Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Hallucinations”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed2007

Competition for neuronal resources: how hallucinations make themselves heard.

BACKGROUND: Hallucinations are perceptions in the absence of a corresponding external sensory stimulus. However, during auditory verbal hallucinations, activation of the primary auditory cortex has been described. AIMS: The objective of this study was to investigate whether this activation of the auditory cortex contributes essentially to the character of hallucinations and attributes them to alien sources, or whether the auditory activation is a sign of increased general auditory attention to external sounds. METHOD: The responsiveness of the auditory cortex was investigated by auditory evoked potentials (N100) during the simultaneous occurrence of hallucinations and external stimuli. Evoked potentials were computed separately for periods with and without hallucinations; N100 power, topography and brain electrical sources were analysed. RESULTS: Hallucinations lowered the N100 amplitudes and changed the topography, presumably due to a reduced left temporal responsivity. CONCLUSIONS: This finding indicates competition between auditory stimuli and hallucinations for physiological resources in the primary auditory cortex. The abnormal activation of the primary auditory cortex may thus be a constituent of auditory hallucinations.

Adult↗
PubMed2005

Is it necessary to differentiate tinnitus from auditory hallucination in schizophrenic patients?

Although the definitions of subjective tinnitus and auditory hallucination are very similar, the origins and underlying causes of each symptom clearly differ. This study examined whether the differentiation of tinnitus from auditory hallucination is necessary for the proper management of these symptoms in schizophrenic patients. We investigated the characteristics of auditory hallucinations in 15 schizophrenic patients, and measured their pure-tone hearing levels and auditory brainstem responses (ABR). The average hearing level was 20.6 +/- 16.2 dB, with a mild decrease at high frequencies. We classified the patients into three groups: pure hallucination, tinnitus, and hallucination plus tinnitus. Eight patients (53.3 per cent) complained of pure hallucination and only one of them had a mild hearing loss. Hearing deficits were observed in six of seven tinnitus patients. Abnormal findings of ABR were found only in the pure hallucination group. The results suggest that tinnitus should be differentiated from auditory hallucination in the evaluation of schizophrenic patients.

Adult↗
PubMed2004

Complex visual hallucinations (Charles Bonnet syndrome) in visual field defects following cerebral surgery. Report of four cases.

The development of visual hallucinations after loss of vision is known as the Charles Bonnet syndrome. This phenomenon was first described in 1760 by Charles Bonnet and others during their observations of elderly patients with degeneration of the retina or cornea. To date a clear association between visual hallucinations and neurosurgical procedures has not been reported. Because of their clear demarcation, however, surgical lesions in the cerebrum offer a unique opportunity to determine the pathoanatomical aspects of visual hallucinations. During a 3-year period, 41 consecutive patients who acquired visual field defects after neurosurgery were examined for the occurrence of visual hallucination. Postoperatively, four of these patients experienced visual hallucinations. In two of them an upper quadrantanopia developed after the patients had undergone selective amygdalohippocampectomy. In the other two patients a complete hemianopia developed, in one case after resection of a parietal astrocytoma and in the other after resection of an occipital glioblastoma multiforme. The visual hallucinations were transient and gradually disappeared between 4 days and 6 months postoperatively. The patients were aware of the fact that their hallucinations were fictitious and displayed no psychosis. Electroencephalographic recordings were obtained in only two patients and epileptic discharges were found. Deafferentiation of cortical association areas may lead to the spontaneous generation of complex visual phenomena. In the present series this phenomenon occurred in approximately 10% of patients with postoperative visual field defects. In all four cases the central optic radiation was damaged between the lateral geniculate nucleus and the primary visual cortex. The complex nature of the visual hallucination indicates that they were generated in visual association areas.

Adult↗
PubMed2002

[Complex visual hallucinations in partially sighted elderly: Charles Bonnet syndrome].

