Patent Publication Number: US-2022218980-A1

Title: Systems, devices and methods for treating post-infection symptoms of covid-19 using vestibular nerve stimulation

Description:
BACKGROUND 
     Field of the Invention 
     Systems, methods and devices provided herein relate to vestibular stimulation, and more specifically to stimulating the vestibular nucleus to treat post-infection symptoms of COVID-19. 
     Related Art 
     The COVID-19 pandemic has wrought untold damage on the global population. In the United States alone, over 53 million cases have been confirmed since it first appeared around January 2020, but experts estimate that millions more have been infected and simply not diagnosed. SARS-CoV-2, the virus which causes COVID-19, has been shown to invade all parts of the human body, including the lungs, stomach, intestines, nerves and even the brain. While the most common pathway to severe disease from COVID-19 is usually the respiratory tract, significant pathology has been observed in essentially every system in the body, resulting in both physical and mental ailments. 
     While many of those infected with COVID-19 have moderate or mild symptoms and recover quickly, others may experience severe symptoms which require treatment and hospitalization. Furthermore, it has become apparent that many of those who recover from COVID-19 continue to experience symptoms or side-effects of the infection weeks or months later. These long-term symptoms are officially termed “Post-COVID Conditions” by the Centers for Disease Control and Prevention (CDC) but are often medically termed “Post-Acute Sequelae of SARS-CoV-2 infection” (“PASO”), and more popularly referred in the public as “long COVID.” 
     The mechanisms which lead to long-term post-infection symptoms of COVID-19 are poorly understood, partially because of the wide range of symptoms that affect all parts of the body, including both physical and mental health issues. Recent studies have confirmed that the SARS-CoV-2 virus may persist in certain areas of the body for months after infection, while other studies confirm that the initial infection by the virus causes a wide range of damage even after the virus is no longer present. 
     Many of the most common symptoms, most of which are acknowledged by the CDC, include: difficulty breathing or shortness of breath, tiredness or fatigue, malaise, difficulty thinking or concentrating, cough, chest or stomach pain, headache, fast-beating or pounding heart (heart palpitations), joint or muscle pain, pins-and-needles feeling, nausea, vomiting, diarrhea, abdominal pain, sleep problems and insomnia, fever, dizziness on standing (lightheadedness), rash, depression, mood changes or anxiety, change in smell or taste, and changes in menstrual period cycles. Due to the breadth of symptoms, there are likely numerous physiological pathways that result in these issues which may not be directly linked to the initial viral infection, but potentially to the body&#39;s response to the infection, such as the oft-cited inflammatory response by the immune system. 
     While some long-term symptoms can be easily explained as the result of direct cellular damage as a result of the viral infection, other symptoms, such as cognitive brain dysfunction, psychosocial stress and immune disorders have much more complex and unknown pathways. These pathways may be tied to the nervous system or the immune system, particularly with regard to brain functions that lead to fatigue, migraines and the inability to focus or concentrate. 
     There are many areas within the brain stem that control automatic functions of the body which are linked to these long-term symptoms, such as blood pressure, heart rate, kidney function, body fat and sleep. As with many brain functions, these are complex biological and neurological processes that are influenced by different physiological and neurological factors. For example, key areas of the brain thought to influence sleep include the hypothalamus, the suprachiasmatic nucleus (SCN) and the intergeniculate leaflet (IGL). 
     The vestibular system may be one pathway to treating many of these long-term symptoms. The vestibular system is a major contributor to our sense of balance and spatial orientation, and consists in each inner ear of three semicircular canals (which detect rotational movement) and the two otolith organs, termed the utricle and saccule, which detect linear acceleration and gravity (Khan &amp; Chang, 2013). They are called otolith organs as they are fluid filled sacs containing numerous free moving calcium carbonate crystals—called otoliths—which move under the influence of gravity or linear acceleration to act upon receptor cells to alter vestibular afferent nerve activity. Moreover, various studies, including a systematic review, have found dysfunction of the vestibular system following COVID-19. (See: Tan M, Cengiz D U, Demir I, et al. Effects of COVID-19 on the audio-vestibular system. Am J Otolaryngol. 2022; 43(1):103173. doi:10.1016/j.amjoto.2021.103173; Maharaj S, Bello Alvarez M, Mungul S, Hari K. Otologic dysfunction in patients with COVID-19: A systematic review.  Laryngoscope Investig Otolaryngol.  2020; 5(6):1192-1196. Published 2020 Nov. 17. doi:10.1002/lio2.498). 
     Vestibular dysfunction following COVID-19 is noteworthy as many of the symptoms associated with “long COVID” can also be brought on by vestibular dysfunction. In particular, the following symptoms are commonly seen in both vestibular dysfunction and “long COVID:” difficulty breathing or shortness of breath, tiredness or fatigue, malaise, difficulty thinking or concentrating, headache, fast-beating or pounding heart (heart palpitations), nausea, vomiting, diarrhea, abdominal pain, sleep problems and insomnia, dizziness on standing (lightheadedness), depression, mood changes or anxiety. (See: Balaban and Yates, 2004). 
     The reason for this wide array of symptoms associated with vestibular dysfunction is that the vestibular system plays a very wide (and underappreciated) role in what is called homeostasis—the maintenance of a stable internal physiological state in the body. The vestibular system is not just a sense of balance, but also provides the brain with a constantly updated account of the body&#39;s movement in space and relationship to gravity. A consequence of this is that vestibular system dysfunction can generate an array of symptoms—including but not limited to those outlined above. 
     In humans, merely standing up can cause both orthostatic hypotension (from blood pooling in the lower limbs) and decreased airflow to the lungs (from an alteration in the resting length of the respiratory musculature) (Yates, 2008). However, activation of the vestibular system acts, via the sympathetic nervous system, to normalize these homeostatic perturbations. (Balaban and Yates, 2004; McGeoch, 2010). Conversely though, vestibular dysfunction has the potential to threaten both blood pressure and blood oxygenation levels. Vestibular dysfunction could thus lead to respiratory and cardiac symptoms such as difficulty breathing or shortness of breath, fast-beating or pounding heart (heart palpitations), and dizziness on standing (lightheadedness) due to inadequate blood supply to the brain. (Balaban and Yates, 2004; McGeoch, 2010). 
