Effects of the novel neuroprotective agent, riluzole, on human brain function and behavior: I. Double-blind, placebo-controlled EEG mapping and psychometric studies under normoxia

In a double-blind, placebo-controlled, crossover study, the encephalotropic and psychotropic properties of single oral doses of the novel neuroprotective agent, riluzole, were investigated utilizing EEG mapping and psychometry. Twenty healthy young volunteers received randomly at weekly intervals, placebo, 50, 100 and 200 mg riluzole. EEG recordings and evaluation of 9 noopsychic and 5 thymopsychic variables were carried out at 0, 2, 4, 6 and 8 h after oral drug administration. EEG maps on the multivariate analysis demonstrated that all three doses induced significant changes in human brain function, as compared with placebo, between 2 and 8 h, with effect only increasing slightly with dose. EEG maps on univariate analysis demonstrated generally an increase of delta/theta, decrease of alpha and beta power, as well as a slowing of the centroid of the total power spectrum, which suggests sedative properties of the drug. Only after the two highest doses at 6 h were some different findings observed. Multivariate statistics on psychometry failed to show any significant effects on the noopsyche, while for the thymopsyche, all three doses of riluzole produced a deterioration. The latter was characterized by a decrease in drive and wakefulness as well as deterioration in well-being, mood and affectivity. Thus, under normoxia, in all three doses riluzole produced neurophysiologically a sedative effect, accompanied at the behavioral level by a deterioration in the thymopsyche, which may be expected from a drug with antiglutamatergic effects in normals.

Effects of the novel neuroprotective agent, riluzole, on human brain function and behavior: II. Double-blind, placebo-controlled EEG mapping and psychometric studies under hypoxia

In a double-blind, placebo-controlled study, the antihypoxidotic properties of the novel neuroprotective agent, riluzole, were investigated utilizing blood gas analysis, EEG mapping and psychometry under a transient, reversible, hypoxic hypoxidosis. The latter was induced by a fixed gas combination of 9.8% oxygen (O2) and 90.2% nitrogen (N2) (found at 6000 m altitude), which was inhaled for 23 min under normobaric conditions by 20 healthy, young volunteers. They randomly received, after an adaptation session, single oral doses of placebo, and 50, 100 and 200 mg riluzole. Evaluation of blood gases, EEG mapping and psychometry were carried out 0, 2, 4, 6 and 8 h postdrug, each time under the 23-min hypoxia. Blood gas analysis demonstrated a drop in PO2 from 106 to 37 and 36 mmHg, in PCO2 from 35 to 31 and 31 mmHg at 14 and 23 min of inhalation, respectively, while pH increased from 7.43 to 7.48 and 7.48. Base excess and standard bicarbonate remained stable. EEG mapping exhibited under hypoxia a marked increase of delta/theta, decrease of alpha and an increase of superimposed beta activity, as well as a slowing of the centroid of the total activity, which reflects deterioration of vigilance. Riluzole in lower doses and at early hours after higher doses did not attenuate this hypoxia-induced vigilance decrement, while with higher doses (100-200 mg) in later recording periods (6-8 h) brain protection occurred. As compared with placebo, delta/theta power increased at 2-8 h after 50 mg riluzole and up to 4 h after 100 mg riluzole, while a decrease occurred at 4 and 8 h after 100 mg and at 6-8 h after 200 mg. Alpha power showed no changes after 50 mg, an increase at 2 and 8 h after 100 mg and a decrease at 4 h after 200 mg, with no changes thereafter. Beta power decreased at various times after all three doses. At the behavioral level, hypoxic hypoxidosis induced a deterioration of the noopsyche, which was not mitigated by riluzole. In regard to the thymopsyche, there was even a slight deterioration after all three doses, as compared with placebo.

Double-blind, placebo-controlled, hormonal, syndromal and EEG mapping studies with transdermal oestradiol therapy in menopausal depression

In a double-blind, placebo-controlled study, the antidepressant and vigilance-promoting properties of transdermal oestrogen in post-menopausal depression were investigated utilizing hormonal, syndromal and EEG mapping evaluations. Sixty-nine menopausal women, aged 45-60 years without previous hormonal replacement therapy, diagnosed as major depression without psychotic or suicidal symptoms (DSM-III-R criteria), were randomly assigned to a 3-month treatment with transdermal oestradiol [Estraderm TTS (ETTS) 50 micrograms, applied twice weekly] or placebo. No other psychoactive medication was allowed. After removal of protocol violators, 32 patients were evaluable in each group, which did not differ in age, height or weight. As five patients discontinued prematurely in both groups and in one placebo patient a post-drug EEG could not be obtained, 27 patients remained in the ETTS and 26 in the placebo group for efficacy analysis. While in the placebo group, oestradiol (E2) and follicle stimulating hormone (FSH) remained unchanged, E2 increased and FSH decreased significantly in the ETTS group. Syndromal evaluation showed a significant improvement in the Kupperman Index (KI) as well as Hamilton Depression Rating Scale (HAMD) in both groups, with no inter-group difference. However, EEG mapping demonstrated significant inter-drug differences in brain function, mostly over the left temporal region. While ETTS patients showed an increase of alpha and alpha-adjacent theta activity and a decrease of beta activity, as well as an acceleration of the delta/theta centroid and a slowing of the alpha, beta and total power centroid, no changes occurred in the placebo-treated patients. These neurophysiological findings suggest improvement of vigilance by oestrogen, previously referred to as "mental tonic" effect. There were no changes, however, in the frontal alpha asymmetry index, reflecting left frontal hypo- and right frontal hyperactivation. Thus, this neurophysiological variable represents a state-independent marker for depression. The tolerability of ETTS was very good.