In two patients, women aged 85 and 80 years, who suffered from visual hallucinations involving living creatures, cars and buildings, Charles Bonnet syndrome was diagnosed. Both were worried that these signs were an indication of a severe psychiatric condition. In diagnosing the Charles Bonnet syndrome the following criteria can be used: presence of complex visual hallucinations, retention of insight, absence of hallucinations in other sensory modalities and absence of delusions. Hallucinations in dementia, delirium, migraine, epilepsy, or in extreme states of exhaustion or sensory deprivation, as well as hallucinations due to psychedelic drugs, hallucinations of widowhood and hypnagogic and hypnopompic hallucinations must be excluded. Patient education and reassurance are the cornerstones of treatment. Other possible treatments are: improving visual acuity and the general physical condition, stopping medication with hallucinogenic side effects, activating the patient, coaching the patient in avoiding hallucination-triggering situations and using stopping strategies, and (still experimental) pharmacological treatment with carbamazepine, valproate, ondansetron or cisapride.

Aged↗
PubMed2005

[The neurobiology of hallucinations].

OBJECTIVE: Although hallucinations are among the cardinal features of schizophrenia, the mechanisms underlying these symptoms have not been fully understood yet. In this review our objective is to summarize the studies about the neurobiology of auditory hallucinations in schizophrenia and discuss their significance for understanding schizophrenia. METHOD: This is a retrospective literature review and the relevant studies within the last 10 years are included. For this purpose Pubmed search engine and 'hallucination, schizophrenia, neurobiology' key words are used. RESULTS: Hallucinations cause sensory modality specific activation in cerebral areas involved in normal sensation. A disturbance in perception of speech seems to have a central role in occurrence of auditory hallucinations. Anatomically, auditory hallucinations appear to involve primary and association cortices, Broca's and Wernicke's areas, subcortical, paralimbic, limbic regions, ventral striatum and thalamus. Furthermore they are suggested to be associated with the dysmodulation of the information flow from ventral striatum to thalamus and cortex caused by increased dopaminergic activity in mesolimbic pathway. CONCLUSION: The validity of the models which are proposed to explain neurobiology of hallucinations in schizophrenia should be tested by new studies. The difficulties regarding the assessment and measurement of subjective mental phenomena are important impacts in studying and understanding the neural correlates of hallucinations. Functional neuroimaging, cognitive and molecular biological studies will hopefully enhance our knowledge about this disease.

Brain↗
PubMed1994

Effects of substance abuse on hallucination rates and treatment responses in chronic psychiatric patients.

BACKGROUND: Few data systematically document the effects of illicit drug exposure on psychotic illness. We examined the effect of substance abuse on rates and treatment responses of hallucinations in a chronic psychiatric population. METHOD: 113 cooperative patients consecutively admitted to a state psychiatric hospital were administered the Structured Clinical Diagnostic Interview for DSM-III-R, a Hallucination Interview, and an inventory of past and current substances of abuse. Demographic information was obtained on 104 of 108 patients who declined interview. Medication dosage was analyzed for one third of the interviewed sample; hospital records, nursing reports, contacts with relatives, and urine drug screens were used to confirm information from patient interviews. Hallucination rates and response were compared by diagnostic groups (chi-square). RESULTS: Noninterviewed patients had more frequent hospitalizations, more patients diagnosed with psychosis not otherwise specified or schizoaffective disorder, and fewer females with comorbid substance abuse than the study population. Among interviewed subjects, those with substance abuse and psychiatric illness had first admissions at an earlier age than patients with no substance abuse (p = .005). Schizophrenics experienced higher rates of visual (p = .04) and olfactory (p = .05) hallucinations when using illicit drugs. Substance abuse was associated with decreased treatment responsiveness of auditory (p < .03) and tactile (p < .004) hallucinations in schizophrenic or manic patients. Compared with nonparanoid patients, there was a trend for paranoid schizophrenics with substance abuse to experience more frequent visual (p = .09) and tactile (p = .06) and more refractory auditory (p = .08) hallucinations. No differences in medication dosages were found between patients with treatment-responsive and treatment-refractory hallucinations. CONCLUSIONS: Abused substances may interact selectively with primary psychiatric illness to increase rates and treatment resistance of specific hallucination modalities; etiologies are discussed.