     Similarly, the vestibular system is recognized to be involved in the normal homeostatic regulation of the gastrointestinal tract. (Balaban and Yates, 2004; McGeoch, 2010). A common illustration of this connection is overstimulation of the vestibular system, as is most commonly seen with motion sickness, which is well recognized to cause nausea and vomiting. It thus seems quite plausible that vestibular dysfunction could play a role in the wide array of gastrointestinal disturbances seen in “long COVID.” 
     Headaches, in particular migraines, are well recognized to involve vestibular dysfunction. (See: Dieterich M, Obermann M, Celebisoy N. Vestibular migraine: the most frequent entity of episodic vertigo. J Neurol. 2016 April; 263 Suppl 1:S82-9. doi: 10.1007/s00415-015-7905-2. Epub 2016 Apr. 15. PMID: 27083888; PMCID: PMC4833782.) The exact pathophysiology of these entities is not fully elucidated, but it again seem entirely plausible that headaches could be triggered by vestibular dysfunction. 
     The vestibular system is also recognized to play an important role in general affect (i.e. mood) and, in particular, in the pathogenesis of anxiety. (Balaban and Yates, 2004). The James-Lange theory of emotion posits that the brain generates the emotional state from the incoming sensory data on the physiological state of the body. (Craig, 2007; Craig, 2009; McGeoch, 2010). These data include that from the vestibular system. It has, thus, been recognized that vestibular dysfunction can induce a state of anxiety and thus negatively affect mood to produce negative changes and depression. (Balaban and Yates, 2004). 
     One pathway to regulating sleep via the circadian rhythm system may be through the vestibular system, as the circadian rhythm system has been found to receive input from the vestibular nuclei. Indeed, a connection between the vestibular system and fatigue is well recognized and called the sopite syndrome. The vestibular nuclei (in particular, the medial vestibular nucleus or “MVe”) are located in the pons and medulla and receive input via the vestibular nerve from the vestibular system. The MVe are thought to project (both directly and indirectly via the parieto-insular vestibular cortex (PIVC)) to the brainstem homeostatic sites of the parabrachial nucleus (PB) and the peri-aqueductal gray (PAG) (see Chapter 1 and Chapter 3, Section 8 in doctoral thesis by McGeoch, 2010). The PB seems to act to maintain homeostasis—i.e., a stable internal physiological milieu—by integrating this vestibular input with sympathetic input (via lamina 1 spino- and trigemino-thalamic tract fibers) and parasympathetic input (via the nucleus of the solitary tract) (Balaban and Yates, 2004; Craig, 2007; Craig, 2009; McGeoch et al., 2008, 2009; McGeoch, 2010). 
     It is thought that the PB then acts to maintain homeostasis by means of behavioral, neuroendocrine, and autonomic nervous system efferent (i.e., both sympathetic and parasympathetic) responses (Balaban and Yates, 2004; McGeoch, 2010). Anatomically the PB projects to the insula and anterior cingulate, amygdala and hypothalamus. The insula and anterior cingulate are areas of cerebral cortex implicated in emotional affect and motivation, and hence behavior (Craig, 2009). The hypothalamus plays a vital role in coordinating the neuroendocrine system (Balaban and Yates, 2004; Fuller et al., 2004; Craig, 2007). The amygdala (together again with the hypothalamus and insula) is similarly known to be important in autonomic nervous system control. The PB also outputs to the PAG and basal forebrain, which are also involved in homeostasis (Balaban and Yates, 2004). 
     Vestibular nerve stimulation (“VeNS”) activates all five components of the vestibular apparatus simultaneously using an electrical current (Fitzpatrick &amp; Day, 2004; St. George &amp; Fitzpatrick, 2011), and offers the practical option of being produced commercially for home use without expert supervision. VeNS involves stimulating the vestibular system through the transcutaneous application of a small electric current (usually between 0.1 to 3 milliamps (mA)) via two electrodes. The electrodes can be applied to a variety of locations around the head, but typically one is applied to the skin over each mastoid process, i.e., behind each ear. Some authors term this a “binaural application.” If a cathode and an anode are used with one placed over each mastoid, which is the most common iteration, then this is termed a bipolar binaural application of VeNS. The current can be delivered in a variety of ways, including a constant state, in square waves, a sinusoidal (alternating current) pattern and as a pulse train (Petersen et al., 1994; Carter &amp; Ray, 2007; Fitzpatrick &amp; Day, 2004; St. George &amp; Fitzpatrick, 2011). 
     There have been limited efforts to utilize vestibular stimulation to influence the physiological mechanisms controlled by the vestibular system. One effort is described in U.S. Pat. No. 6,314,324 to Lattner et al. and relies upon known vestibular treatments of counteracting vertigo by rhythmically stimulating the semicircular canal, saccule, utrical and/or ampullae. The stimulation created an artificial rocking sensation that mimics the feeling of being physically rocked back and forth, as with a baby in a bassinet. However, this therapy is designed to be carried out while a person is lying in bed so the rocking sensation will gently induce sleep and is designed to be worn during sleep to provide additional stimulation if the user&#39;s sleep pattern is disrupted. 
     Therefore, there is a need for further development of methods and devices to investigate the effects of vestibular stimulation on various physiological and psychological ailments associated with post-COVID-19 infections. 
     SUMMARY 
     Embodiments described herein provide for systems and methods for utilizing vestibular stimulation to treat post-infection symptoms of COVID-19 by influencing key areas of the brain regulated by the vestibular system which are responsible for various long-term symptoms. Stimulation can be delivered using customized signal shapes and durations delivered to the vestibular nerves via a head-mounted portable electronic device, for a specified period of time at the onset of one or more symptoms or at regular intervals over a period of days or months until the symptoms begin to alleviate. Stimulation can be provided to treat a person&#39;s physical health and/or mental health, which are both influenced by aspects of the vestibular system. 
     In one embodiment, a method of treating long-term symptoms of COVID-19 in a human subject through delivery of vestibular nerve stimulation (VeNS) comprises the steps of: positioning at least one electrode into electrical contact with the human subject and proximate to a location of the subject&#39;s vestibular system; and delivering VeNS to the human subject from a current source connected with the at least one electrode, wherein the VeNS is delivered at the onset of a long-term symptom of COVID-19. 
