TUESDAY August 21, 2018 – Radiation therapy for the most common brain tumor in children can cause memory problems, new research suggests.
Concretely, young survivors struggling with memories of recent personal events can leave the little study found. But the ability of survivors to remember those who had happened before the radiation was not affected.
"There are some known cognitive effects of radiation, including memory loss in the short term and problems at school, but no one had really looked at this preservation of biographical information," said study author Melanie Sekeres.
"But it was surprising that previously acquired memories, which children had before treatment, were preserved," adds Sekeres.
She is assistant professor in psychology and neuroscience at Baylor University in Waco, Texas.
Medulloblastoma, the most common brain cancer in children, is diagnosed annually by 250 to 500 children in the United States. Radiation is usually an important part of the treatment. Although it has helped to increase survival, it also affects the developing brain.
Sekeres and her colleagues looked at 12 medulloblastoma survivors and one survivor of an ependymoma, another brain tumor in children. All were treated with surgery, followed by radiation and chemotherapy. They were compared with nine healthy children. All were between the ages of 7 and 18.
The researchers asked the children to pick up two reminders – one of an event from the past month and another from as long ago as they could remember. Brain tumor survivors reminded far less details of the recent event, such as time and place, than the healthy children.
Sekeres said that radiation can hinder the growth of nerve cells in the hippocampus, a brain area that is responsible for memory.
"Although the reduced volume of the hippocampus can be an important reason, we see changes in the brain" that can contribute to the memory problems of the children, she noted.
Sekeres said that more research is needed to learn how the hippocampus works in children who have had brain radiation. Other studies have identified movement as a way to promote the growth of nerve cells in this part of the brain, she said, and it can be used to help affected children.
"Something that is positive is that the children do seem to have memories of their early life – it is not a complete limitation during the lifetime," Sekeres said.
Dr. Matthew Ladra, director of pediatric radiotherapy oncology at the Johns Hopkins Kimmel Cancer Center at Washington's Sibley Memorial Hospital, D.C., discussed the findings.
He praised the study because he "lifted our understanding to a higher level with regard to these memories of details and a more descriptive measurement of memory loss."
Ladra agreed with Sekeres that more research is needed. He said that the next step is to determine which rehabilitation tools and techniques can help young survivors improve the thinking skills that are influenced by radiation treatment.
"Some medications can help, and there are ways to train your brain to be more involved and to actively participate in the memory process, thereby maintaining the number of memories," Ladra added.
The study was published August 20 in the JNeurosci journal of the Society for Neuroscience.
The American Cancer Association provides more information about brain cancer in children.
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