Neuroimaging of NREM sleep in primary insomnia: a Tc-99-HMPAO single photon emission computed tomography study

STUDY OBJECTIVES

The objectives of this study were to: 1) demonstrate the feasibility of combining polysomnography and SPECT neuroimaging to study NREM sleep in primary insomnia and 2) evaluate possible functional CNS abnormalities associated with insomnia.

DESIGN

Patients with insomnia and good sleeper controls were studied polysomnographically for three nights with a whole brain SPECT Scan of NREM sleep on Night 3. Groups were screened for medical/psychiatric history, substance use, and matched on age, body mass index, and education.

SETTING

Sleep Research Laboratory and Nuclear Medicine Center

PARTICIPANTS

Nine females, 5 patients with chronic psychophysiologic insomnia and 4 healthy good sleepers (mean age 36 years, SD 12, range 27-55).

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Tomographs of regional cerebral blood flow during the 1st NREM sleep cycle were successfully obtained. Contrary to our expectations, patients with insomnia showed a consistent pattern of hypoperfusion across all 8 pre-selected regions of interest, with particular deactivation in the basal ganglia (p=.006). The frontal medial, occipital, and parietal cortices also showed significant decreases in blood flow compared to good sleepers (p<.05). Subjects with insomnia had decreased activity in the basal ganglia relative to the frontal lateral cortex, frontal medial cortex, thalamus, occipital and parietal cortices (p<.05).

CONCLUSIONS

This study demonstrated the feasibility of combining neuroimaging and polysomnography to study cerebral activity in chronic insomnia. These preliminary results suggest that primary insomnia may be associated with abnormal central nervous system activity during NREM sleep that is particularly linked to basal ganglia dysfunction.

The effects of an orally administered cholinergic agonist on REM sleep in major depression

BACKGROUND

Centrally active cholinergic agents such as arecoline and physostigmine shorten rapid eye movement (REM) latency, reduce REM interval times, or both and do so preferentially in patients with depression. We tested an orally administered cholinergic agonist (donepezil HCL 10 mg [Aricept]) to determine whether this agent also alters REM timing in depressed patients (n = 8) compared with age- and gender-matched control subjects (n = 8).

METHODS

All subjects were studied for 3 consecutive nights in the sleep laboratory. The design was a fixed-order placebo-donepezil protocol to accommodate the long half-life of donepezil. Night 1 served as an adaptation night. On night 2, placebo was administered at 8:00 PM. On night 3, donepezil was administered at 8:00 PM.

RESULTS

The cholinergic challenge distinguished the groups. In depressed patients REM latency was reduced compared with baseline (47.6 vs. 64.4, p =.04) following administration of donepezil. Control subjects showed no response: REM latency after donepezil was virtually identical to baseline REM latency (71.7 vs. 69.3).

CONCLUSIONS

These data indicate that donepezil is likely to be useful in testing hypotheses related to cholinergic function in mood disorders.

Comparative meta-analysis of pharmacotherapy and behavior therapy for persistent insomnia

OBJECTIVE

Although four meta-analytic reviews support the efficacy of pharmacotherapy and behavior therapy for the treatment of insomnia, no meta-analysis has evaluated whether these treatment modalities yield comparable outcomes during acute treatment. The authors conducted a quantitative review of the literature on the outcome of the two treatments to compare the short-term efficacy of pharmacotherapy and behavioral therapy in primary insomnia.

METHOD

They identified studies from 1966 through 2000 using MEDLINE, psycINFO, and bibliographies. Investigations were limited to studies using prospective measures and within-subject designs to assess the efficacy of benzodiazepines or benzodiazepine receptor agonists or behavioral treatments for primary insomnia. Benzodiazepine receptor agonists included zolpidem, zopiclone, and zaleplon. Behavioral treatments included stimulus control and sleep restriction therapies. Twenty-one studies summarizing outcomes for 470 subjects met inclusion criteria.

