The association between daytime napping and cognitive functioning in chronic fatigue syndrome

Associations between afternoon napping, left amygdala volume and cognitive performance in elderly with normal cognitive function

BACKGROUND

The relationship between afternoon napping and cognitive function in the elderly is very complex and the mechanism is unknown.

METHODS

In the current study, 194 community elders with normal cognitive functions were included. All subjects completed baseline clinical assessment, baseline neuropsychological test as well as baseline structural MRI. Based on their napping status, these 194 participants were divided into the napping group (n = 88) and the non-napping group (n = 106). We then compared the differences in cognitive performance and structural magnetic resonance between the two groups.

RESULTS

In the intergroup analysis, we found that the nappers showed poorer cognitive performance on both overall cognitive function and domain specific cognitive function; while on the whole sample, we found a significant negative association (F = 20.27, p<0.001) between afternoon napping and left amygdala volume. However, we did not find any effect of night sleep length or napping frequency on cognitive performance or left amygdala volume.

CONCLUSIONS

In community elders with normal cognitive functions, afternoon napping is associated with cognitive performance, and left amygdala may play an important role in this process.

Moderate-to-high risk of obstructive sleep apnea with excessive daytime sleepiness is associated with postoperative neurocognitive disorders: a prospective one-year follow-up cohort study

Background

Few studies found that obstructive sleep apnea (OSA) may be related to postoperative neurocognitive disorders (PND) including postoperative delirium (POD) and cognitive decline (POCD) in the early postoperative period. However, the results are controversial and need further verification, and no research has explored the effect of OSA on the incidence of PND during the 1-year follow-up periods. Furthermore, OSA patients with excessive daytime sleepiness (EDS) as a severe phenotype have more significant neurocognitive impairments, but the relationship between OSA with EDS and PND within 1 year after surgery has not been studied.

Objectives

To explore the effect of moderate-to-high risk of OSA and the moderate-to-high risk of OSA with EDS on PND within 1 year after surgery.

Methods

In this prospective cohort study, including 227 older patients, moderate-to-high risk of OSA (using STOP-BANG), subjective EDS (using Epworth Sleepiness Scale), and objective EDS (using Actigraphy) were selected as exposures. Key outcomes included POD during hospitalization (using Confusion Assessment Method-Severity), POCD at discharge, 1-month and 1-year after surgery (using Mini-Mental State Examination and Telephone Interview for Cognitive Status-40). We applied multiple logistic regression models to estimate the effect of moderate-to-high risk of OSA and moderate-to-high risk of OSA with EDS on PND.

Results

In the multivariate analysis, moderate-to-high risk of OSA was not associated with POD during hospitalization and POCD at discharge, 1-month, and 1-year after surgery (p > 0.05). However, the moderate-to-high risk of OSA with subjective EDS was related to POCD at discharge compared to the moderate-to-high risk of OSA or normal group (no moderate-to-high risk of OSA and no EDS) (p < 0.05). In addition, moderate-to-high risk of OSA with objective EDS was associated with POCD at discharge, 1-month, and 1-year postoperatively compared to the moderate-to-high risk of OSA or normal group (p < 0.05).

Conclusion

Moderate-to-high risk of OSA with EDS, not moderate-to-high risk of OSA alone, was a clinically helpful predictor for POCD within 1-year after surgery and should be routinely assessed before surgery.

Electroencephalography (EEG)-Based Neural Emotional Response to the Vegetation Density and Integrated Sound Environment in a Green Space

