[Prevalence of sleep-related breathing disorders of inpatients with psychiatric disorders]. / Prävalenz schlafbezogener Atmungsstörungen bei stationären Patienten mit psychischen Erkrankungen.

BACKGROUND: Sleep-related breathing disorders seriously impair well-being and increase the risk for relevant somatic and psychiatric disorders. Moreover, risk factors for sleep-related breathing disorders are highly prevalent in psychiatric patients. The aim of this study was for the first time in Germany to study the prevalence of obstructive sleep apnea syndrome (OSAS) as the most common form of sleep-related breathing disorder in patients with psychiatric disorders. METHODS: In 10 psychiatric hospitals in Germany and 1 hospital in Switzerland, a total of 249 inpatients underwent an 8­channel sleep polygraphy to investigate the prevalence of sleep apnea in this group of patients. RESULTS: With a conspicuous screening result of 23.7% of the subjects, a high prevalence of sleep-related breathing disorders was found to occur among this group of patients. Male gender, higher age and high body mass index (BMI) were identified as positive risk factors for the detection of OSAS. DISCUSSION: The high prevalence indicates that sleep apnea is a common sleep disorder among psychiatric patients. Although OSAS can lead to substantial disorders of the mental state and when untreated is accompanied by serious somatic health problems, screening procedures are not part of the routine work-up in psychiatric hospitals; therefore, sleep apnea is presumably underdiagnosed in psychiatric patients. In view of the results of this and previous studies, this topic complex should be the subject of further research studies.

Ethyl glucuronide (EtG): better than breathalyser or self-reports to detect covert short-term relapses into drinking.

AIMS: The assessment of relapses is widely used as an outcome measure of alcohol dependence treatment. However, the methods of assessing relapses range from questionnaires to biological markers of alcohol for different time spans. The aim of this study was to compare the relapse rates of weekend home stays during long-term alcohol dependence treatment, assessed by ethyl glucuronide (EtG), breath alcohol tests and self-reports. METHODS: Two hundred and ninety-seven alcohol-dependent patients receiving a long-term inpatient treatment programme participated. After a weekend at home (Friday to Sunday) they were evaluated for relapse by personal interviews and with breath alcohol tests. A concomitantly collected urine sample was later assessed for EtG with liquid chromatography-tandem mass spectrometry (LC-MS/MS analysis). RESULTS: Of the total, 37.7% of the patients were positive for EtG at least once. Breath alcohol tests had been positive in only 4.4% and in personal interviews only 5.7% of the patients had admitted relapse. 15.6% of EtG tests were positive, but breath alcohol tests were negative (Cohen's kappa = 0.056). Ninety-three per cent of the relapses were only detected by EtG. CONCLUSION: In addition to breath alcohol tests and interviews, urinary EtG can clearly improve the verification of relapse in inpatient treatment programmes allowing for weekend stays at home. Without EtG testing, a high amount of relapses will stay undetected.

[Sleep, learning and memory: relevance for psychiatry and psychotherapy]. / Schlaf, Lernen und Gedächtnis: Relevanz für Psychiatrie und Psychotherapie.

BACKGROUND: Sleep has been identified as a state that optimizes the consolidation of newly acquired information in the memory. Sleep disturbances might essentially contribute to memory impairment in relevant psychiatric disorders, such as major depression and schizophrenia. METHODS: This article provides a brief review of the latest research results on sleep and its association with memory consolidation. RESULTS AND CONCLUSION: Specific disturbances of sleep structure are associated with particular memory deficits in psychiatric patients. Effective treatment of sleep disorders should not only improve signs of sleep but should also heal associated memory impairments.

Reduced olfactory performance in patients with major depression.

The aim of the present study is to investigate olfactory sensitivity and odor evaluations in a homogeneous sample of unipolar depressive patients using pure olfactory odors. Twenty-four in-patients with major depressive disorder (MDD) were investigated during their acute depressive phase. Eighteen of them participated a second time after successful treatment. A group of healthy subjects, matched by age, sex, and smoking behavior, served as a control. Olfactory sensitivity, as measured by threshold tests, was strongly reduced in patients with severe depression. Additional correlative analyses revealed that the lowered sensitivity could partly be predicted by high depression scores. After successful medical treatment, these sensitivity differences were reduced and did not reach the significance level. The subjective odor evaluations (valence and intensity ratings) were not markedly changed in general. The results reveal that olfactory performance in MDD patients is reduced at an early perceptional level of stimulus processing. It is discussed whether this effect can be attributed to the close functional connection between the main olfactory bulb and the amygdala.