RESULTS

Weighted effect sizes for subjective measures of sleep latency, number of awakenings, wake time after sleep onset, total sleep time, and sleep quality before and after treatment were moderate to large. There were no differences in magnitude between pharmacological and behavioral treatments in any measures except latency to sleep onset. Behavior therapy resulted in a greater reduction in sleep latency than pharmacotherapy.

CONCLUSIONS

Overall, behavior therapy and pharmacotherapy produce similar short-term treatment outcomes in primary insomnia.

Response to "Do increases in beta EEG activity uniquely reflect insomnia?" (C. H. Bastein and M. H. Bonnet)

We appreciate the thoughtful comments by Drs, Bastien and Bonnet regarding our article and the opportunity provided by the Editors to respond to the issues raised. The reviewers make several critical points concerning both the beta EEG in insomnia literature and the neurocognitive model. Our summary of their concerns and our thoughts on the issues they raise are as follows.

Beta EEG activity and insomnia

To date there have been seven studies which find that beta EEG is elevated at around sleep onset and during polysomnographic sleep in patients with insomnia. These findings suggest that insomnia may be characterized by central nervous system (CNS) hyperarousal. In this article, the seven studies are critically reviewed, two theoretical perspectives on beta EEG are presented, and the concept of hyperarousal as a three component process is discussed.

The mesograde amnesia of sleep may be attenuated in subjects with primary insomnia

In this study, we pilot tested one of the more controversial components of the Neurocognitive Model of Insomnia; the proposition that subjects with chronic primary insomnia are better able to recall and/or recognize information from sleep onset intervals than good sleeper controls. Nine subjects participated in this pilot study, five of whom had a complaint of insomnia. The remaining four subjects were self-reported good sleeper controls. Subjects were matched for age, sex, and body mass. All subjects spent two nights in the sleep laboratory. The first night served as an adaptation night. The second night served as the experimental night during which a forced awakening and memory task was deployed. In this procedure, subjects were played single-word stimuli across four time periods: at natural sleep onset (Trial 1) and at the sleep onset transitions following three forced awakenings (Trials 2-4 from Stage 2 sleep). All subjects were awakened after about 6 h had elapsed from lights out and were tested for free recall and recognition memory for the word stimuli. The insomnia subjects, tended to identify more of the word stimuli on the recognition task (average for the four trials) and recognized significantly more of the words that were presented at sleep onset proper (Trial 1). This finding suggests that the natural mesograde amnesia of sleep may be attenuated in subjects with insomnia.

Temporal and stagewise distribution of high frequency EEG activity in patients with primary and secondary insomnia and in good sleeper controls

In the present study, we evaluate the temporal and stagewise distribution of high frequency EEG activity (HFA) in primary and secondary insomnia. Three groups (n=9 per group) were compared: primary insomnia (PI), Insomnia secondary to major depression (MDD), and good sleeper controls (GS). Groups were matched for age, sex and body mass. Average spectral profiles were created for each sleep epoch. Grand averages were created for each NREM cycle and each stage of sleep after removing waking and movement epochs and epochs containing micro or miniarousals. It was found that HFA (in terms of relative power) tends to increase across NREM cycles, occurs maximally during stage 1 and during REM sleep, and that both these effects are exaggerated in patients with PI. In addition, HFA was found to be inversely associated with Delta activity and the three groups in our study appear to exhibit characteristic Delta/Beta patterns. Our data are consistent with the perspective that HFA is related to CNS arousal to the extent that Beta/Gamma activity occurs maximally during shallow stages of sleep and maximally in subjects with PI.

