Non-clinical hallucinations and mental imagery across sensory modalities

INTRODUCTION

Vivid mental imagery has been proposed to increase the likelihood of experiencing hallucinations. Typically, studies have employed a modality general approach to mental imagery which compares imagery across multiple domains (e.g., visual, auditory and tactile) to hallucinations in multiple senses. However, modality specific imagery may be a better predictor of hallucinations in the same domain. The study examined the contribution of imagery to hallucinations in a non-clinical sample and specifically whether imagery best predicted hallucinations at a modality general or modality specific level.

METHODS

In study one, modality general and modality specific accounts of the imagery-hallucination relationship were contrasted through application of self-report measures in a sample of 434 students. Study two used a subsample (n = 103) to extend exploration of the imagery-hallucinations relationship using a performance-based imagery task.

RESULTS

A small to moderate modality general relationship was observed between self-report imagery and hallucination proneness. There was only evidence of a modality specific relationship in the tactile domain. Performance-based imagery measures were unrelated to hallucinations and self-report imagery.

CONCLUSIONS

Mental imagery may act as a modality general process increasing hallucination proneness. The observed distinction between self-report and performance-based imagery highlights the difficulty of accurately measuring internal processes.

Functional connectivity in Lewy body disease with visual hallucinations

BACKGROUND AND PURPOSE

Visual hallucinations are a common, potentially distressing experience of people with Lewy body disease (LBD). The underlying brain changes giving rise to visual hallucinations are not fully understood, although previous models have posited that alterations in the connectivity between brain regions involved in attention and visual processing are critical.

METHODS

Data from 41 people with LBD and visual hallucinations, 48 with LBD without visual hallucinations and 60 similarly aged healthy comparator participants were used. Connections were investigated between regions in the visual cortex and ventral attention, dorsal attention and default mode networks.

RESULTS

Participants with visual hallucinations had worse cognition and motor function than those without visual hallucinations. In those with visual hallucinations, reduced functional connectivity within the ventral attention network and from the visual to default mode network was found. Connectivity strength between the visual and default mode network correlated with the number of correct responses on a pareidolia task, and connectivity within the ventral attention network with visuospatial performance.

CONCLUSIONS

Our results add to evidence of dysfunctional connectivity in the visual and attentional networks in those with LBD and visual hallucinations.

Understanding visual hallucinations: a new synthesis

Despite decades of research, we do not definitively know how people sometimes see things that are not there. Eight models of complex visual hallucinations have been published since 2000, including Deafferentation, Reality Monitoring, Perception and Attention Deficit, Activation, Input, and Modulation, Hodological, Attentional Networks, Active inference, and Thalamocortical Dysrhythmia Default Mode Network Decoupling. Each was derived from different understandings of brain organisation. To reduce this variability, representatives from each research group agreed an integrated Visual Hallucination Framework that is consistent with current theories of veridical and hallucinatory vision. The Framework delineates cognitive systems relevant to hallucinations. It allows a systematic, consistent, investigation of relationships between the phenomenology of visual hallucinations and changes in underpinning cognitive structures. The episodic nature of hallucinations highlights separate factors associated with the onset, persistence, and end of specific hallucinations suggesting a complex relationship between state and trait markers of hallucination risk. In addition to a harmonised interpretation of existing evidence, the Framework highlights new avenues of research, and potentially, new approaches to treating distressing hallucinations.

What is the frequency and nature of visual hallucinations in non-clinical participants?

OBJECTIVES

There is a paucity of psychological treatments for visual hallucinations (VH). A key aspect in the psychological treatment of hallucination-related distress is normalisation to explain that these experiences are commonplace and can be non-distressing. In order to normalise VH, it is vital that more is known about VH in non-clinical populations. This study investigated the prevalence, content, context, appraisals, distress, and behavioural reactions to VH in a non-clinical sample.

DESIGN

A cross-sectional study was conducted.

METHODS

466 students completed the Multi-Modality Unusual Sensory Experiences Questionnaire-VH subscale with additional contextual follow-up questions.

RESULTS

Of the 466 participants, 395 (84.8%) reported anomalous visual experiences. 176 (37.77%) participants reported VH similar to the content seen in psychosis. Of the overall sample, 17.38% felt their experience met the VH definition. Participants mainly saw figures, when alone and in the evening. Participants endorsed normalising appraisals: 112 out of 176 (78.87%) believed their mind was playing tricks on them and 83 (58.45%) believed they were tired. However, many also believed the VH was a threat to their mental (66, 46.48%) or physical well-being (41, 28.87%). These negative appraisals were associated with distress.

