More than five million people have had a stroke, according to the Centers for Disease Control and Prevention (Atlanta) and about 22% of survivors end up with foot drop, a partial leg paralysis that prevents the foot from lifting.

Bioness (Valencia, California) reported data at this year’s International Stroke Conference on its therapeutic electrical stimulation device, showing that daily use of the NESS L300 neuroprosthesis over a 12-month period enabled patients experiencing chronic hemiparesis and foot drop following stroke or traumatic brain injury to significantly improve their ability to walk.

Patients typically have relied on rigid plastic braces that restrict ankle movement and sometimes lead to additional problems.

The study served as a one-year follow-up on patient outcomes from a NESS L300 study published last month in the American Journal of Physical Medicine and Rehabilitation. The findings were presented by Gad Alon, associate professor at the University of Maryland School of Medicine (Baltimore).

“The real breakthrough is that [for] the first time a technology really makes it easy and simple for patients to use it,” Alon told Medical Device Daily. “I’m encouraged by the findings that demonstrate the clinical benefits with short-term use of the L300, as well as ongoing improvements with continued use over time, as evidenced by the 12-month study.”

Alon said that the NESS L300 also would benefit survivors of traumatic brain injury with foot drop. It was approved by the FDA in 2006 (Medical Device Daily, August 31, 2006).

The study followed 16 patients with foot drop who were at least six months, post-stroke or traumatic brain injury. Evaluations of their gait with the NESS L300 were conducted in four sessions: at baseline (with and without the NESS L300), then after one month, two months and one year.

Each session measured enrollees on common gait indicators: walking speed, single limb stance, gait symmetry and stride time. Participants were measured with special calibrated insoles that recorded their actions during a six-minute walking test and a 10 meter walk over an obstacle course.

The NESS L300 integrates electronics into a wireless design. Sensors in the system detect whether the patient’s foot is in the air or on the ground and communicate wirelessly to a microprocessor placed just below the knee. As the patient walks, low-level stimulation is sent to the underlying nerves and muscles that control the lifting of the foot.

“Patients feel a tingling sensation with this non-invasive electrostimulation,” Alon said. “You have electrodes that you put over the skin and they give a small amount of electrical current that makes the muscle contract. This device only works on certain types of patients. You really never know if you’re a good candidate unless you are evaluated in a clinic, so it’s not something they can just sell over the Internet.”

The 1.5 ounce neuroprosthesis, less than three inches tall and two inches wide, includes a rechargeable battery with buttons that allow users to adjust intensity. Cost ranges between $5,700 and $5,900.

In other news from the conference:

New indicators for the possibility of stroke were highlighted at this year’s meeting: clues from mammograms, daytime dozing and blood/sugar tests.

• Using mammography, Amy Loden and Paul Dale, MD, of the University of Missouri Medical School (Columbia) studied calcium deposits in the walls of arteries that supply the breasts, which are different from the calcifications in breast tissue that can signal the presence of a tumor.

Dale, a cancer surgeon, said previous studies have linked these deposits with the risk for heart disease. He and his team found these deposits in 11% of roughly 800 women having routine mammograms. They then looked at the mammograms of 204 stroke patients and found the deposits in 56% of them, five times more often.

Greater stroke risk was seen in women of all ages with the deposits, but especially those in their 40s and 50s. Dale said he will follow up with a study to determine if calcium deposits can be used to predict who will suffer strokes later. He said the study data indicates that radiologists should report these deposits to doctors for follow-up evaluation for stroke and heart disease.

• A research team at Columbia University (New York) found that a scoring system to evaluate daytime dozing strongly predicted stroke risk.

They asked 2,100 people, average age 73, how often they nodded off while doing such things as watching TV, reading, sitting and talking to someone, sitting in traffic, or sitting quietly after lunch. In the next two years, 40 had strokes and 127 had other blood vessel-related problems, such as heart attacks or blood clots in the lungs.

The odds of having a stroke were nearly five times greater among those identified as “heavy dozers,” and nearly three times greater among “occasional dozers,” compared with people who rarely nodded off. The chances of other vessel-related problems also increased.

• Tatjana Rundek, MD, at the University of Miami (Florida) led a study of 1,735 non-diabetic people, average age 68, in a long-running study of stroke risk in New York.

This study used a test called HOMA, a ratio of blood-sugar and insulin levels measured after fasting. High scores signal insulin resistance, and one-fourth had high scores. Those in that group had twice the risk of stroke, compared to those with lower HOMA scores.