Neurostimulation--including such modalities as deep brain stimulation (DBS), vagal nerve stimulation (VNS), and spinal cord stimulation (SCS)--has always been an area of incredible promise, though one that does not always meet its expected markets. The excitement that new devices or new indications for existing devices generate can be substantial, even if only because of the ambition of the developers. Products that first started entering the marketplace over a decade ago to treat movement disorders have branched into a wide expanse of diseases: epilepsy, Azheimer's, obsessive-compulsive disorder (OCD), depression, chronic pain, even urinary incontinence. Though not all of these have approved devices available in the United States, the list of trials continues to grow.
These being the circumstances for this class of technology, it comes as no surprise that one device manufacturer has looked to neurostimulation to provide therapy for another highly-prevalent, but challenging condition. Imthera, a San Diego based company announced last week that it had raised one million dollars for the completion of clinical trials of its implantable stimulation device for sleep apnea.
Obstructive sleep apnea (OSA) is estimated to affect roughly 18 million Americans. Challenges of diagnosis hamper the ability of sleep specialists to penetrate that total market, but even the patients that receive a sleep study and are prescribed appropriate therapy are chronically non-compliant. Adding to this patient management challenge are the substantial comorbidities and complications that these patients experience, to which a growing body of clinical evidence has expanded our knowledge of this potentially dangerous condition. It's not simply a condition that disrupts sleep, but one that has been closely linked with cardiovascular conditions such as congestive heart failure, myocardial infarction, hypertension, and stroke, as well as other troublesome conditions such as diabetes and obesity. While at this point the correlations are more certain than the causations, it's clear that treating these challenging chronic diseases must also include addressing underlying sleep disorders.
The most common treatment for OSA remains continuous positive airway pressure (CPAP), which is quite effective. The difficulty with CPAP, however, has always been compliance; patients are uncomfortable sleeping with the bulky masks, or simply are not routinely wearing it each night. Through the Imthera device, which is fully implantable, such issues would be overcome.
Imthera's Targeted Hypoglossal Neurostimulation (THN) Sleep Therapy takes the innovative approach of stimulating the tongue during sleep. The device itself consists of a small pulse generator which is implanted in the upper chest, and an electrode that is placed under the skin in the neck and attached to the Hypoglossal Nerve. Together, these two components deliver electrical energy to select tongue muscles to prevent the tongue from falling back into the throat, and thereby arresting the primary mechanism of OSA.
The clinical data available for the technology is very limited, and US studies have yet to get underway, but the device is an interesting one inasmuch as it connects two vibrant areas of industry. Neurostimulation continues to be a broad spectrum of therapies for an ever widening number of conditions, and sleep medicine continues to grow as providers start to understand the clinical imperative of managing this patient population.