Acute effects of the anxiolytics suriclone and alprazolam on cognitive information processing utilizing topographic mapping of event-related brain potentials (P300) in healthy subjects

In a double-blind, placebo-controlled, cross-over study, acute effects of suriclone--a cyclopyrrolone derivative--were investigated by means of topographic mapping of event-related potentials (ERPs). Fifteen normal volunteers, aged 22-35 years, received randomized, oral single doses of placebo, 0.1 mg, 0.2 mg and 0.4 mg suriclone and 1 mg alprazolam as a reference compound. ERPs were investigated in an auditory oddball paradigm before and 3 h after intake of each drug. In addition to 17 EEG leads, vertical and horizontal electro-oculograms (EOGs) were recorded. After EOG minimization and artifact identification, the peak latencies of the spatial average were determined by an automatic procedure. Compared to placebo, no significant effects of the low and middle doses of suriclone on N1 amplitude were observed; the highest dosage reduced N1 amplitude, as did 1 mg alprazolam to an even greater extent. While no consistent effects on P2 amplitude were observed after suriclone, alprazolam reduced P2 amplitude. P300 amplitude was reduced only after the highest dosage of suriclone, but much more so after alprazolam. P300 latency was not affected significantly by suriclone, but a marked prolongation of P300 latency was observed after 1 mg alprazolam. Concerning N1 and P2 effects, alprazolam, but not suriclone, may have an inhibitory influence on stimulus-induced cortical arousal. Concerning P300 effects, the used doses of suriclone were superior to 1 mg alprazolam, which seemed to have reduced cognitive information processing capacity and prolonged stimulus evaluation time. Self-rated well-being (adjective checklist) showed subtle beneficial effects after 0.1 mg and 0.2 mg, but marked sedative effects after both 0.4 mg suriclone and 1 mg alprazolam.

Cognitive psychophysiology in nootropic drug research: effects of Ginkgo biloba on event-related potentials (P300) in age-associated memory impairment

Extracts from the leaves of Ginkgo biloba have been suggested to be useful in the treatment of various symptoms of impaired brain functions in advanced age. To elucidate specific mechanisms of the possible clinical benefit, the effects of Ginkgo biloba extract Ginkobene on cognitive information-processing were investigated by means of long-latency auditory event-related potentials. In a double-blind placebo-controlled study, 48 patients (29 women and 19 men) aged between 51 and 79 years with the diagnosis of age-associated memory impairment had 57 days' treatment with a daily dosage of 3 x 40 mg Ginkobene or placebo. To evaluate acute, chronic, and superimposed drug effects, psychophysiological investigations were carried out on day 1 and day 57 before and 3 hours after drug administration. ERP investigations were carried out by means of a two-tone auditory oddball paradigm. In addition to 17 EEG leads, vertical and horizontal EOGs were recorded. After minimizing ocular artifacts and visual artifact rejection, latencies and topographic distributions of N1 and P2 components (non-targets) and N2 and P300 components (targets) were calculated by an automatic procedure. When compared to the placebo group, in the Ginkobene group no consistent and unequivocal changes on N1, P2, N2, and P300 amplitudes or on N1, P2, and N2 latencies were observed. P300 latency was shortened by 31 ms, 38 ms, and 32 ms in the Ginkgo biloba group after acute, chronic, and superimposed drug administration. It may therefore be hypothesized that the decrease of P300 latency in the Ginkgo biloba group may reflect shorter stimulus-evaluation time.(ABSTRACT TRUNCATED AT 250 WORDS)

Double-blind, placebo-controlled, pharmacokinetic and -dynamic studies with 2 new formulations of piracetam (infusion and sirup) under hypoxia in man

In a double-blind, placebo-controlled study, pharmacokinetics and pharmacodynamics of 12 g piracetam in 2 different formulations were investigated utilizing blood gas analysis, EEG mapping and psychometry under a transient, reversible, hypoxic hypoxidosis. The latter was induced by a fixed gas combination of 9.8% oxygen (O2) and 90.2% nitrogen (N2, found in 6,000 m altitude), which was inhaled for 23 minutes under normobraic conditions by 18 healthy volunteers. They received after an adaptation session randomized at weekly intervals 12 g piracetam i.v. (250 ml infusion over 30 minutes), 12 g piracetam p.o. (60 ml sirup) and placebo. Blood levels were determined by means of an HPLC at the hours 0, 1, 2, 4, 6, 8 and 24. The 2 formulations showed a very similar time-course, with slightly higher blood levels in the 1st hour after the intravenous than oral administration, and vice versa thereafter. The elimination half-life was 4.3 hours for both formulations, the area under the curve and the clearance value were also almost identical. Evaluation of blood gases, EEG mapping and psychometry were carried out at 0, 2, 4, 6 and 8 hours post-drug. Blood gas analysis demonstrated a drop in SaO2 from 99 to 73 and 70%, in PO2 from 100 to 35 and 33 mmHg, in PCO2 from 36 to 31 and 31 mmHg in the 14th and 23rd minute of inhalation, respectively. pH increased from 7.43 to 7.48 in the respective minutes, while base excess and standard bicarbonate remained stable. EEG mapping exhibited under hypoxia a marked increase of total power, mostly due to an augmentation of delta/theta, and a decrease of alpha activity, which reflects deterioration of vigilance. Both piracetam preparations significantly attenuated this vigilance decrement, with 12 g piracetam i.v. showing its encephalotropic peak effects in the earlier hours, 12 g piracetam sirup in the later hours. At the behavioral level, hypoxic hypoxidosis induced a deterioration of the noo- and thymopsyche, which was mitigated by both piracetam preparations, mostly in the 6th hour. Both formulations were well tolerated.