Receptive properties of afferent nerve fibres associated with the rat saphenous vein.

We tested afferent fibres isolated from the saphenous nerve for their responses to mechanical, osmotic and chemical stimuli applied to a vascularly isolated segment of the saphenous vein in the rat. Fifteen units were excited by local mechanical stimulation and many of them were also activated by distension of the venous segment, however exclusively by presumably noxious pressures. Most mechanosensitive fibres were excited by one of the three pain-producing substances, hyperosmotic saline (HS), potassium chloride (KCl) and bradykinin. Three fibres which were insensitive to mechanical stimulation, responded to injection of HS or KCl into the venous segment. We conclude that the venous afferents most likely have nociceptive function. Most are considered to be polymodal.

Non-linear electroencephalogram dynamics in patients with spontaneous nocturnal migraine attacks.

The present study was conducted to examine non-linear electroencephalogram (EEG) measures during the development of a spontaneous migraine attack. We investigated the sleep EEG of five patients with migraine without aura in the pain-free interval and at the onset of a nocturnal attack. Sleep EEG recordings were analysed using the method of global dimensional complexity compared to conventional sleep scoring techniques. We found no divergence between classical sleep architecture and the estimated dimensional course nor any relevant short-term changes related to the onset of headache. There was, however, a loss of dimensional complexity in the first two non-rapid eye movement sleep states in the migraine night, with statistical significance during the second sleep cycle. For the first time, these results provide evidence of a global dimension decrease that is related to cortical network changes during a migraine attack.

Effects of intranasal hypocretin-1 (orexin A) on sleep in narcolepsy with cataplexy.

BACKGROUND: The neuropeptides hypocretin-1 and -2 (hcrt-1 and -2, also known as orexin A and B) are crucially involved in the regulation of sleep/wake states. On the one hand, the sleep-wake disorder narcolepsy can be caused by an hcrt-1 deficiency. On the other, intracerebral administration of hcrt-1 produces an increase in wakefulness at the expense of REM sleep in normal and narcoleptic animals. In humans intranasal administration has been shown to effectively deliver neuropeptides directly to the central nervous system. We hypothesised that the intranasal application of hcrt-1 increases wakefulness and reduces REM sleep in the natural human hcrt-1 deficiency narcolepsy with cataplexy. METHODS: In this double-blind, random-order crossover, placebo-controlled, within-subject design study we administered human recombinant hcrt-1 (435 nmol) intranasally to eight subjects with narcolepsy with cataplexy before night sleep, followed by standard polysomnography. RESULTS: Although intranasal administration of hcrt-1 had no statistically significant effect on nocturnal wakefulness, we found that it reduced REM sleep quantity, particularly during the second half of the recording. Furthermore, intranasal hcrt-1 had a clear REM sleep stabilising effect and led to significantly reduced direct wake to REM transitions. CONCLUSION: In this pilot study we found, first, evidence that the intranasal administration of hcrt-1 has functional effects on sleep in narcolepsy with cataplexy. Our results may encourage the use of the intranasal approach in further studies on hypocretinergic sleep regulation and might also contribute to the future development of a causal treatment for narcolepsy with cataplexy.

Effects of olanzapine on slow wave sleep, sleep spindles and sleep-related memory consolidation in schizophrenia.

INTRODUCTION: Memory deficits and sleep disturbances are common clinical features of schizophrenia. Sleep is supposed to promote memory consolidation and the antipsychotic olanzapine is suggested to improve both sleep and memory functions. Therefore we performed a study to analyse the acute effects of olanzapine on distinct sleep parameters and sleep-related memory consolidation in parallel. METHODS: We studied 26 patients with schizophrenia on stable antipsychotic medication with amisulpride (age range 19-44 years). Immediately before polysomnography and the morning after we performed neuropsychological tasks. Before the third night in the sleep laboratory, patients received either olanzapine or a placebo. RESULTS: We found a significant positive association for slow wave sleep and declarative memory performance in schizophrenia at baseline. Additionally, Stage 2 sleep spindle density was positively related to overnight memory consolidation. Olanzapine caused a significant increase in the amount of slow wave sleep in accordance with recent studies, but led also to a significant decrease in sleep spindle density, which had not been described before. Memory performance the next morning was not different between the two groups. DISCUSSION: Since not only slow wave sleep but also sleep spindles are supposed to promote sleep-related memory consolidation, we suggest that a putative positive effect on memory performance by slow wave sleep augmentation is neutralised by the decrease in sleep spindles due to olanzapine.