Adult↗
PubMedDate not supplied

Locating voices in space: a perceptual model for auditory hallucinations?

INTRODUCTION: Auditory hallucinations are often perceived as being located in external auditory space ("outside the head"), like real auditory perceptions, but in the absence of a speaker or other external stimulus. METHOD: A selective literature review of the spatial phenomenology of auditory hallucinations and the cognitive neuroscience of locating real voices in external space was undertaken. An auditory-perceptual model of external auditory hallucinations was developed in healthy right-handed subjects using functional magnetic resonance imaging and the presentation of speech in virtual acoustic space. RESULTS: Karl Jaspers inextricably linked "reality" and "externality" of auditory hallucinations. Although these two properties do not always occur simultaneously in hallucinating patients, the issue of "externality" is important from both a clinical and neuroscientific perspective. In an auditory-perceptual model of auditory hallucinations, association cortex in the left planum temporale is critically involved in the perception of real voices as located in external space. Right-sided voice stimuli are associated with greater neural response in the dominant (left) auditory cortex than left-sided stimuli. Subjects are better at identifying the spatial location of voices presented on the right than on the left. CONCLUSION: The auditory-perceptual model described helps identify candidate brain systems likely to be involved in the pathogenesis of auditory hallucinations in schizophrenia, and is distinct from other models, which use concepts of "internal monitoring" and "inner speech". Its application, in the cognitive neuroscientific investigation of the phenomenology of auditory hallucinations, may shed further light on the mechanisms underlying this distressing experience.

Journal Article↗
PubMed1994

Hallucinations and ifosfamide-induced neurotoxicity.

BACKGROUND: Hallucinations as a symptom of central neurotoxicity are a known but poorly described side effect of ifosfamide. Most cases of ifosfamide-induced hallucinations have been reported with other mental status changes. METHODS: The authors interviewed six persons with ifosfamide-induced hallucinations in the presence of a clear sensorium. All patients were receiving high-dose ifosfamide as part of their bone marrow transplant procedure. RESULTS: Hallucinations occurred only when the patient's eyes were closed and, in all but one case, were reported as disturbing or frightening. Underreporting of these hallucinations by patients is likely. CONCLUSIONS: Hallucinations may be the sole or first manifestation of neurotoxicity. The incidence may be dose and infusion-time related. The clinician should be alerted for possible ifosfamide-induced hallucinations, which may occur without other signs of neurotoxicity. "Eyes-closed" hallucinatory experiences appear to be an unusual feature of this presentation. Patients anxious about this experience respond well to support and education about this occurrence. Optimal pharmacologic management of disturbed patients is unclear. If agitation becomes marked, high-potency neuroleptics (i.e., haloperidol) may be effective.

Adult↗
PubMed2005

Relationship between hallucinations, delusions, and rapid eye movement sleep behavior disorder in Parkinson's disease.

