Hans-Peter Volz

Decreased frontal activation in schizophrenics during stimulation with the continuous performance test--a functional magnetic resonance imaging study.

Summary ‐ The Continuous Performance Test (CPT) has become an essential constituent of the neuropsychological investigation of schizophrenia. Also, a vast number of brain imaging studies, mostly PET investigations, have employed the CPT as a cognitive challenge and established a relative hypofrontality in schizophrenics compared to controls. The aim of the present investigation was to clarify whether this predescribed hypofrontality could also be verified using functional magnetic resonance imaging (fMRI). 20 healthy volunteers and 14 schizophrenics on stable neuroleptic medication were included. Imaging was performed using the CPT-double-T-version and a clinical 1.5 T MRI-scanner with a single slice technique and a T2*-weighted gradient-echo-sequence. The schizophrenics exhibited a decreased activation in the right mesial prefrontal cortex, the right cingulate and the left thalamus compared to controls. These results obtained by fMRI are discussed in relation to published findings using PET.

Brain activation during cognitive stimulation with the Wisconsin Card Sorting Test--a functional MRI study on healthy volunteers and schizophrenics.

It has been demonstrated by single photon emission computed tomography (SPECT) and positron emission tomography (PET) that frontal brain regions are stimulated during performance of the Wisconsin Card Sorting Test (WCST). The WCST is also regarded as one of the standard tests for the assessment of frontal activity in brain imaging studies of schizophrenia. In this study cerebral activation was assessed by means of functional magnetic resonance imaging (fMRI). In healthy volunteers WCST stimulation resulted in a right lateralized frontal activation. In 13 chronic schizophrenics on stable neuroleptic medication, a lack of activation in the right prefrontal cortex and--as a trend--an increased left temporal activity during execution of the WCST was noted compared to controls. Since a one-slice technique was used, no information about the activation pattern in adjacent brain regions was obtained. However, as fMRI possesses a superior spatial resolution compared to SPECT and PET, the anatomical localization of the activation effect in the measured slice can be defined more precisely. Beside these methodological considerations, the results are discussed in relation to prior findings of a reduced ability of schizophrenics to coordinate cerebral function.

Time estimation in schizophrenia : an fMRI study at adjusted levels of difficulty

fMRI was performed in nine male schizophrenia patients and 15 healthy male controls during an auditory time estimation (timing), a frequency (i.e. pitch) discrimination task, and rest. An adaptive psychophysical approach, the weighted up–down method, was used to adjust individual performance to a level of 75% probability for correct answers. Although performing on the same level of individual difficulty, schizophrenia patients revealed less activations in prefrontal cortex and caudate nucleus, comparing time vs rest. Timing specific differences (i.e. timing vs pitch) between patients and controls were found in the posterior putamen, anterior thalamus, and right medial prefrontal cortex, with patients showing relative hypoactivity. Impairment in time estimation in schizophrenia might be mediated by specific fronto-thalamo-striatal dysfunction.

31P magnetic resonance spectroscopy in the frontal lobe of major depressed patients

Abstract Most research with 31P-magnetic resonance spectroscopy (31P-MRS) in affective disorders has been done in the field of bipolar disturbances. Reduced frontal and temporal lobe phosphomonoester (PME) concentrations were measured in the euthymic state, whereas increased values were found in the depressed state. In bipolar-II patients reduced phosphocreatine (PCr) concentrations were reported in the euthymic, depressed, and manic state. The aim of the present study was to explore whether PME and PCr were also altered in the frontal lobe of major depressed, unipolar patients. Therefore, we used 31P-MRS to investigate the relative phospholipid and high-energy phosphate concentrations in the frontal lobe of 14 unipolar patients, mostly medicated, and 8 age-matched controls. We found increased PME and decreased ATP values. Other 31P-MRS parameters were not different in both groups. Phosphomonoester percentages correlated negatively with the degree of depression. Thus, the main alterations found in bipolar depressed patients could also be demonstrated in unipolar depressed patients. The results are discussed with regard to disturbed phospholipid and intracellular high-energy phosphate metabolism in depressed patients.

