Automated sleep staging in people with intellectual disabilities using heart rate and respiration variability

BACKGROUND

People with intellectual disabilities (ID) have a higher risk of sleep disorders. Polysomnography (PSG) remains the diagnostic gold standard in sleep medicine. However, PSG in people with ID can be challenging, as sensors can be burdensome and have a negative influence on sleep. Alternative methods of assessing sleep have been proposed that could potentially transfer to less obtrusive monitoring devices. The goal of this study was to investigate whether analysis of heart rate variability and respiration variability is suitable for the automatic scoring of sleep stages in sleep-disordered people with ID.

METHODS

Manually scored sleep stages in PSGs of 73 people with ID (borderline to profound) were compared with the scoring of sleep stages by the CardioRespiratory Sleep Staging (CReSS) algorithm. CReSS uses cardiac and/or respiratory input to score the different sleep stages. Performance of the algorithm was analysed using input from electrocardiogram (ECG), respiratory effort and a combination of both. Agreement was determined by means of epoch-per-epoch Cohen's kappa coefficient. The influence of demographics, comorbidities and potential manual scoring difficulties (based on comments in the PSG report) was explored.

RESULTS

The use of CReSS with combination of both ECG and respiratory effort provided the best agreement in scoring sleep and wake when compared with manually scored PSG (PSG versus ECG = kappa 0.56, PSG versus respiratory effort = kappa 0.53 and PSG versus both = kappa 0.62). Presence of epilepsy or difficulties in manually scoring sleep stages negatively influenced agreement significantly, but nevertheless, performance remained acceptable. In people with ID without epilepsy, the average kappa approximated that of the general population with sleep disorders.

CONCLUSIONS

Using analysis of heart rate and respiration variability, sleep stages can be estimated in people with ID. This could in the future lead to less obtrusive measurements of sleep using, for example, wearables, more suitable to this population.

Safety, Tolerability, Pharmacokinetics and Quantitative Electroencephalography Assessment of ACD856, a Novel Positive Allosteric Modulator of Trk-Receptors Following Multiple Doses in Healthy Subjects

BACKGROUND

ACD856 is a positive allosteric modulator of tropomyosin receptor kinase (Trk) receptors which has shown to have pro-cognitive and anti-depressant-like effects in various animal models. It is currently in clinical development for the treatment of Alzheimer's disease and other disorders where cognition is impaired and is also considered for indications such as depression or other neuropsychiatric diseases. ACD856 has a novel mechanism of action modulating the activity of the Trk-receptors, resulting in increased stimulation of the neurotrophin signaling pathways. Previous studies applying single intravenous and oral doses of ACD856 indicate that ACD856 is safe and well-tolerated by healthy volunteer subjects, and that it has suitable safety and pharmacokinetic properties for further clinical development.

OBJECTIVES

To investigate the safety and tolerability of 7 days of treatment with multiple ascending oral doses of ACD856 in healthy subjects, and to characterize its pharmacokinetic (PK) properties. In addition, pharmacodynamic effects of ACD856 using quantitative electroencephalography (qEEG) as an indicator for central target engagement were assessed.

DESIGN

This was a prospective, phase I, double-blind, parallel-group, placebo-controlled, randomized study of the safety, tolerability, PK and pharmacodynamics of multiple ascending oral doses of ACD856 in healthy subjects. ACD856 or placebo were administered in 3 ascending dose cohorts of 8 subjects. Within each cohort, subjects were randomized to receive either ACD856 (n=6) or placebo (n=2).

SETTING

The study was conducted at a First-in-Human unit in Sweden.

PARTICIPANTS

Twenty-four healthy male and female subjects.

INTERVENTION

The study medication was administered as an oral solution, with ACD856 or the same contents without the active ingredient (placebo). The dose levels ranged from 10 mg to 90 mg. ACD856 was administered once daily for 7 days, targeting steady state.

MEASUREMENTS

Safety and tolerability assessments included adverse events, laboratory, vital signs, 12-lead electrocardiogram (ECG), physical examination, assessment of stool frequency and questionnaires to assess symptoms of anxiety, depression, as well as suicidal ideation and behavior. In addition, cardiodynamic ECGs were extracted to evaluate cardiac safety. PK parameters were calculated based on measured concentrations of ACD856 in plasma, urine, and cerebrospinal fluid (CSF) samples. Metabolite profiling, characterization and analysis was performed based on and urine samples. qEEG was recorded for patients in the two highest dose cohorts (30 and 90 mg/day) as a pharmacodynamic assessment to explore central target engagement.

RESULTS

Treatment with ACD856 was well tolerated with no serious adverse events. No treatment emergent or dose related trends were observed for any of the safety assessments. ACD856 was rapidly absorbed and reached maximum plasma exposure at 30 to 45 minutes after administration. Steady state was reached before Day 6, with an elimination half-life at steady state of approximately 20 hours. At steady state, ACD856 exhibited accumulation ratios for Cmax and AUC of approximately 1.6 and 1.9 respectively. The exposure, Cmax and AUC0-24, increased proportionally with the dose. There was no unchanged ACD856 detected in urine. The metabolic pattern in urine and plasma was similar, and in alignment with the metabolites observed in preclinical toxicology studies. The level of ACD856 measured in CSF at steady state increased with dose, indicating Central Nervous System (CNS) exposure at relevant levels for pharmacodynamic effects. ACD856 demonstrated significant dose-dependent treatment-associated changes on qEEG parameters. Specifically, increase of the relative theta power and decrease of the fast alpha and beta power was observed, leading to an acceleration of the delta+theta centroid and an increase in the theta/beta ratio.

CONCLUSIONS

ACD856 was well tolerated at the tested dose levels (10-90 mg/daily for 7 days) in healthy subjects. The compound has a robust pharmacokinetic profile, with rapid absorption and dose-dependent exposure. ACD856 was shown to pass the blood-brain-barrier, reach relevant exposure in the CNS and to induce dose-dependent treatment-related changes on qEEG parameters, indicating central target engagement.

Direct application of an ECG-based sleep staging algorithm on reflective photoplethysmography data decreases performance

OBJECTIVE

The maturation of neural network-based techniques in combination with the availability of large sleep datasets has increased the interest in alternative methods of sleep monitoring. For unobtrusive sleep staging, the most promising algorithms are based on heart rate variability computed from inter-beat intervals (IBIs) derived from ECG-data. The practical application of these algorithms is even more promising when alternative ways of obtaining IBIs, such as wrist-worn photoplethysmography (PPG) can be used. However, studies validating sleep staging algorithms directly on PPG-based data are limited.

RESULTS

We applied an automatic sleep staging algorithm trained and validated on ECG-data directly on inter-beat intervals derived from a wrist-worn PPG sensor, in 389 polysomnographic recordings of patients with a variety of sleep disorders. While the algorithm reached moderate agreement with gold standard polysomnography, the performance was significantly lower when applied on PPG- versus ECG-derived heart rate variability data (kappa 0.56 versus 0.60, p < 0.001; accuracy 73.0% versus 75.9% p < 0.001). These results show that direct application of an algorithm on a different source of data may negatively affect performance. Algorithms need to be validated using each data source and re-training should be considered whenever possible.