     In a still further embodiment, a device for treating post-infection symptoms of COVID-19 in a human subject comprises: electrodes disposed in electrical contact with the subject&#39;s scalp at a location corresponding to the subject&#39;s vestibular system; and a current source in electrical communication with the electrodes for delivering vestibular nerve stimulation (VeNS) to the subject, wherein the VeNS is delivered at the onset of at least one post-infection symptom of COVID-19. 
     Other features and advantages of the present invention will become more readily apparent to those of ordinary skill in the art after reviewing the following detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The structure and operation of the present invention will be understood from a review of the following detailed description and the accompanying drawings in which like reference numerals refer to like parts and in which: 
         FIG. 1  is a flow diagram illustrating an example method for utilizing VeNS to treat post-infection symptoms of COVID-19, according to an embodiment of the invention; 
         FIG. 2  is a chart illustrating changes in physical health and mental health of a first patient experiencing post-infection symptoms during VeNS treatment, according to one embodiment of the invention; 
         FIG. 3  is a chart illustrating changes in physical health and mental health of a second patient experiencing post-infection symptoms during VeNS treatment, according to one embodiment of the invention; 
         FIG. 4  is a diagram illustrating an exemplary square wave form for use in delivering VeNS, according to one embodiment of the invention; 
         FIGS. 5 and 6  illustrate exemplary wave forms generated by the device, according to one embodiment of the invention; 
         FIG. 7  is a diagram showing a system for treating post-infection symptoms of COVID-19 using a VeNS device with electrodes placed on a human subject, according to one embodiment of the invention; 
         FIG. 8  is a schematic diagram of an exemplary stimulator circuit for a vestibular nerve stimulation (VeNS) device, according to one embodiment of the invention; 
         FIG. 9  is a schematic diagram of an alternative embodiment of the stimulator circuit with a gain control component, according to one embodiment of the invention; 
         FIG. 10  is a schematic diagram of a second alternative embodiment of the stimulator device, according to one embodiment of the invention; 
         FIG. 11  is a diagram illustrating the vestibular system of the left inner ear; 
         FIG. 12  is a model illustrating anatomical features linking the vestibular and circadian timing systems (CTS), and 
         FIG. 13  is a block diagram illustrating an example wired or wireless processor enabled device that may be used in connection with various embodiments described herein. 
     
    
    
     DETAILED DESCRIPTION 
     Certain embodiments disclosed herein provide for stimulation of the vestibular system in such a way as to alleviate post-infection symptoms of COVID-19. For example, one method disclosed herein allows for a device with one or more electrodes placed over a subject&#39;s scalp to deliver vestibular nerve stimulation (VeNS) to the vestibular nerve, which is then carried into the vestibular nucleus in the brainstem and thereafter transmitted to the neurological components which affect sleep, mood and other biological systems which affect the numerous post-infection symptoms of COVID-19. The characteristics of the stimulation signal and duration of the treatment are configured to allow the treatment to be delivered at the onset of the one or more symptoms in order to immediately alleviate the symptoms, or at regular intervals over the course of days or weeks in order to gradually alleviate the symptoms. 
     After reading this description it will become apparent to one skilled in the art how to implement the invention in various alternative embodiments and alternative applications. However, although various embodiments of the present invention will be described herein, it is understood that these embodiments are presented by way of example only, and not limitation. As such, this detailed description of various alternative embodiments should not be construed to limit the scope or breadth of the present invention as set forth in the appended claims. 
     Methods for Treatment 
       FIG. 1  is a diagram of a method for treating a human for post-infection symptoms of COVID-19. In step  102 , one or more post-infection symptoms of COVID-19 are identified. In one embodiment, the symptoms most likely to be associated with the vestibular system may be identified in order to determine if the patient will benefit from VeNS treatment. For example, symptoms relating to cognition, sleep, anxiety and inflammation may be particularly suited for treatment via vestibular nerve stimulation. Once the specific symptoms are identified, treatment parameters are selected for applying VeNS in step  104 , including parameters relating to time intervals, wavelengths, signal shape, pulse, frequency, and duration of treatment. The specific post-infection symptoms experienced by the patient may dictate the parameters of the VeNS, based on the particular physiological or neurological mechanisms controlled by the vestibular system that are affected in different ways by the different parameters of VeNS. In step  106 , a device for delivering VeNS is positioned on the human subject by placing electrodes on one or both sides of the subject&#39;s scalp proximate to a location of the vestibular system, such as a mastoid process, as shown further below. In step  108 , the VeNS treatment is then initiated using the selected parameters and delivered to the patient for a period of time. The treatment is terminated at step  110 , after which the patient may, in step  112 , provide feedback and evaluate any changes in their physical or mental health as it relates to their identified post-infection symptoms. In step  114 , if needed, the treatment parameters may be adjusted based on the patient feedback before the VeNS treatment is applied again. 
     In one embodiment, the subject&#39;s response to the treatment may be monitored to determine the effectiveness of the treatment, for example via remote or wearable sensors, the subject&#39;s own observations about their symptoms and relative severity, and other physiological and psychological factors that may be measured over longer periods of time after multiple treatment sessions. The subject&#39;s response to the treatment may be utilized to adjust the overall treatment schedule, the parameters of the VeNS or other observed factors that may be contributing to the post-infection symptoms. 
     In order to evaluate the potential benefits of VeNS in subjects with post-infection symptoms, subjects were administered the VeNS treatment over a period of weeks and asked to evaluate various aspects of their physical health and mental health after receiving a treatment session.  FIG. 2  is an illustration of a chart showing a change in physical health and mental health for a first Patient A, as 23 year old female, over a period of 5 weeks before, during and after the beginning of regular intervals of VeNS therapy. Prior to, during and after a treatment regimen, Patient A was asked several general questions about her health and asked to provide an appropriate answer, which can then be translated into a numerical value such as a wellness score to objectively. For example, the patient may be asked to rate their physical health, mental health, mood, physical ability, fatigue, satisfaction with social activities, and other factors or specific post-infection symptoms of COVID-19 by rating them as poor, fair, or good. The answers may then be translated into a numerical score such as a Global Physics Health (T Score) or Mental Health (T Score). Subjects are asked to begin evaluating their health prior to the delivery of treatment so the affect on their health can be compared with their evaluation of their health after several weeks of treatment. 
