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At least 469 records · Page 26Linked to original sources
PubMed2000

Hyperperfusion in the lateral temporal cortex, the striatum and the thalamus during complex visual hallucinations: single photon emission computed tomography findings in patients with Charles Bonnet syndrome.

We report the findings of single photon emission computed tomography using 123I-IMP and magnetic resonance image studies of five patients with Charles Bonnet syndrome (CBS) while they were having visual hallucinations. All patients developed complex visual hallucinations after suffering from eye disease. The mean age at onset of CBS was 71.6 years. Single photon emission computed tomography studies in all patients disclosed hyperperfusion areas with some asymmetrical appearances in the lateral temporal cortex, striatum and thalamus. These results suggest that when elderly people suffer from eye disease, subsequent excessive cortical compensation in the lateral temporal cortex, striatum and thalamus may precipitate the development of visual hallucinations.

Aged↗
PubMed2003

Persisting visual hallucinations and illusions in previously drug-addicted patients.

BACKGROUND: Tetrahydrocannabinol (cannabis) and lysergic acid diethylamide (LSD) are psychomimetic agents that induce impairment of sensory perception. Illusions and hallucinations are mostly visual. Most frequently the visual phenomena occur in conjunction with drug abuse. PATIENTS AND METHODS: Three previously drug-addicted patients were examined for either persisting or spontaneously recurrent visual phenomena. Two patients complained of persisting visual illusions (vibrations, dyskinetopsia and impaired depth perception) during more than 12 months after an excessive use of cannabis. The third patient was a multiple drug abuser (LSD for 6 years) and complained of visual hallucinations and palinopsia following heavy ethanol intake, 20 years after stopping the use of any drug. RESULTS: Results from neuro-ophthalmic and neurological examinations were normal for the first two patients. The third patient presented abnormal visual fields with preserved visual acuity; electroencephalography was abnormal, suggesting an underlying toxic encephalopathy. CONCLUSIONS: Persistent visual illusions or hallucinations can occur during several months after an intake of cannabis. Flash-back phenomena are frequent amongst LSD abusers. They rarely occur at long times after the last intake (20 years in the present case); when they do so, precipitating factors are often present (ethanol, medication, anesthesia). Such phenomena reflect the cortical dysfunctions that can be induced by illegal substances.

Adolescent↗
PubMed2006

Using a speech perception neural network computer simulation to contrast neuroanatomic versus neuromodulatory models of auditory hallucinations.

A number of studies suggest that schizophrenia may arise from overzealous pruning of synapses that are an extension of normal developmental pruning during adolescence. Moreover, there has been a long history of studies suggesting that this disorder arises from alterations in the dopaminergic neuromodulatory systems. In order to further assess and compare these two hypotheses, a computer simulation of some aspects of speech perception was developed utilizing a recurrent, backpropagation model of working memory previously reported by Elman . This system was found to produce spontaneous percepts simulating hallucinated speech when the working memory component either was excessively pruned or when neuronal responses were modulated to simulatea hyperdopaminergic system. These hallucinogenic systems also demonstrated disruptions in processing input information when "phonetic information" was degraded. The perceptual performance of these systems were compared to that of actual hallucinating patients and normal controls while tracking (repeating while simultaneously listening to) speech that was phonetically degraded. We found that the neural network simulation producing the best match to speech tracking performance of human hallucinators was an overpruned system with compensatory hypodopaminergic adjustments. These data suggest that the primary pathophysiology of schizophrenia arises from curtailed connectivity in working memory systems and that dopaminergic alterations reflect secondary compensatory adjustments.

Adolescent↗
PubMed1992

[Musical pseudo-hallucination in acquired hearing loss].

Auditory hallucinations take various forms including the perception of tinnitus, voices, and, rarely, music. While formed hallucinations are usually ascribed to psychiatric illness, we describe a syndrome of musical hallucinations in mentally sane patients, who are hard of hearing or deaf. 26 cases from the literature are supplemented by 6 own observations, including the first description of two cases in a single family. The different modes of emergence, the spectrum of clinical features and their course are outlined. Differential diagnostic, pathogenetic and therapeutic aspects are discussed.

Aged↗
PubMed1981

Tests of hallucinations of "Ruth'.

