Memory difficulties are a common problem for people with epilepsy and can be associated with perceptions of poor quality of life, academic underachievement and a lack of overall wellbeing. Although we tend to think of memory as a simple process of remembering or forgetting information, the cognitive construct is far more complex. Indeed, what people report as memory difficulties might in fact reflect poor attention skills or even a language processing problem like the inability to retrieve words quickly. Even within the cognitive memory system there are numerous sub-processes that contribute to taking in, storing and retrieving information. Each of these processes can be associated with the function of different brain regions. Much of what we know about memory representation in the brain has come from clinical reports of people with epilepsy whose seizures were treated with surgery.
For some people whose seizures are not well controlled by anti-seizure medications, including children, surgery to specific areas of the brain can be a successful approach. Epilepsy surgery in children offers the prospect of fewer seizures and improved overall quality of life. However, when brain regions that are important for cognition (thinking, learning and memory) are involved, it can have an impact on some people’s abilities following surgery. In adults, imaging-based techniques have emerged that can help predict who will experience cognitive effects after epilepsy surgery without the need for more invasive procedures. However, it is not clear how applicable these are to children, whose brains are still developing and who may be unable to perform reading tasks designed for adults.
Using scans that measure activity of different brain areas, myself, Prof Seri, Dr Foley and collaborators at Aston University’s Institute of Health and Neurodevelopment have measured brain activity of children with and without epilepsy while performing a novel verbal memory task. The task was designed to measure function of key brain areas in an area called the mesial temporal lobe, which is vital to the formation of new memories. Adults performing our task showed the expected pattern of asymmetric activation, whereas children without epilepsy showed more symmetrical activity during the same memory tasks. This suggested that the brain’s representation of memory in childhood is different to that in adults. This has been observed in other studies of children’s language representation using similar brain scanning techniques. Our findings provided important information for paediatric healthcare teams who are performing and interpreting functional brain scanning (specifically magnetic resonance imaging, MRI) in clinical practice. In particular, the presence of some activity in the opposite mesial temporal lobe in young children should be interpreted cautiously, as it might reflect a typical developmental pattern rather than activation in both sides of their brain (referred to as bilateral representation). Our ongoing research is refining the use of advanced imaging techniques, such as magnetoencephalography (or MEG) which, under Professor Seri’s leadership Aston University, has been pioneered for use in children with epilepsy.
Importantly, for children being considered for epilepsy surgery, neuropsychological assessment provides detailed information that helps to identify risk to memory skills after surgery, but there remains a need for imaging tools that can help in uncertain situations. Neuropsychological evaluation can also be helpful for children with well-controlled seizures who experience forgetfulness or difficulty learning, so that supportive strategies in the classroom can be implemented. Like adults, children who appear ‘forgetful’ sometimes have strong primary memory abilities but poor attention skills. Through understanding brain-behaviour relationships, we can provide specific recommendations on how to best support children’s education, ongoing neurodevelopment and wellbeing.
-Professor Amanda Wood