Acute central effects of the calcium channel blocker and antiglutamatergic drug caroverine. Double-blind, placebo-controlled, EEG mapping and psychometric studies after intravenous and oral administration

In a double-blind, placebo-controlled study, the effects of caroverine (CAS 23465-76-1, Spasmium)--a quinoxaline derived from isoquinoline, the basic structure of papaverine, originally developed as a spasmolytic drug which may, however, exert central effects due to an unspecific calcium channel blocking action and glutamate antagonism--were investigated utilizing EEG-mapping, psychometric and psychophysiological measures. Fifteen healthy volunteers (8 males and 7 females), aged 20-35 years, received randomized and at weekly intervals 40 and 80 mg caroverine intravenously, 40 and 80 mg caroverine orally, as well as placebo. EEG recordings, psychometric and psychophysiological tests, as well as evaluation of pulse, blood pressure and side-effects were carried out at 0, 1, 2, 4, 6 and 8 h. Multivariate analysis of EEG mapping data demonstrated that caroverine exerted a significant action on human brain function, as compared with placebo, at all given dosages, as early as in the 1st and as late as in the 8th hour after both intravenous and oral administration during resting (R-EEG) and vigilance-controlled recording (V-EEG). Subsequent univariate analyses revealed, however, differential effects of caroverine--dependent on recording conditions and doses. In the resting condition, an increase of absolute and relative delta and theta power, a decrease of alpha and beta power and a slowing of the centroid of the delta and theta activity occurred, reflecting sedative action. The latter was slightly time- and dose-dependent (more sedation in earlier hours after higher doses). However, in the vigilance-controlled EEG, a dose-dependent decrease of delta and theta power, an increase of alpha power and an acceleration of the centroid of the delta and theta suggested vigilance-promoting effects, which were more pronounced in the later than earlier hours. Psychometric investigations confirmed these differential central effects. In regard to the noopsyche, an improvement was noted 6 h after the lowest oral dose. In the thymopsyche, a deterioration occurred after all doses except the highest oral dose, suggesting sedation. The latter was also seen after all active compounds as a trend in psychophysiological variables. The drug was well tolerated.

Nicergoline in senile dementia of Alzheimer type and multi-infarct dementia: a double-blind, placebo-controlled, clinical and EEG/ERP mapping study

In a double-blind, placebo-controlled study on the therapeutic efficacy and central effects of nicergoline, an ergot alkaloid with metabolic, antithrombotic and vasoactive action, 112 patients with mild to moderate dementia, diagnosed according to DSM III-R criteria (MMS 13-25), living in pensioners' homes, were included. Fifty-six were subdiagnosed as senile dementia of the Alzheimer type (SDAT), 56 as multiinfarct dementia (MID), based on computed tomography and Hachinski scores (< or = 49 SDAT, > or = 7 MID). They received, after 2 weeks' run-in period (placebo), randomized for 8 weeks either 2 x 30 mg nicergoline (NIC) or 2 x 1 placebo (PLAC) orally. The four subgroups (SDAT/NIC. SDAT/PLAC, MID/NIC, MID/PLAC; 4 x 28 patients) were comparable in regard to age and sex. Only four, four, four and two patients of the respective groups did not finish the study for minor reasons. Confirmatory statistical analysis demonstrated in the target variable-the Clinical Global Impression (CGI)-a significant superiority of Global Impression (CGI)-a significant superiority of NIC over PLAC in both the SDAT and MID groups. Global improvement (CGI item 2) was seen in both nicergoline subgroups (3 and 3), while no changes occurred under placebo (4 and 4, respectively). The responder versus non-responder ratio was in the SDAT/NIC group 16/8, versus 8/16 in the SDAT/PLAC group (chi 2 = 4.1, P = 0.04); in the MID/NIC group 17/7, versus 7/19 in the MID/PLAC group (chi 2 = 7.96, P < 0.005). Furthermore, there was a significant improvement of the Mini-Mental State and the SCAG score in both the MID and SDAT group after 8 weeks of nicergoline, which was significantly superior to the minimal improvement or no change in placebo-treated SDAT and MID patients. EEG mapping demonstrated in NIC-treated SDAT and MID patients a significant decrease in delta and theta, increase in alpha 2 and beta activity and an acceleration of the centroid of the total power spectrum as compared with pretreatment, while opposite changes occurred in PLAC-treated SDAT and MID patients. The differences between PLAC and NIC reached the level of statistical significance. Event-related potential (ERP) recordings demonstrated a significantly shortened P300 latency under NIC treatment in both SDAT and MID patients, while there was a trend towards lengthening under PLAC. Thus, nicergoline improved vigilance and information processing at the neurophysiological level, which leads at the behavioural level to clinical improvement both in degenerative and vascular dementia.