Challenging the anterior attentional system with a continuous performance task: a functional magnetic resonance imaging approach

Abstract Combining the Continuous Performance Test (CPT) with a modern functional imaging technique provides a powerful tool for investigating neurophysiological processes in the human brain. There is increasing evidence from single photon emission tomography (SPECT), positron emission tomography (PET) and presently also functional magnetic resonance imaging (fMRI) studies proposing the existence of a distributed large-scale attentional network, mediated by the dorsolateral prefrontal and mesial frontal cortex, thalamus, basal ganglia and posterior parietal and superior temporal lobe. The aim of this study is to show that fMRI is a useful tool for in vivo localization of attentional tasks and to compare the results with established imaging techniques. Functional MRI was performed on a clinical 1.5-T system using gradient-echo acquisition. For data processing, the Statistical Parametric Mapping (SPM96) package was used. A right lateralized activation pattern in the dorsolateral prefrontal and mesial frontal cortex, the thalamus and the basal ganglia was found in a group of 12 male subjects. These findings support theories suggesting right hemispheric dominance of human attention.

The effect of venlafaxine compared with other antidepressants and placebo in the treatment of major depression

ObjectiveMeta-analysis of all available trials of Venlafaxine in the treatment of major depressive disorders, including treatment resistant depression and long-term relapse prevention.MethodsWe conducted a meta-analysis comparing venlafaxine and tricyclics, or selective serotonin reuptake inhibitors (SSRIs), in major depression. We also included trials comparing venlafaxine and alternative antidepressants in subjects with treatment resistant depression, or compared with placebo in long-term relapse prevention. Trials were identified through searches of Medline, Embase, Cochrane Library and through accessing unpublished trials held by the manufacturer. Results based on intention to treat analyses where available, were pooled using theoretically exact conditional maximum likelihood methods for fixed effects (primary analyses), and numerical simulation using a Gibbs sampler for full random effects.ResultsCompared to all SSRIs for the treatment of major depression (fluoxetine, paroxetine, sertraline, citalopram, escitalopram and fluvoxamine), venlafaxine was associated with a greater response [odds ratio 1.15 (95% CI 1.02–1.29)] and remission [odds ratio 1.19 (95% CI 1.06–1.34)]. Overall drop out rates appeared similar for SSRIs and venlafaxine. Compared to tricyclics, response to venlafaxine was estimated to be greater by exact method, odds ratio 1.21 (95% CI 1.03–1.43), but not statistically significantly different, using a full random effects method odds ratio 1.22 (95% CI 0.96–1.54). We observed no difference in remission rates (odds ratio 1.06 (95% CI 0.74–1.63)). Tricyclics were less well tolerated with higher overall drop out rates. Compared to alternative antidepressants in treatment resistant depression (trials included comparison with sertraline, bupropion, fluoxetine, citalopram, and one with a range of agents—mostly SSRIs), the odds ratio for response was 1.35 (95% CI 1.19–1.54). The odds ratio for remission was 1.35 (95% CI 1.20–1.52). Compared to placebo the odds ratio for relapse prevention with venlafaxine was 0.37 (95% CI 0.27–0.51).ConclusionThis meta analysis provides evidence of the clinical efficacy of venlafaxine in achieving therapeutic response and remission in patients with major depression. Venlafaxine appears more effective than SSRIs, and at least as effective as tricyclic antidepressants, in the treatment of major depressive episode. Venlafaxine appeared more effective than comparators in treatment resistant depression. In addition, venlafaxine effective in reducing relapse when given long term after major depressive episode.

Hypofrontality in neuroleptic-naive schizophrenic patients during the Wisconsin Card Sorting Test – a fMRI study

Abstract Functional neuroimaging findings of “hypofrontality” in schizophrenic patients – as tested with the Wisconsin Card Sorting Test (WCST) – are still controversial, mainly due to methodological aspects and the heterogeneity of the patient samples. To measure WCST specific and reproducible reduced cerebral activations in schizophrenic patients, we revised the study design and patient recruitment, respectively. For this purpose, we used an adequate active control task instead of an undefined rest condition to determine exclusively WCST specific cerebral activations. In addition, we focused on the investigation of modified activations between a selected group of neuroleptic-naive schizophrenic patients and carefully matched healthy controls by means of functional magnetic resonance imaging.The results indicate that neuroleptic-naive schizophrenic patients show reduced activations in the right frontal and left temporal lobe, as well as in the left cerebellum. By utilizing an active control task all unwanted activations are suppressed. Furthermore the influence of different task performances is reduced. The findings are in line with previous PET and SPECT studies and confirm the “hypofrontality” hypothesis. The findings suggest that “hypofrontality” is not caused by neuroleptic medication.

Silexan, an orally administered Lavandula oil preparation, is effective in the treatment of 'subsyndromal' anxiety disorder: a randomized, double-blind, placebo controlled trial.