Properties of afferent nerve fibres supplying the saphenous vein in the cat.

1. We examined the responses of primary afferent neurones supplying a vascularly isolated segment of the saphenous vein to mechanical and chemical stimuli in anaesthetized cats. Activity was recorded from centrally cut axons of afferent nerve fibres which were isolated from the saphenous nerve near its junction with the femoral nerve. 2. A total of thirty units responded to one of these stimuli and twenty-three of them were activated by local mechanical stimulation of the venous wall. Most receptive fields were circular spots. The response of the isolated venous segment to distension was tested in fifteen out of thirty units and eight out of fifteen were activated. Intravasal threshold pressures inducing discharges were in the range of 35-250 mmHg with a mean of 120 mmHg. 3. Twenty-seven out of the thirty units were tested for both mechano- and chemosensitivity. Thirteen were classified as A fibres and fourteen as C fibres with conduction velocities of 5-30 m s-1 and less than 2.5 m s-1 respectively. Twenty fibres (12/13 A, 8/14 C) were mechanosensitive. Two-thirds of the mechanosensitive A (8/12) and all of the mechanosensitive C fibres (8/8) responded to at least one of the chemical stimuli used: hypertonic saline, bradykinin (BK) or capsaicin. 4. The remaining seven units (6 C, 1 A) were activated by injection of BK into the isolated venous segment but failed to respond to mechanical stimuli. Six were found during five experiments in which BK was used as a search stimulus. Injection of bradykinin into the isolated venous segment repeatedly induced an increase in systemic blood pressure. 5. The proportion of unmyelinated fibres responding to mechanical stimulation of the venous segment was systematically examined in three experiments and amounted to about 1% of the unmyelinated afferents in the saphenous nerve. 6. In conclusion, a small proportion of afferent nerve fibres in the saphenous nerve responds to presumably noxious mechanical and/or chemical stimuli applied to the saphenous vein. These fibres, together with some chemospecific venous afferents, may be capable of encoding nociceptive information from the vein especially under pathological conditions.

[Zolpidem: the risk of tolerance and dependence according to case reports, systematic studies and recent molecularbiological data]. / Zolpidem: Zur Entwicklung von Toleranz und Abhängigkeit anhand von Fallberichten, systematischen Studien und aktuellen molekularbiologischen Daten.

Our group as well as about 20 other publications report cases of dependence from zolpidem. Furthermore, there is epidemiological and polysomnographic evidence that there is a risk for tolerance and dependence for zolpidem although lower than in the case of benzodiazepines. Recent molecularbiological findings offer interesting data in this respect. Whereas in the recommended dose range zolpidem almost exclusively binds to the alpha(1) subunit of the GABA(A) receptor associated with sleep promotion, in higher doses it also binds the alpha(2), alpha(3) and alpha(5) subunits typically targeted by benzodiazepines and associated with anxiolytic effects. Moreover, because age, gender and alcohol were shown to significantly affect expression of these subunits in individual brain regions, dosage and duration of treatment with zolpidem as well as age, gender and additional consumption of alcohol, a history of abuse and dependence might play a role in the development of tolerance and dependence in individual patients.

Polysomnographic findings in nights preceding a migraine attack.

Sleep recordings were performed in eight patients to analyse sleep alterations preceding migraine attacks. Polysomnographic recordings from nights before an attack were compared with nights without following migraine. We analysed standard sleep parameters and electroencephalogram (EEG) power spectra. The main findings preceding migraine attacks were a significant decrease in the number of arousals, a decrease in rapid eye movement (REM) density, a significant decrease of beta power in the slow wave sleep, and a decrease of alpha power during the first REM period. The results suggest a decrease in cortical activation during sleep preceding migraine attacks. According to the models of sleep regulation, alterations in the function of aminergic or cholinergic brainstem nuclei have to be discussed.