0436 Deep Learning for Scoring Sleep Based on Signals Available in Home Sleep Apnea Test Studies: Cardiorespiratory Sleep Staging

Introduction

Typically, neurological signals are not recorded in home sleep apnea testing (HSAT) and thus standard sleep scoring is not applicable. The respiratory event index is calculated using total recording time rather than total sleep time (TST) resulting in a risk of underestimating sleep apnea severity. The objective of the study was to evaluate if artificial intelligence approaches can provide sleep scoring based on cardiorespiratory signals (CReSS) with reasonable accuracy.

Methods

Supervised deep learning for scoring sleep was trained with 472 and tested in 116 polysomnographies (PSG), scored independently by two experts and by a consensus scorer. The resulting bidirectional long short-term memory recurrent neural network (RNN) was integrated in the Somnolyzer system and validated in 97 PSGs of patients with obstructive sleep apnea (OSA) which had been scored independently by four human experts. Cohen’s kappa agreement for four stages (W, L: N1+N2, D: N3, R) was determined as compared to a consensus scoring.

Results

Epoch-by-epoch comparison between CReSS autoscoring and manual consensus scoring resulted in Cohen’s kappa of 0.68 (W: 0.74, L: 0.63, D: 0.54, R: 0.79). The intra-class correlation coefficient (ICC) between TST derived from CReSS and from neurological scoring was 0.86 (95%-CI: 0.79-0.90), while the ICC between subjective TST from sleep questionnaire and the objective TST was only 0.65 (95%-CI: 0.45-0.77). REM-related OSA had a prevalence of 16% and was detected with an accuracy of 95%.

Conclusion

With a kappa of 0.68, the cardiorespiratory-based RNN classifier is far above previously published values and reflects a substantial agreement with the manual consensus scoring in patients with sleep-disordered breathing. Thus, applying CReSS allows a more accurate determination of the OSA-severity and even a detection of REM related OSA in HSAT studies.

Support

All authors are employees of Philips

0435 Autoscoring of Sleep and Associated Events Versus a Reference Scorer Competing with Three Additional Manual Scorings: A Clinical Validation Study

Introduction

Manual scoring of polysomnographic (PSG) data is a time-consuming and tedious process with noticeable inter-rater variability. Autoscoring may overcome these limitations if it delivers valid results. The goal of this study was to validate a comprehensive autoscoring system in a clinically representative population.

Methods

The validation data consisted of 97 PSGs in patients with sleep-related breathing disorder, scored manually by a reference scorer and three further experts. The Somnolyzer autoscoring system combined pattern recognition for events such as spindles, k-complexes, slow-waves, eye-movements, apneas, hypopneas, desaturations and leg movements with an artificial intelligence classifier consisting of a bidirectional long short-term memory recurrent neural network (RNN) architecture. Intra-class correlation coefficients (ICC) for absolute agreement were determined for the commonly used metrics in sleep medicine to compare both, the three human expert scorings and the autoscoring versus the reference scoring.

Results

ICC coefficients for autoscoring and the three manual scorings versus the reference scoring were for sleep efficiency: .95, .83, .91, .93; N1(%): .71, .44, .39, .56; N2(%): .87, .63, .55, .45; N3(%): .80, .62, .44, .32; R(%): .92, .89, .91, .88; arousal index: .88, .81, .22, .78; PLMI: .97, .88, .86, .91; AHI: .91, .89, .87, .78; OA: .94, .89, .91, .90; CA: .96, .96, .96, .82; MA: .93, .77, .43, .41. Thus, the ICCs between autoscoring and the reference scoring were equal or higher than the ICCs between any of the three manual scorings and the reference scoring for all endpoints.

Conclusion

Autoscoring of PSGs based on artificial intelligence outperformed even the best of three human expert scorers. Since the autoscoring performs pattern recognition in real-time, the final autoscoring results are available immediately after the end of the recording.

Support

All authors are employees of Philips

CS03-03 - Sleep and sleep disorders in somatoform pain disorder

Introduction

Somatoform pain disorder (SPD) is frequently associated with sleep disorders, specifically restless legs syndrome and insomnia, which in turn lowers the pain threshold and worsens pain.

Objectives

The aim of the present study was to investigate differences in wake-EEG by low-resolution electromagnetic tomography (LORETA) and objective and subjective sleep and awakening quality in SPD patients as compared with controls and study acute and chronic effects of trazodone CR on these variables and pain measures.

Methods

Fifteen patients with SPD (F45.4) and co-morbid insomnia (F51.0) were compared with 15 controls and participated in a single-blind, placebo-controlled, cross-over study on the acute effect of 100 mg trazodone CR, followed by a six-week open titration period. Statistics involved clinical, EEG-LORETA, PSG and psychometry.

Results

LORETA showed reduced power, mainly in the beta band in almost all pain matrix areas (SI, SII, ACC, SMA, PFC, PPC, insula, amygdala, hippocampus). PSG demonstrated a lack of deep sleep and increased arousals and stage shifts, with opposite changes induced by trazodone after acute and chronic therapy. Improvement of sleep was associated with improvement of pain, evaluated by visual-analog scales.

Conclusion

Our LORETA findings demonstrate a dysfunctional pain modulation in SPD. Trazodone induced changes in subjective and objective sleep and awakening quality that were opposite to the differences between SPD patients and controls (key-lock principle) and associated with pain improvement.

Quantitative electrophysiology during night- and daytime including electroencephalography and event-related potential EEG/ERP topography and tomography (LORETA) in hyperthyroidism

Introduction

In contrast to the abundance of visual qualitative EEG reports in patho-endocrinology, there is a paucity of quantitative EEG findings.

Objectives

Electrophysiology may be utilized for differential diagnosis of hypersomnolence.

Aims

To investigate long-term daytime sleepiness in a young female neurologist with the tentative diagnosis of narcolepsy in addition to moderate depression/anxiety and congenital thyroid hypoplasia treated with thyroxin.

Methods

Three-night polysomnography, multiple sleep latency test (MSLT), visual EEG/ERP-mapping, LORETA, psychometrics and blood analyses were performed.

Results

Polysomnography revealed normal sleep efficiency and sleep architecture, but a high arousal index of up to 63/h TST. The MSLT showed a shortened mean sleep latency of 3.7 min. without REM-sleep onsets, objectifying the high Epworth Sleepiness score of 18. Visual EEG evaluation exhibited a fast alpha rhythm with intermittent theta and delta intrusions and paroxysmal activities. EEG-mapping showed an accelerated dominant frequency and ubiquitous increase in absolute (especially delta and beta) power, ERP revealed shortened N1 latency and very high amplitudes in all components (P300 > 5 SD). LORETA demonstrated significant regional increases in delta, alpha-2 and beta-1 power in the anterior cingulate, orbital, ventromedial, dorsolateral prefrontal cortex and temporal cortex, predominantly right hemispherically. Psychometry showed increased anxiety (SAS) and depression (SDS) and reduced quality of life. Finally, hormonal analysis pointed to thyrotoxicosis factitia (ICD-10 E05.4).

Conclusion

Diagnostic investigations clearly elucidated the pathogenesis of the presenting diagnosis of organic hypersomnia triggered by increased sleep-microarousals due to thyrotoxicosis factitia. Discontinuation of hormone substitution led to a normalization process that will be discussed.

FC12-06 - On the relevance of comorbidity in psychiatry: EEG loreta in generalized anxiety disorder with and without nonorganic Insomnia

Introduction

Comorbidity is increasingly regarded as important for both diagnosis and treatment of psychiatric disorders.

Objectives

Electrophysiological neuroimaging such as low-resolution brain electromagnetic tomography (LORETA) may be utilized to obtain insight into the pathogenesis of mental diseases.