Some tests are reported on a young woman who was believed to have unusual powers of eidetic imagery and voluntary control of vivid hallucinations. No evidence was found of abnormal eidetic ability. Measurements of detection thresholds for light of different wavelengths, while the subject tried to hallucinate various colours, suggested that the supposed hallucinations acted like coloured filters held over the eye.

Afterimage↗
PubMed1991

Delusions and hallucinations of cocaine abusers and paranoid schizophrenics: a comparative study.

We compared delusions and hallucinations of 100 cocaine abusers and 100 paranoid schizophrenic subjects admitted to an East Texas state psychiatric hospital. Subjects in both groups feared that individuals or organized groups might harm them in some way, but delusions of the paranoid schizophrenic subjects were more often bizarre than those of the cocaine abuse subjects. "Cocaine bugs" (parasitosis) were more often found in the cocaine abuse subjects. Command hallucinations were found in both groups, but the commands of the schizophrenic group more often related to harming or killing others. Cocaine abusers had a greater frequency of visual hallucinations (47 to 7), distinguished by shadows, flashing lights ("snow lights"), objects moving and bugs crawling on the arm. Finally, the most distinguishing characteristics were identity delusions, possession delusions, grandiose delusions (other than identities and possessions), and delusions that their families were imposters (Capgras Syndrome) reported by paranoid schizophrenics. No such delusions were reported by the cocaine abusers.

Adolescent↗
PubMed1994

Hallucinations following occipital lobe damage: the pathological activation of visual representations.

Neuropsychological investigation of hallucinations may provide insight into the nature of these subjective phenomena, as well as inform theories of perception and recall. We studied a man who described continuous visual hallucinations of object fragments (e.g., lines, corners, patterns) in the left visual field following a stroke in the right occipital cortex. The subject performed normally on standardized measures of visual perception and other cognitive abilities. He had no personality disturbance, and EEG during hallucinations was normal. Review of our records of 211 cases with focal lesions involving visual cortex revealed 5 patients with similar complaints. The hallucinatory experience of such patients probably reflects pathological activation of neural ensembles in the regions bordering an occipital lesion. These regions are presumed to contain records of visual feature fragments which are co-activated by feedback projections in the earliest visual association cortices, where they produce meaningful patterns during normal recall.

Aged↗
PubMed2006

Neuropsychiatry of complex visual hallucinations.

OBJECTIVE: To describe the phenomenology and pathophysiology of complex visual hallucinations (CVH) in various organic states, in particular Charles Bonnet syndrome and peduncular hallucinosis. METHOD: Three cases of CVH in the setting of pontine infarction, thalamic infarction and temporoparietal epileptiform activity are presented and the available psychiatric, neurological and biological literature on the structures of the central nervous system involved in producing hallucinatory states is reviewed. RESULTS: Complex visual hallucinations can arise from a variety of processes involving the retinogeniculocalcarine tract, or ascending brainstem modulatory structures. The cortical activity responsible for hallucinations results from altered or reduced input into these regions, or a loss of ascending inhibition of their afferent pathways. CONCLUSIONS: A significant degree of overlaps exists between the concepts of Charles Bonnet syndrome and peduncular hallucinosis. The fluidity of these eponymous syndromes reduces their validity and meaning, and may result in an inappropriate attribution of the underlying pathology. An understanding of how differing pathologies may produce CVH allows for the appropriate tailoring of treatment, depending on the site and nature of the lesion and content of perceptual disturbance.

Adult↗
PubMed1996

Pathogenesis of schizophrenic delusions and hallucinations: a neural model.

We implement and study a computational model of Stevens' theory of the pathogenesis of schizophrenia. This theory hypothesizes that the onset of schizophrenia is associated with reactive synaptic regeneration in brain regions that receive degenerating temporal lobe projections. Concentrating on one such area, the frontal cortex, we model a frontal module as an associative memory neural network whose input synapses represent incoming temporal projections. Modeling Stevens' hypothesized pathological synaptic changes in this framework results in adverse side effects similar to hallucinations and delusions seen in schizophrenia: spontaneous, stimulus-independent retrieval of stored memories focused on just a few of the stored patterns. These could account for the delusions and hallucinations that occur in schizophrenia without any apparent external trigger and for their tendency to concentrate on a few central cognitive and perceptual themes. The model explains why the positive symptoms of schizophrenia tend to wane as the disease progresses, why delayed therapeutic intervention leads to a much slower response, and why delusions and hallucinations may persist for a long time when they do occur.

