Elena Miró

CPAP and behavioral therapies in patients with obstructive sleep apnea: Effects on daytime sleepiness, mood, and cognitive function

Obstructive sleep apnea (OSA) is a disorder characterized by repeated episodes of complete (apneas) or partial (hypopneas) cessations of breathing while sleeping. While continuous positive airway pressure (CPAP) treatment is commonly chosen to treat OSA, various conservative behavioral therapies are also used, particularly in patients unable to tolerate or benefit from CPAP or who have mild OSA. The principal purpose of these behavioral measures is to reduce risk factors which may underlie or exacerbate the disorder (e.g., weight reduction, smoking cessation, reduction/elimination of alcohol consumption, change in sleeping posture and sleep hygiene). Numerous studies have been conducted to evaluate the efficacy and/or effectiveness of CPAP in treating a wide range of OSA symptomatology. The present study consists of an exhaustive bibliographic search in Medline, PsycINFO, and Cochrane Review (1994-2007) databases and selection of works which have evaluated the efficacy and/or effectiveness of CPAP vis-a-vis daytime sleepiness, depression and cognitive functioning in OSA patients. The selected studies include randomized clinical trials in which CPAP was compared with more conservative measures, sham CPAP and oral placebos. The most important studies which evaluate the efficacy of behavioral treatments for OSA are also reviewed and the most remarkable results are presented. Various conclusions derived from the studies are discussed.

Age-related changes and gender differences in time estimation.

A study was carried out in which age and gender differences were studied in the performance of an empty interval production task. The duration of these intervals was 10 s, 1 and 5 min. The sample was made up of 140 subjects, half male and half female, in seven different age groups from 8 to 70 years old. The age range permitted us to identify when differences begin to be significant. The results show an age-related increase in the underproduction of the intervals. The differences between age groups attained significance from 51 to 60 years onward. With regard to gender, the main result was a greater underproduction of longer intervals (1 and 5 min) for women. These findings were interpreted in terms of different models of time estimation.

When is pain related to emotional distress and daily functioning in fibromyalgia syndrome? The mediating roles of self-efficacy and sleep quality.

OBJECTIVES Fibromyalgia (FM) is a chronic pain syndrome associated with adverse symptoms of cognitive, behavioural, and emotional dysfunction. Accumulating evidence supports the notion that sleep dysfunction, which affects almost all FM patients, has a reciprocal influence on pain. Yet, little is known about the relationship between sleep and other FM symptoms. The present study analysed the role of sleep dysfunction as a mediator of the impact of pain intensity on anxiety, depression, and daily functioning, comparing them with the mediating role of self-efficacy. DESIGN A cross-sectional design was used. METHODS A sample of 104 women with FM and 86 healthy control women completed a semi-structured interview and self-reported measures of pain, sleep quality, anxiety, depression, and daily functioning. Multiple mediation models were proposed and a bootstrapping approach was used to test these models. RESULTS Women diagnosed with FM had more dysfunctional scores on the variables examined than control participants, and there were significant relationships between all the variables examined in the mediation models for the FM group. The mediation analyses suggested that sleep quality and self-efficacy significantly mediated the relationship between pain and emotional distress. Additionally, self-efficacy was a significant mediator and sleep quality a likely mediator that was marginally significant in the relationship between pain and functioning. CONCLUSIONS Sleep dysfunction is importantly related to FM symptoms and deserves more attention in both research and clinical practice. Our results suggest that, in addition to the usual treatment of FM, improving sleep could optimize the current management of the syndrome.

Attentional deficits in fibromyalgia and its relationships with pain, emotional distress and sleep dysfunction complaints.

Cognitive complaints are common among subjects with fibromyalgia (FM). Yet, few studies have been able to document these deficits with cognitive tasks. A main limitation of existing studies is that attention has been broadly defined and the tasks used to measure attention are not designed to cover all the main components of the attentional system. Research on attention has identified three primary functions of attention, known as alerting, orienting and executive functioning. This study used the attentional network test-interactions task to explore whether and which of the three attentional networks are altered in FM. Results showed that FM patients have impaired executive control (greater interference), reduced vigilance (slower overall reaction time) and greater alertness (higher reduction in errors after a warning cue). Vigilance and alertness showed several relations with depression, anxiety and sleep quality. Sleep dysfunction was a significant predictor for alertness, whereas there were no significant predictors for vigilance. These findings highlight that the treatment of sleep difficulties in FM patients may help with some of their cognitive complaints.

Cognitive-behavioral therapy for insomnia improves attentional function in fibromyalgia syndrome: a pilot, randomized controlled trial.

This pilot, randomized controlled trial analyzed the effects of a cognitive behavioral therapy (CBT, n = 20) for insomnia vs a sleep hygiene (SH, n = 20) program on the three attentional networks (alertness, orienting, and executive function) and other additional outcome measures (sleep, pain, depression, anxiety, and daily functioning) of fibromyalgia patients. The CBT group showed significant improvement in alertness (F(1, 28) = 11.84, p = .0018), executive functioning (F(1, 28) = 15.76, p = .00059), sleep quality ( F(1, 38) = 6.33, p = .016), and a trend to improvement in daily functioning (p > .06), as compared with the SH group. The improvement in executive functioning was significantly related to the changes in sleep (r = 0.40, p = .026). A CBT for insomnia represents a useful intervention in fibromyalgia patients not only regarding sleep disturbance but also attentional dysfunction and probably daily functioning.

