Measurement of nocturnal body motility: behaviour of osteoarthritic patients and healthy controls

Spontaneous painful disease in companion animals can facilitate the development of chronic pain therapies for humans

OBJECTIVE

To outline the role that spontaneous osteoarthritis (OA) in companion animals can play in translational research and therapeutic pharmacological development.

OUTLINE

Narrative review summarizing the opportunities and limitations of naturally occurring, spontaneous OA as models of human OA pain, with a focus on companion animal pets. The background leading to considering inserting spontaneous disease models in the translational paradigm is provided. The utility of this model is discussed in terms of outcome measures that have been validated as being related to pain, and in terms of the potential for target discovery is outlined. The limitations to using companion animal pets as models of human disease are discussed.

CONCLUSIONS

Although many steps along the translational drug development pathway have been identified as needing improvement, spontaneous painful OA in companion animals offers translational potential. Such 'models' may better reflect the complex genetic, environmental, temporal and physiological influences present in humans and current data suggests the predictive validity of the models are good. The opportunity for target discovery exists but is, as yet, unproven.

Sleep, Pain Catastrophizing, and Central Sensitization in Knee Osteoarthritis Patients With and Without Insomnia

OBJECTIVE

Osteoarthritis (OA), a chronic degenerative joint disorder, is characterized by joint pain. Emerging research demonstrates that a significant number of patients evidence central sensitization (CS), a hyperexcitability in nociceptive pathways, which is known to amplify and maintain clinical pain. The clinical correlates of CS in OA, however, are poorly understood. Insomnia is prevalent in older adults with OA, and recent experiments suggest associations between poor sleep and measures of CS. Catastrophizing, a potent predictor of pain outcomes, has also been associated with CS, but few studies have investigated possible interactions between catastrophizing, sleep, and CS.

METHODS

We conducted a case-control study of 4 well-characterized groups of adults with insomnia and/or knee OA. A total of 208 participants completed multimodal sleep assessments (questionnaire, diary, actigraphy, and polysomnography) and extensive evaluation of pain using clinical measures and quantitative sensory testing to evaluate associations between CS, catastrophizing, and insomnia. Descriptive characterization of each measure is presented, with specific focus on sleep efficiency and CS.

RESULTS

The knee OA-insomnia group demonstrated the greatest degree of CS compared to controls. In the overall sample, we found that catastrophizing moderated the relationship between sleep efficiency and CS. Specifically those with low sleep efficiency and high catastrophizing scores reported increased levels of CS. In addition, CS was significantly associated with increased clinical pain.

CONCLUSION

These findings highlight the importance of assessing sleep efficiency, CS, and catastrophizing in chronic pain patients and have important clinical implications for treatment planning.

Initial evaluation of nighttime restlessness in a naturally occurring canine model of osteoarthritis pain

Chronic pain due to osteoarthritis (OA) can lead to significant disruption of sleep and increased restlessness. Our objective was to assess whether naturally occurring canine OA is associated with nighttime restlessness and so has potential as a model of OA-associated sleep disturbance. The study was designed as a two-part prospective masked, placebo-controlled study using client-owned dogs (Part A n = 60; Part B n = 19). Inclusion criteria consisted of OA-associated joint pain and mobility impairment. The primary outcome measure for both parts was nighttime accelerometry. In Part B, quality of sleep was assessed using a clinical metrology instrument (Sleep and Night Time Restlessness Evaluation Score, SNoRE). Part A included dogs receiving two weeks of non-steroidal anti-inflammatory drug (NSAID) preceded with two weeks of no treatment. Part B was a crossover study, with NSAID/placebo administered for two weeks followed by a washout period of one week and another two weeks of NSAID/placebo. Repeated measures analysis of variance was used to assess differences between baseline and treatment. There were no significant changes in accelerometry-measured nighttime activity as a result of NSAID administration. SNoRE measures indicated significant improvements in aspects of the quality of nighttime sleep that did not involve obvious movement. These results reflect the few similar studies in human OA patients. Although accelerometry does not appear to be useful, this model has potential to model the human pain-related nighttime sleep disturbance, and other outcome measures should be explored in this model.