CONCLUSION

VH are seemingly common in non-clinical populations and are similar in a number of ways to those of people with psychosis. Awareness that VH occur on a continuum could normalise people's experiences and reduce their negative appraisals and related distress.

Transcranial Direct Current Stimulation in the Treatment of Visual Hallucinations in Charles Bonnet Syndrome: A Randomized Placebo-Controlled Crossover Trial

OBJECTIVE

To investigate the potential therapeutic benefits and tolerability of inhibitory transcranial direct current stimulation (tDCS) on the remediation of visual hallucinations in Charles Bonnet syndrome (CBS).

DESIGN

Randomized, double-masked, placebo-controlled crossover trial.

PARTICIPANTS

Sixteen individuals diagnosed with CBS secondary to visual impairment caused by eye disease experiencing recurrent visual hallucinations.

INTERVENTION

All participants received 4 consecutive days of active and placebo cathodal stimulation (current density: 0.29 mA/cm²) to the visual cortex (Oz) over 2 defined treatment weeks, separated by a 4-week washout period.

MAIN OUTCOME MEASURES

Ratings of visual hallucination frequency and duration following active and placebo stimulation, accounting for treatment order, using a 2 × 2 repeated-measures model. Secondary outcomes included impact ratings of visual hallucinations and electrophysiological measures.

RESULTS

When compared with placebo treatment, active inhibitory stimulation of visual cortex resulted in a significant reduction in the frequency of visual hallucinations measured by the North East Visual Hallucinations Interview, with a moderate-to-large effect size. Impact measures of visual hallucinations improved in both placebo and active conditions, suggesting support and education for CBS may have therapeutic benefits. Participants who demonstrated greater occipital excitability on electroencephalography assessment at the start of treatment were more likely to report a positive treatment response. Stimulation was found to be tolerable in all participants, with no significant adverse effects reported, including no deterioration in preexisting visual impairment.

CONCLUSIONS

Findings indicate that inhibitory tDCS of visual cortex may reduce the frequency of visual hallucinations in people with CBS, particularly individuals who demonstrate greater occipital excitability prior to stimulation. tDCS may offer a feasible intervention option for CBS with no significant side effects, warranting larger-scale clinical trials to further characterize its efficacy.

Investigation of structural brain changes in Charles Bonnet Syndrome

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Reduced grey matter in the occipital cortex in eye disease groups.

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Widespread altered diffusivity in eye disease groups.

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No cortical or white matter changes associated with presence of visual hallucinations.

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Negative association between hippocampal volume and Hallucination severity.

Background and objectives

In Charles Bonnet Syndrome (CBS), visual hallucinations (VH) are experienced by people with sight loss due to eye disease or lesional damage to early visual pathways. The aim of this cross-sectional study was to investigate structural brain changes using magnetic resonance imaging (MRI) in CBS.

Methods

Sixteen CBS patients, 17 with eye disease but no VH, and 19 normally sighted people took part. Participants were imaged on a 3T scanner, with 1 mm resolution T1 weighted structural imaging, and diffusion tensor imaging with 64 diffusion directions.

Results

The three groups were well matched for age, sex and cognitive scores (MMSE). The two eye disease groups were matched on visual acuity. Compared to the sighted controls, we found reduced grey matter in the occipital cortex in both eye disease groups. We also found reductions of fractional anisotropy and increased diffusivity in widespread areas, including occipital tracts, the corpus callosum, and the anterior thalamic radiation. We did not find any significant differences between the eye disease participants with VH versus without VH, but did observe a negative association between hippocampal volume and VH severity in the CBS group.

Discussion

Our findings suggest that although there are cortical and subcortical effects associated with sight loss, structural changes do not explain the occurrence of VHs. CBS may relate instead to connectivity or excitability changes in brain networks linked to vision.

Functional and structural brain network correlates of visual hallucinations in Lewy body dementia

Visual hallucinations are a common feature of Lewy body dementia. Previous studies have shown that visual hallucinations are highly specific in differentiating Lewy body dementia from Alzheimer’s disease dementia and Alzheimer–Lewy body mixed pathology cases. Computational models propose that impairment of visual and attentional networks is aetiologically key to the manifestation of visual hallucinations symptomatology. However, there is still a lack of experimental evidence on functional and structural brain network abnormalities associated with visual hallucinations in Lewy body dementia.