Aims

The aim of the present study was to compare EEG tomographic data obtained in generalized anxiety disorder (GAD) with and without nonorganic insomnia.

Methods

In the first study, LORETA was performed in 44 untreated patients (25 females) with the primary diagnosis of nonorganic insomnia (F51.0) associated with GAD (F41.1) and 44 age- and sex-matched normal controls. In the second study, 18 patients (9 females) with the primary diagnosis of GAD without mandatory insomnia were compared with 18 controls.

Results

While patients with F51.0 and concomitant F41.1 showed an increase in LORETA power in the delta, theta, alpha-1 and alpha-2 frequencies, GAD patients without mandatory insomnia demonstrated a decrease in LORETA power - specifically in delta (more left than right hemisphere, involving occipital cortex, insula, cingulate and frontal cortex) and beta (occipital cortex), mirroring neuroimaging findings on the neural circuitry of anxiety.

Conclusions

Different EEG LORETA findings were obtained in GAD patients, depending on the comorbidity: While in daytime recordings patients with nonorganic insomnia demonstrated increased slow activities reflecting daytime tiredness and sleepiness, GAD patients without insomnia exhibited a decrease in slow activity and thus hypervigilance. According to the key-lock principle different pharmacological strategies have to be applied, which will be demonstrated on the basis our own data sets.

Sleep habits and sleep complaints in Austria: current self-reported data on sleep behaviour, sleep disturbances and their treatment

OBJECTIVES

To acquire current information on sleep habits, disturbances and treatment options in the adult population of Austria and compare results with previously collected data.

MATERIALS AND METHODS

A representative sample of the Austrian population (women: n = 522, men: n = 478).

RESULTS

Seventy-five percent reported daily sleep-duration between 6 and 8 h. In 76%, sleep latency was <30 min, 15% described difficulties in sleep maintenance. Longer sleep on weekends was prevalent in 54%, 23% took a nap. Concerning sleep environment, 31% reported sleeping alone; the rest had a constant or occasional bed partner. Sleep disturbances such as sleep disruption or prolonged sleep latency were reported by 18%. Predominant symptoms included snoring/apneas (22%), nightmares (22%) and restless legs (21%). Daytime tiredness was reported by 17% and sleepiness by 20%. Twenty-four percent did not take treatment. Only 7% asked for medical help: 96% consulted their physician; 47% tried to change their way of living. Sleep promoting drugs were taken by 7%. Sleep improving measures were: sleep promoters (45%), general measures (20%), consultation of general practitioner (20%), psychotherapy (6%), and technical tools (3%). Comparison with a dataset of 1993 revealed only a slight increase in short sleepers and a slight decrease in long sleepers.

CONCLUSIONS

Subjectively reported sleep disorders proved to be relatively stable between 1993 and 2007.

EEG topography and tomography (LORETA) in diagnosis and pharmacotherapy of depression

Earlier investigations suggested an involvement of the right hemisphere and the left prefrontal cortex (PFC) in the pathogenesis of depression. This paper presents our own electroencephalographic (EEG) topography and low-resolution brain electromagnetic tomography (LORETA) data obtained in unmedicated depressed patients, and the effects of two representative drugs of non-sedative and sedative antidepressants, i.e., citalopram (CIT) and imipramine (IMI), as compared with placebo in normal subjects. Sixty female menopausal syndrome patients with the diagnosis of a depressive episode without psychotic symptoms as well as 30 healthy controls were investigated. Concerning the effects of antidepressants, normal healthy subjects received single oral doses of 20 mg CIT, 75 mg IMI and placebo p.o. A 3-min vigilance-controlled EEG and a 4-min resting EEG was recorded pre- and post-drug administration and analyzed by means of EEG mapping and LORETA. In the EEG mapping, depressed patients demonstrated a decrease in absolute power in all frequency bands, an augmentation of relative delta/theta and beta and a decrease in alpha activity as well as a slowing of the delta/theta centroid and an acceleration of the alpha and beta centroid, which suggests vigilance decrements. In the alpha asymmetry index, they showed right frontal hyper- and left frontal hypoactivation correlated with the Hamilton Depression Score (HAMD). LORETA predominantly revealed decreased power in the theta and alpha-1 frequency band. Negative correlations between theta power and the HAMD were observed in the ventro-medial PFC, the bilateral rostral anterior cingulate cortex (ACC) and the left insular cortex; between alpha-1 power and the HAMD in the right PFC. In the EEG mapping of antidepressants, 20 mg CIT showed mainly activating, 75 mg IMI partly sedative properties. LORETA revealed that CIT increased alpha-2, beta-1, beta-2 and beta-3 power more over the right than over the left hemisphere. However, also a left temporal and frontal delta increase was observed. In conclusion, EEG topography and tomography of depressed menopausal patients demonstrated a right frontal hyper- and left frontal hypoactivation in the alpha asymmetry index as well as a vigilance decrease, with a right-hemispheric preponderance. Within antidepressants at least 2 subtypes may be distinguished from the electrophysiological point of view, a non-sedative and a sedative. LORETA identifies cerebral generators responsible for the pathogenesis of depression as well as for the mode of action of antidepressants.

Effects of a mandibular repositioning appliance on sleep structure, morning behavior and clinical symptomatology in patients with snoring and sleep-disordered breathing

BACKGROUND

Mandibular repositioning appliances (MRAs) have become an established treatment for snoring and sleep-disordered breathing - though most studies only focused on the evaluation of respiratory variables.

METHODS

This single-blind, placebo-controlled case-series study investigated the effects of an individually adjustable MRA on psychopathology, macro-/microstructure of sleep, periodic leg movements, morning performance, mood/affect and psychophysiology. Fifty patients (37 males) aged 59.7 +/- 10.3 years, suffering from primary snoring (7), mild (22), moderate (15) and severe apnea (6), spent 4 nights in the sleep laboratory (adaptation, placebo, drug and MRA night). The drug night is not subject of the present paper.

RESULTS

Confirmatory statistics showed an improvement of the snoring index by 72%. Descriptively, the apnea index and the apnea-hypopnea index normalized. A clinical improvement was seen in the Pittsburgh Sleep Quality Index, the Zung Anxiety/Depression Scales and the Epworth Sleepiness Scale. The restless legs syndrome also improved. Polysomnographically, sleep stages REM and 4 as well as REM latency increased, stage 3, movement time, stage shifts and periodic leg movements decreased, as did all arousal measures. Subjectively, morning well-being, drive, affectivity and wakefulness improved. Objectively, attention, motor and reaction time performance, critical flicker frequency as well as muscular strength increased, diastolic blood pressure and the pulse rate decreased.

CONCLUSION

Apart from its good therapeutic effects on snoring and respiratory variables (snoring showed complete or partial response in 68%, the apnea-hypopnea index in 67% of the apnea patients), the MRA also improved psychopathology, objective and subjective sleep and awakening quality.