A pilot study of gentle yoga for sleep disturbance in women with osteoarthritis

OBJECTIVES

The purpose of this study was to test the feasibility and acceptability of a gentle yoga intervention for sleep disturbance in older women with osteoarthritis (OA) and to collect initial efficacy data on the intervention.

METHODS

All participants completed an 8-week yoga program that included 75-min weekly classes and 20 min of nightly home practice. Participants were women with OA and symptoms consistent with insomnia. Symptom questionnaires and 1 week of wrist actigraphy and sleep diaries were completed for 1 week pre- and post-intervention.

RESULTS

Fourteen women were enrolled of whom 13 completed the study (mean age 65.2 ± 6.9 years). Participants attended a mean of 7.2 ± 1.0 classes and practiced at home 5.83 ± 1.66 nights/week. The Insomnia Severity Index and diary-reported sleep onset latency, sleep efficiency, and number of nights with insomnia were significantly improved at post-intervention versus pre-intervention (p < .05). Other sleep outcomes (Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, diary-reported total sleep time and wake after sleep onset) showed improvement on mean scores at post-intervention, but these were not statistically significant. Actigraphic sleep outcomes were not significantly changed.

CONCLUSIONS

This study supports the feasibility and acceptability of a standardized evening yoga practice for middle-aged to older women with OA. Preliminary efficacy findings support further research on this program as a potential treatment option for OA-related insomnia.

The multidimensionality of sleep quality and its relationship to fatigue in older adults with painful osteoarthritis

OBJECTIVE

To evaluate subjective sleep quality and its relationship to fatigue in older adults with osteoarthritis (OA).

METHOD

In a community cohort with hip/knee OA, subjective sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) and fatigue was measured by the Profile of Mood States - Fatigue subscale (POMS-F). Correlates of sleep quality and fatigue were determined by standardized interviews including socio-demographics, OA severity (Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) summary score), comorbidity, depression (Center for Epidemiologic Studies Depression Scale, CES-D), stressful life events, daytime napping, symptoms of restless legs syndrome (RLS) and prior sleep disorder diagnoses. Logistic regression examined correlates of poor sleep (PSQI score>5). Linear regression evaluated the relationship between poor sleep and fatigue, and the effect of napping on this relationship.

RESULTS

In 613 respondents, mean age was 78 years, 78% were female, 11% had concomitant fibromyalgia, and 26% had 3+ comorbid conditions. Responses indicated moderate OA severity. Seventy percent reported poor sleep; 25% met criteria for RLS and 6.5% reported a diagnosed sleep disorder. Independent correlates of poor sleep were: greater arthritis severity (adjusted odds ratio (OR) per unit increase in WOMAC score=1.03, P<0.0001), 3+ comorbid conditions (adjusted OR=1.88; P=0.03), depressed mood (adjusted OR per unit increase in CES-D score=1.09, P<0.0001), and RLS (adjusted OR=1.87; P=0.02). Controlling for previously reported fatigue correlates, poor sleep was significantly associated with greater fatigue (parameter estimate=1.63, P=0.0003) and napping did not moderate this relationship (P=0.55 for the interaction between napping and poor sleep).

CONCLUSIONS

Among older people with OA, poor sleep is highly prevalent and significantly linked with fatigue. Identifying the nature of sleep disturbances in OA is important as treatment of sleep disturbances may reduce OA-related fatigue.

A comparison of fatigue correlates in rheumatoid arthritis and osteoarthritis: disparity in associations with disability, anxiety and sleep disturbance

OBJECTIVES

To investigate correlates of fatigue among individuals with RA and OA, including mood, sleep, disease activity and radiographic damage.

METHODS

Fatigue was assessed using the Multidimensional Assessment of Fatigue-Global Fatigue Index (MAF-GFI) in 103 patients with RA and 103 with OA. Sleep disturbance and pain were assessed using a visual analogue scale anxiety and depression using the Hospital Anxiety and Depression scale and disability using the HAQ. In the RA cohort, the disease activity score-28 joint count (DAS-28) and the Van der Heijde modified Sharp score were calculated, and in the OA cohort, the Kellgren-Lawrence score and the WOMAC score calculated.

