Exploring serial positioning effects in Claeson-Dahl's Test for verbal learning and retention – a naturalistic study

Abstract: Serial positioning effects and the derived recency ratio has shown increasing promise as clinical tools for evaluating neurocognitive disorders. These measures have remained unexplored in Claeson-Dahl’s Test for verbal learning and retention (CDT). To correct this, the present study used naturalistic sample data (N = 110) from a project intended to update CDT’s norms. I hypothesized the prevalence of three serial positioning curves: learning trial one (LT-1), retention and learning phase. Curves were constructed based on correctly recalled words for LT-1, retention, and learning phase proportional recall scores. Assessment of serial positioning patterns were made using visual inspection followed by statistical confirmation. Following this, regional variables of primacy, middle, and recency, were computed using the corrected regional scoring method on learning phase scores. These scores answered the research question, which was directed at exploring regional variables relationships with age, sex-related differences, and education. LT-1 and learning phase curves were confirmed to assume this pattern, while retention didn’t. No significant differences between sexes on regional variables were found, joined by an absence of shared relationships between age and education. Exclusive relationships were however confirmed between regions, age, and education. The second research hypothesis assumed that recency ratio scores were positively predicted by age, independent of sex and education. No statistically significant differences between sexes were found, neither were there a statistically significant correlation with education. This, combined with age positively correlated with recency ratio scores, confirmed the second research hypothesis. Further research with these measures using CDT in clinical samples seems feasible.