Specific Cognitive Training Normalizes Auditory Sensory Gating in Schizophrenia: A Randomized Trial

Background: The ratio of scalp-recorded brain responses occurring 50 msec after paired clicks (S2-evoked P50/S1-evoked P50) serves as a measure of sensory gating. An abnormally large ratio is commonly found in schizophrenia and is considered as a sign of reduced sensory gating or otherwise dysfunctional organization of the auditory/verbal system as a factor contributing to psychopathology and cognitive dysfunction in schizophrenia. This initial randomized clinical trial compared the efficacy of two 4-week, computer-based cognitive training methods that emphasize either auditory discrimination and verbal memory or a broader range of cognitive functions in schizophrenia. Methods: Thirty-nine schizophrenia patients (ICD-F20.0 diagnosis) were assigned to Cognitive Exercises (CE) or Cognitive Package (Cogpack). The M50, the magnetoencephalographic analogue of electroencephalographic P50, and performance on verbal learning and memory tests were used to evaluate training effects. Results: As expected, patients exhibited higher pretreatment gating ratios than 28 age-matched healthy comparison participants. Gating ratios decreased after CE but not after Cogpack. Cognitive test performance improved more after CE than after Cogpack. Conclusions: Appropriately specific psychological training changes the neural performance in schizophrenia, normalizing sensory and cognitive function.