Spatial Memory Rehabilitation in Virtual Reality - Extending findings from Epilepsy Patients to the General Population

Spatial memory is a critical function. Without it, we cannot understand our environment, situate ourselves within it, or remember where items are located. Most research on the neural basis of spatial memory is conducted either with invasive brain recordings from animals or with non-invasive imaging in humans. An emerging way to link these areas is by studying rare invasive recordings from the human brain, which can be obtained from epilepsy patients who have electrodes surgically implanted for seizure mapping. In recent years this invasive method has expanded our understanding of how the human brain represents space and has also suggested methods for modulating and potentially rehabilitating memory. However, it is unclear whether these results from epilepsy patients generalize to the non-epileptic population, and from testing in hospital rooms to more immersive and comfortable setups. Here, groups of epilepsy patients (n=69) and healthy participants (n=17) performed the same virtual spatial memory task, enabling us to compare their spatial memory performance. Moreover, we compared spatial memory performance between a standard computer screen versus a head-mounted display. We found that the spatial memory performance of epilepsy patients performing our task in a hospital was similar to that of matched healthy participants performing the task in the lab. Furthermore, actual spatial memory performance was similar on the group level irrespective of the interface used, despite the fact that subjects reported higher immersion with the head mounted display. By showing consistent spatial memory performance with a single paradigm across epilepsy patients and healthy participants, as well as with the use of different display modalities, our results provide a baseline for evaluating findings regarding the neural basis of spatial memory and neuromodulation for rehabilitation. More broadly, these results demonstrate that findings from neurosurgical patients are comparable to the wider population.