Biomedical subjects

B Saletu

Publications and source records attributed to B Saletu.

At least 19 recordsLinked to original sources

PubMed2006

Structural and serum surrogate markers of cerebrovascular disease in obstructive sleep apnea (OSA): association of mild OSA with early atherosclerosis.

There is increasing evidence of a causal interaction between obstructive sleep apnea (OSA) and cerebrovascular disease. The aim of the study was to elucidate the relationship between the polysomnographically (PSG) measured severity of OSA and carotid atherosclerosis determined by ultrasonography and serum surrogate markers. 147 patients (102 males, 45 females) referred to our sleep laboratory for evaluation of snoring and sleep-disordered breathing were investigated. Carotid atherosclerosis was evaluated by serum analysis of high-sensitivity C-reactive protein (hs-CRP) and fibrinogen and four sonographic indices: intima-media thickness (IMT) of the common carotid artery (CCA), IMT from bulb to internal carotid artery (Bulb-ICA), combined IMT measurements from all segments and a plaque score (PlaS). Pearson correlation analysis, intergroup comparison (ANOVA), covariance analysis and a multiple regression were performed to assess the association between surrogate markers and respiratory variables. 44 patients had no OSA (apnea-hypopnea index AHI < 5/h), 27 mild (AHI 5-15), 25 moderate (AHI 15-30) and 51 severe OSA (AHI > 30). After adjusting for potential confounders, significant differences between the controls and all three OSA groups were observed in the CCA-IMT (p = 0.032) and in the PlaS between the controls and the severe group (p = 0.034). Multiple regression revealed the AHI as an independent predictor of CCA-IMT (p = 0.001) and combined IMT (p = 0.001), whereas the percentage of total sleep time with an oxygen saturation below 90 % was associated with Bulb-ICA IMT (p = 0.018) and hs-CRP (p = 0.015). OSA is associated with higher surrogate levels of cerebrovascular disease. Even mild OSA seems to predispose to early atherosclerosis.

Adult↗

PubMed2006

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.

Adult↗

PubMed2005

Effects of socio-demographic variables on health-related quality of life determined by the quality of life index--German version.

STUDY OBJECTIVE: The purpose of this study was to determine subjective health-related quality of life (HRQoL) in a sample of the Austrian population over 14 years of age in order to evaluate the effect of socio-demographic variables on HRQoL. DESIGN/SETTING: HRQoL was determined by means of the quality of life index-German version (QLI-Ge). The influence of socio-demographic variables on HRQoL was assessed by statistical analysis using the Kruskal-Wallis test and an analysis of variance. PARTICIPANTS: A random-quota procedure was used to get balanced representation from regions and demographic groups of the Austrian population. The sample consisted of 1049 participants, 493 men and 556 women. MAIN RESULTS: Age was found to influence the QLI-Ge total score (index score) and most individual items, with increasing age resulting in a decrease in HRQoL. Differences between the sexes were observed in three dimensions: males scored higher in 'physical well-being', 'psychological well-being' and 'occupational functioning'. Marital status impacted most items with married persons showing better values than divorced persons or singles. Profession had only a minor effect on HRQoL, the level of education showed no influence at all. CONCLUSIONS: The socio-demographic variables age, sex and objective living conditions had a major influence on subjectively rated HRQoL, whereas profession and education were found to play a minor role in this context. It is recommended that in the interpretation of studies assessing HRQoL the above-mentioned objective factors be considered. This will be of particular importance when determining the effect of a pharmacotherapy on HRQoL in patients.

Adolescent↗

PubMed2005

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.

Aged↗

PubMed2004

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.

Arousal↗

PubMed2004

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.

Adult↗

PubMed2003

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.

Adult↗

PubMed2003

Recollection of dreams after short general anaesthesia: influence on patient anxiety and satisfaction.

BACKGROUND AND OBJECTIVE: We ascertained whether dreams during short general anaesthesia influence subsequent patient satisfaction and anxiety. METHODS: Fifty female patients were randomized into two groups to test for a difference between intravenous and inhalational anaesthesias. In Group Propo, anaesthesia was induced and maintained with propofol; in Group Metho-Iso, anaesthesia was induced with methohexital and maintained with isoflurane. Satisfaction and anxiety with anaesthesia were evaluated using a visual analogue scale from 0 to 100. Dream incidence rate, satisfaction and anxiety were assessed from immediately after waking until 3 months later. RESULTS: Seventeen patients (34%) dreamed during anaesthesia. There were no significant differences in satisfaction or anxiety after anaesthesia between the dreaming and non-dreaming patients (satisfaction, 92.3 +/- 21.6 versus 92.1 +/- 21.6; anxiety, 21.1 +/- 21.1 versus 30.3 +/- 32.1), or between Group Propo and Group Metho-Iso (satisfaction, 94.4 +/- 19.3 versus 90.0 +/- 23.4; anxiety, 26.0 +/- 27.6 versus 28.4 +/- 30.7). There was no significant difference in the incidence rate of dreaming with the type of anaesthesia used (Group Propo, 11 patients; Group Metho-Iso, 6 patients). CONCLUSIONS: Dreaming during general anaesthesia is common but does not influence satisfaction or anxiety after anaesthesia.