Emotion plays an important role in physical and mental health. Green space is an environment conducive to physical and mental recovery and influences human emotions through visual and auditory stimulation. Both the visual environment and sound environment of a green space are important factors affecting its quality. Most of the previous relevant studies have focused solely on the visual or sound environment of green spaces and its impacts. This study focused on the combination of vegetation density (VD) and integrated sound environment (ISE) based on neural emotional evaluation criteria. VD was used as the visual variable, with three levels: high (H), moderate (M) and low (L). ISE was used as the sound variable, with four levels: low-decibel natural and low-decibel artificial sounds (LL), low-decibel natural and high-decibel artificial sounds (LH), high-decibel natural and low-decibel artificial sounds (HL) and high-decibel natural and high-decibel artificial sounds (HH). These two variables were combined into 12 unique groups. A total of 360 volunteer college students were recruited and randomly assigned to the 12 groups (N = 30). All 12 groups underwent the same 5 min high-pressure learning task (pretest baseline), followed by a 5 min audio-visual recovery (posttest). Six indicators of neural emotion (engagement, excitement, focus, interest, relaxation and stress) were dynamically measured by an Emotiv EPOC X device during the pretest and posttest. Analysis of covariance was used to determine the main and coupled effects of the variables. (1) VD and ISE have significant effects on human neural emotions. In moderate- and high-VD spaces, artificial sound levels may have a positive effect on excitement. (2) A higher VD is more likely to result in excitatory neural emotion expression. (3) Low-VD and high-VD spaces have a higher degree of visual continuity. Both extremely low and extremely high VDs result in a higher expression of stressful emotions than observed for a moderate VD. (4) High-decibel artificial sounds are more likely to attract attention, possibly because artificial sounds are easier to recognize than natural sounds. However, when both the natural and artificial sounds are low, it is difficult to induce higher tones, and the lower the artificial sound decibel level, the easier it is to relax. Additionally, under the influence of an ISE, attention recovery and stress recovery may be negatively correlated. The results show that an appropriate combination of VD and ISE can improve the health benefits of a green space and thus the well-being of visitors.

Effects of Different Bamboo Forest Spaces on Psychophysiological Stress and Spatial Scale Evaluation

Forests are large-scale green space resources that may exert a positive impact on human physiology and psychology. Forests can be divided into mixed forest and pure forest, according to the number of dominant tree species. Pure forest offers specific advantages for the study of spatial structure and scale. In this study, a type of pure forest (i.e., bamboo forest) was adopted as a research object to investigate differences in the physiological and psychological responses of psychologically pressured college students to different types of forest space. We recruited 60 participants and randomly assigned them to three experimental groups: forest interior space (FIS), forest external space (FES) and forest path space (FPS). All participants were asked to perform the same pre-test task but different post-test tasks. The pre-test involved performing a pressure-inducing task, whereas the post-test involved viewing photographs of each space type. The same indicators were measured in both the pre- and post-test, including a β/α index from each lobe, positive emotion, negative emotion and total mood disturbance (TMD) values, according to the profile of mood states (POMS), in addition to spatial scale preferences obtained through a questionnaire and interviews. We analysed brain waves and mood indicators through analysis of covariance (ANCOVA), whereby the FES group exhibited the best physiological and psychological relaxation effect. The FPS group displayed a medium effect, and the FIS group exhibited the worst effect. Analysis of variance (ANOVA) was used to analyse the spatial scale scores. The FPS and FES types achieved a higher spatial scale preference scores than the FIS type. Based on a comparison of the psychophysiological results with the spatial scale preference results, spatial structure and scale are considered to be important intrinsic factors that influence the health effects of pure forest. The results can provide guidance for forest-related human health activities and their management.

Sitting or Walking? Analyzing the Neural Emotional Indicators of Urban Green Space Behavior with Mobile EEG

There is a close relationship between urban green space and the physical and mental health of individuals. Most previous studies have discussed the impact of the structure of green space and its elements. This study focused on the emotional changes caused by common behaviors in urban green space (walking and sitting). We recruited 40 college students and randomly assigned them to walking and sitting groups (20 students per group). The two groups performed the same 8-min high-pressure learning task indoors and then performed 8-min recovery activities in a simulated urban green space (a bamboo-lawn space). We used the Emotiv EPOC+ EEG headset to dynamically measure six neural emotional parameters: "engagement," "valence," "meditation," "frustration," "focus," and "excitement." We conducted a pretest and posttest and used analysis of covariance (ANCOVA) to analyze the posttest data (with the pretest data as covariates). The results of the comparison of the two behaviors showed that the "valence" and "meditation" values of the walking group were higher than those of the sitting group, which suggests that walking in urban green space is more favorable for stress reduction. The sitting group had a higher "focus" value than did the walking group, which suggests that sitting in urban green space is better for attention restoration. The results of this study can provide guidance for urban green space planning and design as well as health guidance for urban residents.