Sleep spindle-related activity in the human EEG and its relation to general cognitive and learning abilities

Stage 2 sleep spindles have been previously viewed as useful markers for the development and integrity of the CNS and were more currently linked to 'offline re-processing' of implicit as well as explicit memory traces. Additionally, it had been discussed if spindles might be related to a more general learning or cognitive ability. In the present multicentre study we examined the relationship of automatically detected slow (< 13 Hz) and fast (> 13 Hz) stage 2 sleep spindles with: (i) the Raven's Advanced Progressive Matrices (testing 'general cognitive ability'); as well as (ii) the Wechsler Memory scale-revised (evaluating memory in various subdomains). Forty-eight healthy subjects slept three times (separated by 1 week) for a whole night in a sleep laboratory with complete polysomnographic montage. Whereas the first night only served adaptation and screening purposes, the two remaining nights were preceded either by an implicit mirror-tracing or an explicit word-pair association learning or (corresponding) control task. Robust relationships of slow and fast sleep spindles with both cognitive as well as memory abilities were found irrespectively of whether learning occurred before sleep. Based on the present findings we suggest that besides being involved in shaping neuronal networks after learning, sleep spindles do reflect important aspects of efficient cortical-subcortical connectivity, and are thereby linked to cognitive- and memory-related abilities alike.

Double-blind, placebo-controlled pharmacodynamic studies with a nutraceutical and a pharmaceutical dose of ademetionine (SAMe) in elderly subjects, utilizing EEG mapping and psychometry

In a double-blind, placebo-controlled crossover study, the effects of S-adenosyl-l-methionine (SAMe) on brain function measures of 12 normal elderly volunteers (6 m/6 f, aged 57-73 years, mean: 61 years) were investigated by means of EEG mapping and psychometry. In random order, the subjects were orally administered a pharmaceutical dose of 1600 mg SAMe, a nutraceutical dose of 400 mg SAMe and placebo, each over a period of 15 days, with wash-out periods of 2 weeks in between. EEG recordings, psychometric tests and evaluations of tolerability and side effects were carried out 0, 1, 3 and 6 h after drug administration on days 1 and 15. Multivariate analysis based on MANOVA/Hotelling T2 tests of quantitative EEG data demonstrated significant central effects of SAMe as compared with placebo after acute, subacute and superimposed drug administration of both the nutraceutical and the pharmaceutical dose. EEG changes induced by SAMe were characterized by an increase in total power, a decrease in absolute and relative power in the delta/theta and slow alpha frequencies, an increase in absolute and relative power in the alpha-2 and beta frequencies as well as an acceleration of the alpha centroid and the centroid of the total power spectrum. The delta/theta and the beta centroid showed variable changes over time. The dominant alpha frequency was accelerated, the absolute and relative power in the dominant alpha frequency attenuated after SAMe as compared with placebo. These acute and subacute pharmaco-EEG findings in elderly subjects are typical of activating antidepressants. Time-efficacy calculations showed that acute oral administration of SAMe in both the nutraceutical and the pharmaceutical dose induced the pharmacodynamic peak effect in the first hour with a subsequent decline. The 3rd and 6th hours still showed a significant encephalotropic effect after the 1600 mg dose. The maximum EEG effect was noted after 2 weeks of oral administration of both 1600 mg/die and 400 mg/die. The superimposed dose induced significant encephalotropic effects in the 3rd hour after 400 mg and in the 3rd and 6th hours after 1600 mg as compared with pre-treatment. Dose-efficacy calculations showed that the pharmaceutical dose of 1600 mg had a more pronounced effect on the CNS than the nutraceutical dose of 400 mg, with both doses being superior to placebo. Psychometric tests concerning noopsychic and thymopsychic measures as well as critical flicker fusion frequency generally demonstrated a lack of differences between SAMe and placebo, which reflects a good tolerability of the drug in elderly subjects. This was corroborated by the findings on side effects, pulse and blood pressure.

Identifying target regions for vigilance improvement under hormone replacement therapy in postmenopausal syndrome patients by means of electroencephalographic tomography (LORETA)

RATIONALE

Daytime fatigue, which at the neurophysiological level is due to vigilance decrements, is a frequent complaint in postmenopausal women.

OBJECTIVES

In a three-arm, 2-month, parallel group-design study, vigilance-promoting effects of a novel continuous combination (=Climodien 2/3) of estradiol valerate (EV; 2 mg) and dienogest (DNG; 3 mg) were compared with the effects of both EV alone and placebo in 55 insomniac, postmenopausal syndrome patients.

METHODS

Low-resolution brain electromagnetic tomography (LORETA) was undertaken to identify the cerebral target regions of hormone replacement therapy.

RESULTS

An omnibus significance test revealed Climodien to increase activity in 882 of 2,394 voxels in the alpha-2 band, followed by 733, 706, and 664 voxels in the beta-2, beta-1, and beta-3 bands, and 509 voxels in the delta band, whereas 2 mg EV alone did not produce a significant suprathreshold activity. Current density increased predominantly in the right hemisphere, which had already been described in the literature as the center of the vigilance system. In the fast alpha range, which plays a major role in the context of vigilance, increased activity was found in the right prefrontal, temporal, and superior parietal cortices, i.e., those brain areas of the right-sided fronto-parietal neuronal network that are responsible for sustained attention. A further activity increase was seen in the anterior cingulate gyrus associated with attentional control and conflict monitoring. The right temporal lobe showed increased current density in all frequency bands.

CONCLUSIONS

Electroencephalographic tomography (LORETA) identified the right-hemispheric vigilance system as the target region of Climodien.

EEG-tomographic studies with LORETA on vigilance differences between narcolepsy patients and controls and subsequent double-blind, placebo-controlled studies with modafinil

The aim of the present study was to identify brain regions associated with vigilance in untreated and modafinil-treated narcoleptic patients by means of low-resolution brain electromagnetic tomography (LORETA). 16 drug-free narcoleptics and 16 normal controls were included in the baseline investigation. Subsequently patients participated in a double-blind, placebo-controlled crossover study receiving a three-week fixed titration of modafinil (200, 300, 400 mg) and placebo. Measurements comprised LORETA, the Multiple Sleep Latency Test (MSLT) and the Epworth Sleepiness Scale (ESS) obtained before and after three weeks' therapy. Statistical overall analysis by means of the omnibus significance test demonstrated significant inter-group differences in the resting (R-EEG), but not in the vigilance-controlled recordings (V-EEG). Subsequent univariate analysis revealed a decrease in alpha-2 and beta 1-3 power in prefrontal, temporal and parietal cortices, with the right hemisphere slightly more involved in this vigilance decrement. Modafinil 400 mg/d as compared with placebo induced changes opposite to the aforementioned baseline differences (key-lock principle) with a preponderance in the left hemisphere. This increase in vigilance resulted in an improvement in the MSLT and the ESS. LORETA provided evidence of a functional deterioration of the fronto-temporo-parietal network of the right-hemispheric vigilance system in narcolepsy and a therapeutic effect of modafinil on the left hemisphere, which is less affected by the disease.

The key-lock principle in the diagnosis and treatment of nonorganic insomnia related to psychiatric disorders: sleep laboratory investigations

Nonorganic insomnia is a frequent sleep disorder that has a high comorbidity with other psychiatric illnesses. In our sleep outpatient clinic, 41% of the patients showed neurotic, stress-related and somatoform disorders, 31% affective disorders and 1.6% schizophrenia. Sleep laboratory investigations in patients for diagnostic purposes and in normal subjects for the evaluation of drug effects suggest that changes in the sleep architecture of patients with nonorganic insomnia due to psychiatric disorders, compared with normal controls, are opposite to alterations induced by psychotropic drugs intended for their treatment, compared with placebo (key-lock principle). Evidence for this principle was found regarding nonorganic insomnia related to generalized anxiety disorder or panic disorders and benzodiazepines, depressive episodes, recurrent depression or dysthymia and sedative antidepressants and finally schizophrenia and sedative neuroleptics. Polysomnography (PSG) findings of other mental disorders are rather scarce and often depend upon the subtype and stage of the disease. In conclusion, sleep laboratory studies may be helpful for choosing the right drug for an individual insomniac patient.

