Learning Slope and Position Effects in Rey Auditory Verbal Learning Test: Diagnostic Value in Schizophrenia

<p>Impairments of verbal episodic memory are a central component of cognitive deficits in schizophrenia, and their investigation is important for solving diagnostic, expert and rehabilitation tasks. The study aimed to test the ability of learning slope and serial position effects to differentiate schizophrenia patients from non-psychiatric controls. Schizophrenia patients (n=618; mean age 30.31±7.46 years; 54% female) were compared to 425 healthy people (24.15±5.44 years; 60% female) and 121 individuals with the postoperative fatigue (31.56±6.20 years; 42% female) on the performance of the Rey Auditory Verbal Learning Test (RAVLT). The participants’ age range was 18–45 years. Covariate analysis adjusted for sex and age showed a decrease in all four studied learning slope measures (all p<0.001) and an increase in the recency effect (F=35.26; p<0.001; η²p=0.06) in schizophrenia patients compared to both control groups. Logistic regression differentiating patients and controls demonstrated that only the recency measure explained more variance above and beyond the total recall (p<0.001). In the schizophrenia group, a correlation analysis conditioned on total recall revealed an association between the recency and the RAVLT retroactive interference indicator (ρ=0.13; p=0.001), but not with symptoms, processing speed, or executive functions. Thus, an increased recency effect, which is likely arises, in part, due to a heightened retroactive interference, may have diagnostic significance for schizophrenia, in addition to the overall poor learning efficiency.</p>