Brain↗
PubMedDate not supplied

Long-term evaluation of the effect of quetiapine on hallucinations, delusions and motor function in advanced Parkinson disease.

OBJECTIVES: Mental disorders (MDs) are disabling complications of Parkinson disease (PD). We set out to demonstrate the short- and long-term efficacy of quetiapine, an antipsychotic drug, in controlling hallucinations and delusions in parkinsonian patients without worsening their motor function. Since current guidelines recommend that dopaminergic drugs be decreased or even withdrawn altogether upon the appearance of MDs, we also sought to establish whether quetiapine enables a modification of this common course of action, and hence improve the management of pre-existing motor complications in affected subjects. METHOD: Thirty-five PD patients with disabling MDs were enrolled in this open-label study. Motor function, MDs and cognitive state were evaluated before starting quetiapine therapy and after 1, 3, and 12 months of treatment. RESULTS: MDs significantly improved after 1, 3, and 12 months of quetiapine treatment. At the end of the study the mean daily dose of quetiapine (185 mg) did not produce significant changes in motor or cognitive function. Isolated hallucinations responded to low doses of quetiapine (110 mg daily), while delusions needed 265 mg daily. After 12 months, global dopaminergic therapy was reduced in 3 patients, modified (purely in terms of its components) in 17 patients, and increased in 15 patients. CONCLUSIONS: Quetiapine was effective in the treatment of hallucinations and delusions in PD. It did not worsen motor functions and allowed the dopaminergic treatment in PD patients affected by MDs to be managed safely.

Aged↗
PubMed1982

Imagery and hallucination in schizophrenic patients.

Volitional auditory imagery and spontaneous imagery/fantasy are examined in schizophrenic vs. nonschizophrenic psychiatric inpatients. Imaginal aspects of schizophrenia are also studied with regard to concurrent presence or absence of hallucination. Comparisons of imaginal function between diagnostic groups and among hallucinatory subgroups turned up few significant differences. Findings do not support the Mintz and Alpert (Mintz, S., and Alpert, M. Imagery vividness, reality testing, and schizophrenic hallucinations. J. Abnorm. Psychol., 79: 310-316, 1972) enhanced vividness model of schizophrenic hallucination but do provide some support for an imagery deficit model.

Adult↗
PubMed1986

The Hopi Indian's mourning hallucinations.

One of the 76 alcoholic patients with hallucinations studied in an inpatient alcoholism service was a 24-year-old half-Hopi Pueblo Indian male, who developed a prolonged course of hallucinations after the death of his father. The author suggests that hallucinating experiences might be pathognomy-specific to the Hopi Indians' mourning process, to allow the release of their intensive feelings.

Adult↗
PubMed1998

Auditory hallucinations: a comparison between patients and nonpatients.

The form and the content of chronic auditory hallucinations were compared in three cohorts, namely patients with schizophrenia, patients with a dissociative disorder, and nonpatient voice-hearers. The form of the hallucinatory experiences was not significantly different between the three groups. The subjects in the nonpatient group, unlike those in the patient groups, perceived their voices as predominantly positive: they were not alarmed or upset by their voices and felt in control of the experience. In most patients, the onset of auditory hallucinations was preceded by either a traumatic event or an event that activated the memory of earlier trauma. The significance of this study is that it presents evidence that the form of the hallucinations experienced by both patient and nonpatient groups is similar, irrespective of diagnosis. Differences between groups were predominantly related to the content, emotional quality, and locus of control of the voices. In this study the disability incurred by hearing voices is associated with (the reactivation of) previous trauma and abuse.

Adult↗
PubMed2005

A double-blind sham-controlled trial of repetitive transcranial magnetic stimulation in the treatment of refractory auditory hallucinations.