Psychotic symptoms are the main and the most disabling "nonmotor" complications of Parkinson's disease (PD), the pathophysiology of which is poorly recognized. Polysomnographic studies have shown a relationship between visual hallucinations and rapid eye movement (REM) sleep. The objective of this study is to clarify the relationship between psychotic symptoms and REM sleep behavior disorder (RBD) in PD. In a Parkinson's disease outpatient unit, 289 consecutive subjects with idiopathic PD were administered (in the period from January to December 2002) a multiple-choice questionnaire and structured interview on sleep and mental disorders. RBD was diagnosed in accordance with the minimal diagnostic criteria of the International Classification of Sleep Disorders. Hallucinations and delusional disorders were diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders-IV criteria. The presence or absence of psychotic symptoms, of RBD, and of daytime sleepiness, as well as motor status, cognitive status, and mood were assessed. Approximately 32% (n = 92) of the subjects presented with psychotic disorders; 30% (n = 86) had experienced hallucinations; 2% (n = 6) had delusions without hallucinations. Sixty-two (72%) hallucinators reported nocturnal hallucinations. A total of 6.6% (n = 19) of the subjects complained of a delusional disorder. There were 26.6% (n = 77) of subjects who presented with RBD: 28 (36%) with onset before and 49 (63%) with onset after PD diagnosis. The presence of RBD was associated with an increased risk of manifesting hallucinations and delusions (odds ratio [OR], 2.73). Other independent clinical factors found to have an effect on psychotic disorders were cognitive impairment (OR, 3.92), disease duration (OR, 2.46), advanced age (OR, 2.34), and severity of motor symptoms (OR, 2.06). These results suggest that RBD is widely associated with psychosis in PD.

Aged↗
PubMed2006

REM sleep behavior disorder, hallucinations, and cognitive impairment in Parkinson's disease.

The objective of this study was to evaluate the relationship between REM sleep behavior disorder (RBD), hallucinations, and cognitive impairment in Parkinson's disease (PD). One hundred and ten PD patients, divided into three groups (without RBD or hallucinations; with RBD but no hallucinations; with RBD and hallucinations), were submitted to neuropsychological evaluation. The group without RBD and hallucinations showed normal neuropsychological tests when compared to normal controls. The group with hallucinations was characterized by a more severe cognitive impairment affecting both short- and long-term memory, logical abilities, and frontal functions, while the RBD-only group presented frontal impairment. The hypothesis that RBD in PD can be considered a risk factor not only of the hallucinations but also of more severe and diffuse cognitive abnormalities needs to be strengthened through a longitudinal evaluation.

Aged↗
PubMed2005

Temporoparietal transcranial magnetic stimulation for auditory hallucinations: safety, efficacy and moderators in a fifty patient sample.

BACKGROUND: Auditory hallucinations are often resistant to treatment and can produce significant distress and behavioral difficulties. A preliminary report based on 24 patients with schizophrenia or schizoaffective disorder indicated greater improvement in auditory hallucinations following 1-hertz left temporoparietal repetitive transcranial magnetic stimulation (rTMS) compared to sham stimulation. Data from the full 50-subject sample incorporating 26 new patients are now presented to more comprehensively assess safety/tolerability, efficacy and moderators of this intervention. METHODS: Right-handed patients experiencing auditory hallucinations at least 5 times per day were randomly allocated to receive either rTMS or sham stimulation. A total of 132 minutes of rTMS was administered over 9 days at 90% motor threshold using a double-masked, sham-controlled, parallel design. RESULTS: Hallucination Change Score was more improved for rTMS relative to sham stimulation (p = .008) as was the Clinical Global Impressions Scale (p = .0004). Hallucination frequency was significantly decreased during rTMS relative to sham stimulation (p = .0014) and was a moderator of rTMS effects (p = .008). There was no evidence of neurocognitive impairment associated with rTMS. CONCLUSIONS: Left temporoparietal 1-hertz rTMS warrants further study as an intervention for auditory hallucinations. Data suggest that this intervention selectively alters neurobiological factors determining frequency of these hallucinations.

Adult↗
PubMed2005

Repetitive transcranial magnetic stimulation in schizophrenic patients reporting auditory hallucinations.