We used EEG source localization and network based statistics to assess differential topographical patterns in Lewy body dementia between 25 participants with visual hallucinations and 17 participants without hallucinations. Diffusion tensor imaging was used to assess structural connectivity between thalamus, basal forebrain and cortical regions belonging to the functionally affected network component in the hallucinating group, as assessed with network based statistics. The number of white matter streamlines within the cortex and between subcortical and cortical regions was compared between hallucinating and not hallucinating groups and correlated with average EEG source connectivity of the affected subnetwork. Moreover, modular organization of the EEG source network was obtained, compared between groups and tested for correlation with structural connectivity.

Network analysis showed that compared to non-hallucinating patients, those with hallucinations feature consistent weakened connectivity within the visual ventral network, and between this network and default mode and ventral attentional networks, but not between or within attentional networks. The occipital lobe was the most functionally disconnected region. Structural analysis yielded significantly affected white matter streamlines connecting the cortical regions to the nucleus basalis of Meynert and the thalamus in hallucinating compared to not hallucinating patients. The number of streamlines in the tract between the basal forebrain and the cortex correlated with cortical functional connectivity in non-hallucinating patients, while a correlation emerged for the white matter streamlines connecting the functionally affected cortical regions in the hallucinating group.

This study proposes, for the first time, differential functional networks between hallucinating and not hallucinating Lewy body dementia patients, and provides empirical evidence for existing models of visual hallucinations. Specifically, the outcome of the present study shows that the hallucinating condition is associated with functional network segregation in Lewy body dementia and supports the involvement of the cholinergic system as proposed in the current literature.

Cognition, hallucination severity and hallucination-specific insight in neurodegenerative disorders and eye disease

Introduction: Hallucinations occur across neurodegenerative disorders, with increasing severity, poorer cognition and impaired hallucination-specific insight associated with worse outcomes and faster disease progression. It remains unclear how changes in cognition, temporal aspects of hallucinations, hallucination-specific insight and distress relate to each other.Methods: Extant samples of patients experiencing visual hallucinations were included in the analyses: Parkinson's Disease (n = 103), Parkinson's Disease Dementia (n = 41), Dementia with Lewy Bodies (n = 27) and Eye Disease (n = 113). We explored the relationship between factors of interest with Spearman's correlations and random-effect linear models.Results: Spearman's correlation analyses at the whole-group level showed that higher hallucination-specific insight was related to higher MMSE score (r_s = 0.39, p < 0.001) and less severe hallucinations (r_s = -0.28, p < .01). Linear mixed-models controlling for diagnostic group showed that insight was related to higher MMSE (p < .001), to hallucination severity (p = 0.003), and to VH duration (p = 0.04). Interestingly, insight was linked to the distress component but not the frequency component of severity. No significant relationship was found between MMSE and hallucination severity in these analyses.Conclusion: Our findings highlight the importance of hallucination-specific insight, distress and duration across groups. A better understanding of the role these factors play in VH may help with the development of future therapeutic interventions trans-diagnostically.

Exploring Bottom-Up Visual Processing and Visual Hallucinations in Parkinson's Disease With Dementia

Visual hallucinations (VH) are a common symptom of Parkinson's disease with dementia (PDD), affecting up to 65% of cases. Integrative models of their etiology posit that a decline in executive control of the visuo-perceptual system is a primary mechanism of VH generation. The role of bottom-up processing in the manifestation of VH in this condition is still not clear although visual evoked potential (VEP) differences have been associated with VH at an earlier stage of PD. Here we compared the amplitude and latency pattern reversal VEPs in healthy controls (n = 21) and PDD patients (n = 34) with a range of VH severities. PDD patients showed increased N2 latency relative to controls, but no significant differences in VEP measures were found for patients reporting complex VH (CVH) (n = 17) compared to those without VH. Our VEP findings support previous reports of declining visual system physiology in PDD and some evidence of visual system differences between patients with and without VH. However, we did not replicate previous findings of a major relationship s between the integrity of the visual pathway and VH.