RESULTS

The MAF-GFI scores were higher in the OA cohort (P = 0.02). This was not significant after controlling for disability (P = 0.59). OA participants reported greater pain, disability, depression and sleeplessness than those with RA (all P < 0.01). The strongest correlates of fatigue in the RA cohort were depression (P < 0.001) and anxiety (P < 0.001). There was no significant association with pain (P = 0.43), DAS-28 (P = 0.07), HAQ (P = 0.10) or Sharp score (P = 0.78). In OA, the correlates of fatigue were older age (P = 0.02), sleep disturbance (P = 0.03), depression (P = 0.04), disability (P = 0.04) and lower CRP (P = 0.001).

CONCLUSIONS

Fatigue is common and severe in both RA and OA. In RA, fatigue had no significant association with pain, disease activity, disability or erosions, but was associated with depression and anxiety. The disparity in correlates indicates that generalizing the experience of fatigue between OA and RA is not appropriate. Fatigue is an important domain in the assessment of disease impact.

Comparison of sleep variables between chronic widespread musculoskeletal pain, insomnia, periodic leg movements syndrome and control subjects in a clinical sleep medicine practice

BACKGROUND

Between 50% and 89% of chronic pain patients report unrefreshing sleep. The aim of this retrospective analysis was to compare the sleep of normal subjects with the sleep of a clinical population presenting musculoskeletal chronic widespread pain (CWP), psychophysiological insomnia and restless legs syndrome/periodic limb movements during sleep (RLS/PLMS) in order to identify sleep variables that may explain the poor sleep complaints of CWP patients.

METHODS

Sleep data from 10 normal subjects and 37 patients (mean age 55+/-3 yo), matched for age and sex, were retrieved from our sleep data bank. Sub-analysis controlled for the effects of medication.

RESULTS

In comparison to normal subjects, sleep duration was shorter in CWP patients (-71 min; p<0.01); sleep efficiency was significantly lower in CWP and insomnia patients (-10.1% and -11.1%, respectively; p<0.05). CWP and PLMS patients lost one non-rapid eye movement (REM) to REM sleep cycle (p<0.04). An intermediate level of PLM was observed during the sleep of CWP patients in comparison to normal subjects (8.8/h vs. 2.0/h) and PLMS patients (33/h). Regular use of non-narcotic analgesics did not seem to interfere with sleep variables.

CONCLUSIONS

The sleep of middle-aged patients with CWP is comparable to that of insomnia patients. The moderate level of PLM during sleep suggests that such sensory motor activity needs to be evaluated in patients suffering from chronic pain.

Sleep and pain

Noxious stimuli and painful disorders interfere with sleep, but disturbances in sleep also contribute to the experience of pain.Chronic paroxysmal hemicrania and possibly cluster headaches are related to REM sleep. Whereas headache is associated with snoring and sleep apnea, morning headaches are not specific for any primary sleep disorder. Nevertheless, the management of the sleep disorder ameliorates both morning headache and migraine.Noxious stimuli administered into muscles during slow-wave sleep (SWS) result in decreases in delta and sigma but an increase in alpha and beta EEG frequencies during sleep. Noise stimuli that disrupt SWS result in unrefreshing sleep, diffuse musculoskeletal pain, tenderness, and fatigue in normal healthy subjects. Such symptoms accompany alpha EEG sleep patterns that often occur in patients with fibromyalgia. The alpha EEG patterns include phasic and tonic alpha EEG sleep as well as periodic K alpha EEG sleep or frequent periodic cyclical alternating pattern. Moreover, alpha EEG sleep, as well as sleep-related breathing disorder and periodic limb movement disorder, occur in some patients with fibromyalgia, rheumatoid arthritis and osteoarthritis. Depression and not alpha EEG sleep are features of somatoform pain disorder. Disturbances in sleep, pain behaviour and psychological distress influence return to work in workers who have suffered a soft tissue injury, e.g. low back pain. Patients with irritable bowel disorder have disturbed sleep and have increased REM sleep. In conclusion, there is a reciprocal relationship between sleep quality and pain. The recognition of disturbed or unrefreshing sleep influences the management of painful medical disorders.

