The Effects of Working Memory Updating Training in Parkinson's Disease: A Feasibility and Single-Subject Study on Cognition, Movement and Functional Brain Response.

Lois Walton,Magdalena Eriksson Domellöf,Erik Domellöf,Anna Stigsdotter Neely,Lars Forsgren,Louise Rönnqvist,Carl-Johan Boraxbekk,David Bäckström

doi:10.3389/fpsyg.2020.587925

Abstract

In Parkinson’s disease (PD), the fronto-striatal network is involved in motor and cognitive symptoms. Working memory (WM) updating training engages this network in healthy populations, as observed by improved cognitive performance and increased striatal BOLD signal. This two-part study aimed to assess the feasibility of WM updating training in PD and measure change in cognition, movement and functional brain response in one individual with PD after WM updating training. A feasibility and single-subject (FL) study were performed in which patients with PD completed computerized WM updating training. The outcome measures were the pre-post changes in criterion and transfer cognitive tests; cognitive complaints; psychological health; movement kinematics; and task-related BOLD signal. Participants in the feasibility study showed improvements on the criterion tests at post-test. FL displayed the largest improvements on the criterion tests and smaller improvements on transfer tests. Furthermore, FL reported improved cognitive performance in everyday life. A shorter onset latency and smoother upper-limb goal-directed movements were measured at post-test, as well as increased activation within the striatum and decreased activation throughout the fronto-parietal WM network. This two-part study demonstrated that WM updating training is feasible to complete for PD patients and that change occurred in FL at post-test in the domains of cognition, movement and functional brain response.

Highlights

Parkinson’s disease (PD) has traditionally been defined as a predominantly motor disorder due to dopamine (DA) depletion, which has led to cognitive symptoms being under recognized in the clinical practice (Barone et al, 2011)
An improvement on the criterion test was seen by an increase in the total number of items correct and number of correct recalled 4-letter sequences with z-score changes of 2.96 and 2.84, respectively
Substantial near transfer effects were visible through an increase in the total number of items correct and number of correct recalled 4-digit sequences in the Number Memory test with corresponding z-score changes of 1.39 and 1.3

Summary

Introduction

Parkinson’s disease (PD) has traditionally been defined as a predominantly motor disorder due to dopamine (DA) depletion, which has led to cognitive symptoms being under recognized in the clinical practice (Barone et al, 2011). PD patients with cognitive symptoms report lower overall quality of life (Leroi et al, 2012), display a faster decline in cognitive abilities (Broeders et al, 2013) and are more likely to be diagnosed with PD dementia at a 5-year follow-up (Domellöf et al, 2015). Some motor and cognitive symptoms, such as bradykinesia and working memory (WM), show a positive correlation (Domellöf et al, 2011) and share an underlying reliance on DA availability in the fronto-striatal network (Kehagia et al, 2012). Standard treatment in the form of dopamine replacement therapy aims to increase dopaminergic availability, yet does not lead to clear benefits in cognitive functioning (MacDonald and Monchi, 2011; Roy et al, 2018). Non-pharmacological interventions that aim to enhance DA are interesting candidates in the PD population

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