A Review of Multimodal Hallucinations: Categorization, Assessment, Theoretical Perspectives, and Clinical Recommendations

Hallucinations can occur in different sensory modalities, both simultaneously and serially in time. They have typically been studied in clinical populations as phenomena occurring in a single sensory modality. Hallucinatory experiences occurring in multiple sensory systems-multimodal hallucinations (MMHs)-are more prevalent than previously thought and may have greater adverse impact than unimodal ones, but they remain relatively underresearched. Here, we review and discuss: (1) the definition and categorization of both serial and simultaneous MMHs, (2) available assessment tools and how they can be improved, and (3) the explanatory power that current hallucination theories have for MMHs. Overall, we suggest that current models need to be updated or developed to account for MMHs and to inform research into the underlying processes of such hallucinatory phenomena. We make recommendations for future research and for clinical practice, including the need for service user involvement and for better assessment tools that can reliably measure MMHs and distinguish them from other related phenomena.

Hallucinations in Older Adults: A Practical Review

Older adults experience hallucinations in a variety of social, physical, and mental health contexts. Not everyone is open about these experiences, as hallucinations are surrounded with stigma. Hence, hallucinatory experiences in older individuals are often under-recognized. They are also commonly misunderstood by service providers, suggesting that there is significant scope for improvement in the training and practice of professionals working with this age group. The aim of the present article is to increase knowledge about hallucinations in older adults and provide a practical resource for the health and aged-care workforce. Specifically, we provide a concise narrative review and critique of (1) workforce competency and training issues, (2) assessment tools, and (3) current treatments and management guidelines. We conclude with a brief summary including suggestions for service and training providers and future research.

Visual hallucinations in neurological and ophthalmological disease: pathophysiology and management

Visual hallucinations are common in older people and are especially associated with ophthalmological and neurological disorders, including dementia and Parkinson's disease. Uncertainties remain whether there is a single underlying mechanism for visual hallucinations or they have different disease-dependent causes. However, irrespective of mechanism, visual hallucinations are difficult to treat. The National Institute for Health Research (NIHR) funded a research programme to investigate visual hallucinations in the key and high burden areas of eye disease, dementia and Parkinson's disease, culminating in a workshop to develop a unified framework for their clinical management. Here we summarise the evidence base, current practice and consensus guidelines that emerged from the workshop.Irrespective of clinical condition, case ascertainment strategies are required to overcome reporting stigma. Once hallucinations are identified, physical, cognitive and ophthalmological health should be reviewed, with education and self-help techniques provided. Not all hallucinations require intervention but for those that are clinically significant, current evidence supports pharmacological modification of cholinergic, GABAergic, serotonergic or dopaminergic systems, or reduction of cortical excitability. A broad treatment perspective is needed, including carer support. Despite their frequency and clinical significance, there is a paucity of randomised, placebo-controlled clinical trial evidence where the primary outcome is an improvement in visual hallucinations. Key areas for future research include the development of valid and reliable assessment tools for use in mechanistic studies and clinical trials, transdiagnostic studies of shared and distinct mechanisms and when and how to treat visual hallucinations.

A comparison of visual hallucinations across disorders

Research into hallucinations typically regards them as single sensory or unimodal experiences leading to a comparative neglect of co-occurring multi-sensory hallucinations (MSH). People with psychosis who have visual hallucinations (VH) report high rates of hallucinations in other senses (auditory, olfactory, tactile). However, it is not known if this is similar to other groups who report VH. Consequently, this study explored MSH in four different patient groups who all had current VH. Archival data from standardised assessments of visual hallucinations in people with psychosis (n = 22), eye disease (ED) (n = 82), Lewy body Dementia (LBD) (n = 41), and Parkinson's disease (PD) (n = 41) determined the presence of MSH. People with psychosis and visual hallucinations reported significantly higher rates of MSH (auditory, 73%; tactile, 82%; olfactory/gustatory hallucinations, 27%) than the LBD group (auditory, 21%; tactile, 28%; olfactory/gustatory, 6%), ED (auditory, 1%; tactile, 11%; olfactory/gustatory, 0%) and PD patients (auditory, 3%; tactile, 8%; olfactory/gustatory, 3%). Regardless of diagnostic grouping, participants with MSH reported greater conviction that the VH were real, and reported greater distress. People with psychosis with VH report high rates of MSH unlike groups of older adults with VH. These between group differences in MSH prevalence have implications for clinical practice and theory.