This study was performed to investigate the anxiolytic efficacy of silexan, a new oral lavender oil capsule preparation, in comparison to placebo in primary care. In 27 general and psychiatric practices 221 adults suffering from anxiety disorder not otherwise specified (Diagnostic and Statistical Manual of Mental disorders–IV 300.00 or International Statistical Classification of Diseases and Related Health Problems, Tenth revision F41.9) were randomized to 80 mg/day of a defined, orally administered preparation from Lavandula species or placebo for 10 weeks with visits every 2 weeks. A Hamilton Anxiety Scale (HAMA) total score ≥18 and a total score >5 for the Pittsburgh Sleep Quality Index (PSQI) were required. The primary outcome measures were HAMA and PSQI total score decrease between baseline and week 10. Secondary efficacy measures included the Clinical Global Impressions scale, the Zung Self-rating Anxiety Scale, and the SF–36 Health Survey Questionnaire. Patients treated with silexan showed a total score decrease by 16.0±8.3 points (mean±SD, 59.3%) for the HAMA and by 5.5±4.4 points (44.7%) for the PSQI compared to 9.5±9.1 (35.4%) and 3.8±4.1 points (30.9%) in the placebo group (P<0.01 one-sided, intention to treat). Silexan was superior to placebo regarding the percentage of responders (76.9 vs. 49.1%, P<0.001) and remitters (60.6 vs. 42.6%, P=0.009). Lavandula oil preparation had a significant beneficial influence on quality and duration of sleep and improved general mental and physical health without causing any unwanted sedative or other drug specific effects. Lavandula oil preparation silexan is both efficacious and safe for the relief of anxiety disorder not otherwise specified. It has a clinically meaningful anxiolytic effect and alleviates anxiety related disturbed sleep.

Opipramol for the treatment of generalized anxiety disorder: a placebo-controlled trial including an alprazolam-treated group.

Opipramol, a drug widely prescribed in Germany, is a tricyclic compound with no reuptake-inhibiting properties. However, it has pronounced D2-, 5-HT2-, and H1-blocking potential and high affinity to sigma receptors (sigma-1 and sigma-2). In early controlled trials, anxiolytic effects were revealed. However, those studies were performed before the concept of generalized anxiety disorder (GAD) was established. Because of the interesting receptor-binding profile and promising results of the early clinical trials, the authors performed a state-of-the-art placebo-controlled trial using alprazolam as an active control. Three hundred seven outpatients with GAD were included. After a 7-day single-blind placebo washout, patients were randomly assigned to receive either opipramol (final dose, 200 mg/day), alprazolam (2 mg/day), or placebo and were treated for 28 days. The efficacy of both active compounds was higher than the effects with placebo treatment. There were statistically significant differences (p < 0.05, according to the analysis of co-variance) in the main outcome criterion (baseline-adjusted final means of an intent-to-treat analysis of the total scores on the Hamilton Rating Scale for Anxiety) and in secondary efficacy parameters, with global improvement of 47% for placebo and significantly more for opipramol (63%) and alprazolam (64%). Regarding safety and tolerability, no substantial differences in the number of adverse events observed between treatment groups were obvious. Sedation seemed more pronounced with alprazolam treatment than with opipramol or placebo. In this trial, it was demonstrated for the first time that opipramol, a strong but nonselective sigma site ligand, possesses anxiolytic efficacy superior to placebo in the treatment of GAD.

Reduced phosphodiesters and high-energy phosphates in the frontal lobe of schizophrenic patients: a 31P chemical shift spectroscopic-imaging study

BACKGROUND (31)Phosphorous magnetic resonance spectroscopy has been widely used to evaluate schizophrenic patients in comparison to control subjects, because it allows the investigation of both phospholipid and energy metabolism in vivo; however, the results achieved so far are inconsistent. Chemical shift imaging (CSI) has the advantage that instead of only one or a few preselected voxels the tissue of a whole brain slice can be examined. The aim of the present investigation was to determine whether the results of previous studies of our group, showing that phosphodiesters (PDE) are decreased in the frontal lobe of schizophrenic patients as compared to control subjects, might be confirmed in an independent unmedicated patient sample using the CSI technique. METHODS A carefully selected new cohort including 11 neuroleptic-free schizophrenic patients and 11 age- and gender-matched healthy control subjects was recruited. CSI was applied and an innovative analysis method for CSI data based on a general linear model was used. RESULTS PDE, phosphocreatine, and adenosine triphosphate (ATP) were found to be significantly decreased in the frontal lobe of patients with schizophrenia. CONCLUSIONS Because PDE was decreased in schizophrenic patients, the membrane phospholipid hypothesis of schizophrenia could not be corroborated. Further results indicate decreased ATP production in the frontal lobe of patients with schizophrenia.