Relevance of neurocognition in chronic pain syndrome: a systematic and methodical approach

INTRODUCTION

Subjective and objective deficits in neurocognitive domains are well-documented in patients with chronic pain. However, neurocognitive deficits have not been investigated consistently. The main objective of this study was to conduct a comprehensive assessment of self-rated and objectively assessed cognitive differences between patients with chronic pain (CP) and healthy controls (HC).

METHOD

The cognitive functioning of 40 CP and 41 HC was assessed using a standardized computer-based test battery, enabling a comparison of subjective and objective neurocognitive factors. To achieve this, the Vienna Test System (VTS) was utilized, incorporating standardized tests from the Cognitive Basic Assessment Battery (COGBAT) with the advantage of objectivity, reliability, validity, efficiency, utility, and standardization. This approach enables the evaluation of cognitive functioning across all pertinent domains.

RESULTS

CP reported cognitive deficits in overall performance as well as specific functions, such as attention, memory, and executive functions. Across all neurocognitive domains, CP showed a poorer performance. Affected subdomains of attention were intensity and selectivity of attention. Lower performance was found also in concentration performance, obtaining and overview, visual orientation performance and reactive stress tolerance. Regarding memory, CP performed worse in figural episodic memory and recognition tasks. In addition, CP exhibited poorer performance in mental flexibility, working memory, planning ability, and inhibition as components of executive functioning, when compared to HC.

CONCLUSIONS

CP expressed subjective cognitive deficits and demonstrated impaired neurocognitive performance.

Longitudinal resting-state electroencephalography in patients with chronic pain undergoing interdisciplinary multimodal pain therapy

ABSTRACT

Chronic pain is a major healthcare issue posing a large burden on individuals and society. Converging lines of evidence indicate that chronic pain is associated with substantial changes of brain structure and function. However, it remains unclear which neuronal measures relate to changes of clinical parameters over time and could thus monitor chronic pain and treatment responses. We therefore performed a longitudinal study in which we assessed clinical characteristics and resting-state electroencephalography data of 41 patients with chronic pain before and 6 months after interdisciplinary multimodal pain therapy. We specifically assessed electroencephalography measures that have previously been shown to differ between patients with chronic pain and healthy people. These included the dominant peak frequency; the amplitudes of neuronal oscillations at theta, alpha, beta, and gamma frequencies; as well as graph theory-based measures of brain network organization. The results show that pain intensity, pain-related disability, and depression were significantly improved after interdisciplinary multimodal pain therapy. Bayesian hypothesis testing indicated that these clinical changes were not related to changes of the dominant peak frequency or amplitudes of oscillations at any frequency band. Clinical changes were, however, associated with an increase in global network efficiency at theta frequencies. Thus, changes in chronic pain might be reflected by global network changes in the theta band. These longitudinal insights further the understanding of the brain mechanisms of chronic pain. Beyond, they might help to identify biomarkers for the monitoring of chronic pain.

Effect of Additional Pain Neuroscience Education in Interdisciplinary Multimodal Pain Therapy on Current Pain. A Non-Randomized, Controlled Intervention Study

Purpose

Interdisciplinary multimodal pain therapy (IMPT) programs for chronic back pain are effective and recommended. The patient-centered and biopsychosocial nature of IMPT is grounded in contemporary understanding that chronic pain states reflect heightened sensitization of the nervous system rather than an issue in the tissue. Teaching patients about pain is part of IMPT programs, though a clinical guideline is lacking. This study aims to answer the following question: Does the addition of an evidence-based pain neuroscience education (PNE) lecture for patients, into an IMPT program, produce superior results than the IMPT program itself?

Patients and Methods

A non-randomized, controlled intervention study was performed with 179 back pain patients indicated for IMPT. Intervention group (N=102) received a four-week IMPT program, which contained 4 one-hour sessions PNE. Control group (N=77) received the same IMPT without the additional PNE. Primary outcome was current pain after intervention. Pain knowledge, physical function, depression, anxiety, stress, quality of life and fear-avoidance were analyzed as secondary outcomes. Outcomes were defined as change of the parameter measured before and immediately after the four-week IMPT. For each outcome, linear regression models were used to estimate the raw and adjusted (sex, age and BMI) effect of additional PNE.

Results

Despite improvement in all outcomes for both groups during the treatment phase, the implemented PNE did not result in additional pain reduction (regression coefficient for PNE effect on pain level 0.34; 95% CI −6.23–6.97). Between-group differences could only be shown for pain-related knowledge in favor for the intervention group (0.78; 95% CI 0.35–1.20).

Conclusion

The additional PNE lecture did not lead to pain reduction beyond the usual IMPT. However, the PNE did increase pain-related knowledge and, therefore, might be helpful in coping with pain after the IMPT program.

A Meta-Epidemiological Appraisal of the Effects of Interdisciplinary Multimodal Pain Therapy Dosing for Chronic Low Back Pain

Using a meta-analysis, meta-regression, and a meta-epidemiological approach, we conducted a systematic review to examine the influence of interdisciplinary multimodal pain therapy (IMPT) dosage on pain, disability, return to work, quality of life, depression, and anxiety in published randomised controlled trials (RCTs) in patients with non-specific chronic low back pain (CLBP). We considered all RCTs of IMPT from a Cochrane review and searched PubMed for additional RCTs through 30 September 2018. A subgroup random-effects meta-analysis by length, contact, and intensity of treatment was performed followed by a meta-regression analysis. Using random and fixed-effect models and a summary relative odds ratio (ROR), we compared the effect sizes (ES) from short-length, non-daily contact, and low-intensity RCTs with long-length, daily contact, and high-intensity RCTs. Heterogeneity was quantified with the I² metric. A total of 47 RCTs were selected. Subgroup meta-analysis showed that there were larger ES for pain and disability in RCTs with long-length, non-daily contact, and low intensity of treatment. Larger ES were also observed for quality of life in RCTs with short-length, non-daily contact, and low intensity treatment. However, these findings were not confirmed by the meta-regression analysis. Likewise, the summary RORs were not significant, indicating that the length, contact, and intensity of treatment did not have an overall effect on the investigated outcomes. For the outcomes investigated here, IMPT dosage is not generally associated with better ES, and an optimal dosage was not determined.