Auditory hallucinations are experienced by 60-80% of person with schizophrenia and can often cause significant distress behavioural dyscontrol. The application of rTMS in the left temporoparietal cortex could modulate the neuronal activation and reduce the occurrence of auditory disperceptions. Sixteen schizophrenic patients (treated with atypical antipsycothic drugs) reporting auditory hallucinations were included in the study. Low frequency rTMS (1 Hz) was performed at the 90% of resting motor threshold (MT), during 4 sessions in four consecutive days for 15 minutes each application. Eight patients received active stimulation, while eight patients received sham stimulation. Scale for the assessment of positive symptoms (SAPS), scale for the assessment of negative symptoms (SANS) and a scale to asses the severity of the auditory hallucinations (SAH) were administered at the beginning and at regular intervals during the follow-up. The present study confirms the reduction in auditory hallucinations by means of rTMS. The main finding was the long-term reduction in auditory hallucinations in the active group, with a return to the baseline in the sham group. The negative symptomatology improved only in the later sessions and lasted during the follow-up. The improvements in auditory hallucinations and positive symptomatology increased and lasted during the follow-up till the end-point. These data suggest that this approach may lead to an alternative somatic intervention for auditory hallucination in patients with schizophrenia.

Adult↗
PubMed2004

Misattribution of external speech in patients with hallucinations and delusions.

BACKGROUND: One of the main cognitive models of positive symptoms in schizophrenia proposes that they arise through impaired self-monitoring. This is supported by evidence of behavioural deficits on tasks designed to engage self-monitoring, but these deficits could also result from an externalising response bias. We examined whether patients with hallucinations and delusions would demonstrate an externalising bias on a task that did not involve cognitive self-monitoring. METHOD: Participants passively listened (without speaking) to recordings of single adjectives spoken in their own and another person's voice, and made self/nonself judgements about their source. The acoustic quality of recorded speech was experimentally manipulated by altering the pitch. Fifteen patients with schizophrenia who were currently experiencing hallucinations and delusions, 13 patients with schizophrenia not experiencing current hallucinations and delusions and 15 healthy controls were compared. RESULTS: When listening to distorted words, patients with hallucinations and delusions were more likely than both the group with no hallucinations and delusions and the control group to misidentify their own speech as alien (i.e. spoken by someone else). Across the combined patient groups, the tendency to misidentify self-generated speech as alien was positively correlated with current severity of hallucinations but not with ratings of delusions or positive symptoms in general. CONCLUSIONS: These findings indicate that patients with hallucinations and delusions are prone to misidentifying their own verbal material as alien in a task which does not involve cognitive self-monitoring. This suggests that these symptoms are related to an externalising bias in the processing of sensory material, and not solely a function of defective self-monitoring.

Acoustic Stimulation↗
PubMed2006

Left superior temporal gyrus activation during sentence perception negatively correlates with auditory hallucination severity in schizophrenia patients.

The left superior temporal cortex, which supports linguistic functions, has consistently been reported to activate during auditory-verbal hallucinations in schizophrenia patients. It has been suggested that auditory hallucinations and the processing of normal external speech compete for common neurophysiological resources. We tested the hypothesis of a negative relationship between the clinical severity of hallucinations and local brain activity in posterior linguistic regions while patients were listening to external speech. Fifteen right-handed patients with schizophrenia and daily auditory hallucinations for at least 3 months were studied with event-related fMRI while listening to sentences in French or to silence. Severity of hallucinations, assessed using the auditory hallucination subscales of the Psychotic Symptom Rating Scales (PSYRATS) and of the Scale for the Assessment of Positive Symptoms (SAPS-AH), negatively correlated with activation in the left temporal superior region in the French minus silence condition. This finding supports the hypothesis that auditory hallucinations compete with normal external speech for processing sites within the temporal cortex in schizophrenia.

Adult↗
PubMed1999

Hallucinations in the acute schizophrenic-type psychosis: effects of gender and age of illness onset.

Our objective was to test the hypothesis that gender, the age of illness onset, or the interaction between these two variables, would distinguish acutely ill schizophrenic and schizoaffective patients who hallucinated from those who did not. Hallucinatory experiences were measured by the hallucination item of the Brief Psychiatric Rating Scale in a sample of 160 drug-free inpatients admitted for the treatment of an acute episode. Patients were categorized as either non-hallucinators or hallucinators. An additional analysis included only those who had 'severe' hallucinations (i.e., score > or = 5). Female gender, but not age of onset, predicted a higher frequency of hallucinations (irrespective of degree of severity) in the total sample, but specifically in the schizophrenic patients. These results indicate that there may be gender differences in the propensity to experience hallucinations during the acute schizophrenic episode.