Behavioral treatment of insomnia: treatment outcome and the relevance of medical and psychiatric morbidity

Recently, we undertook a case series study and found that behavior therapy for insomnia was effective as plied in the clinic setting and that the findings were similar to those in the "clinical trial" literature. In the present study, we evaluate a second set of case series data to assess (1) the replicability of our original findings, (2) if our treatment outcomes are statistically comparable to those in the literature, and (3) if medical and psychiatric morbidity influence treatment outcome. It was found that patients who completed four or more sessions of cognitive behavioral therapy for insomnia (CBT) were, on average, 33% improved. This average corresponded to a 56% reduction in wake time after sleep onset, a 34% reduction in sleep latency, a 29% increase in total sleep time, and a 13% decrease in number of awakenings per night. These findings are not significantly different from those reported in literature for both CBT and pharmacotherapy interventions. Medical and psychiatric comorbidity did not influence treatment outcome.

The diagnosis of primary insomnia and treatment alternatives

This review provides information about the diagnosis and treatment of primary insomnia. Several treatment strategies are reviewed including the use of hypnotics, naturopathic remedies and behavioral interventions. We suggest that nonpharmacologic interventions are likely to be the most safe and effective.

Presleep cognitions in patients with insomnia secondary to chronic pain

This study had two primary objectives: (1) characterize the content of presleep cognitions of chronic pain patients and (2) evaluate the association between presleep cognitions and sleep disturbance. Thirty-one outpatients with benign chronic pain completed the Beck Depression Inventory, pain and sleep diaries and participated in an in vivo, presleep thought sampling procedure for 1 week in their homes. The three most frequently reported presleep cognitions were general pain-related thoughts (36%), thoughts about the experimental procedure (27%), and negative sleep-related thoughts (26%). Stepwise multiple regression analyses found the presleep thoughts pertaining to pain and environmental stimuli were significantly associated with sleep continuity, independent from the effects of depression and nightly pain severity. Pain severity was found to be positively associated with Wake After Sleep Onset Time. These results are consistent with cognitive-behavioral models of primary insomnia and suggest the content of presleep cognitive arousal may contribute to sleep disturbance secondary to pain.

Beta/Gamma EEG activity in patients with primary and secondary insomnia and good sleeper controls

STUDY OBJECTIVE

Several studies have shown that patients with insomnia exhibit elevated levels of Beta EEG activity (14-35 Hz) at or around sleep onset and during NREM sleep. In this study, we evaluated 1) the extent to which high frequency EEG activity is limited to the 14-32 Hz domain, 2) whether high frequency EEG activity (HFA) is associated with discrepancies between subjective and PSG measures of sleep continuity, and 3) the extent to which high frequency EEG activity occurs in patients with primary, as opposed to secondary, insomnia.

DESIGN

Three groups (n=9 per group) were compared: Primary Insomnia, Insomnia secondary to Major Depression, and Good Sleeper Controls. Groups were matched for age, sex and body mass. Average spectral profiles were created for each NREM cycle after removing waking and movement epochs and epochs containing micro- or mini-arousals.

SETTING

Sleep Research Laboratory

PATIENTS OR PARTICIPANTS

Patients with primary and secondary insomnia

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Subjects with Primary Insomnia exhibited more average NREM activity for Beta-1 (14-20Hz), Beta-2 (20-35Hz) and Gamma activity (35-45Hz) than the other two groups (p.<.01). Group differences were also suggestive for Omega activity (45.0-125Hz) (p.<.10), with MDD subjects tending to exhibit more activity than the other groups. Correlational analyses revealed that average NREM Beta-1 and Beta-2 activity tended to be negatively correlated with subjective-objective discrepancy measures for total sleep time and sleep latency.

CONCLUSIONS

Our results confirm that Beta activity is increased in Primary Insomnia. In addition, our data suggest that high frequency activity in patients with Primary Insomnia is limited to the Beta/Gamma range (14-45 Hz), and is negatively associated with the perception of sleep.

