Sleep and pain are definitely coupled—but how tight is this coupling?

Does Spinal Cord Stimulation Improve Sleep Disturbances Independently of Pain Relief in Patients With Chronic Pain? An Explorative, Observational Study

OBJECTIVES

Chronic pain poses a significant health challenge worldwide and is associated with both disability and reduced quality of life. Sleep disturbances are reported in 67% to 88% of patients with chronic pain. Pain and sleep affect each other reciprocally; we aimed to study this bidirectional relationship in patients treated with spinal cord stimulation (SCS) for chronic pain. Specifically, we investigated whether sleep improves after treatment with SCS and whether this improvement may be mediated by pain reduction.

MATERIALS AND METHODS

An observational cohort study was conducted in patients with chronic neuropathic pain treated with SCS at a single neurosurgical department in Denmark. Outcomes were assessed preoperatively and at three, six, and 12 months postoperatively, and thereafter annually. Primary outcomes were pain intensity (numeric rating scale) and insomnia at first follow-up (Insomnia Severity Index). The association between sleep and pain was investigated using linear regression and mediation analysis.

RESULTS

Forty-three patients were included in the study. The mean insomnia score was reduced by 25% from 18.1 (SD 6.0) to 13.5 (SD 6.6) (p = 0.0001). Pain intensity was reduced 38% from 7.4 (SD 1.6) to 4.6 (SD 2.1) at the first follow-up (p ≤ 0.0001). Changes in pain and changes in insomnia scores were significantly but weakly associated (regression coefficient = 1.3, 95% CI [0.3; 2.2], p = 0.008, r2 = 15.7%); and changes in pain score were not found to mediate changes in sleep score (β = -0.02, 95% CI [-0.15; 0.11], p = 0.76).

CONCLUSIONS

We found that patients treated with SCS showed significant improvements in both insomnia and pain intensity at first follow-up. Improvements in insomnia and pain intensity were significantly but weakly associated, and improvements in pain intensity score did not mediate improvements in insomnia score. Thus, improvements in self-reported insomnia in patients treated with SCS for chronic pain may predominantly be caused by other factors than reduced pain intensity.

Pathological Cycle between Pain, Insomnia, and Anxiety in Women with Fibromyalgia and its Association with Disease Impact

BACKGROUND

Pain, sleep disturbances, and mood disorders are considered common symptoms of fibromyalgia (FM). However, the interactions that are established between them and the implication that this has in the disease are not clear. The main objective of this study is to clarify the relationships established between insomnia, pain intensity and anxiety in women with FM. Additionally, the effect that the indicated pathological cycle between pain, insomnia and anxiety may have on the impact of the disease in these patients is explored.

METHODS

A total of 228 women diagnosed with FM participated in this study (mean age = 56.99 years, SD = 10.35). Measurements were conducted at two time points. Initially, the women completed self-report questionnaires about anxiety (The Hospital Anxiety and Depression Scale; HADS), sleep problems (The Insomnia Severity Index; ISI) and pain intensity (Brief Pain Inventory; BPI), and a week later, they answered questions about the impact of fibromyalgia (Fibromyalgia Impact Questionnaire- Revised; FIQ-R). For data analysis, models 4 and 6 of the Macro Process for SPSS were used.

RESULTS

Insomnia predicts higher levels of pain, which in turn predicts higher levels of anxiety, which in turn predicts a higher impact of fibromyalgia (B = 2.76, SE = 1.10, 95% CI = [0.79,5.11]). No significant results were found for the other interactions between the variables.

CONCLUSIONS

Due to the clinical and scientific relevance of the insomnia-pain-anxiety pathological cycle and given the impact it has on FM, it is especially relevant to develop programs for patients with fibromyalgia based mainly on improving sleep quality.

Obstructive sleep apnea is common in patients with high-impact chronic pain - an exploratory study from an interdisciplinary pain center

OBJECTIVES

Sleep disturbances are increasingly recognized as a major part of chronic pain pathology. Obstructive sleep apnea (OSA) is a common occurrence in patients with chronic pain attending specialized pain clinics, yet its prevalence remains unclear. Using screening tools such as the Berlin and STOP-BANG questionnaires may aid in early identification of OSA and improve clinical care. This study i) examined the frequency of OSA based on objective sleep monitoring in patients with high-impact chronic pain, ii) explored potential differences in self-reported pain and sleep characteristics between patients with and without OSA, and iii) tested the agreement between OSA classification based on objective assessment and two OSA screening questionnaires.

METHODS

A consecutive cohort of 90 patients (71 women and 19 men; mean age: 47.1 ± 11.0 years) referred for interdisciplinary pain treatment, underwent one night of sleep monitoring using portable respiratory polygraphy (RP), and suspected OSA was confirmed with polysomnography (PSG). Self-reported data on clinical pain (severity, pain drawings and health-related quality of life), sleep characteristics (sleep quality insomnia, sleepiness), and risk of OSA (Berlin and STOP-BANG questionnaires) were collected the day before RP assessment.

