Clinical Applications

Afferent’s core technology directly improves the sensitivity of the mechanical senses in the periphery. The resulting increase in high-fidelity, information-rich sensory information provides a means to treat a range of clinical problems (Figure 1). Depending upon the medical circumstances and method of use, boosting sensory information in this manner can produce acute (i.e. immediate) beneficial neurological impact or can lead to durable changes in sensorimotor function.

Figure 1.  Building from a core ability to enhance sensory function, Afferent’s technology has a range of important clinical applications. Utility of the technology stems from both acute (i.e. immediate) neuromodulation benefits and as a driver of durable neurological impact known as neuroplasticity.

Acute Neuromodulation
Using the technology to provide continuous stimulation leads clearly to “assistive” applications in which devices are worn during activities of daily living. Of particular clinical importance is boosting lower extremity sensation as a means to improve balance and gait. In the elderly population, for whom falls and resulting injuries represent a leading cause of disability, death, and fear, sensory enhancement products can play a key role in increasing mobility and confidence. For people suffering from diabetic neuropathy, which often results in markedly compromised sensory function in the extremities, boosting sensation can help avoid skin ulceration and related morbidities. Together, these two clinical populations represent literally millions of individuals in the U.S. who could benefit from Afferent’s technology.

Durable Neurological Impact
A central finding from neuroscience research in the last two decades is that the human nervous system, including the brain, is highly changeable and adaptable. Through a process called “neuroplasticity,” the nervous system establishes new, long-lasting connections and pathways in response to changes in the person’s activities, environment, and health status. Of particular interest is the ability of the brain to recover function following stroke or trauma. Healthy regions of the brain can take up functions that previously resided at the site of injury. One of the key drivers of neuroplasticity and the attendant recovery of function following brain injury is the flow of appropriate sensory information from the periphery. Boosting sensory signaling with Afferent’s technology can improve outcomes of rehabilitation regimens.

Stroke Rehabilitation

Afferent’s lead clinical application is rehabilitation of patients with motor impairment resulting from stroke. According to the American Stroke Association, stroke is the leading cause of serious, long-term disability in the U.S., with the annual cost of stroke-related care expected to surpass $50 billion for 2006. Approximately 700,000 new strokes occur each year in the U.S. As a result, over 460,000 patients a year are left with motor impairments, the most common of which is hemiparesis, a weakness or partial paralysis on one side of the body. In addition, a majority of the 5.5 million stroke survivors in the U.S. have some degree of motor impairment. Full recovery from stroke is uncommon.

Sensory enhancement stimulation is used in conjunction with physical therapy. The goal of the combined approach is to accelerate the rate of recovery and to achieve higher levels of function attained by the rehabilitation regimen.

Afferent has extensive pre-clinical research underway at leading centers that focus on advanced methods and technologies for stroke rehabilitation. Both animal models and human subjects are being utilized to explore and establish meaningful clinical outcomes. Based on the findings of these programs, Afferent will initiate a pivotal clinical study in 2008 whose results will form the basis of regulatory filings to FDA.

Product Definitions

Afferent’s sensory enhancement technology can be realized as either noninvasive or implantable devices. Which form is optimal depends primarily upon clinical factors, e.g. whether the device is used episodically or continuously.

Noninvasive Devices
A noninvasive product under development provides both mechanical and electrical stimulation. This product consists of two primary components: 1) a battery-powered controller, and 2) skin-surface stimulation mechtrode devices. The mechtrode inputs surface mechanical stimulation to superficial sensory structures in the skin as well as electrical stimulation of deep structures.

Implantable Devices
Electrical sensory enhancement stimulation can also be delivered subcutaneously using implantable technology. Such a device would be similar to a cardiac pacemaker with its central stimulator, wire leads and electrodes, and external programmer. The rechargeable stimulator would be implanted in the abdomen or chest and leads would provide stimulation to the extremities of interest. The number of leads and the areas to be stimulated would vary depending on the needs of the patient.

Several published studies have established the ability of the Company’s technology to boost sensorimotor function in humans, including stroke patients, who exhibit chronic sensory loss or motor dysfunction. An implantable stimulator targets this condition on a continuous lifetime basis, outside the specific context of rehabilitation, and offers compliance and ease-of-use benefits.