Until now, most bladder control research has focused on treating incontinence, a major cause of health problems such as urinary tract and kidney infections, and of skin degradation. Other research teams have reported that electrical pulses with low frequencies, about 2 to 20 cycles per second, help control incontinence by calming involuntary bladder contractions, while higher-frequency pulses do not help.
The new research demonstrates that the higher-frequency pulses fail to control incontinence because they trigger bladder contractions. The team found that frequencies in the range of 20 to 40 cycles per second work best for bladder emptying.
"It was a surprise that no one had figured this out yet. But now that we understand the whole picture, we can pursue an engineered solution to help people restore bladder control," Boggs said.
"With this new understanding of the function of the pudendal nerve and the beneficial application of both high- and low-frequency pulses in controlling bladder emptying and incontinence, it should be possible for us to create a 'bladder pacemaker' analogous to a heart pacemaker," said Grill, who previously (in 2004) published preliminary human research that supports his optimism in extrapolating from the new studies with cats. Those earlier studies showed that a similar reflex in bladder contraction exists in people with SCI.
In January 2005, the National Institutes of Health awarded Grill a 5-year, $1.8 million grant to develop a system to sense involuntary bladder contractions and trigger a calming low-frequency electrical signal. The project also seeks to enable patients to generate a high-frequency signal on demand so they can emp
Contact: Deborah Hill