Measuring Somatosensory Working Memory Deficits in Fibromyalgia
Research type
Research Study
Full title
Towards a neuropsychological profile of chronic pain: Development and validation of a novel measure of somatosensory working memory deficits in fibromyalgia.
IRAS ID
281672
Contact name
Christopher Brown
Contact email
Sponsor organisation
University of Liverpool
Duration of Study in the UK
1 years, 5 months, 31 days
Research summary
Summary of Research
Aims: Working memory (WM) is the ability to hold information in mind for short periods. This study aims to assess atypical WM and a subtype of WM, somatosensory working memory (SWM) – which is the ability to hold tactile information in mind for short periods - in people with fibromyalgia, a chronic pain condition. Objectives:
1. To validate a new measure of the way ‘higher’ thinking skills influence SWM by assessing whether it produces consistent effects across patient and healthy groups.
2. To provide preliminary data and indicators of how large differences in WM and SWM ability between patient and control groups might be. This will inform and contribute to a future larger-scale study.Summary of Results
Background: This study explored the role of Working Memory (WM), a cognitive process, in contributing to Chronic Pain (CP) conditions. It was a quantitative study seeking to validate a novel measure of WM, while also providing pilot data concerning potential differences in WM functioning between participants with Fibromyalgia (FM), a CP condition, and Healthy Controls (HC). Working Memory deficits are frequently reported and demonstrated through formal assessment in people with a diagnosis of fibromyalgia, but the precise characterisation of these difficulties remains vague. At the time of conducting this study, measures of Working Memory only cover a limited range of timescales and sensory modalities, restricting research into the topic and assessment in clinical settings.
Objective: This study aimed primarily to develop and provide evidence for the population and construct validity of a measure of Auditory Working Memory on a timescale of 10s of seconds to minutes by assessing reproducibility across clinical and control groups. The auditory sensory modality was chosen as most practical in the context of the COVID-19 pandemic, allowing home-based online task administration. Its secondary aims were to provide pilot data concerning differences between participants with fibromyalgia and healthy controls on measures of general and Auditory Working Memory; and to provide preliminary evidence for any relationships between clinical and experimental measures of Working Memory, and between general Working Memory and Auditory Working Memory capacity.
Methods: A newly developed measure of Auditory Working Memory was administered to 17 participants with fibromyalgia and 17 healthy controls, aged between 18-64 years old. Fifteen of each group were included in the final analysis. This novel measure manipulated the exposure to different probabilities of auditory stimulus parameters across different blocks in a within-subjects design, allowing to quantify top-down influences (prior experience) on parametric Auditory Working Memory. Accuracy and reaction times were analysed to validate the measure across the two groups separately, and both combined. It was hypothesised that increased probabilities would decrease top-down influences on parametric Auditory Working Memory, while decreased probabilities would lead to an increase in this effect, which would be consistent across groups, providing evidence of population and construct validity. A partial correlation between the novel measure and existing Working Memory tests was also hypothesised, providing evidence towards criterion validity. Preliminary evidence of Auditory Working Memory deficits for participants with fibromyalgia, and a positive correlation between clinical and experimental measures of Working Memory, which would provide evidence towards concurrent validity of the experimental measure, were further hypotheses.
Results: Consistent outcomes regarding Auditory Working Memory were found across the separate and combined groups in terms of effect sizes and means, suggesting population validity, although statistical significance was only reached for the combined group. As expected, manipulating the probability of auditory stimulus parameters across blocks biased participants’ judgements towards their average characteristics, thereby supporting construct validity of the measure, although this was not the case for all probability distributions. Evidence of criterion validity was not found, which may reflect the different constructs being measured in the novel and existing measures. Further analysis found a significant association between clinical and experimental measures of Working Memory with a large effect size, suggesting concurrent validity for the experimental measure, and subtle evidence of poorer performance on measures of Working Memory and Auditory Working Memory by participants with fibromyalgia than healthy controls.
Conclusions: This study met its objectives by providing evidence of population and construct validity for a measure of Auditory Working Memory on a scale of 10s of seconds to minutes, demonstrating its ability to elicit reproducible top-down effects on working memory, and supporting its utility for further research into Working Memory deficits in fibromyalgia and ultimately for assessment in clinical settings. Some unexpected findings which contradicted the hypotheses, particularly that there was no evidence of an impact of top-down Working Memory on parametric Working Memory in one experimental condition, can be used to inform further refinement of this measurement tool.
Dissemination: This study was written-up and presented internally within the University of Liverpool as part of a Doctorate in Clinical Psychology thesis submitted by Dr Chris Knaggs. There are plans for publications of the findings in a suitable peer-reviewed scientific journal. Participants who opted to receive a summary of the results of the study will be sent a lay version of this report in due course.REC name
London - Bloomsbury Research Ethics Committee
REC reference
20/PR/0545
Date of REC Opinion
15 Jan 2021
REC opinion
Further Information Favourable Opinion