Adult↗

PubMed2003

Sleep, vigilance and cognition in postmenopausal women: placebo-controlled studies with 2 mg estradiol valerate, with and without 3 mg dienogest.

OBJECTIVE: To determine the effects in postmenopausal women with insomnia of hormone replacement therapy (HRT) with 2 mg estradiol valerate (E2V) alone, or in combination with 3 mg dienogest (DNG), in the context of the introduction of the novel preparation Climodien (2 mg E2V/2 mg DNG) (Schering AG, Berlin, Germany). METHODS: Parallel groups of women with insomnia related to the postmenopausal syndrome were randomized to 2 months' treatment with 2 mg E2V, 2 mg E2V/3 mg DNG or placebo (respectively, n = 17, 16, 16). Patients were then studied with techniques for assessing sleep quality, vigilance and cognition. Sleep quality was determined subjectively by means of the questionnaire-based sleep and awakening quality scale (SSA), and objectively with polysomnography. Sleep-related breathing disorders were evaluated by means of the apnea/hypopnea index. Vigilance was measured using quantitative electroencephalography with statistical probability mapping. Cognition (speed of information processing, cognition processing capacity and perceptual processing resources) was studied using the techniques of auditory event-related potentials (P300 latency and amplitude). RESULTS AND CONCLUSIONS: Treatment with 2 mg E2V and 2 mg E2V/3 mg DNG significantly improved subjective sleep quality and showed trends towards improvements in objective sleep quality. The combination of 2 mg E2V/3 mg DNG also improved the apnea/hypopnea index. Vigilance was slightly improved by treatment with 2 mg E2V and markedly with 2 mg E2V/3 mg DNG. Speed of information processing was improved with 2 mg EV2 and 2 mg E2V/3 mg DNG, whilst the latter also improved cognitive processing capacity and perceptual processing resources. The study provides evidence that HRT can improve sleep quality and mental functioning in postmenopausal women and that E2V/DNG combinations, such as 2 mg E2V/2 mg DNG, should be considered for this indication and also for the treatment of sleep-related breathing disorders in the menopause. The addition of dienogest to estradiol valerate did not antagonize the benefits of estradiol valerate in terms of sleep quality but rather potentiated estradiol valerate-related improvements in vigilance and some aspects of cognition.

Aged↗

PubMed2002

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.

Adult↗

PubMed2002

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.

Aged↗

PubMed2002

Sleeping habits in the Austrian population.

OBJECTIVES: To gain reliable data on sleeping habits and sleep disturbances of the Austrian population. BACKGROUND: Exact data on sleeping habits are of interest in relation to assessment of sleep disturbance-related illnesses and general social processes. METHODS: A prospective, cross-sectional study was performed with recruitment of a representative sample of 1049 Austrians (aged 15-82 years), according to the Federal Statistics population characteristics. Interviews were conducted in the households of the participants by specially trained interviewers of an institute for empirical research. RESULTS: Men consider their quality of sleep to be significantly better than women (P=0.00234), and younger persons consider their quality of sleep to be significantly better than older persons (P=0.00001). In comparison, women and people over the age of 50 report worse subjective sleep quality, worse sleep efficiency, more difficulty in falling asleep and sleep maintenance, more apneic events, more pathologic limb movements, more daytime dysfunction, and more intake of sleeping medication. Other sociodemographic factors influence sleep reports to a lesser extent. CONCLUSIONS: Subjectively disturbed sleep (prevalence in the total population 24.9%), excessive hypnotic drug intake (prevalence 13.0%), and daytime dysfunction (prevalence 17.4%) are a widespread problem, especially in women and older people. With increasing life expectancy in Western societies, the prevalence of sleep disturbances will increase.

Journal Article↗

PubMed2002

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.

Journal Article↗

PubMed2002

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.

Humans↗

PubMed2002

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.

Acoustic Stimulation↗

PubMed2002

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.

Brain Mapping↗

PubMed2002

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.

Brain Mapping↗

PubMed2002

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.

Adult↗