Behavioral sleep medicine. An emerging subspecialty in health psychology and sleep medicine

As the knowledge base in sleep disorders medicine has broadened, a subspecialty that we will refer to as "behavioral sleep medicine" area is emerging. This article will define this subspecialty area, provide some historical context for its emergence, review issues related to specialty training and clinical practice, and suggest needs for future research.The term "behavioral sleep medicine" was selected because it clearly denoted the two fields from which our subspecialty emerged (health psychology/behavioral medicine and sleep disorders medicine). It suggests much about our approach to training, clinical practice, and research, and it appropriately implies that the field is open to PhD sleep specialists, MD sleep specialists, and other health care providers with the relevant training. Formally, behavioral sleep medicine refers to the branch of clinical sleep medicine and health psychology that: (1) focuses on the identification of the psychological (e.g. cognitive and/or behavioral) factors that contribute to the development and/or maintenance of sleep disorders and (2) specializes in developing and providing empirically validated cognitive, behavioral, and/or other nonpharmacologic interventions for the entire spectrum of sleep disorders.

EEG sleep in African-American patients with major depression: a historical case control study

This study was designed to evaluate the effect of race, specifically African-American, on electroencephalographic (EEG) sleep and clinical symptom profile in unipolar major depression. A clinical research database was used to identify appropriate subjects and a double-matched historical case-control design was implemented. African-American depression patients were double matched within protocol to Euro-American depressed patients. Age, sex, and protocol of origin were matching variables. African-American depressed patients had less total sleep, less slow wave sleep, more stage 2 sleep, longer rapid eye movement (REM) sleep latency, less REM sleep, and lower REM density than Euro-American depressed patients. African-American depressed patients did not differ from Euro-American patients in symptom severity, age of onset, number of episodes, socio-economic status, and, as planned, did not differ in age and sex distribution. Depressive symptom constellation also did not distinguish the two groups. African-American depressed patients demonstrated differences in EEG sleep profile, with less total sleep, overall lighter nonREM sleep, and relatively preserved REM sleep, despite a clinical symptom profile that did not differ from Euro-American depressed patients. The sleep profile appeared to be consonant with the sleep findings in chronic insomnia. The pathological implications of these differences remained to be explored in careful prospective studies of African-American depressed patients and in well-characterized, racially matched normal control comparisons.

Sleep quality and presleep arousal in chronic pain

This study was designed (1) to characterize the extent and nature of sleep complaints of chronic pain patients and (2) to examine the factors that predict sleep quality. A heterogeneous sample of 51 outpatients with benign, chronic pain was recruited from newspaper and pain clinic advertisements. Patients completed a variety of self-report instruments including the Multidimensional Pain Inventory, the Pittsburgh Sleep Quality Index, the Pre-Sleep Arousal Scale, and the Beck Depression Inventory. Sleep complaints were reported by 88% of the sample. Presleep cognitive arousal, rather than pain severity, was found to be the primary predictor of sleep quality.

Which depressive symptoms are related to which sleep electroencephalographic variables?

Sleep complaints and electroencephalographic (EEG) sleep abnormalities are associated with risk for new onset depression, illness severity, treatment outcome, and vulnerability for recurrence of depression. The aim of this study was to evaluate the strength of association between EEG sleep measures and depression symptoms, and to identify the variables that account for the majority of the association. Depression ratings from the Hamilton Rating Scale for Depression and the Beck Depression Inventory and polysomnographic measures were examined in 361 adult outpatients with major depressive disorder. Canonical correlation and serial multiple regression analyses were used to determine the associations between depressive symptoms and sleep measures. Canonical correlation showed a unidimensional relationship between depressive symptoms and sleep measures (R = .55, p < .05). Fifteen depression items and nine sleep measures accounted for 95% of the correlation. Depression variables encompassed a core set of mood, neurovegetative, and cognitive symptoms. Sleep variables were primarily related to delta EEG activity, and this may be reflective of impaired sleep "drive" or heightened arousal during sleep.

