Working memory recall precision is a more sensitive index than span.

Nahid Zokaei,Stephanie Burnett Heyes,Masud Husain,Sanjay Budhdeo,Nikos Gorgoraptis

doi:10.1111/jnp.12052

Nahid Zokaei, Stephanie Burnett Heyes + Show 3 more

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https://doi.org/10.1111/jnp.12052

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Abstract

Delayed adjustment tasks have recently been developed to examine working memory (WM) precision, that is, the resolution with which items maintained in memory are recalled. However, despite their emerging use in experimental studies of healthy people, evaluation of patient populations is sparse. We first investigated the validity of adjustment tasks, comparing precision with classical span measures of memory across the lifespan in 114 people. Second, we asked whether precision measures can potentially provide a more sensitive measure of WM than traditional span measures. Specifically, we tested this hypothesis examining WM in a group with early, untreated Parkinson's disease (PD) and its modulation by subsequent treatment on dopaminergic medication. Span measures correlated with precision across the lifespan: in children, young, and elderly participants. However, they failed to detect changes in WM in PD patients, either pre- or post-treatment initiation. By contrast, recall precision was sensitive enough to pick up such changes. PD patients pre-medication were significantly impaired compared to controls, but improved significantly after 3months of being established on dopaminergic medication. These findings suggest that precision methods might provide a sensitive means to investigate WM and its modulation by interventions in clinical populations.

Highlights

The storage or short-term memory component of working memory (WM) has been tested using ‘span’ measures where participants are asked to remember a string of stimuli and recall them in the same order
WM precision correlates with span, across different age ranges We first examined whether precision measures of WM correlate with digit or spatial span tasks of memory in healthy participants
WM precision correlated with traditional measures of WM, but only an index of ‘processing demand plus storage’ – backwards span – rather than forwards span, which is considered a measure of simple storage

Summary

Introduction

The storage or short-term memory component of WM has been tested using ‘span’ measures where participants are asked to remember a string of stimuli (e.g., digits) and recall them in the same order (forwards). The effects of such extra demands have been indexed by performance on Participants are presented with a sequence of oriented coloured bars and are asked to reproduce the exact orientation of one of the bars, probed by its colour, following a delay Despite their emerging use in studies of WM (Peich, Husain, & Bays, 2013; Pertzov et al, 2013), adjustment tasks have received little attention in testing patient populations. An alternative hypothesis might be that precision of recall might correlate with performance on backwards span tasks, which increase processing demand compared to forward span tests

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