Rapid eye movement sleep dreaming is characterized by uncoupled EEG activity between frontal and perceptual cortical regions

EEG coherent activity is involved in the binding of spatially separated but temporally correlated stimuli into whole events. Cognitive features of rapid eye movement sleep (REM) dreaming resemble frontal lobe dysfunction. Therefore, temporal coupling of EEG activity between frontal and perceptual regions was analyzed from 10 min prior to dream reports (8 adults) from stage-2 and REM sleep. EEG correlation between frontal and perceptual regions decreased and, among perceptual regions increased during REM. The temporal dissociation of EEG activity between executive and perceptual regions supplies an inadequate mechanism for the binding and interpretation of ongoing perceptual activity resulting in dream bizarreness.

Cognitive-behavioral therapy for insomnia and sleep hygiene in fibromyalgia: a randomized controlled trial

Sleep disturbances play an important role in the exacerbation of pain and other troubling symptoms reported by patients with fibromyalgia (FM). The objective of this trial was to analyze the efficacy of a cognitive-behavioral therapy for insomnia (CBT-I) versus a sleep hygiene (SH) education program at improving sleep and other clinical manifestations in FM. Sixty-four FM women with insomnia were randomly assigned to the CBT-I or the SH groups, and 59 completed the treatments (30 in the CBT-I group and 29 in the SH group). Participants completed several self-report questionnaires at pre-, post-treatment and follow-ups. The CBT-I group reported significant improvements at post-treatment in several sleep variables, fatigue, daily functioning, pain catastrophizing, anxiety and depression. The SH group only improved significantly in subjective sleep quality. Patients in the CBT-I group showed significantly greater changes than those in the SH group in most outcome measures. The findings underscore the usefulness of CBT-I in the multidisciplinary management of FM.

Electrodermal activity during total sleep deprivation and its relationship with other activation and performance measures

The present study analyses the variations of the skin resistance level (SRL) during 48 h of total sleep deprivation (TSD) and its relationship to body temperature, self‐informed sleepiness in the Stanford Sleepiness Scale (SSS), and reaction time (RT). All of the variables were evaluated every 2 h except for the SSS, which was evaluated every hour. A total of 30 healthy subjects (15 men and 15 women) from 18 to 24 years old participated in the experiment. Analyses of variance (ANOVAs) with TSD days and time‐of‐day as factors showed a substantial increase of SRL, SSS, and RT, and a decrease in body temperature marked by strong circadian oscillations. The interaction between day by time‐of‐day was only significant for RT. Furthermore, Pearsons correlations showed that the increase of SRL is associated to the decrease in temperature (mean r=−0.511), the increase of SSS (mean r=0.509), and the deterioration of RT (mean r=0.425). The results support previous TSD reports and demonstrate the sensitivity of SRL to TSD. The non‐invasive character of SRL, its simplicity, and its relationships with other activation parameters, widely validated by previous literature, convert SRL into an interesting and useful measure in this field.

The relationship between the fear-avoidance model of pain and personality traits in fibromyalgia patients.

This study examined the relationship between several cognitive-affective factors of the fear-avoidance model of pain, the big five model of personality, and functional impairment in fibromyalgia (FM). Seventy-four FM patients completed the NEO Five-Factor Inventory, the Pain Catastrophizing Scale, the Pain Anxiety Symptoms Scale-20, the Pain VigilanceandAwareness Questionnaire, and the Impairment and Functioning Inventory. Results indicated that the cognitive-affective factors of pain are differentially associated with personality traits. Neuroticism and conscientiousness were significant predictors of pain catastrophizing, and neuroticism, openness, and agreeableness were significant predictors of pain anxiety. Personality traits did not contribute significantly to vigilance to pain. The effect of neuroticism upon pain anxiety was mediated by pain catastrophizing, and neuroticism showed a trend to moderate the relationship between impairment and pain anxiety. Results support the fear-avoidance model of pain. Implications of the findings for the understanding and management of FM are discussed.

TIME ESTIMATION DURING PROLONGED SLEEP DEPRIVATION AND ITS RELATION TO ACTIVATION MEASURES

This is the first study to analyze variations in time estimation during 60 h of sleep deprivation and the relation between time estimation performance and the activation measures of skin resistance level, body temperature, and Stanford Sleepiness Scale (SSS) scores. Among 30 healthy participants 18 to 24 years of age, for a 10-s interval using the production method, we found a lengthening in time estimations that was modulated by circadian oscillations. No differences in gender were found in the time estimation task during sleep deprivation. The variations in time estimation correlated significantly with body temperature, skin resistance level, and SSS throughout the sleep deprivation period. When body temperature is elevated, indicating a high level of activation, the interval tends to be underestimated, and vice versa. When the skin resistance level or SSS is elevated (low activation), time estimation is lengthened, and vice versa. This lengthening is important because many everyday situations involve duration estimation under moderate to severe sleep loss. Actual or potential applications of this research include transportation systems, emergency response work, sporting activities, and industrial settings in which accuracy in anticipation or coincidence timing is important for safety or efficiency.