Using movies to assess cognitive and neural functioning in temporal lobe epilepsy
Abstract
Individuals with focal epilepsy whose seizures are poorly managed with medication will often undergo extensive investigations to determine surgical candidacy. These investigations make use of various methodologies to localize normal and pathological brain tissue. Temporal lobe epilepsy (TLE), the most common type of medically refractory epilepsy, can often be detected through structural and functional changes to the affected temporal lobe. On neuropsychological assessment, this dysfunction may be inferred from material-specific memory deficits, with left TLE associated with reduced verbal memory and right TLE associated with reduced visual memory. Although, simple, artificial stimuli may be useful when a clearly lateralizing pattern emerges on testing, other memory deficits may be more subtle or recruit both temporal lobes. Our primary goal with this work was to investigate the utility of a brief, engaging audiovisual film clip to assess temporal-lobe dysfunction in TLE. The first two investigations offer an evaluation of the psychometric properties of a memory test designed to investigate various aspects of memory for the movie. In the first investigation, we used a variety of recall- and recognition-based measures derived from the movie-memory test, whereas the second investigation focused on temporal memory, memory for the temporal context of events in the movie. Both chapters demonstrate the sensitivity of movie-based measures to detect cognitive deficits in TLE. In fact, movie measures appear to be more sensitive than some commonly used standardized tests. The third investigation integrated structural and movie-driven functional neuroimaging measures with performance on the movie-memory test to investigate the combined utility of these methodologies in studying temporal-lobe dysfunction in TLE. Measures of hippocampal volume and connectivity could sensitively distinguish participants with TLE from controls, and abnormal neuroimaging markers could be directly related to cognitive measures to better understand their behavioural consequences. In summary, the current investigations suggest a promising role for movie-based assessment tools in TLE, and motivate their further validation as potential clinical tools to inform surgical planning in TLE.