Prevalence and characteristics of multi-modal hallucinations in people with psychosis who experience visual hallucinations

Hallucinations can occur in single or multiple sensory modalities. Historically, greater attention has been paid to single sensory modality experiences with a comparative neglect of hallucinations that occur across two or more sensory modalities (multi-modal hallucinations). With growing evidence suggesting that visual hallucinations may be experienced along with other hallucinations, this study aimed to explore multi-modal hallucinations in a sample of people with psychotic disorders who reported visual hallucinations (n = 22). No participants reported just visual hallucinations i.e. all reported related or unrelated auditory hallucinations. Twenty-one participants reported multi-modal hallucinations that were serial in nature, whereby they saw visual hallucinations and heard unrelated auditory hallucinations at other times. Nineteen people out of the twenty two also reported simultaneous multi-modal hallucinations, with the most common being an image that talked to and touched them. Multi-modal related and simultaneous hallucinations appeared to be associated with greater conviction that the experiences were real, and greater distress. Theoretical and clinical implications of multi-modal hallucinations are discussed.

The utility and application of electrophysiological methods in the study of visual hallucinations

Visual hallucinations (VH) are a common symptom in multiple clinical and non-clinical populations. Although structural and functional neuroimaging has informed the understanding of VH, temporal resolution is limited. Electrophysiological techniques provide a complementary perspective on dynamic and temporal aspects of neural functioning, offering greater insight into the mechanisms underlying their formation. In this review we examine and critically evaluate the emerging evidence base utilising electrophysiological approaches in the study of VH. Overall, increased visual system excitability, dysfunctional visual processing and network connectivity, and cholinergic dysfunction have been consistently observed in VH-prone pathologies. However, a major limitation is in the lack of robust experimental studies and the reliance on single case reports. We conclude that electrophysiology provides tentative evidence for the contribution of bottom-up, top-down, and network dysfunction in the aetiology of VH, supporting several existing VH models. Furthermore, we discuss how electrophysiology has been directly utilised in specific clinical interventions for VH. Further exploration utilising electrophysiology in combination with, for example, neuroimaging will help better understand VH aetiology while aiding in the development of novel therapeutic interventions for this difficult to treat symptom.

Reduced occipital GABA in Parkinson disease with visual hallucinations

Objective

To investigate the relationship between visual hallucinations in Parkinson disease (PD) and levels of γ-aminobutyric acid (GABA) in the primary visual cortex.

Methods

We utilized magnetic resonance spectroscopy to investigate occipital GABA levels in 36 participants with PD, 19 with and 17 without complex visual hallucinations, together with 20 healthy controls without hallucinations. In addition, we acquired T1-weighted MRI, whole-brain fMRI during a visual task, and diffusion tensor imaging.

Results

We found lower GABA+/creatine in PD with visual hallucinations (0.091 ± 0.010) vs those without (0.101 ± 0.010) and controls (0.099 ± 0.010) (F_2,49 = 4.5; p = 0.016). Reduced gray matter in the hallucinations group was also observed in the anterior temporal lobe. Although there were widespread reductions in white matter integrity in the visual hallucinations group, this was no longer significant after controlling for cognitive function.

Conclusions

The data suggest that reduced levels of GABA are associated with visual hallucinations in PD and implicate changes to the ventral visual stream in the genesis of visual hallucinations. Modulation of visual cortical excitability through, for example, pharmacologic intervention, may be a promising treatment avenue to explore.

Cognitive impairment in Parkinson's disease: impact on quality of life of carers

BACKGROUND

The quality of life (QoL) of informal caregivers of people with Parkinson's disease (PD) (PwP) can be affected by the caring role. Because of cognitive symptoms and diminished activities of daily living, in addition to the management of motor symptoms, carers of PwP and cognitive impairment may experience increased levels of burden and poorer QoL compared with carers of PwP without cognitive impairment. This study aimed to investigate the impact of cognitive impairment in PD upon QoL of carers.

METHODS

Approximately 36 months after diagnosis, 66 dyadic couples of PwP and carers completed assessments. PwP completed a schedule of neuropsychological assessments and QoL measures; carers of PwP completed demographic questionnaires and assessments of QoL. Factor scores of attention, memory/executive function and global cognition, as derived by principal component analysis, were used to evaluate cognitive domains.