Reduced heart rate variability predicts fatigue severity in individuals with chronic fatigue syndrome/myalgic encephalomyelitis

Background

Heart rate variability (HRV) is an objective, non-invasive tool to assessing autonomic dysfunction in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME). People with CFS/ME tend to have lower HRV; however, in the literature there are only a few previous studies (most of them inconclusive) on their association with illness-related complaints. To address this issue, we assessed the value of different diurnal HRV parameters as potential biomarker in CFS/ME and also investigated the relationship between these HRV indices and self-reported symptoms in individuals with CFS/ME.

Methods

In this case–control study, 45 female patients who met the 1994 CDC/Fukuda definition for CFS/ME and 25 age- and gender-matched healthy controls underwent HRV recording-resting state tests. The intervals between consecutive heartbeats (RR) were continuously recorded over three 5-min periods. Time- and frequency-domain analyses were applied to estimate HRV variables. Demographic and clinical features, and self-reported symptom measures were also recorded.

Results

CFS/ME patients showed significantly higher scores in all symptom questionnaires (p < 0.001), decreased RR intervals (p < 0.01), and decreased HRV time- and frequency-domain parameters (p < 0.005), except for the LF/HF ratio than in the healthy controls. Overall, the correlation analysis reached significant associations between the questionnaires scores and HRV time- and frequency-domain measurements (p < 0.05). Furthermore, separate linear regression analyses showed significant relationships between self-reported fatigue symptoms and mean RR (p = 0.005), RMSSD (p = 0.0268) and HFnu indices (p = 0.0067) in CFS/ME patients, but not in healthy controls.

Conclusions

Our findings suggest that ANS dysfunction presenting as increased sympathetic hyperactivity may contribute to fatigue severity in individuals with ME/CFS. Further studies comparing short- and long-term HRV recording and self-reported outcome measures with previous studies in larger CFS/ME cohorts are urgently warranted.

A unifying theory for cognitive abnormalities in functional neurological disorders, fibromyalgia and chronic fatigue syndrome: systematic review

BACKGROUND

Functional cognitive disorder (FCD) describes cognitive dysfunction in the absence of an organic cause. It is increasingly prevalent in healthcare settings yet its key neuropsychological features have not been reported in large patient cohorts. We hypothesised that cognitive profiles in fibromyalgia (FM), chronic fatigue syndrome (CFS) and functional neurological disorders (FNDs) would provide a template for characterising FCD.

METHODS

We conducted a systematic review of studies with cognition-related outcomes in FM, CFS and FND.

RESULTS

We selected 52 studies on FM, 95 on CFS and 39 on FND. We found a general discordance between high rates of subjective cognitive symptoms, including forgetfulness, distractibility and word-finding difficulties, and inconsistent objective neuropsychological deficits. Objective deficits were reported, including poor selective and divided attention, slow information processing and vulnerability to distraction. In some studies, cognitive performance was inversely correlated with pain, exertion and fatigue. Performance validity testing demonstrated poor effort in only a minority of subjects, and patients with CFS showed a heightened perception of effort.

DISCUSSION

The cognitive profiles of FM, CFS and non-cognitive FND are similar to the proposed features of FCD, suggesting common mechanistic underpinnings. Similar findings have been reported in patients with mild traumatic brain injury and whiplash. We hypothesise that pain, fatigue and excessive interoceptive monitoring produce a decrease in externally directed attention. This increases susceptibility to distraction and slows information processing, interfering with cognitive function, in particular multitasking. Routine cognitive processes are experienced as unduly effortful. This may reflect a switch from an automatic to a less efficient controlled or explicit cognitive mode, a mechanism that has also been proposed for impaired motor control in FND. These experiences might then be overinterpreted due to memory perfectionism and heightened self-monitoring of cognitive performance.

Chronic fatigue syndrome and quality of life

Chronic fatigue syndrome (CFS), also known as myalgic encephalomyelitis (ME), is a challenging long-term condition (LTC) with complex and fluctuating symptoms. It is heterogeneous in presentation without diagnostic indicators; therefore, in health care encounters, insight must be gained from the patient's perspective. One indicator of impact can be gained by measuring quality of life (QoL). By applying a patient-reported outcome measure (PROM), professionals can gather insights with direct relevance to the patient questioned. Such a tool can act therapeutically tool to promote holistic and individualized professional interventions and interval measurement can inform commissioning of specialist services. Standard practice appears not fully to capture the experience of CFS, while a search of the literature turned up QoL patient-reported outcome tools, but failed to reveal a CFS/ME-specific measure. The author explores a valid and reliable PROM that can monitor change and evaluate the UK National Institute of Clinical Excellence rehabilitation program, as delivered by specialist National Health Service units. An alternative, the World Health Organization's quality-of life instrument (WHOQoL)-Bref26, is reviewed for relevance to the condition, measuring treatment outcomes and the wider debate of measuring QoL in LTCs.

