Evidence for working memory deficits in chronic pain: A systematic review and meta-analysis

Abstract

People with chronic pain commonly report impaired cognitive function. However, to date, there has been no systematic evaluation of the body of literature concerning cognitive impairment and pain. Nor have modern meta-analytical methods been used to verify and clarify the extent to which cognition may be impaired. The objective of this study was to systematically evaluate and critically appraise the literature concerning working memory function in people with chronic pain. The study was conducted along Cochrane collaboration and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines. A sensitive search strategy was designed and conducted with the help of an expert librarian using 6 databases. Twenty-four observational studies evaluating behavioural and/or physiological outcomes in a chronic pain group and a control group met the inclusion criteria. All studies had a high risk of bias, owing primarily to lack of assessor blinding to outcome. High heterogeneity within the field was found with the inclusion of 24 papers using 21 different working memory tests encompassing 9 different working memory constructs and 9 different chronic pain populations. Notwithstanding high heterogeneity, pooled results from behavioural outcomes reflected a consistent, significant moderate effect in favour of better performance by healthy controls and, with the exception of one study, pooled results from physiological outcomes reflected no evidence for an effect. Future research would benefit from the use of clearly defined constructs of working memory, as well as standardised methods of testing.

Are Fibromyalgia Patients Cognitively Impaired? Objective and Subjective Neuropsychological Evidence

“…Reports about working memory functions are common across a wide variety of chronic pain states and, as reviewed by Berryman et al, moderate impairment in working memory can be consistently observed across studies and paradigms (35). Consistent with previous studies showing a slowdown in the response processing of FM patients (36), our patients were slower in selecting whether the target was similar to or different than a previous stimulus.…”

Cognitive deficits in chronic pain patients, in a brief screening test, are independent of comorbidities and medication use

“…Some previous studies, have associated psychological aspects to problems in cognitive areas 14 and others results have indicated that, independently of depressive symptoms, basic neurocognitive functions are impaired in patients with severe chronic pain 15 . Therefore, the main objective of the present study was to describe and analyze the cognitive evaluation of patients with chronic pain compared to control subjects with no pain.…”

The experimental analysis of the interruptive, interfering, and identity-distorting effects of chronic pain

“…Pain is a hardwired signal of bodily harm, and is designed to capture attention, and to interrupt ongoing activities (Eccleston & Crombez, 1999;Gatzounis, Schrooten, Crombez, & Vlaeyen, 2014. There is a wealth of experimental studies that demonstrate this automatic function of pain (Moore, Keogh, & Eccleston, 2012) (Berryman et al, 2013). In an example of the primary task paradigm, participants perform as quickly as possible an auditory discrimination task in the presence or absence of painful stimuli (Crombez, Eccleston, Baeyens, & Eelen, 1996.…”