Cognitive evoked potentials in narcolepsy: a review of the literature

Subtle cognitive deficits have been described in narcolepsy. They have been hypothesised to be related to changes in the hypocretin system. Event-related potential (ERP) paradigms are known to be useful tools in the investigation of information processing and seem to be sensitive to subtle neuropsychological changes. We review empirical articles on ERPs in narcolepsy in order to contribute to clarify the pattern of cognitive deficits that are specific to this disease and, possibly, to identify specific cognitive domains that improve with treatment. Fourteen peer-reviewed articles were selected for this review. These studies were conducted with passive and active oddball paradigms and support the existence of changes in cognitive attentive processing in narcolepsy, possibly in association with altered functioning of the prefrontal cortex. ERP low-resolution electromagnetic tomography revealed that modafinil improved information processing speed and increased energetic resources in prefrontal cortical areas. These findings suggest that it is worthwhile to further evaluate the usefulness of ERPs in the detection of cognitive dysfunction in this disorder before and after treatment.