BMS-181168 for protection of the human brain against hypoxia: double-blind, placebo-controlled EEG mapping studies

In a double-blind, placebo-controlled, cross-over trial, the antihypoxidotic properties of BMS-181168 (previously BMY 21502)--a 1-[[1-[2-(trifluoromethyl)-4-pyrimidinyl]-4-piperidinyl]methyl]-2- pyrrolidinone alleviating impairment of learning and memory in the animal--were studied utilizing EEG mapping under an experimental hypoxic hypoxidosis. The latter was induced by a fixed gas combination of 9.8% oxygen (O2) and 90.2% nitrogen (N2) (found at 6000 m altitude), which was inhaled for 23 minutes under normobaric conditions by 16 healthy male volunteers (aged 23-35 years, mean 27.2 years). After an adaptation session, they received in randomized order at weekly intervals oral single doses of placebo, or of 100 mg, 200 mg, and 400 mg BMS-181168. Evaluation of blood gases (PO2, PCO2, SO2), adverse events, and EEG mapping was carried out prior to drug administration and 2, 4, 6 and 8 hours post-drug, on each occasion under normoxic and transient hypoxic conditions. Hypoxemia was controlled by drawing arterialized capillary blood samples from the earlobes after hyperemization of the latter (after 0, 14, and 23 minutes of hypoxic gas inhalation) and by oximetry. After 23 minutes of inhalation, analysis showed a drop in PO2 from 98 to 48 mm Hg, in PCO2 from 41 to 31 mm Hg, and in SO2 from 97 to 80%. Descriptive statistical analyses of EEG mapping data demonstrated under hypoxia/placebo conditions an increase in delta/theta activity and a decrease in alpha activity as well as a slowing of the delta/theta centroid and an increase in the alpha and beta centroid, which suggests a marked deterioration in physiological vigilance.(ABSTRACT TRUNCATED AT 250 WORDS)

Discrimination between demented patients and normals based on topographic EEG slow wave activity: comparison between z statistics, discriminant analysis and artificial neural network classifiers

The topographic distributions of absolute delta and theta powers were used to classify demented patients and normals by means of z statistics, discriminant analysis and artificial neural networks (NN). The data were taken from two psychopharmacological studies in mildly to moderately demented patients (111 and 96 patients for studies I and II, respectively) and from 56 normal healthy controls. All patients were diagnosed according to DSM-III criteria and were free of medication for at least 2 weeks. The NN used was a strictly layered feed-forward network with complete connections. The z-transformed absolute power values in the combined delta and theta frequency range at 17 electrodes, recorded in a 3 min vigilance-controlled EEG with eyes closed, were used as input. After having trained the NN successfully by backpropagating of errors, the generalization test with independent data results in a classification performance of 90% determined by "relative operating characteristic" analysis. The NN out-performed z statistics and discriminant analysis. This high percentage of correct classifications may justify the development of further application of NNs based on topographic EEG data.

Effect-kinetics on brain protection of two codergocrine-mesylate preparations (Aramexe retard® and Hydergine®) by EEG mapping and psychometry under hypoxia

In a double-blind, placebo-controlled study the effect-kinetics on brain protection of a new retard formulation of codergocrine-mesylate (CDM) (Aramexe retard, 5 mg) were investigated and compared with a standard CDM drug (5 mg Hydergine) utilizing blood gas analysis, EEG mapping and psychometry. A transient, reversible hypoxic hypoxidosis (i.e. impairment of cerebral metabolism due to hypoxia) was experimentally induced by a fixed gas combination of 9.8% oxygen (O(2)) and 90.2% nitrogen (N(2)) (found at an altitude of 6000 m), which was inhaled for 23 min under normobaric conditions by 18 healthy volunteers. After an adaptation session they received randomized 5 mg Aramexe retard, 5 mg Hydergine and placebo. Evaluation of blood gases, EEG mapping and psychometry was carried out at 0,2, 4,6, and 8 h after oral drug administration - each time under normoxic and hypoxic conditions. Blood gas analysis demonstrated a drop in SaO(2) from 99% under normoxia to 70% under hypoxia, in Po(2) from 100 to 33 mmHg, and in Pco(2) from 36 to 31 mmHg, while pH increased from 7.43 to 7.48. Base excess and standard bicarbonate remained stable. Under hypoxia EEG mapping exhibited an increase in delta/theta, a decrease of alpha and increase of beta activity, as well as a slowing of the centroid of the total power spectrum, which reflects deterioration of vigilance. Both CDM preparations significantly attenuated this vigilance decrement, with 5 mg Hydergine showing its encephalotropic peak effect in the second hour, 5 mg Aramexe retard in the sixth and eighth hours. At the behavioral level, hypoxic hypoxidosis induced a deterioration of the noo- and thymopsyche (by 53% under placebo), which was significantly mitigated by both 5 mg Aramexe retard (19%) and Hydergine (32%).