BACKGROUND: Previous research suggests that repetitive transcranial magnetic stimulation (rTMS) applied to the temporoparietal cortex may have therapeutic benefits for patients with schizophrenia and treatment-resistant auditory hallucinations. We aimed to test this hypothesis in a randomized double-blind trial. METHODS: Thirty-three patients with treatment-resistant auditory hallucinations entered a randomized sham-controlled, double-blind trial. rTMS was applied for 10 consecutive weekdays, for 15 minutes at 1 Hz and 90% of the resting motor threshold. We assessed clinical symptoms and cognitive function. RESULTS: rTMS was safe with no adverse effects on memory and cognitive parameters assessed. Active treatment did not result in a greater therapeutic effect than sham on any measure except for the loudness of hallucinations where there was a significant reduction in the active versus the sham group over time. CONCLUSIONS: The study does not support the effectiveness of rTMS using the stimulation parameters provided. However, it does suggest that rTMS methods may have a therapeutic role and indicates the need for further exploration of alternative and more effective stimulation methods.

Adolescent↗
PubMed2004

Factors associated with compliance and resistance to command hallucinations.

Command hallucinations (CHs) are hallucinations that direct the patient to perform an action. Beyond issues related to the danger that some CHs may pose, comparatively little is known about the broader clinical context of CHs. To investigate this, 199 patients were interviewed using the Mental Health Research Institute Unusual Perceptions Scale. More than two thirds of the sample reported hearing CHs. A quarter of these patients felt unable to resist them. Patients with CHs reported their voices more negatively than those who did not hear commands. More of those unable to resist CHs rated their hallucinations as intrusive, they had fewer coping strategies than those able to resist, and they were prescribed higher dosages of medication. CHs are associated with a greater degree of adverse hallucinatory and illness experience. Patients who experience CHs may have a more malignant form of the underlying disorder. Thus, CHs warrant special therapeutic attention for reasons beyond any harm that their commands pose to themselves or others.

Adaptation, Psychological↗
PubMed2006

Association between FOXP2 polymorphisms and schizophrenia with auditory hallucinations.

OBJECTIVE: A mutation in the FOXP2 gene has been the first genetic association with a language disorder. Language disorder is considered as a core symptom of schizophrenia. Therefore, the FOXP2 gene could be considered a good candidate gene for the vulnerability to schizophrenia. METHODS: A set of single nucleotide polymorphisms mainly located in the 5' regulatory region of the FOXP2 gene was analysed in a sample of 186 DSM-IV schizophrenic patients with auditory hallucinations and in 160 healthy controls. RESULTS: Statistically significant differences in the genotype (P=0.007) and allele frequencies (P=0.0027) between schizophrenic patients with auditory hallucinations and controls were found in the single nucleotide polymorphism rs2396753. These P values changed to 0.07 and 0.0273, respectively, after Bonferroni sequential correction. The haplotype rs7803667T/rs10447760C/rs923875A/rs1358278A/rs2396753A (TCAAA) also showed a significant difference confirmed with a permutation test (P=0.009). CONCLUSIONS: These results suggested that the FOXP2 gene may confer vulnerability to schizophrenic patients with auditory hallucinations.

Adult↗
PubMed2005

Sleep paralysis episode frequency and number, types, and structure of associated hallucinations.

Sleep paralysis (SP) episodes are often accompanied by vivid hallucinoid experiences that have been found to fall into three major categories thought to be organized according to intrinsic rapid eye movement (REM) processes. Prior research has, however, combined data for individuals with varying degrees of experience with SP episodes, rendering interpretations of the source of this structure ambiguous. The present study of 5799 current SP experients compares the nature and structure of the hallucinations of novice SP experients with those reporting varying numbers of episodes. Both qualitative and quantitative differences were found in reported hallucinations as a function of episode frequency, although the underlying three-factor structure of the hallucinoid experiences was highly similar for all groups. Novice experients' reports were, however, characterized by clearer differentiation of factors, likely because of a tendency of experienced SP experients to conflate experiences across episodes. Age and age of onset of SP episodes were associated with differences in the variety and types of hallucinations but not their underlying structure. Earlier onset of SP episodes was also associated with more frequent episodes. The results are consistent with the hypothesis that the basic form and patterning of hallucinatory experiences is a result of intrinsic processes, independent of prior experience, likely associated with underlying REM neurophysiology.

Adult↗