Researchers at Seoul National University Hospital have discovered that neuromuscular mechanism can maintain memory functions for an extended period in epilepsy patients who received partial brain resection surgery, the hospital said Wednesday.
|Professor Chung Chun-kee|
The team, led by Professor Chung Chun-kee of the neurology department at the hospital, published a study on patients who did not show memory impairment after removing parts of their hippocampus to treat brain tumors.
“Even after the hippocampus is partially resected, the activity of the remaining hippocampus plays a major role in maintaining memory function,” the team said. “However, the partial hippocampus remaining on the surgery side does not memory functions.”
Most of the temporal lobe epilepsy, which accounts for the majority of adult brain tumors, is mostly due to the hardening of the hippocampus. If patients do not respond to medication, doctors remove part of their temporal lobe. About 80 percent of patients that receive the operation have their symptoms improved or cured.
In the case of surgery, however, there is a possibility that it might damage the hippocampus, which is responsible for a person’s memory, inside the temporal lobe. Therefore, it is essential for doctors to choose if surgery is optimal and how much of the temporal lobe they will remove.
To confirm that patients maintained their memory functions after surgery, the team recruited patients who underwent partial resection of the medial temporal lobe to treat brain tumors. The team confirmed that the patients had proper memory functions for an average of six years after surgery.
The researchers used functional magnetic resonance imaging to measure their hippocampal activation while subjects performed tasks to memorize words and pictures. As a result, the team confirmed that the higher the hippocampal activation level on the contralateral side of the resected area, the better the memory function were for patients.
In comparison with a healthy subject, patients who had a stronger connection between the medial prefrontal lobe and the remaining hippocampus tended to have better memory functions, while such connective traits did not appear in the brain function of the healthy subject.
“The research will help medical professionals in choosing whether surgery is optimal and how much of the temporal lobe they will remove,” Professor Chung said. “The team hopes that the research will also help design other brain surgery treatments and minimize memory impairment.”
The results of the study were published in two international journals -- Journal of Neurosurgery and Human Brain Mapping.