Chronic fatigue syndrome - an update

BACKGROUND

Chronic fatigue syndrome is a widespread condition with a huge impact not only on a patient's life, but also on society as evidenced by substantial losses of productivity, informal costs, and medical expenses. The high prevalence rates (0.2-6.4%) and the low employment rates (27-41%) are responsible for the enormous burden imposed on society, with loss of productivity representing the highest cost. The objective of this review is to systematically review the recent literature on chronic fatigue syndrome/myalgic encephalomyelitis.

METHODS

The published literature between 1 January 1990 and 1 April 2015 was searched using the MEDLINE, Cochrane Library, and Web of Sciences databases. The reference lists of the selected articles were screened for other relevant articles.

RESULTS AND CONCLUSIONS

Despite extensive research, none of the proposed etiological factors have shown strong, reproducible scientific evidence. Over the years, the biopsychosocial model integrating many of the proposed hypotheses has been gaining popularity over the biomedical model, where the focus is on one physical cause. Since the etiological mechanism underlying chronic fatigue syndrome is currently unknown, disease-specific treatments do not exist. Various treatments have been investigated but only cognitive behavior therapy (CBT) and graded exercise therapy (GET) have shown moderate effectiveness.

Subjective but Not Actigraphy-Defined Sleep Predicts Next-Day Fatigue in Chronic Fatigue Syndrome: A Prospective Daily Diary Study

STUDY OBJECTIVES

This study aimed to (1) examine the relationship between subjective and actigraphy-defined sleep, and next-day fatigue in chronic fatigue syndrome (CFS); and (2) investigate the potential mediating role of negative mood on this relationship. We also sought to examine the effect of presleep arousal on perceptions of sleep.

METHODS

Twenty-seven adults meeting the Oxford criteria for CFS and self-identifying as experiencing sleep difficulties were recruited to take part in a prospective daily diary study, enabling symptom capture in real time over a 6-day period. A paper diary was used to record nightly subjective sleep and presleep arousal. Mood and fatigue symptoms were rated four times each day. Actigraphy was employed to provide objective estimations of sleep duration and continuity.

RESULTS

Multilevel modelling revealed that subjective sleep variables, namely sleep quality, efficiency, and perceiving sleep to be unrefreshing, predicted following-day fatigue levels, with poorer subjective sleep related to increased fatigue. Lower subjective sleep efficiency and perceiving sleep as unrefreshing predicted reduced variance in fatigue across the following day. Negative mood on waking partially mediated these relationships. Increased presleep cognitive and somatic arousal predicted self-reported poor sleep. Actigraphy-defined sleep, however, was not found to predict following-day fatigue.

CONCLUSIONS

For the first time we show that nightly subjective sleep predicts next-day fatigue in CFS and identify important factors driving this relationship. Our data suggest that sleep specific interventions, targeting presleep arousal, perceptions of sleep and negative mood on waking, may improve fatigue in CFS.

Neurocognitive complaints and functional status among patients with chronic fatigue syndrome and fibromyalgia

PURPOSE

The purpose of this study was to conduct a longitudinal examination of cognitive complaints and functional status in patients with chronic fatigue syndrome (CFS) alone and those who also had fibromyalgia (CFS/FM).

METHODS

A total of 93 patients from a tertiary care fatigue clinic were evaluated on four occasions, each 6 months apart. Each evaluation included a tender point assessment, and self-reported functional status and cognitive complaints.

RESULTS

Patients with CFS/FM reported significantly worse physical functioning, more bodily pain, and more cognitive difficulties (visuo-perceptual ability and verbal memory) than patients with CFS alone. Over time, bodily pain decreased only for participants with CFS alone. Verbal memory problems were associated with more bodily pain for both patient groups, whereas visuo-perceptual problems were associated with worse functional status for patients with CFS alone.

