January 22, 2008 - By Madolyn Rogers
Jessica Rose is director of the Motion & Gait Analysis Laboratory, which provides data on the mechanics of human movement to help diagnose walking problems.
On a recent Wednesday morning, physiologist Jessica Rose, PhD, director of the Motion & Gait Analysis Laboratory at Lucile Packard Children's Hospital, sat at a table in a darkened room along with about a dozen other experts. Their attention was focused on a video of a little boy struggling to walk across a room. The boy, a 7-year-old with cerebral palsy, walked with a low crouch, one foot turning inward, and seemed constantly on the verge of tripping over his own feet.
The orthopedic surgeons, physical therapists and neurologists around the table observed him closely, debating how they could best help this patient. Was his foot giving him the most trouble? Was it his hamstrings? Or perhaps his hip?
'Let's see the data,' said a surgeon, and on the screen appeared various graphs produced by the gait lab. The graphs depicted the mechanics of the boy's walk: when he flexed his knee or ankle, how much force he generated, how his muscles were acting. Suddenly the picture became clear. The boy's hamstrings, the tendons that connect thigh muscles to the knee, were too short. The patient could be helped by a simple outpatient surgery that would lengthen his hamstrings and give him greater freedom of movement. The data from the gait lab was the crucial factor in deciding his treatment plan.
'People walk in a crouched gait for several different reasons,' explained Rose. 'It's crucial to have objective information and move the field from being an art to a science.'
Rose, assistant professor of orthopedic surgery, has been the director of the Motion & Gait Analysis Laboratory since 1989. A native of Palo Alto, her interest in gait was first sparked by a UC-Davis undergraduate class in human biomechanics. Her interest became more personal during her final year at Davis, when her sister was in a severe car accident caused by a drunken driver. Rose watched her sister struggle back from intensive care and go through years of physical therapy learning to walk again.
'She still has some difficulties walking, but does very well - swims, lives on her own and is an inspiration,' Rose said. Rose went on to get her master's degree in physical therapy and her doctoral degree in physiology, both from Stanford. She became director of the gait lab while finishing her doctorate.
The study of walking was then a very young field. It developed after World War II as physicians sought to help the many veterans who returned as amputees. One of Rose's graduate advisors, Henry Ralston, MD, PhD, of UC-San Francisco, was one of the field's founders. Ralston co-authored the first textbook on gait, Human Walking.
Rose is part of the field's second generation, and editor of the second and third editions of Human Walking. She's seen tremendous changes in the science of walking. Bioengineering and computer science have taken a much greater role, giving physicians state-of-the-art diagnostic tools. For example, the computer model that reveals hamstring performance was developed by Stanford bioengineer Scott Delp, PhD, less than five years ago, but is now an invaluable part of analysis done at the gait lab.
The lab's mission is to diagnose the underlying causes of walking problems. With this knowledge, physicians can prescribe correct treatment for their patients and avoid unnecessary surgeries. Walking is a complex activity involving bones, muscles, nerves and brain, so it's not easy to dissect the cause of a problem, Rose said. The gait lab uses a sophisticated suite of tools, including 3-D motion-capture, a technology later co-opted by Hollywood to create special effects such as the animation of Gollum in the Lord of the Rings films. Reflective markers are fastened to a patient's legs and joints to record the patient's precise movements, which are viewed in a computer animation. The lab also measures muscle activity, balance, joint movement, forces acting on the joints and energy expended during walking. All this data comes together to create a complete picture of the patient's gait, Rose said.
Most of the lab's patients are between 3 and 15 years old, and their most common disorder is cerebral palsy. This condition is the result of neurological damage occurring around the time of birth, Rose said. Premature babies are particularly susceptible; about 15 percent of babies born before 32 weeks' gestation develop the disorder.
Rose investigates the mechanisms underlying motor deficits in cerebral palsy. Her recent research revealed the strong relationship between neonatal brain abnormalities and the severity of later gait and motor deficits in preterm children. In children with cerebral palsy, muscle growth lags behind bone growth, which along with muscle spasticity (overly strong muscle tone) and impaired motor control leads to progressive difficulty in walking. Early diagnosis and intervention can help the children gain mobility, but walking may always be a challenge .
'We walk using about 30 percent of our maximum muscle activity. Kids with cerebral palsy walk using very close to 100 percent,' Rose said.
Reflecting on the struggles of her patients and her sister, she added, 'Sometimes you just have no idea how much it takes to be able to do something we all take for granted.'
Madolyn Bowman Rogers is a former science-writing intern in the School of Medicine's Office of Communication & Public Affairs.
Stanford Medicine integrates research, medical education and health care at its three institutions - Stanford School of Medicine, Stanford Health Care, and Stanford Children's Health. For more information, please visit the Office of Communications website at http://mednews.stanford.edu.