Pharmacokinetic and -dynamic studies with a new anxiolytic, suriclone, utilizing EEG mapping and psychometry

1. In a double-blind, placebo-controlled, cross-over study, acute pharmacokinetic, neurophysiological and psychotropic effects of suriclone, a new cyclopyrrolone derivative, were investigated and compared with alprazolam. 2. Fifteen normal young volunteers received randomized oral single doses of placebo, 0.1, 0.2 and 0.4 mg suriclone as well as 1 mg alprazolam as reference compound. Investigations were carried out before and 1, 2, 4, 6 and 8 h after drug administration. 3. Pharmacokinetic investigations by radioimmunoassay showed a dose-dependent fast rise of plasma concentrations with a peak at 1 h and a rapid decline thereafter. Both the Cmax and the AUC values exhibited a linear relationship to dose. 4. EEG brain mapping demonstrated significant CNS effects of both compounds, characteristic for tranquillizers (increase of beta, decrease of alpha and increase of delta activity; attenuation of total power and acceleration of the centroid, i.e. centre of gravity frequency). When compared with alprazolam, suriclone exerted less sedative effects. 5. Time-efficacy calculations showed the pharmacodynamic peak effect of suriclone from the 2nd to the 4th hour, and of alprazolam in the 1st hour. Dose-efficacy calculations showed that the most pronounced CNS changes occurred after 1 mg alprazolam, followed by 0.4, 0.2 and 0.1 mg suriclone. 6. Psychometric investigations demonstrated no significant effects after the two lower doses of suriclone, while 0.4 mg and 1 mg alprazolam induced a decrement both in noopsychic and thymopsychic variables seen after higher doses of anxiolytic sedatives. Psychophysiology (critical flicker fusion, pupillometry, and skin conductance measures) pulse rate, systolic and diastolic blood pressure remained unchanged. 7. Psychophysiology (critical flicker fusion, pupillometry and skin conductance measures) showed differential dose-dependent effects. Pulse rate, systolic and diastolic blood pressure remained unchanged. Anxiolytic-characteristic side-effects (tiredness, drowsiness, etc.) occurred predominantly after the highest doses 0.4 mg suriclone and 1 mg alprazolam.

Clinical, EEG mapping and psychometric studies in negative schizophrenia: comparative trials with amisulpride and fluphenazine

Based on recent quantitative EEG findings of increased slow activity in negative schizophrenia indicating organicity, it was hypothesized that neuroleptics decreasing delta/theta activity should be beneficial for schizophrenics with predominantly negative symptoms. Thus, a double-blind, clinical, psychometric and neurophysiological study was carried out in 40 hospitalized patients with unproductive schizophrenia (mean age: 31 years; ICD diagnoses: 295.0, 295.1 and 295.6) who were treated randomly either with the benzamide amisulpride (AMI; n = 19) or low doses of fluphenazine (FLU; n = 21). In the first 2 weeks the daily doses were 50 mg AMI or 2 mg FLU, respectively, from the third week on up to the sixth week 100 mg AMI and 4 mg FLU. Clinical evaluations, psychometry and EEG mapping were performed on day 1 (hours 0 and 4--acute effect), on day 14 (hour 0--subacute effect) and on day 42 (hours 0 and 4--chronic and superimposed effects). Three AMI patients discontinued therapy prematurely because of productive symptoms (days 14, 28 and 35), while in the FLU group 2 patients dropped out due to depressive symptoms (days 21, 28), 1 due to productive symptoms (day 35), 1 due to ineffectiveness (day 28), and 1 because of an akinetic crisis (day 6). Statistical evaluation demonstrated a significant improvement in the AMDP apathy and Andreasen SANS score in both groups with the patients remaining severely ill as rated by the CGI. FLU-treated patients needed significantly more anticholinergic medication than the AMI-treated group. Psychometric evaluation showed in regard to the noopsyche significant improvement after subacute, chronic and superimposed AMI, while FLU-treated patients showed significant improvement only after subacute treatment. AMI was significantly superior to FLU at the hours 0 and 4 of day 42. The thymopsyche improved after subacute, chronic and superimposed administration of both compounds with a significant superiority of AMI on days 14 and 42 (4 h postdrug). EEG mapping showed a decrease of delta/theta and increase of beta activity as well as an acceleration of the centroid after acute and superimposed AMI on day 42 as compared with baseline; FLU patients exhibited a decrease of delta/theta activity and an acceleration of the total centroid too, while alpha activity was augmented and beta activity tended to be reduced. Our study demonstrated that, in addition to the new benzamide AMI, FLU in low doses may also be regarded as a neuroleptic with activating properties and may be utilized in the treatment of schizophrenics with predominantly negative symptoms.

Automatic sleep-spindle detection procedure: aspects of reliability and validity

The paper describes a reliable and valid method for the automatic detection of sleep spindles in whole night polygraphy. The recording of a multi-channel EEG during sleep polysomnography was performed in 10 healthy volunteers aged 20-35 years. This objective method should improve the time-consuming and subjective visual evaluation by increasing the accuracy and allowing the calculation of quantitative variables (i.e., frequency and amplitude), thereby facilitating scientific work with quantitative data. An important part of the method is the treatment of artifacts (i.e., muscle and spindle-like alpha activity). Compared to hardware solutions, our software method has the advantage of higher flexibility in regard to artifact identification and usual spindle definitions.