EEG topography and tomography in diagnosis and treatment of mental disorders: evidence for a key-lock principle

Clinically well-defined diagnostic subgroups of mental disorders, such as schizophrenia with predominantly plus and minus symptomatology, major depression, generalized anxiety disorder, agoraphobia, obsessive-compulsive disorder, multiinfarct dementia, senile dementia of the Alzheimer type and alcohol dependence, show electroencephalogram (EEG) maps that differ statistically both from each other and from normal controls. Representative drugs of the main psychopharmacological classes, such as sedative and nonsedative neuroleptics and antidepressants, tranquilizers, hypnotics, psychostimulants and cognition-enhancing drugs, induce significant and typical changes to normal human brain function compared with placebo, in which many variables are opposite to the above-mentioned differences between psychiatric patients and normal controls. Thus, by considering these differences between psychotropic drugs and placebo in normal subjects, as well as between mental disorder patients and normal controls, it may be possible to choose the optimum drug for a specific patient according to a key-lock principle, since the drug should normalize the deviant brain function. This is supported by low-resolution brain electromagnetic tomography (LORETA), which identifies brain regions affected by psychiatric disorders and psychotropic drugs.

Perceptual and cognitive event-related potentials in neuropsychopharmacology: methodological aspects and clinical applications (pharmaco-ERP topography and tomography)

Middle latency and late components of event-related brain potential (ERPs) are closely related to perceptual and cognitive information processing, respectively. In a double-blind, placebo-controlled study, the acute effects of lorazepam (2 mg), haloperidol (3 mg), methylphenidate (20 mg) and citalopram (20 mg) on ERP latencies, amplitudes, topographies and tomographies were investigated in 20 healthy subjects of 23-34 years of age. After automatic artifact minimization and rejection, standard N1 and P2 and target N2 and P300 components were determined. The tranquilizer lorazepam prolonged P300 latency, which indicates an impairment of stimulus evaluation time. Low-resolution brain electromagnetic tomography (LORETA) revealed decreases in N1 and P300 source strength in those brain regions with relevant generators of these components, which reflects impairments of attentional and cognitive processing resources. The neuroleptic haloperidol decreased N1 and P300 source strength predominantly in those brain regions not involved in the generation of these components, suggesting a shift of resources. The psychostimulant methylphenidate increased P300 source strength in brain regions with major P3b generators, indicating increases in energetic resources associated with stimulus encoding. The antidepressant citalopram increased N1 and P3b source strength in multiple brain regions specifically in the left prefrontal cortex, a brain region in which reduced blood flow and metabolism was found in depressed patients.

Structural and energetic processes related to P300: LORETA findings in depression and effects of antidepressant drugs

Noninvasive electrophysiological neuroimaging applied to cognitive components of event-related potentials (ERPs) may differentiate between structural and energetic processes related to information processing. The structural level, revealed by the location of the local maxima of the current source density distribution, describes the time-dependent network of activated brain areas. The magnitude of the source strength, a measure of the energetic component, describes the allocation of processing resources. ERPs were recorded in an odd-ball paradigm and low-resolution brain electromagnetic tomography (LORETA) was applied for standard and target ERP components. In a group of 60 menopausal depressed patients of 45-60 years of age, reduced P300 source strength was observed bilaterally, temporally and medially prefrontally reaching to rostal parts of the anterior cingulate, compared with 29 age-matched controls. In a double-blind, placebo-controlled study, 2 mg of the antidepressant citalopram induced a significant increase of P300 source strength in the (left) prefrontal cortex and precuneus compared with placebo, reaching to the posterior cingulate. Similar increases were observed after 800 mg S-adenosyl-L-methionine (SAMe) administered intravenously in ten young healthy subjects aged 22-33, and they were even more pronounced in ten elderly healthy subjects aged 56-71. Thus, ERP-tomography identified changes in energetic sources in brain areas predominantly involved in depression and in antidepressant action.

Classification and evaluation of the pharmacodynamics of psychotropic drugs by single-lead pharmaco-EEG, EEG mapping and tomography (LORETA)

Utilizing computer-assisted quantitative analyses of human scalp-recorded electroencephalogram (EEG) in combination with certain statistical procedures (quantitative pharmaco-EEG) and mapping techniques (pharmaco-EEG mapping), it is possible to classify psychotropic substances and objectively evaluate their bioavailability at the target organ: the human brain. Specifically, one may determine at an early stage of drug development whether a drug is effective on the central nervous system (CNS) compared with placebo, what its clinical efficacy will be like, at which dosage it acts, when it acts and the equipotent dosages of different galenic formulations. Pharmaco-EEG profiles and maps of neuroleptics, antidepressants, tranquilizers, hypnotics, psychostimulants and nootropics/cognition-enhancing drugs will be described in this paper. Methodological problems, as well as the relationships between acute and chronic drug effects, alterations in normal subjects and patients, CNS effects, therapeutic efficacy and pharmacokinetic and pharmacodynamic data will be discussed. In recent times, imaging of drug effects on the regional brain electrical activity of healthy subjects by means of EEG tomography such as low-resolution electromagnetic tomography (LORETA) has been used for identifying brain areas predominantly involved in psychopharmacological action. This will be demonstrated for the representative drugs of the four main psychopharmacological classes, such as 3 mg haloperidol for neuroleptics, 20 mg citalopram for antidepressants, 2 mg lorazepam for tranquilizers and 20 mg methylphenidate for psychostimulants. LORETA demonstrates that these psychopharmacological classes affect brain structures differently.

Acute double-blind, placebo-controlled sleep laboratory and clinical follow-up studies with a combination treatment of rr-L-dopa and sr-L-dopa in restless legs syndrome

In a double-blind, placebo-controlled randomized crossover trial, the acute efficacy of a combination treatment of 100 mg regular-release (rr) and 100 mg sustained-release (sr) L-dopa/benserazide in RLS was investigated by means of sleep laboratory methods, with a subsequent open clinical follow-up for 4 weeks. 21 RLS patients classified according to ICSD and IRLSSG criteria were included; 18 completed the study. Objective sleep quality was determined by polysomnography (PSG) in 3 subsequent nights (adaptation/screening, placebo and drug night), subjective sleep and awakening quality was evaluated by rating scales, objective awakening quality by psychometric tests. Clinical follow-up consisted of daily ratings of subjective sleep and awakening quality (SSA) and VAS for RLS symptomatology ratings, completion of the RLS (IRLSSG) Scale weekly and the Zung Depression (SDS) and Anxiety (SAS) Scale, Quality of Life Index, Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale before and after therapy. Acute L-dopa/benserazide significantly (p < 0.001) and markedly (75%) decreased the target variable PLM/h of sleep as well as all other RLS/PLM variables, but failed to improve objective sleep efficiency and subjective sleep quality in comparison to placebo. After 4 weeks of therapy, however, subjective sleep and awakening quality also improved significantly. While RLS/PLM measures showed an immediate significant and marked response to the combination therapy subjective sleep quality only improved after chronic treatment.