Nighttime sleep and daytime functioning (sleepiness and fatigue) in well-defined chronic rheumatic diseases

Wake/sleep complaints are very common in the rheumatic diseases, and include: insomnia, non-restorative sleep, frequent awakenings, daytime fatigue and excessive daytime sleepiness. Imprecise use of terminology has confused 'sleep dissatisfaction' (i.e. 'non-restorative sleep') with specific sleep disorders (i.e. 'insomnia' or 'sleep fragmentation') and 'fatigue' with 'daytime sleepiness'. This review examines current concepts from the literature of disparate disciplines pertaining to the complaint of poor sleep and daytime fatigue in patients with rheumatic disorders. The ability to monitor multiple physiologic parameters during sleep (polysomnography) has led to a greater understanding of normal and abnormal phenomena which occur during sleep, and has resulted in the identification of a variety of sleep disorders which have specific therapeutic implications. Actigraphy allows the prolonged monitoring of wake/sleep patterns, and the multiple sleep latency test permits the determination of physiologic sleepiness during the daytime. These techniques enable identification of objective sleep disorders in those whose complaint is subjective sleep dissatisfaction, and permit differentiation between the easily confused complaints of excessive daytime sleepiness and fatigue. The abnormal sleep/wake symptoms in patients with rheumatic diseases may not simply be a 'non-specific' or systemic effect of the disease. Some patients may have a specific sleep disorder (either independent from, or due to, the underlying rheumatic condition) which should be diagnosed and treated specifically. Conversely, subjective 'sleep dissatisfaction' does not necessarily imply an underlying sleep disorder. The primary intent of this review is to encourage systematic, objective study of sleep and daytime function in these common, often disabling conditions.

Sleep and hypnotics among the elderly in relation to body weight and somatic disease

OBJECTIVES

To investigate the interrelationship between sleep complaints and hypnotics in relation to general health and somatic diseases.

DESIGN

An epidemiological survey conducted by means of a questionnaire.

SETTING

The counties of Västerbotten and Norrbotten in northern Sweden.

SUBJECTS

All 10,216 members of the Swedish Pensioners' Association.

MAIN OUTCOME MEASURES

Sleep disturbances, health, somatic diseases and hypnotic medication.

RESULTS

General ill health, cardiovascular diseases, different painful diseases and increased nocturnal voiding frequency were all associated with poor sleep and increased treatment with hypnotics. Hypnotics were used by 13.5% of the men and 22.3% of the women. Of the men aged < 70 years, 7.9% were receiving such treatment, of those aged 70-80 years 14.4% were using hypnotics, and of those aged > or = 80 years 21.8% were taking hypnotics (P < 0.0001). The corresponding frequencies among women were 15.0%, 23.0% and 34.9%, respectively (P < 0.0001). Half of all men and women treated with hypnotics in all age groups reported a good night's sleep. Among these both angina pectoris and cardiac arrhythmia were twice as common as among elderly subjects who experienced poor sleep and were receiving treatment with hypnotics.

CONCLUSIONS

Poor health and different somatic diseases are over-represented in elderly persons treated with hypnotics.

Objective and subjective sleep disturbances in patients with rheumatoid arthritis. A reappraisal

OBJECTIVE

To assess objective and subjective evidence of sleep disturbances in patients with rheumatoid arthritis (RA) and to examine correlations between parameters of inflammatory activity and sleep pathology.

METHODS

Nineteen RA patients and 19 age-matched healthy control subjects underwent all-night polysomnography on 2 consecutive nights. RA patients were also evaluated for daytime sleepiness by mean sleep latency test and responded to a self-report questionnaire on their first night.

RESULTS

Whereas normal sleep architecture is conserved in RA, we confirmed former findings of severe sleep fragmentation and an enhanced presence of primary sleep disorders. No correlation exists between RA activity and the sleep disorders. Subjective assessment was not consistent with the objective evidence of sleep disruption, unlike the findings in patients with fibrositis.

CONCLUSION

Sleep is severely disturbed in patients with RA, regardless of the inflammatory disease activity. The specificity of the sleep disorders assessed needs confirmation, as does specific sleep therapy for these patients.