CONCLUSIONS

This study adds to the literature on functional status, longitudinal course, and cognitive difficulties among patients with CFS and those with CFS and FM. The results suggest that patients with CFS/FM are more disabled, have more cognitive complaints, and improve more slowly over time than patients with CFS alone. Specific cognitive difficulties are related to worse functional status, which supports the addition of cognitive difficulties to the FM case criteria.

Frontier studies on fatigue, autonomic nerve dysfunction, and sleep-rhythm disorder

Fatigue is defined as a condition or phenomenon of decreased ability and efficiency of mental and/or physical activities, caused by excessive mental or physical activities, diseases, or syndromes. It is often accompanied by a peculiar sense of discomfort, a desire to rest, and reduced motivation, referred to as fatigue sensation. Acute fatigue is a normal condition or phenomenon that disappears after a period of rest; in contrast, chronic fatigue, lasting at least 6 months, does not disappear after ordinary rest. Chronic fatigue impairs activities and contributes to various medical conditions, such as cardiovascular disease, epileptic seizures, and death. In addition, many people complain of chronic fatigue. For example, in Japan, more than one third of the general adult population complains of chronic fatigue. It would thus be of great value to clarify the mechanisms underlying chronic fatigue and to develop efficient treatment methods to overcome it. Here, we review data primarily from behavioral, electrophysiological, and neuroimaging experiments related to neural dysfunction as well as autonomic nervous system, sleep, and circadian rhythm disorders in fatigue. These data provide new perspectives on the mechanisms underlying chronic fatigue and on overcoming it.

Fatigue in rheumatic diseases

Fatigue is a common and important problem in many diseases including rheumatologic illnesses, and it has a negative impact on health-related quality of life. Fatigue is described as having an impact on multiple aspects of a patient's life. There is a need for knowledge about causes of and treatments for fatigue to ensure that patient outcomes are improved. There are several effective treatment strategies available for fatigue including pharmacological and non-pharmacological therapies. We aim to provide an overview of fatigue in rheumatologic disorders and some recommendations on its optimal management.

The experience of sleep in chronic fatigue syndrome: A qualitative interview study with patients

OBJECTIVES

Sleep disturbances are common in chronic fatigue syndrome (CFS), and one of the key symptom complaints, yet it has been neglected by previous qualitative research. The aim was to explore the specific role of sleep in patients' experience of their illness.

DESIGN

A qualitative semi-structured interview format facilitated a detailed and open exploration of sleep, and the extent to which its management and problems were linked to the lived experience of CFS.

METHODS

Eleven semi-structured interviews were conducted with individuals with CFS. Data were transcribed verbatim and analysed thematically, to explore and describe patients' experience of their sleep, and its impact on their condition.

RESULTS

Sleep emerged as a key aspect of the illness experience, and its management and effect on daytime functioning was a central pre-occupation for all 11 participants; all of them saw sleep as playing a critical role in their illness through either maintaining or exacerbating existing symptoms. Exploration of individual experiences presented three overarching themes: (1) sleep pattern variability over illness course and from day to day; (2) effect of sleep on daytime functioning; and (3) attempts at coping and sleep management.

CONCLUSIONS

Each patient with CFS has a unique experience of sleep. Despite the differing narratives regarding the role of sleep in CFS, all participants held the belief that sleep is a vital process for health and well-being which has had a direct bearing on the course and progression of their CFS. Also, every participant regarded their sleep as in some way 'broken' and in need of management/repair. Patients' insights demonstrate sleep-specific influences on their CFS, and the impact of disturbed sleep should be a consideration for clinical and research work.

STATEMENT OF CONTRIBUTION

What is already known on this subject? Sleep disturbances are common in CFS, and one of the key symptom complaints, yet it has been neglected by previous qualitative research. Ontology of CFS is a matter of dispute, with models ranging from the biological to the psychological competing to explain symptomatology in this illness. A qualitative study has the potential to add some clarity to the debate by making the patients' lived experience of the condition, and their own understanding of it, the focus of research. What this study adds? Coping and attempts at managing sleep problems in CFS adds to the 'illness burden' experienced by patients. Disturbed sleep is universally seen by patients with CFS as impacting on other daytime symptoms. Broken sleep may contribute to a biopsychosocial cycle that serves to maintain this illness.