Non-invasive localization of P300 sources in normal aging and age-associated memory impairment

Cognitive event-related potentials were recorded from 17 EEG leads in an auditory two-tone paradigm in 43 patients aged 51-79 years with the diagnosis of age-associated memory impairment (AAMI), in age-and sex-matched normal controls and in a control group 10 years older than the AAMI patients. In addition to P300 latencies, amplitudes and topographies, three-dimensional current density distribution utilizing low-resolution brain electromagnetic tomography (LORETA) was computed. P300 latency was delayed and P300 amplitude was reduced in both AAMI and older subjects. Topographically this amplitude reduction was most pronounced frontally. LORETA revealed medial (frontal and parietal) and lateral (dorso- and ventrolateral prefrontal, middle/superior temporal, posterior superior temporal/inferior parietal) sources. Significant reductions in LORETA source strength in normal aging and in AAMI were found mainly medially frontally, right dorsolaterally prefrontally and right inferiorly parietally. Since these anatomically highly interconnected brain regions in the right hemisphere are part of a network associated with sustained attention, the results speak for a decline in attentional resource capacity in AAMI patients and elderly subjects.

Pharmacodynamic studies on the central mode of action of S-adenosyl-L-methionine (SAMe) infusions in elderly subjects, utilizing EEG mapping and psychometry

In a double-blind, placebo-controlled cross-over study, the acute and subacute effects of S-adenosyl-L-methionine (SAMe), or ademetionine, on brain function and behavior of 10 elderly normal healthy volunteers (5 males and 5 females, aged 56-71 years, mean: 59.3 years) were investigated by means of EEG mapping and psychometry. In random order they received infusions of 800 mg SAMe and placebo, administered over 30 minutes for 7 days, with a wash-out period of 3 weeks in between. EEG recordings and psychometric tests were carried out 0, 1, 3 and 6 hours after drug administration on days 1 and 7. Multivariate analysis based on MANOVA/Hotelling T(2) tests demonstrated significant central effects of SAMe as compared with placebo after acute, subacute and superimposed drug administration. Acute SAMe-induced changes were characterized by a decrease in total power, an increase in absolute delta and a decrease in absolute alpha power, further by an increase in relative delta and a decrease in relative alpha power, a slowing of the delta/theta centroid as well as a slowing of the centroid of the total power spectrum. These changes are typical of classical antidepressants of the thymoleptic type such as imipramine and amitriptyline. After one week of daily infusions there was a marked increase in total power, reminiscent of nootropic drug effects. One additional superimposed dosage mitigated these effects in the direction of an antidepressant profile, with the inter-drug differences waning in the 6(th) hour. Our pharmaco-EEG findings suggest both inhibitory and excitatory drug effects underlying the antidepressant properties of SAMe well-documented in clinical trials. Psychometric tests concerning noopsychic and thymopsychic measures as well as critical flicker frequency generally demonstrated a lack of differences between SAMe and placebo, which again reflects a good tolerability of the drug in elderly subjects.

EEG mapping, psychometric, and polysomnographic studies in restless legs syndrome (RLS) and periodic limb movement disorder (PLMD) patients as compared with normal controls

OBJECTIVES

Investigation of daytime brain function, psychopathology, and objective and subjective sleep and awakening quality in restless legs syndrome (RLS) and periodic limb movement disorder (PLMD).

METHODS

Thirty-three RLS and 26 PLMD patients free of psychotropic drugs were studied as compared with age- and sex-matched normal controls, utilizing electroencephalographic (EEG) mapping and clinical evaluations by the Zung Self-Rating Depression (SDS) and Anxiety Scale (SAS), the Quality of Life Index, the Pittsburgh Sleep Quality Index (PSQI), and the Epworth Sleepiness Scale. In a subsample of 12 RLS patients, 12 PLMD patients, and 12 controls, objective and subjective sleep and awakening quality were evaluated in two sleep laboratory nights (adaptation and baseline night).

RESULTS

Scores of the PSQI, SDS, and SAS were found increased in both patient groups; RLS patients showed reduced quality of life, while in the PLMD group daytime sleepiness was increased. EEG mapping demonstrated findings characteristic of major depression in RLS patients and of generalized anxiety disorder in PLMD patients. Polysomnography showed a significant deterioration of sleep efficiency only for RLS patients, while nocturnal awakenings were increased in both patient groups. Concerning sleep architecture, both groups exhibited increased S1 and stage shifts and decreased S2, while only PLMD patients showed an increase in S4. The PLM/(h TST), the PLM/(h wake) and the PLMS-arousal index were significantly increased in both patient groups as compared with controls. Subjective sleep and awakening quality and thymopsychic measures were deteriorated in RLS. Morning mental performance and fine motor activity were deteriorated in both groups, reaction time only in RLS, numerical memory and attention variability only in PLMD.

CONCLUSION

EEG mapping revealed neurophysiological correlates of depression and anxiety in RLS and PLMD, respectively, which were confirmed by self-ratings of symptoms.

Acute placebo-controlled sleep laboratory studies and clinical follow-up with pramipexole in restless legs syndrome

In a single-blind, placebo-controlled crossover trial, the acute efficacy of the dopamine agonist pramipexole was investigated in 11 restless legs syndrome (RLS) patients by sleep laboratory methods, with a clinical follow-up for 4 weeks. In 3 nights (pre-treatment, placebo and drug night), objective sleep quality was determined by polysomnography (PSG), subjective sleep and awakening quality by rating scales, objective awakening quality by psychometry. Clinical follow-up consisted of completion of the International RLS Study Group (IRLSSG) Scale, Zung Depression (SDS) and Anxiety (SAS) Scale, Quality of Life Index, Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale. Concerning acute effects, an omnibus significance test for PSG variables demonstrated a global difference between placebo and pramipexole, but none between pre-treatment and placebo. Pramipexole 0.27 mg significantly decreased the target variable periodic leg movements (PLM)/h of sleep as well as all other RLS/PLM variables and improved objective sleep efficiency and subjective sleep quality as compared with placebo. In sleep architecture, sleep stages S1 and S2 and stage shifts increased, while slow-wave sleep and SREM decreased. After 4 weeks of therapy, the total scores of the IRLSSG questionnaire, sleep quality and daytime sleepiness, depression and quality of life also improved. Thus, acute pramipexole markedly reduced PLM measures and slightly improved objective and subjective sleep quality. Follow-up ratings showed a moderate improvement of RLS and sleep quality, and to a lesser extent of daytime sleepiness, depression and quality of life. The psychopathological findings as well as acute sleep architecture changes are reminiscent of those seen after activating antidepressants.

Insomnia related to dysthymia: polysomnographic and psychometric comparison with normal controls and acute therapeutic trials with trazodone

Utilizing polysomnography (PSG) and psychometry, objective and subjective sleep and awakening quality was investigated in 11 patients (mean age 50 +/- 14) with nonorganic insomnia (F 51.0) related to dysthymia (F 34.1) as compared with 11 age- and sex-matched normal controls. Patients demonstrated decreased sleep efficiency and sleep stage S2 as well as increased sleep latency to S1, S2 and S3, wakefulness within the total sleep period, number of awakenings, S1 and REM sleep. There was no intergroup difference in REM latency. Subjective sleep quality and the total score of the Self-Assessment Scale for Sleep and Awakening Quality (SSA) were deteriorated as were evening and morning well-being, mood, affectivity and drowsiness. Noopsychic measures showed deteriorated numerical memory, fine motor activity and reaction time variability. In a placebo-controlled crossover design study, the acute effects of 100 mg trazodone, a serotonin reuptake inhibitor with a sedative action due to 5HT(2) and alpha(1) receptor blockade, were investigated in the patients. As compared with placebo, trazodone induced an increase in slow-wave sleep (S3 + 4), a lengthening of REM latency, a decrease in REM sleep and a normalization of the periodic leg movement (PLM) index. In the morning, there was a minimal increase in somatic complaints and a decrease in critical flicker frequency and systolic blood pressure. In conclusion, our study demonstrated that dysthymia induced significant changes in objective and subjective sleep and awakening quality, which were counteracted by 100 mg trazodone, thus suggesting a key-lock principle in the treatment of nonorganic insomnia related to dysthymia with this drug.

