The following reports summarize some of the findings presented at the 2011 International Stroke Conference.
LOS ANGELES—Silent strokes, which have no immediate symptoms but can cause long-term cognitive and learning deficits, occur in a significant number of severely anemic children, especially those with sickle cell disease, researchers reported at the 2011 International Stroke Conference.
One-quarter to one-third of children with sickle cell disease have evidence of silent strokes in their brains, according to Michael M. Dowling, MD, PhD, lead author and Assistant Professor of Pediatrics and Neurology at the University of Texas Southwestern Medical Center in Dallas.
“These are 5- to 10-year-old children who have brains that look like the brains of 80-year-olds,” Dr. Dowling said. “These strokes are called ‘silent,’ because they don’t cause you to be weak on one side or have any obvious neurologic symptoms. But they can lead to poor academic performance and severe cognitive impairments.”
Sickle cell disease is a blood disorder characterized by low levels of hemoglobin, and low hemoglobin causes anemia. In sickle cell disease, the blood cells are misshapen (sickle-shaped) and may form clots or block blood vessels. About 10% of children with sickle cell disease have a stroke, and blood transfusions can reduce the high risk of repeat strokes.
Dr. Dowling and colleagues hypothesized that silent strokes occur during severe anemia and may be detectable by MRI. They used MRI on the brains of 52 hospitalized children, ages 2 to 19, at the Children’s Medical Center Dallas with hemoglobin concentrations decreasing below 5.5 g/dL. The investigators compared severely anemic children with sickle cell disease with a group of children without sickle cell disease who had hemoglobin levels below 5.5 g/dL.
The researchers identified silent strokes in about 20% of the children with sickle cell disease who were experiencing acute anemia. They also saw evidence of silent strokes, though not as often, in severely anemic children who did not have sickle cell disease.
Children could have anemia due to other reasons as well, including trauma, surgery, iron deficiency, or cancers such as leukemia.
“These are brain injuries that go unnoticed by doctors, unless the children have testing with a special MRI,” Dr. Dowling said. “We looked at every child who went to the hospital for a 30-month period and identified about 400 children who came in with hemoglobin below 5.5 g/dL. That represented about 12% of the admissions for sickle cell disease and about 1% of the total admissions to the Children’s Medical Center.”
The findings suggest that children with or without sickle cell disease who have acute anemia could have undetected brain damage. The researchers advise that all children with severe anemia be carefully examined for silent strokes. They also noted that improved recognition and timely transfusion to increase blood hemoglobin levels could prevent permanent brain damage in children with silent strokes.
Future studies should focus on larger groups of children for longer periods to better understand the impact of acute anemia on children, according to Dr. Dowling.
Robot Therapy Can Improve Arm and Shoulder Mobility After Stroke
Therapy in which robots manipulate paralyzed arms, combined with standard rehabilitation, can improve arm and shoulder mobility in patients after stroke, investigators reported.
Patients on robotic therapy showed marked improvement in two measures of upper extremity function: the Fugl-Meyer flexor synergy score, a 0-to-12 scale with higher numbers reflecting recovery of voluntary arm movement; and the Fugl-Meyer shoulder/elbow/forearm score, a 0-to-36 scale with higher numbers reflecting recovery of motor function in the shoulder, elbow, and forearm.
“Combining robotic exercise with regular rehabilitation may be the key to successful intervention,” said Kayoko Takahashi, ScD, OTR, lead author of the study and Clinician and Research Associate in the Department of Occupational Therapy in Kitasato University East Hospital in Kanagawa, Japan. Robots could allow therapists to focus on helping patients master daily activities while maintaining repetitive training, Dr. Takahashi said.
The new study involved 60 stroke survivors with hemiplegia (paralysis on one side of the body) treated at six rehabilitation centers in Japan. The patients, average age 65, had had a stroke in the previous four to eight weeks. All received standard rehabilitation therapy from an occupational therapist.
Half the group received robotic therapy every day for six weeks, in sessions lasting 40 minutes. The other half spent the same amount of time working through a standard self-training program for hemiplegic patients, performing stretches and passive-to-active exercises of their affected arm.
With a recent trend in helping patients function with one arm, “many poststroke patients have given up hope of recovery of their affected arms,” Dr. Takahashi said. “Participating in such robotic exercise is, therefore, expected to give patients insights about their future ability and a more positive image regarding their affected arm, increasing their self-efficacy and motivation toward rehabilitation.”