Insomnia in generalized anxiety disorder: polysomnographic, psychometric and clinical investigations before, during and after therapy with a long- versus a short-half-life benzodiazepine (quazepam versus triazolam)

Within a double-blind, comparative study on the effects of the long-half-life benzodiazepine (BDZ), quazepam, and the short-half-life BDZ, triazolam, on clinical symptomatology, sleep and anxiety of 45 patients with insomnia based on a mild to moderate generalized anxiety disorder (GAD) (ICD-9 code: 307.42-1, 300,0; ASDC-APSS-Code: A.2.a), we compared, in a first step at baseline, drug-free polysomnographic and psychometric data of 22 patients recorded in the laboratory (L-group) and 21 patients recorded by the Oxford Medilog 9000 system at home (H-group) with those of normal controls. Sleep efficiency, total sleep time, wake within total sleep period (middle insomnia) and wake before buzzer (late insomnia) were significantly deteriorated in both patient groups as compared with controls, while sleep induction time only differed significantly in home recordings. Regarding sleep architecture, stage (S)2 was reduced, S3 and S4 increased in the H-group only, while no intergroup differences were seen in S1, SREM and REM latency. Subjective sleep quality was reduced in both patient groups, but not awakening quality. Psychometric tests in the morning demonstrated for the noopsyche, only a significantly deteriorated psychomotor activity in both patient groups. In the thymopsyche, evening well-being and mood in the morning were reduced in both the L- and H-group, affectivity and morning well-being only in the H-group. The psychopharmacological part of the study was completed by 40 patients (there were 4 drop-outs in the triazolam, 1 in the quazepam group). They were treated after 1 week placebo with either 15-30 mg (median 15 mg) quazepam or 0.25-0.5 mg (median 0.25 mg) triazolam for 4 weeks, and thereafter for 2 weeks with placebo. Anxiety (rated by HAMA and SAS) improved significantly with both drugs and remained improved throughout 2 weeks post-drug placebo, with quazepam being slightly superior to triazolam. Polysomnography demonstrated a shortened sleep onset only after quazepam. Sleep efficiency improved after acute administration of both drugs, but the improvement was maintained by quazepam only (tolerance development with triazolam). Rebound insomnia was observed only in the 1st post-triazolam placebo night (significant intergroup difference based on confirmatory testing). S2 increased, S3 + S4 decreased under and after quazepam, which represents a normalization in home-recorded GAD patients. S1 decreased with both drugs, SREM only under quazepam. Subjective sleep quality behaved very similarly to objective sleep efficiency. Awakening quality improved after acute therapy with both drugs, somatic complaints only with quazepam.(ABSTRACT TRUNCATED AT 400 WORDS)

Topographic mapping of EEG during sleep

Topographic aspects of all night sleep EEG were investigated in 10 healthy volunteers (age 20-35 years). EEG brain maps showed an increase of delta power from stage 1 to 4, a decrease of alpha power most pronounced parieto-occipitally and a slowing of the dominant alpha frequency. Differences of EEG power in different sleep stages (as compared to wakefulness) are displayed topographically. Analysis of the course of stage 2 showed an increase of delta power and a decrease of theta power in the first sections of the night, and an increase of beta power later in the night.

Clinical-pharmacological study with the two isomers (d-, l-) of fenfluramine and its comparison with chlorpromazine and d-amphetamine: blood levels, EEG mapping and safety evaluation

In a double-blind, placebo-controlled, crossover study, the blood levels and pharmacodynamic properties of single oral doses of 15 and 30 mg d-fenfluramine (d-FEN) and 30 mg l-fenfluramine (l-FEN) were investigated as compared with 50 mg chlorpromazine (CPZ) and 20 mg d-amphetamine (AMPH) utilizing pharmaco-electroencephalogram (EEG) mapping as well as prolactin and safety assessments. Eighteen healthy young volunteers randomly (Latin square) received at weekly intervals the different treatments. Blood sampling to determine AMPH, FEN and its main metabolite norFEN, as well as plasma prolactic levels, EEG recordings and evaluation of hemodynamics and spontaneous side effects were carried out at 0, 2, 4, 6 and 8 h after drug administration. Before and 24 h after drug intake morning subjective sleep quality was also assessed. Blood level investigations after d-FEN demonstrated dose-dependent blood concentrations peaking after 2-4 h and slowly declining thereafter. NorFEN, the main metabolite, exhibited a steady increase in plasma concentrations up to the 8th h. After l-FEN a similar time course was obtained but the concentrations of the parent compound were higher and those of the metabolite lower in comparison with the d-isomer, suggesting stereoselective kinetics. d-FEN induced significant and dose-dependent pharmaco-EEG changes characterized by a decrease in total power and combined delta/theta activity and by an increase in beta activity and an acceleration of the centroid of the total activity with no changes in alpha power, which were quite different from those of the reference drugs. l-FEN produced only minimal changes (of the same type as d-FEN). 50 mg CPZ and 20 mg d-AMPH produced significant changes as compared to placebo but with quite opposite patterns, the former exhibiting the typical sedative-neuroleptic profile and the latter that typical of psychostimulants. Dose/treatment- and time-efficacy calculations based on all variables showed in the V-EEG that only 30 mg d-FEN and 50 mg CPZ were different from placebo (with peak effects in the 8th and 4th h, respectively), while in the resting condition (R-EEG) all drugs/dosages but 30 mg l-FEN differed from placebo (with the peak effect occurring in the 4th-6th h after d-FEN and l-FEN, in the 2nd h after CPZ and in the 4th-6th h after AMPH). Plasma prolactin levels were only modified by CPZ (maximal increase in the 2nd h).(ABSTRACT TRUNCATED AT 400 WORDS)