Impaired conditional discrimination learning in schizophrenia

Learning deficits have repeatedly been found in patients with schizophrenia. Eyelid conditional discrimination learning (ECDL) is a test of discriminative aversive conditioning and places minimal demands on motivation. An ECDL task was used to examine residual and paranoid type individuals with schizophrenia and age- and gender-equivalent healthy controls. In the experiment two differently colored light stimuli were randomly presented. Only one of the stimuli (in reinforced trials) was followed by an aversive airpuff to the cornea, as opposed to unreinforced trials where the stimulus was not followed by an aversive airpuff. Conditioned responses develop to both trial types during the course of the experiment. These conditioned responses consist of reflectory eyelid closures already upon light presentation. The patients showed significantly impaired conditional discrimination learning abilities. There was no significant difference between the results in the two schizophrenia subtypes. Patients failed to increase response frequencies on reinforced trials during the course of the experiment, while controls showed appropriate conditional discrimination ability. Thus the results show an impairment of adequate behavior modification in an aversive conditioning task in individuals with schizophrenia. It is concluded that ECDL might be a trait marker for schizophrenia.

Low-resolution brain electromagnetic tomography revealed simultaneously active frontal and parietal sleep spindle sources in the human cortex

Analyses of scalp-recorded sleep spindles have demonstrated topographically distinct slow and fast spindle waves. In the present paper, the electrical activity in the brain corresponding to different types of sleep spindles was estimated by means of low-resolution electromagnetic tomography. In its new implementation, this method is based on realistic head geometry and solution space is restricted to the cortical gray matter and hippocampus. In multichannel all-night electroencephalographic recordings, 10-20 artifact-free 1.25-s epochs with frontally, parietally and approximately equally distributed spindles were marked visually in 10 normal healthy subjects aged 20-35years. As a control condition, artifact-free non-spindle epochs 1-3s before or after the corresponding spindle episodes were marked. Low-resolution electromagnetic tomography demonstrated, independent of the scalp distribution, a distributed spindle source in the prefrontal cortex (Brodmann areas 9 and 10), oscillating with a frequency below 13Hz, and in the precuneus (Brodmann area 7), oscillating with a frequency above 13Hz. In extremely rare cases only the prefrontal or the parietal source was active. Brodmann areas 9 and 10 have principal connections to the dorsomedial thalamic nucleus; Brodmann area 7 is connected to the lateroposterior, laterodorsal and rostral intralaminar centrolateral thalamic nuclei. Thus, the localized cortical brain regions are directly connected with adjacent parts of the dorsal thalamus, where sleep spindles are generated. The results demonstrated simultaneously active cortical spindle sources which differed in frequency by approximately 2Hz and were located in brain regions known to be critically involved in the processing of sensory input, which is in line with the assumed functional role of sleep spindles.

[Nonorganic hypersomnia: epidemiology, diagnosis, and therapy]

Daytime tiredness and daytime sleepiness are frequent complaints occurring in 29% and 14% of the Austrian population. Epidemiological studies demonstrate a high comorbidity between nonorganic hypersomnia and mental disorders. Especially comorbidity with affective disorders increases steadily from the general population over primary to tertiary care settings. Diagnostic criteria of nonorganic hypersomnia have been described in the International Classification of Diseases (ICD-10). Nonorganic hypersomnia can be primary or associated with a number of psychiatric disorders such as reaction to severe stress or adjustment disorders, affective disorders, other functional disorders, tolerance to or withdrawal of CNS-stimulating substances and chronic use of CNS-sedating substances. Diagnostic procedures comprise case history and symptom evaluation, sleep-specific and supplementary investigations. Concerning the latter, this article will focus on sleep questionnaires, vigilance and psychological tests as well as CNS investigations. Therapy of nonorganic hypersomnia rests on 3 pillars: psychological, somatic and pharmacological treatment. In view of the wide variety of psychiatric causes, resulting in a number of therapeutic options, it seems desirable that apart from subjective clinical assessment also objective methods be used in diagnosis and treatment. On the neurophysiological level objective measures can be obtained by means of EEG mapping during the day and polysomnography at night. Different mental disorder patients show different brain activity patterns as compared with normal controls and different classes of psychotropic substances cause different changes in neurophysiological variables. The fact that the changes in electrophysiological brain activity caused by mental disorders are exactly opposite to those induced by the psychotropic drugs used for their treatment suggests a key-lock principle in the diagnosis and treatment of nonorganic hypersomnia.

Activity monitoring in sleep research, medicine and psychopharmacology

Motor activity as a diagnostic parameter has become an important feature in many fields of medicine and psychology. The concept of mobility and immobility implies the assumption that mental and behaviour disorders involve abnormal activity that can be measured to characterise the disorder itself, to diagnose its presence and to document the impact of treatment. In sleep research, activity monitoring by wrist actigraphs has proven its usefulness as an efficient method to assess the rest-activity cycle over long time periods and to estimate sleep-related features such as sleep efficiency and total sleep time. But like many other techniques and devices, activity monitoring has some limitations and drawbacks. This paper describes the basic features of wrist actigraphy in measuring nocturnal and daytime motor activity.

Restless legs syndrome (RLS) and periodic limb movement disorder (PLMD): acute placebo-controlled sleep laboratory studies with clonazepam

Restless legs syndrome (RLS) - a common sensorimotor disorder - and periodic limb movement disorder (PLMD) are currently treated with substances of four classes: dopaminergic agents, which are considered the drugs of choice, benzodiazepines, opioids and anticonvulsants. As their effects on sleep variables differ considerably, the aim of the present placebo-controlled sleep laboratory study was to measure the acute effects of 1 mg clonazepam on objective and subjective sleep and awakening quality in ten RLS and 16 PLMD patients, utilizing polysomnography (PSG) and psychometry. Descriptive data analysis demonstrated at the confirmatory level concerning three target variables that - as compared with placebo - clonazepam significantly improved objective sleep efficiency and subjective sleep quality in both patient groups, but failed to reduce the index PLM/h of sleep. At the descriptive level, in PLMD clonazepam improved PLM during time in bed, REM and wakefulness and showed more significant changes in various sleep and awakening measures than in RLS patients, though there were no significant inter-group differences. In conclusion, in both PLMD and RLS clonazepam exhibited acute therapeutic efficacy regarding insomnia, which is quite different from the mode of action of dopamine agonists.