     In  FIG. 2 , Patient A was asked to evaluate her physical health and mental health over a 5 week period beginning 1 week prior to the beginning of the delivery of VeNS treatment (baseline) at approximately 0.25 Hz and through a 4 week period after the treatment began. In this example, Patient A&#39;s physical health remained steady initially but improved starting after week 1. Meanwhile, Patient A&#39;s mental health immediately began to improve after the beginning of VeNS, despite showing no change in the week prior to the beginning of treatment, suggesting that the VeNS treatment was effective at improving Patient A&#39;s physical health and mental health. 
       FIG. 3  illustrates a chart of a change in the physical health and mental health of Patient B, a 41-year old male, over the course of delivery of VeNS for a period of 5 weeks, according to one embodiment of the invention. In this example, Patient A&#39;s physical health and mental health immediately began to improve after the beginning of VeNS and continued to improve throughout the course of treatment over the 4 week period. 
     Treatment Parameters 
     In one embodiment, the VeNS device is activated to deliver a current of approximately 0.1 mA (given a trans-mastoid resistance of about 500 kOhm) with a sinusoidal waveform at approximately 0.25 Hz. A typical current range for the device would be around 0.001 mA to around 5 mA. The subject should remain seated or lying flat throughout the session to avoid mishap due to altered balance during vestibular stimulation. The device may be set up to automatically stop after one hour however, the subject may discontinue the treatment sooner if desired. In the event the subject&#39;s balance is affected during the treatment, the subject should remain seated until their balance has returned to normal, which should occur within a short period of time after the VeNS device has been turned off. 
     The method of treatment may include delivery of vestibular stimulation at a range of frequencies that are effective at regulating various physiological and neurological mechanisms which are related to post-infection symptoms of COVID-19. In one embodiment illustrated in  FIG. 4 , the parameters of a VeNS treatment includes use of a square wave with a frequency of approximately 0.25 Hz and a current range of approximately 0.01 mA-1 mA delivered at an approximately 50 percent duty cycle. The electrodes may be placed bilaterally for delivery of stimulation to both sides of the user&#39;s head. The session length of treatment may be approximately 30 minutes to approximately 60 minutes, and the subject may initiate treatment within approximately 3 hours before the expected initiation of sleep. 
     Pulse-width modulation (PWM) in the VeNS device allows the output waveform to be accurately controlled. In this case, the waveform takes a repeating half-sine wave pattern in a positive deflection, as shown in  FIG. 5 . In one embodiment, the frequency has been predefined as 0.25 Hz, but may be set to a different value by manual control or in response to input from a sensor, such as a heart rate sensor (see, e.g.,  FIG. 7 ). The user can manually control the amplitude by adjusting the potentiometer  48 , allowing a range of 0 to 14.8V to be supplied to the electrodes. This adjustment may be effected by rotating a knob, moving a slide (physically or via a touch screen), or any other known user control mechanism. Alternatively, the potentiometer setting can automatically adjust in response to an input signal from a sensor. Relay  44  communicates the voltage adjustment to a graphical display  45  to provide a read-out of the selected voltage and/or current. 
     A relay  46  may be employed to effectively reverse the polarity of the current with every second pulse. The effect of this is shown in  FIG. 6 , where the sinusoidal pattern changes polarity, thus generating a complete sine waveform to produce alternating periods of stimulation, on the order of 1 second in duration, to the left and right mastoid electrodes  50 L and  50 R. 
     In another embodiment, the method of treatment may include delivery of vestibular stimulation at varying parameters that may be effective for different types of subjects or with different outcomes relating to the timing of the treatment and the intended start of the treatment. For example, a range of frequencies from approximately 0.0001 Hz to approximately 10000 Hz, with a range of approximately 0.01 mA to approximately 5 mA, may be utilized with any type of waveform and duty cycle, from square to sinusoidal to pulse. The treatment may be delivered via only one electrode placed on one side of the user&#39;s head at the approximate location where stimulation of the vestibular nerve can be made. The user may initiate a treatment at any time, such as the onset of a particular symptom, and may initiate a treatment session of anywhere from approximately 1 minute to approximately 120 minutes. 
     It is also notable that the stimulation is delivered in such a way as to avoid creating a rocking sensation through the delivery of stimulation at approximately 0.25 Hz and at least below approximately 0.5 Hz. These frequencies, which are sometimes referred to as “subsensory VeNS,” are slow and provide low enough power to avoid creating the rocking sensation, allowing the subject to receive the VeNS without further exacerbating existing symptoms related to dizziness. In contrast, a frequency of around 25 Hz has also proven effective but is too high for the subject to detect. 
     Vestibular Stimulation Devices 
     A comparable commercially available VeNS device sold under the trademark VESTIBULATOR™ (Good Vibrations Engineering Ltd. of Ontario, Canada) has previously been used in a number of research studies at other institutions. (Barnett-Cowan &amp; Harris, 2009; Trainor et al., 2009.) This device functions with 8 AA batteries, so that the voltage can never exceed 12 V. According to the manufacturer&#39;s specifications, the maximum current that this device can deliver is 2.5 mA. The present invention uses a more user-friendly device (e.g., the delivered current can be adjusted using a controller (knob, slide, or similar) on the side of the housing, in comparison to the VESTIBULATOR™, where a similar adjustment can only be carried out by first writing a MATLAB® script and then uploading it remotely, via BLUETOOTH®, in order to reprogram the VESTIBULATOR&#39;s™ settings.) 
     Due to the very small currents used during VeNS, the technique is believed to be safe (Fitzpatrick &amp; Day, 2004; Hanson, 2009). In particular, although electrical current can lead to cardiac arrhythmias, including ventricular fibrillation, the threshold for such an occurrence is in the 75 to 400 mA range, well above the current levels the battery powered VeNS devices can deliver. Furthermore, the electrodes will only be applied to the scalp and nowhere near the skin over the chest. 
     Resistive heating can occur with high voltage electrical stimulation of the skin. However, the voltage and current (usually below 1 mA) delivered during VeNS are well below the levels that pose this risk. Nonetheless, skin irritation can occur due to changes in pH. This may be mitigated by using large surface area (approximately 2 inch diameter) platinum electrodes and aloe vera conducting gels. 