Treatment of the alcoholic organic brain syndrome: double-blind, placebo-controlled clinical, psychometric and electroencephalographic mapping studies with modafinil

In a double-blind study 40 abstinent hospitalized male patients with an alcoholic organic brain syndrome (OBS; ICD 9: 291.2) were treated for 6 weeks with either placebo or 200 mg modafinil b.i.d. Modafinil (CRL 40476) is a vigilance-promoting, putative central alpha 1-adrenergic agonist with a pharmacological profile quite different from that of amphetamine. Clinical investigations demonstrated that the spontaneous remission of the alcoholic OBS was augmented and accelerated by modafinil, which was found significant as compared with placebo by confirmatory statistics in the target variable, the Clinical Global Impression scale. The drug was well tolerated. Psychometric tests revealed significant improvement of the noopsyche after modafinil as compared with placebo, while the thymopsyche and psychophysiological measurements were not affected. Electroencephalographic mapping showed significant differences between the central effects of modafinil and placebo indicating an improvement of vigilance under modafinil. Typical vigilance-promoting properties were seen after acute drug administration, were less evident before the morning dose after chronic treatment but re-occurred after super-imposed daily drug administration. Thus, our clinical, psychometric and neurophysiological investigations in alcoholic OBS patients demonstrated a therapeutic effect of modafinil in the early phase of abstinence.

Restriction to a limited set of EEG-target variables may lead to misinterpretation of pharmaco-EEG results

The number and types of target variables quantified from the spectrally analyzed EEG used in topographic pharmaco-EEG studies are still being discussed. Drug-induced changes of target variables obtained in the alpha frequency band--four absolute and four relative powers as well as three frequency measures--were utilized to assess the effects of xantinolnicotinate in demented patients using a parallel group design and the effects of buspirone in a double-blind, placebo-controlled crossover design. We conclude that for the proper evaluation of the different drug effects on the alpha activity, all these target variables should be considered. Descriptive p values of multiple comparisons within the framework of descriptive data analyses are important tools in interpreting drug effects.

Acute effects of the novel antidepressant venlafaxine on cognitive event-related potentials (P300), eye blink rate and mood in young healthy subjects

Venlafaxine is a novel non-tricyclic antidepressant, which preclinically has demonstrated serotonin, norepinephrine, and dopamine reuptake inhibiting effects. In this study acute effects of single oral doses of placebo, 12.5 mg, 25 mg, and 50 mg venlafaxine on event-related potentials (ERPs), eye blink rate and mood were studied in 16 healthy subjects. ERPs were investigated in an auditory odd-ball paradigm before as well as 3 h after each drug intake. In addition to 17 EEG leads, vertical and horizontal EOGs were recorded. After EOG minimization and visual artefact rejection the peak latencies of the spatial average were determined by an automatic procedure. The applied methods of data acquisition, artefact processing, objective component determination and statistical analysis were successful in describing acute effects of venlafaxine on ERPs in normals. N1 and P2 latencies were not affected. An increase in P2 amplitude in the relevant central and frontal regions was seen, reflecting some effect on automatic information processing. Stimulus evaluation time was not affected, as P300 latency remained unchanged. P300 amplitude was not affected at the relevant central and parietal region. Blink rate was not changed. By means of the adjective checklist a dose-dependent decrease of "extroversion" and "high spirits" and an increase of "introversion" was observed. Our findings suggest that venlafaxine affects human information processing less than would be expected from the more centrally inhibiting classical antidepressants.

Topographic mapping of long latency "cognitive" event-related potentials (P 300): a double-blind, placebo-controlled study with amantadine in mild dementia

Amantadine is generally used in the prophylaxis of infection with influenza A, in the treatment of Parkinson's disease and in the treatment of neuroleptic side effects. In this study acute effects of amantadine infusions on event-related potentials (ERP) were studied in 20 mildly demented patients diagnosed according to DSM-III-R criteria. Each patient was treated, in randomized order, with 0.2 g amantadine-sulfate in 500 ml NaCl and 500 ml NaCl placebo, i.v. over one hour with an interval of two weeks in-between. ERPs were investigated in an auditory odd-ball paradigm before as well as 5 hours after the infusion. In addition to 17 EEG records, vertical and horizontal EOGs were recorded. After EOG-minimization and visual artifact rejection the peak latencies of the spatial average were determined by an automatic procedure. There was no effect of amantadine on ERP latencies. N1 of the non-target showed a trend towards amplitude augmentation, P2 amplitude was reduced. As compared to placebo, P300 amplitude of targets was significantly augmented by 3.1 microV (30% of pre-treatment value), confirming the hypothesis that amantadine may influence the P 300 amplitude in the sense of an improved availability of cognitive processing resources.

