Outfitted in scuba gear and 100 feet underwater, Cody Unser noticed a weird tingling in her legs. She dived a second and a third time, and again felt tingling. It was subtle, but it was the first new sensation that she had felt in three years, since becoming paralyzed from the chest down at age 12.
"I couldn't believe I had gotten some feeling back," said Unser, daughter of Indianapolis 500 champ Al Unser Jr., now 24 and leading a foundation focusing on paralysis research and quality-of-life issues called The Cody Unser First Step Foundation.
"I told my doctors, and they were a little bit interested," she said. "Now they can't stop talking about it."
The doctors at the Johns Hopkins Hospital and the Kennedy Krieger Institute have been busy presenting the data they collected in a small study in May, conducted at Unser's insistence and funded by her foundation. They found that other paraplegics showed improvements after a few days of scuba diving — improvements normally expected only after months of therapy, if at all.
Although the findings must be scientifically scrutinized and explained, they're offering rare hope for those who have used a wheelchair for years. More research could lead to new therapies to improve function and quality of life for those paralyzed through accident or disease, even years after the paralysis occurred. Already, scuba has provided Unser and others a renewed sense of well-being.
"There is no treatment for people with chronic spinal cord injury, and many believe once you've lost the communication between the brain and the extremities, there is nothing you can do to restore lost function," said Dr. Adam Kaplin, an assistant professor of psychiatry and behavioral sciences at Hopkins' School of Medicine. "What we saw in the water strongly suggests there is some scuba-facilitated restoration of neurological and psychological function in paraplegics."
The doctors began their study with standard mental and physical tests on Unser and nine veterans, paralyzed for an average of 15 years, as they sought scuba diving certification in nine dives over four days in the Cayman Islands. They retested the group and nine "dive buddies" afterward, and each vet showed temporary improvement on at least one test, while the buddies had no changes.
On physical issues, measured on a scale created by the American Spinal Cord Injury Association, spasticity, or stiffness, was reduced an average of 15 percent, and sensitivity to light touch increased by 10 percent and pinprick by 5 percent. Some disabled vets had improvement in sensation or motor function between 20 percent and 30 percent.
And in the five vets who suffered from post-traumatic stress disorder, symptoms lessened by 80 percent — a jump too big to be explained by the beautiful Caribbean vacation, the doctors said. Symptoms of obsessive-compulsive disorder and depression decreased by 15 percent.
The changes may not seem significant outside of medical circles, but continued therapy could mean permanent life improvements such as greater feeling, bladder control, relief from depression or more, said research co-director Dr. Daniel Becker. He is head of pediatric restoration therapy at Kennedy Krieger's International Center for Spinal Cord Injury and an assistant professor of neurology at Hopkins.
"This is just a pilot study, but to see such a restoration of neurological function and significant improvement in PTSD symptoms over such a short period of time was unprecedented," he said.
Scuba diving falls into an area called exercise therapy, which generally is becoming accepted as a means of improving function for paraplegics, said Kim Anderson-Erisman, a researcher and director of education at the Miami Project to Cure Paralysis at the University of Miami School of Medicine.
She said studies in recent years have shown that activities can not only improve function, but also can reduce complications from infections and other bone, skin and heart problems, particularly in those with "incomplete" injury, or those who have some sensation below the injury site. The scuba study and other research could help determine how long past an injury a person can improve, and how much, she said.
A recent study at the Miami project tested various exercise therapies for 12 weeks on paraplegics a year after injury, and showed that all worked to a degree. All therapies will likely "get a bigger bang for the buck if activity is added on top," said Anderson-Erisman, who was paralyzed by an injury nearly 23 years ago.
"Several people are starting to show activity-based interventions can improve chronic injury, not necessarily make them walk again or fix everything about their paralysis, but take a step in the right direction," she said. "For someone with paralysis, anything is huge, even if it's just improvement in your sensation."
She's watching for more studies from the doctors on scuba diving, specifically measurable data on how well it works — and how it works.
The doctors can't yet explain it, and haven't yet published their data in a medical journal or found much in the way of existing studies on scuba. But they have a theory that has to do with the effect of nitrogen in the air and pressure from the water on the central nervous system.
Because of pressure at greater depths, more nitrogen is dissolved into blood and body tissues. An effect of that process is a large increase in serotonin production in the brain and spinal cord tissues. Serotonin, a neurotransmitter found in the central nervous system, regulates mood and sleep and contributes to cognitive function.
Doctors speculate that all the extra serotonin impacts the central pattern generator in the spinal cord, which acts like a microprocessor and may activate dormant pathways — and restore some function in systems not working properly.
The short-term boost is not a true repair, which may be why the benefits to the vets wore off after a few weeks. But the doctors say treatment at regular intervals may lead to more and longer-lasting mental and physical improvements that might in turn lead to true repair of broken spinal cord pathways.