The clinical utility of serial position effect, contribution of processing speed, and subgroup differences in a rehabilitation sample of people with acquired brain injury

Background & Aims

Serial Positioning Effects (SPE) have been distinguished in clinical populations, and applied in research and clinical practice. In the current study, a paucity of research has been established concerning SPE in brain injury through rigorous review. This research set out to identify SPE in brain injury, further the theoretical understanding of SPE, and investigate its clinical usefulness. No research has queried the effect of processing speed (PS) in SPE, or its use as a predictor of cognitive functioning and brain injury severity. Its potential use as an indicator of effort was tested.

Method

A cross-sectional design was employed, utilising a secondary dataset which was derived from participants (N = 107) between 20-63 year’s old presenting for neuropsychological assessment in post-acute brain injury rehabilitation services. Three SPE scoring algorithms were applied through the RBANS List Learning measure to describe and analyse Primacy, Middle, and Recency region defined profiles. Groups split by Age and RBANS Coding scores constituted PS analysis. Regression analyses were employed alongside non-parametric statistics to test hypotheses.

Results

Analysis found a pronounced Primacy effect in Acquired Brain Injury (ABI). There are important differences between participants with Traumatic Brain Injury (TBI) and Cerebrovascular Accident (CVA) at Trial 1 and Overall. PS appears to be a universal advantage in the Middle region, however PS seems more important to the CVA group. Predictive modelling of SPE on an adjusted RBANS Total Index score accounted for a relatively large amount of the variance. Predicting MPAI-4 using SPE was less clear. A reduced Primacy recall profile in this sample classified participants as sub-optimally performing.

Conclusion

Findings support a Primacy effect in mild ABI, with differences between TBI and CVA evident. PS significantly impacts on SPE, but in different ways for TBI and CVA across learning trials. Future SPE research should consider mixing scoring methods, the contribution of different learning speeds on SPE profile time-points, and TBI and CVA group differences. SPE may be a valid and useful tool for assisting Clinical Psychologists in predicting cognitive functioning and understanding effort. There may be value when used in shortened test batteries.