RESULTS

Forty-six (51.1%) patients were classified with OSA according to RP and verified with PSG. Twenty-eight patients (31.1%) had moderate or severe OSA (apnea-hypopnea index [AHI] >15). Patients with OSA reported lower sleep quality compared with patients without OSA. Scores on pain severity, disability, quality of life, insomnia and sleepiness were comparable between patients with and without OSA. Sensitivity and specificity were 78.6 and 45.2% respectively for the Berlin questionnaire, and 71.4 and 58.1% respectively for the STOP-BANG questionnaire. The agreement for both questionnaires with objective assessment was poor-to-fair. Both questionnaires had acceptable negative predictive values but low positive predictive values reducing the clinical utility to identify patients with low OSA-risk in this sample.

CONCLUSIONS

The current study demonstrates a high prevalence of OSA in patients with high-impact chronic pain referred to specialized pain treatment, however the clinical pain profiles were similar in patients with and without OSA. The Berlin and STOP-BANG questionnaires have poor specificity and low-to-fair agreement with RP/PSG questioning their clinical utility in identifying OSA in this sample.

Association of sleep quality status with worsening low back or knee pain during the COVID-19 state of emergency among old-old adults

Background

Poor sleep quality has a negative effect on pain among older adults. During the coronavirus disease 2019 (COVID-19) state of emergency, lifestyle changes can cause psychologic stressors and lead to poor sleep quality.

Aim

This study examined whether sleep quality status was associated with low back or knee pain changes during the COVID-19 state of emergency among community-dwelling Japanese old-old adults.

Design

Cross-sectional investigation.

Methods

In July 2020, during the COVID-19 epidemic, we conducted a postal survey for old-old adults aged ≥77 years and collected data on 597 participants. For those who had low back or knee pain at the time of the survey (in July), characteristics such as low back pain, knee pain, changes in pain status, and sleep quality status during the COVID-19 state of emergency (in March) were assessed.

Results

Data from 597 participants showed the prevalence of low back pain (50.6%) and knee pain (40.7%) in July. Of those with low back or knee pain, 374 had pain changes during the state of emergency, with 12.3% worsening. Of these, 23.9% had poor sleep quality in March compared to non-change (p = .008). In a multivariate logistic regression model adjusted for potential confounders, poor sleep quality was significantly associated with pain worsening (odds ratio 2.80, 95% confidence interval 1.26-6.22).

Conclusions

During the COVID-19 state of emergency, poor sleep quality was associated with worsening low back or knee pain. This may indicate the need to pay attention to poor sleep quality to prevent the exacerbation of pain among old-old adults.

Self-perception of insomnia, sleep quality, and musculoskeletal pain in dysphonic women: preliminary study

OBJECTIVE

To evaluate the association between musculoskeletal pain, insomnia indices, and sleep quality with voice functioning among women.

METHODS

Thirty women aged between 18 and 50 years old participated in two groups: dysphonic group (DG) - composed of 15 women diagnosed with behavioral dysphonia; and control group (CG) - composed of 15 vocally healthy women. All participants answered the Musculoskeletal Pain Investigation Questionnaire, Pittsburgh Sleep Quality Index (PSQI), and Insomnia Severity Index (ISI) questionnaires. Statistical tests were applied to compare groups and to relate outcome variables, with a significance of 5% (p<.05).

RESULTS

Dysphonic women presented a higher frequency of musculoskeletal pain in the posterior neck, lower back, masseter, submandibular, and larynx regions. There was no statistically significant difference for the other compared variables. We observed that there was a difference in the comparison between pain in some head and neck regions and the quality of sleep and evidence of insomnia, both in DG and CG.

CONCLUSIONS

Dysphonic women have a higher frequency of pain in the head and neck regions when compared to vocally healthy women. There is a difference between sleep quality, insomnia, and musculoskeletal pain, regardless of the presence of vocal and laryngeal alterations.

Less Pain, Better Sleep? The Effect of a Multidisciplinary Back Pain App on Sleep Quality in Individuals Suffering from Back Pain - a Secondary Analysis of App User Data

Purpose

Mobile health solutions are finding their way into health systems. The Kaia app has been shown to be able to reduce back pain in two studies. Since pain often comes along with disturbed sleep and both symptoms are strongly related we investigated whether the Kaia app training is associated with improved sleep quality.

Methods

User data of individuals with back pain were collected in two app versions (cohort 1: N = 180; cohort 2: N = 159). We analyzed the ratings of sleep quality and pain intensity on a 11-point numeric ratings scale (NRS; 0–10) both at the beginning of usage (baseline: BL) and on the individual last day of usage (follow-up: LU) within a 3-month training program.