     It may be desirable to monitor the subject&#39;s heart rate (HR) to determine the cardiac frequency during VeNS treatment. The cardiac frequency can then be used to alter the frequency of the sinusoidal VeNS so as to maintain a certain ratio between the cardiac frequency and the frequency of the sinusoidal VeNS to avoid interference with baroreceptor activity. For example, a sinusoidal VeNS frequency to cardiac frequency ratio of 0.5 would be appropriate. 
       FIG. 7  illustrates one embodiment of a VeNS device attached with a human subject for administering VeNS. An exemplary VeNS electrode  34  may be positioned on the skin behind the pinna of the left ear  36 , and over the left mastoid process, of a subject to be treated. The mastoid process is represented by dashed line  38 . The electrodes may be coated with conducting gel containing aloe vera. The right electrode (not shown) would be placed in the same manner on the skin over the right mastoid process and behind the right pinna. It should be noted that the illustrated placement of the electrodes is provided as an example only. In fact, laterality of the electrode application, e.g., electrodes precisely over both mastoid processes, is not believed to be critical, as long as each electrode is in sufficient proximity to the vestibular system to apply the desired stimulation. 
     The electrodes  34  are connected to stimulation device  40  (inside housing  30 ) by leads  33 . Manual control means, illustrated here as a simple knob  32 , may be operated to control the current or other parameters. As described above, alternative control means include a slide, touch screen, buttons or other conventional control devices. External control signals, for example, a signal from a heart rate monitor  35 , may be input into the device either wirelessly, as illustrated, or by leads running between the sensor and the device. Electrodes such as the widely commercially available 2×2 inch platinum electrodes used for transcutaneous electrical nerve stimulation (TENS) may be used in order to minimize any possible skin irritation. A conducting gel  37  may be applied between the subject&#39;s scalp and the contact surface of the electrodes to enhance conduction and reduce the risk of skin irritation. 
     The amount of current the subject actually receives depends on the scalp resistance (Iscalp=Velectrodes/Rscalp), which may vary as the user perspires, if the electrode position changes, or if contact with the skin is partially lost. It appears that the current levels quoted in the literature could only be delivered if the scalp resistance was much lower than it actually is. Measurements conducted in conjunction with the development of the inventive method and device indicate that the trans-mastoid resistance is typically between 200 to 500 k-Ohm. Thus, if a VeNS device were actually being used to deliver 1 mA, the voltage would be between 200 to 500V according to Ohm&#39;s law. The battery-powered devices that are usually used to administer VeNS are simply not capable of generating such an output. Hence, the existing reports appear to be inaccurate with regard to the actual current being delivered in VeNS. 
     Prior art designs lack consideration for each subject&#39;s unique scalp resistance, and therefore may not deliver an effective current to each patient. In the present invention, this limitation can be overcome by taking into account inter-subject scalp resistance variability as well as compensating for fluctuations in the scalp resistance that may occur throughout the procedure. To compensate for slight and fluctuating changes in scalp resistance during the administration of current, the inventive VeNS device may include an internal feedback loop that continuously compares the desired current against the actual measured current across the scalp and automatically compensates for any differences. If Rscalp increases, the Velectrodes increases to compensate. Conversely, voltage decreases when Rscalp drops. This dynamic feedback compensation loop provides constant current across the scalp for the duration of the procedure regardless of fluctuating changes in electrode-scalp impedance. 
     In one embodiment, a VeNS device provided by the company Neurovalens Ltd was used to deliver the stimulation. This device delivers a VeNS current waveform as illustrated in  FIG. 4 , which consists of an AC square wave at 0.25 Hz with a 50% duty cycle. The protocol followed was that for the first 30 minutes each subject underwent indirect calorimetry alone in order to establish a baseline. Each subject then underwent a one-hour session of binaural, bipolar VeNS with electrodes placed on the skin over each mastoid as shown in  FIG. 7 . As stated above an AC square wave at 0.25 Hz with a 50% duty cycle was delivered, in all subjects with a current of 0.6 mA, although the device used is capable of delivering more. 
     VeNS Device Circuitry 
       FIG. 8  and  FIG. 9  illustrate one possible embodiment of the VeNS circuitry that can be employed to carry out the method of the present invention. The VeNS device  20  includes a source of time-varying galvanic current that may be software programmable using a microcontroller. In one embodiment, vestibular stimulation may be provided via a head-mounted portable electronic device which is comfortably positioned onto a user&#39;s head in an area where stimulation can be delivered to one or both sides of the user&#39;s vestibular nerves. 
       FIG. 8  illustrates the basic components of an embodiment of the stimulation device  20 , which includes an operational-amplifier (“op-amp”) based constant-current source. A voltage is placed across the scalp  10  through electrodes  4  and  6  and measured by the op-amp  12 . In the exemplary embodiment, op-amp  12  may be a general purpose operational amplifier, an example of which is the LM741 series op-amp, which is widely commercially available. Selection of an appropriate operational amplifier will be within the level of skill in the art. If the voltage returning from the scalp  10  to pin  2  (inverting input) of op-amp  12  is different than the reference voltage +9V at pin  3  (non-inverting input), the operational amplifier draws from the +18V input through pin  7  to increase the amount of voltage output at pin  6 , thereby increasing the current across the scalp  10  to maintain a constant current level. Load resistor  16  is 250 ohms. Adjustment of potentiometer  14  provides gain control by decreasing the voltage input into op-amp  12  at pin  2 , thus controlling the amount of current flowing across the scalp. In the preferred embodiment, the +9V and +18V inputs are provided by one or more batteries (not shown), or a conventional DC converter may be used with appropriate safety provisions. 
     The schematic in  FIG. 9  adds control components to the basic stimulator circuit  20  of  FIG. 8 . Transistor  22 , powered by the pulse-width-modulation (PWM) output (MOSI (master output/slave input, pin  5 ) of an ATtinyl3 microcontroller  24  (Atmel Corporation, San Jose, Calif.) or similar device, may be used to control the gain of the stimulator. The PWM causes the transistor to draw more or less of the voltage entering the Op-Amp  12  (pin  2 ) to ground, thus modulating the amount of current flowing across the scalp. 
