common medications prescribed for PD is L-Dopa, which is used to increase levels of dopamine in the brain. While effective, a common issue with the use of L-Dopa is that there is a fine line between the correct amount of medication and too much. Too much medication results in dyskinesias, or wild, uncontrollable movements. Also, the effectiveness of L-Dopa decreases over time.

When L-Dopa is no longer effective as a treatment for PD symptoms, patients can consider a surgical procedure called deep brain stimulation, or DBS. When patients opt to have DBS surgery, tiny electrodes are implanted in the brain through a hole in the skull which emit pulses of stimulation that aide in symptom alleviation. The location of the electrode can vary depending on the patient but the two most common are subthalamic nucleus (STN) and the globus pallidus interna (GPi). A patient can also have electrodes implanted on one side of the brain or both, depending on whether their symptoms are unilateral or bilateral. The electrode or electrodes connect to a pulse generator which is typically implanted below the skin near the collarbone. The implanted pulse generator, or IPG, controls the electrode stimulation output. Parameters such as amplitude (the power of the stimulation), frequency (how often the stimulations pulses occur) and duration (how long each pulse lasts) must be set.

During DBS surgery the patient is awake and fully aware. This is because a nurse must perform motor assessments with the patient to determine if the electrode has been placed in an optimum location and depth. This assessment includes motor tasks that the patient is asked to complete to determine the severity levels of their symptoms. This can sometimes be time consuming as the patient must complete the assessment each time the electrode is moved.

Once surgery is completed, patients will return to the clinic to have the IPG settings adjusted. Again, a nurse will administer a motor assessment and alter the amplitude, frequency and duration of the pulses until an optimum combination is found with best alleviates the patient’s symptoms. This adjustment is repeated a number of times as symptoms worsen due to the progression of the disease.

While the exact reason DBS works is still not known, the number of PD patient lives the surgery has improved is dramatic. Patients with debilitating motor symptoms that leave them nearly incapable of performing activities of daily living can have the ability to move and function as they did before their diagnosis of PD. This is not to say that DBS does not have risks. It is a major surgical operation and results are not the same for each patient. The first step to determining whether or not DBS would be appropriate for any PD patient would be to discuss their options with a certified movement disorder clinician or neurologist.

CleveMed is a medical device company that specializes in developing and manufacturing miniaturized wireless monitoring devices for the clinical, research and educational fields. Every device that is developed, whether it’s for sleep disorder monitoring, movement disorder monitoring, physiological research or biomedical engineering education, is wireless and handheld or patient worn. So, why the emphasis on wireless technology?

Wireless devices are emerging as a stronghold in the medical device and research fields because of the many advantages the technology offers. Wireless equipment gives the patient or subject being monitored the ability to move freely and naturally. Using a wireless device while monitoring a patient for a sleep disorder provides the ability to get up during the study and move around without the need to be disconnected. Wireless physiological monitoring equipment increases the environments in which a subject can be monitored, such as running on a treadmill or riding a bike.

In addition to increased applications, wireless equipment increases patient and subject safety. The need to be connected to a computer or large cart mounted system is eliminated when using a wireless device. Large obtrusive wires are not necessary and not a concern to the user, letting them move naturally without the worry of pulling on wires that are connected to computers or large cart mounted systems. Wireless also means that the user does not need to be connected to any power outlets, as all CleveMed devices are powered by batteries.

Many organizations are taking advantage of the increased flexibility and reduced costs that wireless devices offer. Using wireless systems can help turn any room into a sleep lab, motion analysis center or physiological monitoring research room because there is no need for complicated wiring or extensive setup.