Modafinil improves information processing speed and increases energetic resources for orientation of attention in narcoleptics: Double-blind, placebo-controlled ERP studies with low-resolution brain electromagnetic tomography (LORETA)

Background and purposeRecent neuroimaging studies in narcolepsy discovered significant gray matter loss in the right prefrontal and frontomesial cortex, a critical region for executive processing. In the present study, event-related potential (ERP) low-resolution brain electromagnetic tomography (LORETA) was used to investigate cognition before and after modafinil as compared with placebo.Patients and methodsIn a double-blind, placebo-controlled cross-over design, 15 patients were treated with a 3-week fixed titration scheme of modafinil and placebo. The Epworth Sleepiness Scale (ESS), Maintenance of Wakefulness Test (MWT) and auditory ERPs (odd-ball paradigm) were obtained before and after the 3 weeks of therapy. Latencies, amplitudes and LORETA sources were determined for standard (N1 and P2) and target (N2 and P300) ERP components.ResultsThe ESS score improved significantly from 15.4 (± 4.0) under placebo to 10.2 (± 4.1) under 400 mg modafinil (p = 0.004). In the MWT, latency to sleep increased nonsignificantly after modafinil treatment (11.9 ± 6.9 versus 13.3 ± 7.1 min). In the ERP, N2 and P300 latencies were shortened significantly. While ERP amplitudes showed only minor changes, LORETA revealed increased source strengths: for N1 in the left auditory cortex and for P300 in the medial and right dorsolateral prefrontal cortex.ConclusionLORETA revealed that modafinil improved information processing speed and increased energetic resources in prefrontal cortical regions, which is in agreement with other neuroimaging studies.