     In a preferred embodiment, the device components and any external interfaces will be enclosed within a housing  30  (shown in  FIG. 4 ) with appropriate user controls  32  for selecting stimulation parameters as appropriate. Note that a knob is shown for illustrative purposes only and that other types of controls, including switches, buttons, pressure bumps, slides, touch screens or other interface devices may be used. Optional design components that may be added to expand the functionality of the device include a memory storage device, such as a memory card or electrically erasable programmable read-only memory (EEPROM), which will allow the time, duration, and intensity of stimulations to be recorded. This can be accomplished by programming the microcontroller  24  to output a logic-level 3.4V pulse (TTL (transistor-transistor logic)) from the remaining digital out (MISO (master input/slave output, pin  6 ) to a secure digital (SD) memory card, EEPROM, USB flash drive or other data storage device via an appropriate port on the device housing. Additionally, the +18V input may be derived by integrating a charge pump, or DC-DC step-up converter, such as the MAX629 or MAX1683 (not shown). This design feature would have the benefit of reducing the size of the device by producing the necessary+18V input from smaller batteries, which can be disposable or lithium ion rechargeable. Additional features may include wireless communication circuitry, as is known in the art, for programming and/or data collection from a remote computing device, which may include a personal computer, smart phone or tablet computer. 
     Other functions for implementing VeNS in the present invention may include the ability to pulse the current at precise intervals and durations, in a sinusoidal wave with adjustable amplitude and period, and even switch polarity at precise intervals. 
     Additional options for facilitating and/or enhancing the administration of VeNS may include a built-in biofeedback capability to adjust the stimulation parameters for optimal effect based on signals generated by sensors that monitor the subject&#39;s activity and/or biometric characteristics, such as motion, position, heart rate, etc. For example, real-time heart measured by a heart-rate sensor or monitor can be used as input into the VeNS device, triggering an automatic adjustment of the sinusoidal VeNS frequency to an appropriate, possibly pre-programmed, fraction of the cardiac frequency. Real-time data on the user&#39;s motion or position measured by accelerometers may also be used as input to control stimulation, to improve effectiveness and safety. For example, treatment could be terminated if excessive motion or change in the user&#39;s position is detected, or the user can be alerted about changes in position that could have adverse effects. The heart rate sensor/monitor and/or accelerometers may be separate devices that communicate with the inventive VeNS device through a wired or wireless connection. Alternatively, sensors may be incorporated directly into the VeNS device to form a wearable “sense-and-treat” system. As new sensors are developed and adapted to mobile computing technologies for “smart”, wearable mobile health devices, a “sense-and-treat” VeNS device may provide closely tailored stimulation based on a wide array of sensor data input into the device. 
       FIG. 10  schematically illustrates an exemplary prototype of the inventive device  40  implemented using the widely commercially-available ARDUINO® Uno single board microcontroller  42  (Arduino, LLC, Cambridge, Mass.), which is based on the ATmega328 microcontroller (ATMEL® Corporation, San Jose, Calif.). Microcontroller  42  includes fourteen digital input/output pins (of which six can be used as pulse width modulation (PWM) outputs), six analog inputs, a 16 MHz ceramic resonator, a USB connection, a power jack, an ICSP header, and a reset button. The +14.8 V DC power to the circuit is provided by batteries  49 . For example, four lithium ion batteries, each providing 3.7V (1300 mAh) are used, and are preferably rechargeable via charging port  51 . 
     The device may optionally include a three color LED  52  that provides a visual display of device conditions, i.e., diagnostic guidance, such as an indication that the device is working correctly or that the battery requires recharging. 
     Optional design components may include a touch screen configuration that incorporates the potentiometer controls, a digital display of voltage and current, plus other operational parameters and/or usage history. For example, remaining battery charge, previous stimulation statistics and variations in resistance could be displayed. Additional features may include controls for alterations in the waveform such as change of frequency and change of wave type (for example square, pulse or random noise). The ARDUINO® microprocessor platform (or any similar platform) is ideally suited to incorporate feedback control or manual control of frequency, intensity or other stimulation parameters based on an external signal source. For example, the ARDUINO® microprocessor platform, if provided with BLUETOOTH® capability, can be wirelessly controlled by an iPHONE®, ANDROID®, or other smart phone, laptop or personal computer, tablet or mobile device, so that the touchscreen of the mobile device can be used to control and/or display the VeNS stimulation parameters rather than requiring a dedicated screen on the device. The mobile device may also be configured to store and analyze data from previous stimulations, providing trends and statistics about long periods of stimulation, such as over 6 months. Applications of this could allow for programs to monitor and guide users on their progress and goals, highlighting body measurements and changes in weight relative to the periods of stimulation. 
     An exemplary operational sequence for the embodiment of  FIG. 10  for use in promoting sleep may include the following steps:
         1. When the push button power switch  41  is activated, the battery(ies)  49  supply 5 volts DC to the microprocessor  42  through a 5 volt regulator and a 1 amp fuse (shown in the figure but not separately labeled.)   2. The LED  52  will flash green three times to indicate the power is “on”. If the blue light flashes the battery needs charging. While the voltage is supplied to the electrodes  50 L and  50 R, the LED  52  will flash red at regular intervals, e.g., 30 seconds to a minute.   3. The microprocessor  42  generates a 0.75 VDC half wave sign wave. The voltage is amplified to 14.8 volts by the amplifier. The sine wave completes one-half cycle in 1 second (i.e., the frequency of the sine wave is 0.25 Hz). The voltage can be varied by the potentiometer  48  from 0 to 14.8 volts.   4. After a half cycle is completed, relay  46  switches polarity of the electrodes  50 L,  50 R and the microprocessor  42  sends another half cycle. The relay  46  again switches polarity and continues for as long as the unit is “on”. This sends a full sine wave of up to +14.8 VDC to the electrodes, with the full voltage swing modulated by the potentiometer  48 .   5. A digital display  45  provides a visual indication of the voltage and current delivered to the electrodes  50 L,  50 R. Depending on the size and complexity of the display, voltage and current values may be displayed simultaneously or alternately for a short duration, e.g., 3 seconds.       

     Other device options may include user controls to allow the current to be pulsed at precise intervals and durations, a sinusoidal wave to be generated with adjustable amplitude and period, and/or to switch polarity at precise intervals. External control and monitoring via a smart phone or other mobile device as described above may also be included. Further input and processing capability for interfacing and feedback control through external or internal sensors may be included. 