Psychophysiological insomnia: the behavioural model and a neurocognitive perspective

A number of paradoxes are apparent in the assessment and treatment of psychophysiological insomnia and sleep state misperception. Three of these paradoxes exist as discrepancies between polysomnographic (PSG) measures and the subjective impressions regarding sleep quality and quantity. The remaining incongruity exists largely within the objective domain. In the case of subjective-objective discrepancies, patients with insomnia: (1) frequently identify themselves as having been awake when awakened from PSG defined sleep; (2) tend to overestimate sleep latency and underestimate total sleep time as compared with PSG measures; (3) appear to derive more benefit from pharmacotherapy that can be explained by objective gains. The remaining paradox pertains to the observation that hypnotic medications, by and large, do not normalize sleep architecture or produce a more 'sleep-like' EEG. In this paper, we review possible explanations for these various paradoxes, introduce a new perspective and suggest possible research avenues. The model introduced is based on the observation that beta and/or gamma activity (which have been found to be associated with cognitive processes) is enhanced in insomnia at or around sleep onset. We propose that this kind of high frequency EEG activity may interfere with the normal establishment of sleep onset-related mesograde amnesia. As a result, the patient with insomnia maintains a level of information and/or memory processing that blurs the phenomenological distinction between sleep and wakefulness and influences retrospective judgments about sleep initiation and duration.

Sleep complaints in chronic postconcussion syndrome

This study was designed to identify the incidence of sleep complaints in 39 patients with chronic postconcussion syndrome compared to those of a control group of 27 patients with orthopedic injuries. Patients with orthopedic injuries were selected as a comparison group to control for the effects of traumatic injury or chronic pain. There were no differences in age, sex distribution, or time from injury between the patient groups. Type and frequency of sleep disturbances in a mean two-year postinjury period were evaluated. Patients with chronic postconcussion syndrome reported more difficulty in initiating and maintaining sleep at night and greater difficulty with sleepiness during the day.

Alpha sleep and information processing, perception of sleep, pain, and arousability in fibromyalgia

This study examined the relationship between alpha sleep and information processing during sleep, perception of sleep, musculoskeletal pain, and arousability in patients with fibromyalgia. Patients (n = 20) were allowed to sleep undisturbed for the first 60 minutes of the study to assess amount of alpha sleep and were classified as high or low alpha generators based on quantitative analyses of alpha activity during this period. The groups were compared for performance on two memory tasks, perceptions of polysomnographically-defined sleep and EEG arousals in response to auditory stimuli. Correlations between symptoms of fibromyalgia and alpha activity were also examined. Alpha activity during sleep in fibromyalgic patients was associated with the perception of shallow sleep and an increased tendency to arouse in relation to auditory stimuli. Alpha activity was not associated with increased memory for auditory stimuli presented during sleep, sleep state misperception, or with myalgia symptoms. Alpha sleep appears to be, electrophysiologically, a shallow form of sleep. Our results suggest that it is perceived as such phenomenologically and that it is also associated with increased arousability.

Sustained facial muscle activity during REM sleep and its correlation with depression

Recently, we proposed that the coupling of cognitive activation and diminished arousal during REM sleep may have a mood regulating effect. Conversely, increased arousal during REM sleep may be associated with mood dysregulation. In this paper, the desensitization model is described, and data are presented on the association between motor activity during REM sleep, wakefulness and severity of depression. Motor activity sleep EEG data and two measures of depressive severity (BDI and HRSD) were obtained from 23 depressed patients. BDI scores were significantly correlated with motor activity only during REM sleep. HRSD scores were correlated with motor activity only during quiet wakefulness. These findings are consistent with the theoretical perspective that dysregulation in arousal mechanisms during REM sleep may promote mood disturbance during the depressive episode.

Nonpharmacologic treatments of insomnia

Nonpharmacologic treatments that have been evaluated for insomnia are reviewed. These include sleep hygiene techniques, stimulus control instructions, sleep restriction, chronotherapy, bright light therapy, relaxation training, biofeedback, paradoxical intention, and cognitive therapy. Comparative studies of the different treatments indicate considerable overlap in effectiveness. Direct comparisons between treatments have shown stimulus control instructions to be more effective than either relaxation training or paradoxical intention. Further research is needed on the tailoring of treatments to patient needs, as are more detailed comparisons between pharmacologic and nonpharmacologic treatments.