In a recent study of individuals with schizophrenia-spectrum illness (ESZ), targeted auditory training appeared to improve the function of the efference copy/corollary discharge mechanism, which tended to deteriorate with computer games. 49 individuals early in the course of an ESZ were randomly assigned to 40 hours of Targeted Auditory Training (TAT; n=23) or Computer Games (CG; n=26). The N1 event-related brain potential (ERP) component was elicited during production (Talk) and playback (Listen) of vocalization. Effects of Treatment on Global Cognition, N1 suppression (Talk-Listen), and N1 during Talking and Listening were assessed. Simple effects of the passage of time were also assessed in healthy controls after 28 weeks. Researchers found:
- There was a Treatment × Time interaction revealing that N1 suppression was improved with TAT, but not with CG.
- TAT, but not CG, also improved Global Cognition.
- However, TAT and CG groups differed in their pre-treatment N1 suppression, and greater N1-suppression abnormalities were strongly associated with greater improvement in N1 suppression.
Roach BJ, Ford JM, Biagianti B, et al. Efference copy/corollary discharge function and targeted cognitive training in patients with schizophrenia. [Published online ahead of print December 29, 2018]. Int J Psychophysiol. doi:10.1016/j.ijpsycho.2018.12.015.
Corollary discharge is the mechanism whereby individuals can distinguish self-generated from externally generated perceptions. When an individual talks, corollary discharge mechanisms suppress the normal auditory cortical response to self-generated sounds. However, corollary discharge is abnormal in schizophrenia and this abnormality is speculated to explain some of the positive symptoms of schizophrenia, including auditory hallucinations. This comparative trial compared the effects of Targeted Auditory Training (TAT) vs computer game exposure and found that TAT improved markers of corollary discharge. While interpretation of findings need to be made with caution given the small sample size and other design limitations, the results are exciting and potentially important. Current existing pharmacologic treatments for patients with schizophrenia can reduce auditory hallucinations, but drug treatments are also often accompanied by burdensome side effects and/or can fail to fully resolve symptoms.—Martha Sajatovic, MD, Professor of Psychiatry and of Neurology; Willard Brown Chair in Neurological Outcomes Research; Director, Neurological and Behavioral Outcomes CenterUniversity Hospitals Cleveland Medical Center; Case Western Reserve University School of Medicine.