     Physiological Mechanisms of VeNS 
       FIG. 11  illustrates the vestibular system of the left inner ear. The cochlea  68 , which is the peripheral organ of hearing, is also shown. It demonstrates: the anterior  62 , posterior  67 , and horizontal  63  semicircular canals, which transduce rotational movements; and the otolith organs (the utricle  66  and saccule  65 ), which transduce linear acceleration and gravity. The vestibulocochlear nerve  64  (also known as the eighth cranial nerve) is composed of the cochlear nerve (which carries signals from the cochlea), and the vestibular nerve (which carries signals from the vestibular system). 
       FIG. 12  is a model outlining potential anatomical features linking the vestibular and circadian timing systems (CTS). Light, the primary synchronizing agent for the CTS, is transmitted to the suprachiasmatic nucleus (SCN) via the retinohypothalamic tract (RHT). Nonphotic stimuli, such as locomotor activity (running wheel), are transmitted to the SCN via the intergeniculate leaflet (IGL) and the geniculohypothalamic tract (GHT). There is also evidence supporting involvement of the serotonergic midbrain raphe (dorsal and medial, dRN and mRN, respectively) in the transmission of activity information to the SCN and IGL. Morphological data also suggest that the vestibular nuclei (VN) may influence the raphe nuclei, particularly the dRN. MGR are the macular gravity receptors, T is the circadian period, and Tb is body temperature. 
     In this example, vestibular stimulation activates key areas of the brain indirectly by using the vestibular nucleus as a relay, transmitting stimulation of the vestibular system from the vestibular nucleus to the SCN, IGL and hypothalamus. In one embodiment, these neurological components act as the circadian rhythm system and may influence sleep in the human body, so the application of VeNS essentially re-regulates the circadian rhythm and excites the areas that promote sleep (while decreasing wakefulness), allowing the body to enter the sleep state at the correct time. Therefore, VeNS is capable of treating many of the post-infection symptoms of COVID-19 relating to sleep disorders, including insomnia, which also have related pathologies influencing neurological disorders such as anxiety and depression. 
     Computer-Enabled Embodiment 
       FIG. 13  is a block diagram illustrating an example wired or wireless system  550  that may be used in connection with various embodiments described herein. For example the system  550  may be used as or in conjunction with a vestibular nerve stimulation device as previously described with respect to  FIGS. 1-12 . The system  550  can be a conventional personal computer, computer server, personal digital assistant, smart phone, tablet computer, or any other processor enabled device that is capable of wired or wireless data communication. Other computer systems and/or architectures may be also used, as will be clear to those skilled in the art. 
     The system  550  preferably includes one or more processors, such as processor  560 . Additional processors may be provided, such as an auxiliary processor to manage input/output, an auxiliary processor to perform floating point mathematical operations, a special-purpose microprocessor having an architecture suitable for fast execution of signal processing algorithms (e.g., digital signal processor), a slave processor subordinate to the main processing system (e.g., back-end processor), an additional microprocessor or controller for dual or multiple processor systems, or a coprocessor. Such auxiliary processors may be discrete processors or may be integrated with the processor  560 . 
     The processor  560  is preferably connected to a communication bus  555 . The communication bus  555  may include a data channel for facilitating information transfer between storage and other peripheral components of the system  550 . The communication bus  555  further may provide a set of signals used for communication with the processor  560 , including a data bus, address bus, and control bus (not shown). The communication bus  555  may comprise any standard or non-standard bus architecture such as, for example, bus architectures compliant with industry standard architecture (“ISA”), extended industry standard architecture (“EISA”), Micro Channel Architecture (“MCA”), peripheral component interconnect (“PCI”) local bus, or standards promulgated by the Institute of Electrical and Electronics Engineers (“IEEE”) including IEEE 488 general-purpose interface bus (“GPIB”), IEEE 696/S-100, and the like. 
     System  550  preferably includes a main memory  565  and may also include a secondary memory  570 . The main memory  565  provides storage of instructions and data for programs executing on the processor  560 . The main memory  565  is typically semiconductor-based memory such as dynamic random access memory (“DRAM”) and/or static random access memory (“SRAM”). Other semiconductor-based memory types include, for example, synchronous dynamic random access memory (“SDRAM”), Rambus dynamic random access memory (“RDRAM”), ferroelectric random access memory (“FRAM”), and the like, including read only memory (“ROM”). 
     The secondary memory  570  may optionally include a internal memory  575  and/or a removable medium  580 , for example a floppy disk drive, a magnetic tape drive, a compact disc (“CD”) drive, a digital versatile disc (“DVD”) drive, etc. The removable medium  580  is read from and/or written to in a well-known manner. Removable storage medium  580  may be, for example, a floppy disk, magnetic tape, CD, DVD, SD card, etc. 
     The removable storage medium  580  is a non-transitory computer readable medium having stored thereon computer executable code (i.e., software) and/or data. The computer software or data stored on the removable storage medium  580  is read into the system  550  for execution by the processor  560 . 
     In alternative embodiments, secondary memory  570  may include other similar means for allowing computer programs or other data or instructions to be loaded into the system  550 . Such means may include, for example, an external storage medium  595  and an interface  570 . Examples of external storage medium  595  may include an external hard disk drive or an external optical drive, or and external magneto-optical drive. 
     Other examples of secondary memory  570  may include semiconductor-based memory such as programmable read-only memory (“PROM”), erasable programmable read-only memory (“EPROM”), electrically erasable read-only memory (“EEPROM”), or flash memory (block oriented memory similar to EEPROM). Also included are any other removable storage media  580  and communication interface  590 , which allow software and data to be transferred from an external medium  595  to the system  550 . 
     System  550  may also include an input/output (“I/O”) interface  585 . The I/O interface  585  facilitates input from and output to external devices. For example the I/O interface  585  may receive input from a keyboard or mouse and may provide output to a display. The I/O interface  585  is capable of facilitating input from and output to various alternative types of human interface and machine interface devices alike. 