Acute Disease↗
PubMed2004

P300 alterations in schizophrenic patients experiencing auditory hallucinations.

RATIONALE: Attentional deficits have been implicated in the pathophysiology of auditory hallucinations in schizophrenia. Since the latency of the P300 component of event-related potentials (ERPs) is considered to be a sensitive measure of stimulus classification speed, while its amplitude-a measure of attentional resource allocation when memory updating is engaged, the present study focuses on the comparison of P300 between healthy subjects and schizophrenic patients experiencing auditory hallucinations and treated with clozapine and olanzapine. METHODS: The auditory P300 was assessed during the anticipatory period of a short memory test, in 16 male hallucinated schizophrenic patients and 13 male normal subjects matched for age and educational level. The patients were reexamined under identical conditions when their hallucinations had resolved following treatment with clozapine (8 patients) and olanzapine (8 patients). RESULTS: The patients with hallucinations exhibited significantly reduced P300 amplitude at leads Fp1, F3, (C3-T5)/2, F4, Cz and Fz, when compared to the normal controls and at leads Fp1, F3, F4, (C4-T6)/2, C4, P4, Cz and Fz when compared to themselves during the remission phase. However logistic regression models revealed that the most important leads, differentiating the patient group before treatment either with the healthy controls, or with itself after treatment, were that at the left temporoparietal and at the left prefrontal area. Memory performance of the patient group, even after treatment and in spite of its significant improvement, remained significantly less than that of healthy controls. both antipsychotic agents had similar effects on the p300 amplitude and memory performance. CONCLUSIONS: These findings indicate that auditory hallucinations in schizophrenia manifest abnormal aspects of attention, mediated by a distributed network involving or affecting the left temporoparietal and left prefrontal area. Additionally, the present study points to an improvement of attentional function in schizophrenic patients experiencing auditory hallucinations, both in the clozapine group but also in the olanzapine group.

Adult↗
PubMed2002

Differences in regional cerebral blood flow during musical and verbal hallucinations.

A 51-year-old male patient suffered from both musical and verbal hallucinations with insight. We performed three single photon emission computed tomographic scans with the patient in different conditions: baseline without hallucinations, musical hallucinations, and verbal hallucinations. Clearly, different patterns of regional cerebral blood flow (rCBF) were observed during musical and verbal hallucinations. The findings suggest that musical and verbal hallucinations are associated with different patterns of rCBF, possibly reflecting the different causes of the two types of hallucinations.

Basal Ganglia↗
PubMed2000

Is auditory imagery defective in patients with auditory hallucinations?

BACKGROUND: A variant of the 'inner speech' theory of auditory verbal hallucinations in schizophrenia suggests that there is an abnormality of the relationship between the 'inner voice' and 'inner ear', such that hallucinators are unable to distinguish inner 'imagined' speech from real external speech, and so misrecognize inner speech as alien. METHODS: Five experiments were carried out comparing 12 schizophrenic patients who were highly prone to hallucinate, with seven patients who were not, on a series of auditory imagery tasks that are differentially dependent on inner voice/inner ear partnership for successful performance: parsing meaningful letter/number strings; the verbal transformation effect; phoneme judgements; pitch judgements, and homophony and rhyme judgements. RESULTS: Contrary to our hypothesis, there was no evidence that the group with the propensity to hallucinate were impaired on tasks requiring normal inner ear/inner voice partnership. CONCLUSIONS: Together with previous work indicating no impairment of the phonological loop in patients who hallucinate, these results suggest that inner speech and auditory verbal hallucinations are not connected in a simplistic or direct way. Indeed, a reappraisal of psychological models of hallucinations in general may be warranted.

Adolescent↗