Sleep laboratory studies in periodic limb movement disorder (PLMD) patients as compared with normals and acute effects of ropinirole

Periodic limb movement disorder (PLMD) occurs in a variety of sleep disorders and can cause insomnia as well as hypersomnia with daytime somnolence. The aim of this study was to investigate 12 untreated PLMD patients as compared with 12 normal controls and to measure the acute effects of 0.5 mg ropinirole (Requip((R))) - a non-ergoline dopamine agonist - as compared with placebo. In three nights (adaptation, placebo, ropinirole night) objective and subjective sleep and awakening quality were evaluated. In the target variable 'periodic leg movements per hour of sleep' (PLM/(hTST)) PLMD patients showed an increased value of 42/h (normal 0-5/h) with a greater number of arousals due to periodic leg movements (PLM) in sleep. They further demonstrated an increased number of awakenings, sleep stage S1, S4, stage shifts and decreased S2, but there were no significant differences concerning total sleep time, sleep efficiency (SE), subjective sleep quality and morning measures of mood, drive and drowsiness. However, measures of attention variability, numerical memory, fine motor activity and reaction time performance were impaired. Ropinirole 0.5 mg was shown to significantly improve the index PLM/(hTST) by 64% and arousals due to PLM, increase spontaneous arousals, REM-latency, stage 2 and stage shifts and decrease SREM. In the morning attention variability was attenuated and numerical memory augmented. Thus, ropinirole improved some sleep architecture and early morning measures of performance but specifically all PLM variables, which suggests a dopaminergic pathogenesis in PLMD. Copyright 2001 John Wiley & Sons, Ltd.

Paclitaxel-carboplatin chemotherapy does not cause encephalopathy in patients with ovarian cancer: a prospective EEG mapping study in 28 patients

BACKGROUND

The objective of this study was to evaluate possible effects of a paclitaxel containing chemotherapy, on the central nervous system (CNS) in women with ovarian cancer.

MATERIALS AND METHODS

Twenty-eight women with histologically documented epithelial ovarian carcinoma and treated with a combination chemotherapy consisting of paclitaxel and carboplatin entered the study. Patients were tested with resting EEG (R-EEG) before and after chemotherapy.

RESULTS

Twenty of the 28 patients responded to the chemotherapy (71%). Eleven patients (39%) developed peripheral neurotoxicity. A decrease of beta power and an increase of delta and theta power as well as a deceleration of the total centroid frequency clearly demonstrated a reduced vigilance in patients with ovarian cancer compared to healthy controls. On the other hand, the observed increase of beta power, a decrease of delta and theta power, and an acceleration of the total centroid from pre- to post-treatment demonstrated an improvement of vigilance in patients with ovarian cancer after treatment with paclitaxel/carboplatin.

CONCLUSIONS

The results of this study suggest that chemotherapy consisting of paclitaxel and carboplatin does not cause adverse effects on the central nervous system. Improved vigilance was measured in patients with ovarian cancer after chemotherapy.

Paclitaxel does not cause central nervous adverse effects: a prospective vigilance-controlled EEG mapping study in ovarian cancer patients

BACKGROUND

The objective of this study was to evaluate potential adverse effects of paclitaxel-containing chemotherapy on the central nervous system in women with ovarian cancer.

METHODS

Twenty-eight women with histologically confirmed epithelial ovarian carcinoma and treated with combination chemotherapy consisting of paclitaxel and carboplatin were entered into the study. Patients were tested with vigilance-controlled EEG before and after chemotherapy. Additionally, a battery of neuropsychologic tests before, after 3 cycles and at the end of the chemotherapy were performed.

RESULTS

Twenty of the 28 patients responded to chemotherapy (71%). Eleven patients (39%) developed peripheral neurotoxicity. A reduced vigilance in patients with ovarian cancer prior to chemotherapy compared to healthy controls was observed (clearly demonstrated by an attenuated total power, a decrease in fast alpha and slow beta activity, an increase in delta and theta activity as well as a deceleration of the centroid of the total power spectrum). On the other hand, an improved vigilance in patients with ovarian cancer treated with paclitaxel/carboplatin was observed (demonstrated by an increase in total power and an increase in beta power, being more pronounced in the right than in the left hemisphere, between pre- and post-treatment). The results of EEG mapping concurred with those of psychometric tests. The test results did not deteriorate during chemotherapy. A statistically significant improvement in the alphabetical crossout test from the first to the third measurement was observed, indicating an improvement in short-term attention, concentration and the constancy of work during chemotherapy.

CONCLUSIONS

Combination chemotherapy consisting of paclitaxel and carboplatin does not cause encephalopathy, but a trend towards an improved vigilance and an improvement of short-term attention and concentration was observed in patients with ovarian cancer after chemotherapy.

Effect of the 5-HT(1A) partial agonist buspirone on regional brain electrical activity in man: a functional neuroimaging study using low-resolution electromagnetic tomography (LORETA)

In a double-blind, placebo-controlled study, the effects of 20 mg buspirone - a 5-HT(1A) partial agonist - on regional electrical generators within the human brain were investigated utilizing three-dimensional EEG tomography. Nineteen-channel vigilance-controlled EEG recordings were carried out in 20 healthy subjects before and 1, 2, 4, 6 and 8 h after drug intake. Low-resolution electromagnetic tomography (LORETA; Key Institute for Brain-Mind Research, software: http://www.keyinst.unizh.ch) was computed from spectrally analyzed EEG data, and differences between drug- and placebo-induced changes were displayed as statistical parametric maps. Data were registered to the Talairach-Tournoux human brain atlas available as a digitized MRI (McConnell Brain Imaging Centre: http://www.bic.mni.mcgill.ca). At the pharmacodynamic peak (1st hour), buspirone increased theta and decreased fast alpha and beta sources. Areas of theta increase were mainly the left temporo-occipito-parietal and left prefrontal cortices, which is consistent with PET studies on buspirone-induced decreases in regional cerebral blood flow and fenfluramine-induced serotonin activation demonstrated by changes in regional cerebral glucose metabolism. In later hours (8th hour) with lower buspirone plasma levels, delta, theta, slow alpha and fast beta decreased, predominantly in the prefrontal and anterior limbic lobe. Whereas the results of the 1st hour speak for a slight CNS sedation (more in the sense of relaxation), those obtained in the 8th hour indicate activation. Thus, LORETA may provide useful and direct information on drug-induced changes in central nervous system function in man.

Electrical sources of P300 event-related brain potentials revealed by low resolution electromagnetic tomography. 2. Effects of nootropic therapy in age-associated memory impairment

In a double-blind, placebo-controlled study the effects of Actovegin on frontal and parietal electrical P300 sources revealed by low resolution electromagnetic tomography (LORETA) were studied in age-associated memory impairment (AAMI) patients. Actovegin is a protein-free metabolically active hemoderivative improving oxygen and glucose utilization. Each patient had, in randomized order, a treatment of 2 weeks with 250 ml 20% Actovegin and 250 ml placebo daily. Auditory ERPs were recorded before and 5 h after drug administration on day 1 (acute effect) and on day 15 (subacute and superimposed effect). Compared to age- and sex-matched normal controls, AAMI patients showed a trend towards P300 latency prolongation and a significantly reduced P300 global field power (GFP). Maximal LORETA source strength did not differ from controls. After Actovegin parietal P300 scalp amplitudes increased, while frontal and temporal amplitudes decreased as compared to placebo. This increase in hilliness, measured by the GFP, was significant. Moreover, the parietal P300 source strength increased after acute, subacute and superimposed infusion of Actovegin as compared to placebo. This may reflect improved availability of cognitive processing resources in the parietal cortex, an area that on the one hand plays an important role in fundamental aspects of attention and on the other hand has been found to be functionally impaired in dementia.