Neuroplasticity-based training may normalise auditory gating in schizophrenia and improve verbal processing

Abstract

An unusually large response ratio in the auditory paired-click task is a common finding for schizophrenia patients. In the present magnetoencephalographic (MEG) pairedclick design, sensory gating ratio (SGR) served to study effects of computer-based cognitive exercises (CE, Posit Science, SF), which emphasizes auditory discrimination and verbal memory, with the aim of improving signal-to-noise ratio of auditory/verbal processing in schizophrenia. Across 100 paired-click trials, M50 was scored as peak amplitude of the magnetic field 40 80 ms post S-onset; SGR were determined in source space (activity of two best-fitting equivalent current dipoles, one in each hemisphere). In an ongoing study, 21 patients (F20.0 ICD-10) exhibited higher SGR than 17 sex and age-matched healthy subjects, F(1, 39) 5 6.68, po.01. SGR tended to decrease during the course of CE (20 sessions within 4 weeks) in 12 patients, F(2, 10) 5 7.43, p o .01; right hemisphere SGR declined from .57 to .39, p o .01; left hemisphere .58 to .44, p 5 .09. No such decrease was observed in a 9 patients accomplishing standard cognitive training F(2, 7) 5 .36, p 5 .7 (Cogpack,Markersoftware). Performance in verbal memory improved only after CE (p o .01), though largely unrelated to SGR changes. Results indicate that MEG-based SGR assessment can track the course of successful auditory training and provide preliminary evidence that the auditory training tasks employed here provide a specific impact on sensory gating.