     System  550  may also include a communication interface  590 . The communication interface  590  allows software and data to be transferred between system  550  and external devices (e.g. printers), networks, or information sources. For example, computer software or executable code may be transferred to system  550  from a network server via communication interface  590 . Examples of communication interface  590  include a modem, a network interface card (“NIC”), a wireless data card, a communications port, a PCMCIA slot and card, an infrared interface, and an IEEE 1394 fire-wire, just to name a few. 
     Communication interface  590  preferably implements industry promulgated protocol standards, such as Ethernet IEEE 802 standards, Fiber Channel, digital subscriber line (“DSL”), asynchronous digital subscriber line (“ADSL”), frame relay, asynchronous transfer mode (“ATM”), integrated digital services network (“ISDN”), personal communications services (“PCS”), transmission control protocol/Internet protocol (“TCP/IP”), serial line Internet protocol/point to point protocol (“SLIP/PPP”), and so on, but may also implement customized or non-standard interface protocols as well. 
     Software and data transferred via communication interface  590  are generally in the form of electrical communication signals  605 . These signals  605  are preferably provided to communication interface  590  via a communication channel  600 . In one embodiment, the communication channel  600  may be a wired or wireless network, or any variety of other communication links. Communication channel  600  carries signals  605  and can be implemented using a variety of wired or wireless communication means including wire or cable, fiber optics, conventional phone line, cellular phone link, wireless data communication link, radio frequency (“RF”) link, or infrared link, just to name a few. 
     Computer executable code (i.e., computer programs or software) is stored in the main memory  565  and/or the secondary memory  570 . Computer programs can also be received via communication interface  590  and stored in the main memory  565  and/or the secondary memory  570 . Such computer programs, when executed, enable the system  550  to perform the various functions of the present invention as previously described. 
     In this description, the term “computer readable medium” is used to refer to any non-transitory computer readable storage media used to provide computer executable code (e.g., software and computer programs) to the system  550 . Examples of these media include main memory  565 , secondary memory  570  (including internal memory  575 , removable medium  580 , and external storage medium  595 ), and any peripheral device communicatively coupled with communication interface  590  (including a network information server or other network device). These non-transitory computer readable mediums are means for providing executable code, programming instructions, and software to the system  550 . 
     In an embodiment that is implemented using software, the software may be stored on a computer readable medium and loaded into the system  550  by way of removable medium  580 , I/O interface  585 , or communication interface  590 . In such an embodiment, the software is loaded into the system  550  in the form of electrical communication signals  605 . The software, when executed by the processor  560 , preferably causes the processor  560  to perform the inventive features and functions previously described herein. 
     The system  550  also includes optional wireless communication components that facilitate wireless communication over a voice and over a data network. The wireless communication components comprise an antenna system  610 , a radio system  615  and a baseband system  620 . In the system  550 , radio frequency (“RF”) signals are transmitted and received over the air by the antenna system  610  under the management of the radio system  615 . 
     In one embodiment, the antenna system  610  may comprise one or more antennae and one or more multiplexors (not shown) that perform a switching function to provide the antenna system  610  with transmit and receive signal paths. In the receive path, received RF signals can be coupled from a multiplexor to a low noise amplifier (not shown) that amplifies the received RF signal and sends the amplified signal to the radio system  615 . 
     In alternative embodiments, the radio system  615  may comprise one or more radios that are configured to communicate over various frequencies. In one embodiment, the radio system  615  may combine a demodulator (not shown) and modulator (not shown) in one integrated circuit (“IC”). The demodulator and modulator can also be separate components. In the incoming path, the demodulator strips away the RF carrier signal leaving a baseband receive audio signal, which is sent from the radio system  615  to the baseband system  620 . 
     If the received signal contains audio information, then baseband system  620  decodes the signal and converts it to an analog signal. Then the signal is amplified and sent to a speaker. The baseband system  620  also receives analog audio signals from a microphone. These analog audio signals are converted to digital signals and encoded by the baseband system  620 . The baseband system  620  also codes the digital signals for transmission and generates a baseband transmit audio signal that is routed to the modulator portion of the radio system  615 . The modulator mixes the baseband transmit audio signal with an RF carrier signal generating an RF transmit signal that is routed to the antenna system and may pass through a power amplifier (not shown). The power amplifier amplifies the RF transmit signal and routes it to the antenna system  610  where the signal is switched to the antenna port for transmission. 
     The baseband system  620  is also communicatively coupled with the processor  560 . The central processing unit  560  has access to data storage areas  565  and  570 . The central processing unit  560  is preferably configured to execute instructions (i.e., computer programs or software) that can be stored in the memory  565  or the secondary memory  570 . Computer programs can also be received from the baseband processor  610  and stored in the data storage area  565  or in secondary memory  570 , or executed upon receipt. Such computer programs, when executed, enable the system  550  to perform the various functions of the present invention as previously described. For example, data storage areas  565  may include various software modules (not shown) that are executable by processor  560 . 
     Various embodiments may also be implemented primarily in hardware using, for example, components such as application specific integrated circuits (“ASICs”), or field programmable gate arrays (“FPGAs”). Implementation of a hardware state machine capable of performing the functions described herein will also be apparent to those skilled in the relevant art. Various embodiments may also be implemented using a combination of both hardware and software. 
     Furthermore, those of skill in the art will appreciate that the various illustrative logical blocks, modules, circuits, and method steps described in connection with the above described figures and the embodiments disclosed herein can often be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled persons can implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the invention. In addition, the grouping of functions within a module, block, circuit or step is for ease of description. Specific functions or steps can be moved from one module, block or circuit to another without departing from the invention. 
     Moreover, the various illustrative logical blocks, modules, and methods described in connection with the embodiments disclosed herein can be implemented or performed with a general purpose processor, a digital signal processor (“DSP”), an ASIC, FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor can be a microprocessor, but in the alternative, the processor can be any processor, controller, microcontroller, or state machine. A processor can also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
     Additionally, the steps of a method or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium including a network storage medium. An exemplary storage medium can be coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor. The processor and the storage medium can also reside in an ASIC. 
     The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles described herein can be applied to other embodiments without departing from the spirit or scope of the invention. Thus, it is to be understood that the description and drawings presented herein represent a presently preferred embodiment of the invention and are therefore representative of the subject matter which is broadly contemplated by the present invention. It is further understood that the scope of the present invention fully encompasses other embodiments that may become obvious to those skilled in the art and that the scope of the present invention is accordingly not limited.