Results

In both cohorts, we found a significant reduction in pain intensity from BL to LU (cohort 1: M_BL = 4.80; SD = 1.59 to M_LU = 3.75; SD = 1.76, Δ_pain = –1.04; SD = 2.12; t(158) = 6.207; p<.001/cohort 2: M_BL = 4.20; SD = 1.98 to M_LU = 3.65; SD = 1.78; Δ_pain = –0.50; SD = 2.04; t(147) = 3.001; p = 0.003) and a significant improvement of sleep quality (cohort 1: M_BL = 5.76; SD = 2.12 to M_LU = 6.56; SD = 1.72; Δ_sleep = t(158) = 4.310; p < 0.001/cohort 2: M_BL = 6.08; SD = 2.08 to M_LU = 6.76; SD = 1.55; Δ_sleep = 0.67; SD = 2.13; sleep: t(147) = 3.825; p < 0.001). Interestingly, improvement of sleep quality was not fully mediated by pain reduction.

Conclusion

Our analysis underlines the relationship between pain and sleep in the clinical context. Improvement of sleep quality came along with pain reduction and vice versa. Further study should explain the exact mechanisms of action which are associated with the improvement of both symptom parameters.

Sleep, Experimental Pain and Clinical Pain in Patients with Chronic Musculoskeletal Pain and Healthy Controls

Purpose

Everyday variations in night sleep in healthy pain-free subjects are at most weakly associated with pain, whereas strong alterations (eg, sleep deprivation, insomnia) lead to hyperalgesic pain changes. Since it remains unclear how substantial sleep alterations need to be in order to affect the pain system and lead to a coupling of both functions, the present study aimed at providing sufficient variance for co-variance analyses by examining a sample consisting of both healthy subjects and chronic pain patients.

Methods

A sample of 20 chronic musculoskeletal pain patients and 20 healthy controls was examined. This sample was assumed to show high inter-individual variability in sleep and pain, as pain patients frequently report sleep disturbances, whereas healthy subjects were required to be pain-free and normal sleepers. Sleep of two non-consecutive nights was measured using portable polysomnography and questionnaires. Experimental pain parameters (pressure pain thresholds (PPT), temporal summation of pain (TSP), conditioned pain modulation (CPM)) and situational pain catastrophizing (SCQ) were assessed in laboratory sessions before and after sleep. Pain patients’ clinical pain was assessed via questionnaire.

Results

As expected, both groups differed in several sleep parameters (reduced total sleep time and sleep efficiency, more time awake after sleep onset, lower subjective sleep quality in the patients) and in a few pain parameters (lower PPTs in the patients). In contrast, no differences were found in TSP, CPM, and SCQ. Contrary to our expectations, regression analyses indicated no prediction of overnight pain changes by sleep parameters.

Conclusion

Since sleep parameters were hardly apt to predict overnight pain changes, this leaves the association of both systems mainly unproven when using between-subject variance for verification.

Interacting Influences of Sleep, Pain, and Analgesic Medications on Sleep Studies in Rodents

This overview provides a brief summary of the complex interactions that link sleep, pain, and analgesic medications. Sleep scientists and clinicians are well aware of these relationships and understand that maintaining healthy pain-free subjects in a stable environment is essential to generating interpretable data and valid conclusions. However, these concepts and the data that support bidirectional interactions between sleep and pain may be less known to those who are not sleep scientists yet need such information to protect and advance both animal wellbeing and research validity (for example, veterinarians, IACUC members). Abundant human evidence supports the disruptive effect of pain and the modulatory effects of analgesic drugs on sleep; however, analgesic drugs can alter both sleep and the electroencephalogram, which is the primary objective measure for identifying sleep and evaluating sleep properties in both humans and animals. Consideration of the modulatory and interactive relationships of sleep, pain, and analgesic medications is essential to designing and conducting valid and reproducible sleep research using animal subjects.

Both melatonin and meloxicam improved sleep and pain in females with primary dysmenorrhea-results from a double-blind cross-over intervention pilot study

Up to 25% of ovulating women suffer from primary dysmenorrhea, a condition associated with pain and transient-reduced quality of life, along with greater irritability and impaired sleep. In the present study, we asked whether and if so to what extent melatonin and meloxicam can improve subjective and objective sleep and reduce pain among women with primary dysmenorrhea (PD). To this end, we conducted a double-blind cross-over clinical trial lasting for three menstrual cycles. A total of 14 women (mean age M = 27.5 years) with primary dysmenorrhea took part in the study. At baseline, that is, during the first menstruation, they completed a visual analogue scale to rate pain; sleep continuity was assessed via actigraphs, and overall sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI). Next, participants were randomly assigned to one of two conditions, either melatonin during the second, and meloxicam during the third menstruation, or meloxicam during the second, and melatonin during the third menstruation. Neither participants nor investigators were aware of participants' study assignment. During the second and third menstruations, the assessments described above were repeated. At baseline, sleep assessed both objectively and subjectively was impaired, and pain was high. Subjective sleep improved and pain decreased during the second and third menstruations irrespective of whether melatonin or meloxicam was administered first or second. Likewise, objective sleep efficiency increased and objective sleep latency shortened. The efficacy of melatonin was superior to that of meloxicam. The present pattern of results suggests that both melatonin and meloxicam are suitable to treat pain and PD-related sleep complaints among women with primary dysmenorrhea.