Investigation of pain sensitivity following 3 nights of disrupted sleep in healthy individuals

The Impact of Sleep Disturbances on Endogenous Pain Modulation: A Systematic Review and Meta-Analysis

The bidirectional relationship between sleep and pain problems has been extensively demonstrated but despite all the accumulating evidence, their shared mechanisms are currently not fully understood. This review examined the association between sleep disturbances, defined as a broad array of sleep-related outcomes (eg, poor quality, short duration, insomnia), and endogenous pain modulation (EPM) in healthy and clinical populations. Our search yielded 6,151 references, and 37 studies met the eligibility criteria. Qualitative results showed mixed findings regarding the association between sleep disturbances and temporal summation of pain (TSP) and conditioned pain modulation (CPM), with poor sleep more commonly associated with decreased pain inhibition in both populations. Quantitative results indicated that such associations were not statistically significant, neither in healthy populations when EPM outcomes were assessed for changes pre-/post-sleep intervention (TSP: .31 [95%CI: -.30 to .92]; P = .321; CPM: .40 [95%CI: -.06 to .85] P = .088) nor in clinical populations when such association was assessed via correlation (TSP: -.00 [95%CI: -.22 to .21] P = .970; CPM: .12 [95%CI: -.05 to .29]; P = .181). For studies that reported results by sex, meta-analysis showed that experimental sleep disturbances impaired pain inhibition in females (1.43 [95%CI: .98-1.88]; P < .001) but not in males (-.30 [95%CI: -2.69 to 1.60]; P = .760). Only one study investigating the association between sleep disturbances and offset analgesia was identified, while no studies assessing spatial summation of pain were found. Overall, this review provides a comprehensive overview of the association between sleep disturbances and EPM function, emphasizing the need for further investigation to clarify specific mechanisms and phenotypic subtypes. PERSPECTIVE: This review shines a light on the association between sleep disturbances and endogenous pain modulation function. Qualitatively, we found a frequent association between reduced sleep quality and impaired pain inhibition. However, quantitatively such an association was not corroborated. Sex-specific effects were observed, with females presenting sleep-related impaired pain inhibition but not males.

Personalized assessment and management of non-specific low back pain

BACKGROUND AND OBJECTIVE

Low back pain (LBP), and in particular non-specific low back pain (NSLBP), which accounts for approximately 90% of LBP, is the leading cause of years lived with disability worldwide. In clinical trials, LBP is often poorly categorized into 'specific' versus 'non-specific' and 'acute' versus 'chronic' pain. However, a better understanding of the underlying pain mechanisms might improve study results and reduce the number of NSLBP patients.

DATABASES AND DATA TREATMENT

Narrative review.

RESULTS

NSLBP is a multi-dimensional, biopsychosocial condition that requires all contributing dimensions to be assessed and prioritized. Thereby, the assessment of the contribution of nociceptive, neuropathic and nociplastic pain mechanisms forms the basis for personalized management. In addition, psychosocial (e.g. anxiety, catastrophizing) and contextual factors (e.g. work situation) as well as comorbidities need to be assessed and individually weighted. Personalized treatment of NSLBP further requires individually choosing treatment modalities, for example, exercising, patient education, cognitive-behavioural advice, pharmacotherapy, as well as tailoring treatment within these modalities, for example, the delivery of tailored psychological interventions or exercise programs. As the main pain mechanism and psychosocial factors may vary over time, re-assessment is necessary and treatment success should ideally be assessed quantitatively and qualitatively.

CONCLUSIONS

The identification of the main contributing pain mechanism and the integration of the patients' view on their condition, including beliefs, preferences, concerns and expectations, are key in the personalized clinical management of NSLBP. In research, particular importance should be placed on accurate characterization of patients and on including outcomes relevant to the individual patient.

SIGNIFICANCE STATEMENT

Here, a comprehensive review of the challenges associated with the diagnostic label 'non-specific low back pain' is given. It outlines what is lacking in current treatment guidelines and it is summarized what is currently known with respect to individual phenotyping. It becomes clear that more research on clinically meaningful subgroups is needed to best tailor treatment approaches.

The relation of psychological status and type D personality with central sensitization in knee osteoarthritis: everything is in your mind!

To evaluate the relation of psychosocial parameters and type D personality with central sensitization in knee osteoarthritis (OA). The study included 126 patients with knee OA according to the American College of Rheumatology criteria. Sociodemographic variables (age, gender, education, marital status, annual income), alcohol consumption/smoking, body mass index, comorbidities, and duration of symptoms were noted. Radiographic evaluation was performed according to the Kellgren-Lawrence grading system. The Western Ontario and McMaster Universities Osteoarthritis Index was used for clinical evaluation. Type D personality, negative affectivity, and social inhibition were evaluated using the type D Scale-14 (DS14). Central sensitization was assessed by the central sensitization inventory (CSI), while psychological status, quality of life, and sleep were assessed by the Hospital Anxiety and Depression Scale (HADS), an abbreviated version of the World Health Organization Quality of Life Instrument (WHOQOL-BREF), and the Jenkins Sleep Evaluation Scale (JSS), respectively. The effect of type D personality on study parameters including central sensitization, as well as the risk factors for the development of central sensitization were assessed by regression analyses. Patients with type D personality had higher CSI, HADS scores and lower WHOQOL-BREF scores for psychological health, social relationship, environment and general quality of life. Linear regression analysis showed that the DS14 total score has a significant positive relation with CSI (β = 0.4, p < 0.05), HADS-depression (β = 0.4, p < 0.05), HADS-anxiety (β = 0.5, p < 0.05), and HADS-total scores (β = 0.5, p < 0.05). It also had a significant negative effect on all domains of WHOQOL-BREF (p < 0.05 for all). Logistic regression analysis revealed that JSS [Odds ratio (OR) 0.83, 95% CI 0.73-0.94; p = 0.003] and negative affectivity (OR 0.78, 95% CI 0.65-0.94; p = 0.008) were independent risk factors for the development of central sensitization in knee OA. Type D personality has an impact on quality of life, central sensitization, and psychological health, with negative affectivity and sleep impairment serving as independent risk factors for central sensitization. While managing patients with knee OA, these intimate relationships should be taken into consideration.