EEG mapping and psychopharmacological studies with denbufylline in SDAT and MID

Computed tomography (CT), electroencephalograms (EEG), clinical and psychometric data were obtained in 96 mildly to moderately demented patients (72 women, 24 men), aged 61-96 years (mean 82), diagnosed according to DSM-III criteria. Patients were off drugs for at least 2 weeks and subdiagnosed according to the modified Marshall-Hachinski ischemic score and CT in 45 senile dementia of the Alzheimer type (SDAT) and 51 multiinfarct dementia (MID) patients. Evaluations were carried out before and 12 weeks after treatment with either 100 mg denbufylline BID or placebo and included EEG mapping, the Sandoz Clinical Assessment Geriatric (SCAG) score/factors, the Clinical Global Impression (CGI), the Digit Symbol Substitution Test (DSST), the Trail-Making Test (TMT) and the Digit Span Test (DS). Descriptive data analysis including confirmatory statements found delta/theta activity enhanced, alpha and beta activity reduced, total power augmented, and the centroid slowed down over various brain regions in patients as compared with controls. The two subtypes of dementia could be differentiated in some conventional EEG variables but mostly by means of power asymmetry indices. Denbufylline induced a statistically significant and clinically relevant improvement in both SDAT and MID patients, whereas after placebo this was not the case in CGI, the TMT, and the DS, with interdrug differences being significant in all primary target variables such as the CGI, MMS, SCAG, and DSST. Thus, both the degenerative and vascular type of dementia exhibited a therapeutic benefit that could be objectified at the neurophysiological level by EEG mapping in an improvement of vigilance.

Artifact processing in topographic mapping of electroencephalographic activity in neuropsychopharmacology

Mapping of the electroencephalogram (EEG) has been found to be a valuable method in clinical neuropsychopharmacology. It is evident that careful treatment of artifacts is of utmost importance for EEG data processing, as artifacts that contaminate the EEG data can lead to spurious results. The artifact-processing method described in this article splits signal analysis into a preprocessing step, yielding individual electro-oculographic (EOG) regression factors for EOG minimization, and into a processing step, yielding target variables. The combination of avoiding, minimizing, and identifying artifacts, as well as visual checking of face validity, will help remove artifactual effects from the EEG.

Amantadine infusions in mild dementia: acute double-blind placebo-controlled EEG mapping and psychometric studies

In a double-blind, placebo-controlled study, the acute central effects of amantadine infusions (200 mg for 1 h) were studied in 20 mildly demented patients (DSM-III-R) utilizing EEG mapping as well as psychometry and psychophysiology at the hours 0, 2, 4, 6 and 8. Multivariate analysis of the EEG demonstrated a significant CNS effect of 200 mg amantadine as compared with placebo mostly at the 4th and 6th hour. These effects were primarily over temporo-occipital, fronto-temporal and temporal regions. Univariate analysis showed a decrease of total power and of absolute power in all frequency bands. Furthermore, an increase of relative delta and beta activities, a decrease of theta and alpha activities, as well as an acceleration of the respective centroids of the alpha, beta and total activity were observed. The delta/theta centroid showed initially a slight increase and thereafter a clear decrease. The changes were similar to those seen after psychostimulants. Multivariate analysis of noopsychic variables showed an improvement in the 6th hour after amantadine and no changes after placebo, but inter-drug differences did not reach significance. Univariate analyses revealed differential results which included improvement in digit span and deterioration in the speed related test such as DSST and reaction time. In thymopsychic variables, de-activation was observed after amantadine as compared with placebo in the 2nd to the 6th hour with a maximum in the 4th hour. As patients felt themselves slightly over-activated before treatment, de-activation may be regarded as improvement of vigilance in the narrow sense of the word. There were no psychophysiological changes.

Pharmacodynamics of venlafaxine evaluated by EEG brain mapping, psychometry and psychophysiology

1. In a double-blind, placebo-controlled study the effects of venlafaxine--a novel nontricyclic compound inhibiting neuronal uptake of serotonin, noradrenaline and to a lesser extent dopamine--were investigated utilizing EEG brain mapping, psychometric and psychophysiological measures. 2. Sixteen healthy volunteers (eight males, eight females) aged 21-36 years received randomized and at weekly intervals single oral doses of placebo, 12.5 mg, 25 mg and 50 mg venlafaxine. EEG recordings, psychometric and psychophysiological tests, and evaluation of pulse, blood pressure and side-effects were carried out at 0, 2, 4, 6, and 8 h. 3. EEG brain mapping demonstrated that venlafaxine exerted a significant action on human brain function as compared with placebo at all three doses, characterized mostly by attenuation of absolute power, increase of relative delta/theta and beta, and decrease of alpha power, as well as by an acceleration of the total centroid fronto-temporally and by its slowing centrally and parietally. These findings are similar to antidepressants such as imipramine. Topographically, drug-induced alterations were most pronounced over both fronto-temporal and the right temporal to temporo-occipital regions. 4. Psychometric and psychophysiological investigations demonstrated significant dose-dependent psychotropic properties of the drug. Multivariate statistics exhibited an improvement of both the noopsyche (e.g. attention, concentration, attention variability, memory, fine motor activity, reaction time performance) and thymopsyche (e.g. drive, wakefulness)) but also significant psychophysiological activation (e.g. in c.f.f., pupillary and skin conductance measures). 5. Time-efficiency calculations showed significant central effects from the 2nd hour onwards, with increasing differences between placebo and treatment up to the 8th hour. Nausea was the most frequent complaint and appeared dose dependent.