Search results for "Hallucination"

The Pharmacology of Visual Hallucinations in Synucleinopathies

2019

Visual hallucinations (VH) are commonly found in the course of synucleinopathies like Parkinson's disease and dementia with Lewy bodies. The incidence of VH in these conditions is so high that the absence of VH in the course of the disease should raise questions about the diagnosis. VH may take the form of early and simple phenomena or appear with late and complex presentations that include hallucinatory production and delusions. VH are an unmet treatment need. The review analyzes the past and recent hypotheses that are related to the underlying mechanisms of VH and then discusses their pharmacological modulation. Recent models for VH have been centered on the role played by the decoupling …

Nonlinear EEG dynamics during sleep in depression and schizophrenia.

1994

The article deals with the question, whether nonlinear analysis of the sleep EEG may give clues to understanding of disturbed information processing in psychiatric diseases. We point out how the nonlinear approach to EEG dynamics is motivated and review recent investigations concerning nonlinear dynamical properties of physiological systems. We present calculations of the correlation dimension D2 and the principal Lyapunov-exponent lambda 1 for sleep EEG data from 9 depressive and 11 schizophrenic inpatients compared to healthy controls. Combining the findings for D2 and lambda 1 our results point to altered nonlinear brain dynamics mainly during slow wave sleep in depression and during REM…

Increased amygdala and parahippocampal gyrus activation in schizophrenic patients with auditory hallucinations: An fMRI study using independent compo…

2010

Objective: Hallucinations in patients with schizophrenia have strong emotional connotations. Functional neuroimaging techniques have been widely used to study brain activity in patients with schizophrenia with hallucinations or emotional impairments. However, few of these Studies have investigated the association between hallucinations and emotional dysfunctions using an emotional auditory paradigm. Independent component analysis (ICA) is an analysis method that is especially useful for decomposing activation during complex cognitive tasks in which multiple operations occur simultaneously. Our aim in this Study is to analyze brain activation after the presentation of emotional auditory stim…

Emotional words induce enhanced brain activity in schizophrenic patients with auditory hallucinations.

2005

Neuroimaging studies of emotional response in schizophrenia have mainly used visual (faces) paradigms and shown globally reduced brain activity. None of these studies have used an auditory paradigm. Our principal aim is to evaluate the emotional response of patients with schizophrenia to neutral and emotional words. An auditory emotional paradigm based on the most frequent words heard by psychotic patients with auditory hallucinations was designed. This paradigm was applied to evaluate cerebral activation with functional magnetic resonance imaging (fMRI) in 11 patients with schizophrenia with persistent hallucinations and 10 healthy subjects. We found a clear enhanced activity of the fronta…

Schizophrenia with auditory hallucinations: A voxel-based morphometry study

2006

Many studies have shown widespread but subtle pathological changes in gray matter in patients with schizophrenia. Some of these studies have related specific alterations to the genesis of auditory hallucinations, particularly in the left superior temporal gyrus, but none has analysed the relationship between morphometric data and a specific scale for auditory hallucinations. The present study aims to define the presence and characteristics of structural abnormalities in relation with the intensity and phenomenology of auditory hallucinations by means of magnetic resonance voxel-based morphometry (MR-VBM) method applied on a highly homogeneous group of 18 persistent hallucinatory patients me…

Insight among psychotic patients with auditory hallucinations

2011

Poor insight in psychosis has been described as a seeming lack of awareness of the deficits, consequences of the disorder, and of the need for treatment. The aim of this study is to investigate whether patients with auditory hallucinations have less insight than those without hallucinations, and to determine which hallucination characteristics are related to patient insight. Using the PANSS and PSYRATS, the authors have evaluated the lack of insight data corresponding to 168 psychotic patients divided into three groups: patients with a history of nonpersistent hallucinations, patients with persistent hallucinations, and patients without hallucinations. Patients with persistent hallucination…

Spectroscopic metabolomic abnormalities in the thalamus related to auditory hallucinations in patients with schizophrenia

2008

Abstract Objective Previous studies have found neurochemical abnormalities in thalamic nuclei in patients with schizophrenia. These abnormalities have been associated with information processing deficiencies and symptom formation. There are no metabolic spectroscopy studies in patients with schizophrenia attending to auditory hallucinations. The aim of the present study is to explore metabolic Magnetic Resonance Spectroscopy (MRS) ratio differences in the thalamus between schizophrenic patients with and without auditory hallucinations and control subjects. Methods MRS studies (MRI 1.5 T unit) were performed in 49 patients with schizophrenia (30 with auditory hallucinations and 19 without au…

Increased visual cortical excitability in ecstasy users: a transcranial magnetic stimulation study

2003

To test the presence of abnormalities of visual cortical excitability in people using ecstasy as a recreational drug.Ecstasy users and control subjects underwent single pulse transcranial magnetic stimulation (TMS) of the occipital cortex. The phosphene threshold was analysed and compared in the two groups.Phosphene thresholds were significantly lower in ecstasy users compared with control subjects, and were correlated negatively with frequency of ecstasy use. Frequency of use was positively correlated with the presence of visual hallucinations. The phosphene threshold of subjects with hallucinations was significantly lower than that of subjects without hallucinations.The use of ecstasy as …

REM-associated hallucinations and sleep paralysis are dependent on body posture

2001

Anatomical correlate of positive spontaneous visual phenomena: a voxelwise lesion study.

2010

Objectives: Visual phenomena such as phosphenes, photopsias, or complex visual hallucinations occur in patients with lesions affecting the occipital, parietal, or temporal lobe. Whether these phenomena are provoked by lesions in specific anatomical regions is still uncertain. To determine which brain regions might be involved in such visual phenomena, we used new brain imaging and lesion analysis tools that allow a direct comparison with control patients. Methods: Visual phenomena were investigated in a total of 23 patients with acute infarctions along the visual pathways (6 patients with left-sided and 17 patients with right-sided lesions). Results: Ten of these 23 patients (43%) reported …