RESULTS

Hierarchical regression analysis found lower Montreal Cognitive Assessment was a significant independent predictor of poorer carer QoL, in addition to number of hours spent caregiving, carer depression and PD motor severity. Attentional deficits accounted for the largest proportion of variance of carer QoL. Carers of PwP and dementia (n = 9) had significantly poorer QoL scores compared with PwP and mild cognitive impairment (n = 18) or normal cognition (n = 39) carers (p < 0.01).

CONCLUSIONS

Attentional deficits were the strongest predictor of carer QoL compared with other cognitive predictors. Carers for those with PD dementia reported the poorest QoL. Interventions such as respite or cognitive behavioural therapy to improve mood and self-efficacy in carers may improve carer QoL. © 2016 The Authors. International Journal of Geriatric Psychiatry published by John Wiley & Sons, Ltd.

The Structure and Measurement of Unusual Sensory Experiences in Different Modalities: The Multi-Modality Unusual Sensory Experiences Questionnaire (MUSEQ)

Hallucinations and other unusual sensory experiences (USE) can occur in all modalities in the general population. Yet, the existing literature is dominated by investigations into auditory hallucinations (“voices”), while other modalities remain under-researched. Furthermore, there is a paucity of measures which can systematically assess different modalities, which limits our ability to detect individual and group differences across modalities. The current study explored such differences using a new scale, the Multi-Modality Unusual Sensory Experiences Questionnaire (MUSEQ). The MUSEQ is a 43-item self-report measure which assesses USE in six modalities: auditory, visual, olfactory, gustatory, bodily sensations, and sensed presence. Scale development and validation involved a total of 1,300 participants, which included: 513 students and community members for initial development, 32 individuals with schizophrenia spectrum disorder or bipolar disorder for validation, 659 students for factor replication, and 96 students for test-retest reliability. Confirmatory factor analyses showed that a correlated-factors model and bifactor model yielded acceptable model fit, while a unidimensional model fitted poorly. These findings were confirmed in the replication sample. Results showed contributions from a general common factor, as well as modality-specific factors. The latter accounted for less variance than the general factor, but could still detect theoretically meaningful group differences. The MUSEQ showed good reliability, construct validity, and could discriminate non-clinical and clinical groups. The MUSEQ offers a reliable means of measuring hallucinations and other USE in six different modalities.

Reality monitoring performance and the role of visual imagery in visual hallucinations

BACKGROUND

Auditory Hallucinations may arise from people confusing their own inner speech with external spoken speech. People with visual hallucinations (VH) may similarly confuse vivid mental imagery with external events. This paper reports two experiments exploring confusion between internal and external visual material.

METHOD

Experiment 1 examined reality monitoring in people with psychosis; those with visual hallucinations (n = 16) and those without (n = 15). Experiment 2 used two non-clinical groups of people with high or low predisposition to VH (HVH, n = 26, LVH, n = 21). All participants completed the same reality monitoring task. Participants in Experiment 2 also completed measures of imagery.

RESULTS

Psychosis patients with VH demonstrated biased reality monitoring, where they misremembered items that had been presented as words as having been presented as pictures. Patients without VH did not show this bias. In Experiment 2, the HVH group demonstrated the same bias in reality monitoring that psychosis patients with VH had shown. The LVH group did not show this bias. In addition, the HVH group reported more vivid imagery and particularly more negative imagery.

CONCLUSIONS

Both studies found that people with visual hallucinations or prone-ness to such experiences confused their inner visual experiences with external images. Vivid imagery was also related to proneness to VH. Hence, vivid imagery and reality monitoring confusion could be contributory factors to understanding VH.

Compensatory shifts in visual perception are associated with hallucinations in Lewy body disorders

Visual hallucinations are a common, distressing, and disabling symptom of Lewy body and other diseases. Current models suggest that interactions in internal cognitive processes generate hallucinations. However, these neglect external factors. Pareidolic illusions are an experimental analogue of hallucinations. They are easily induced in Lewy body disease, have similar content to spontaneous hallucinations, and respond to cholinesterase inhibitors in the same way. We used a primed pareidolia task with hallucinating participants with Lewy body disorders (n = 16), non-hallucinating participants with Lewy body disorders (n = 19), and healthy controls (n = 20). Participants were presented with visual “noise” that sometimes contained degraded visual objects and were required to indicate what they saw. Some perceptions were cued in advance by a visual prime. Results showed that hallucinating participants were impaired in discerning visual signals from noise, with a relaxed criterion threshold for perception compared to both other groups. After the presentation of a visual prime, the criterion was comparable to the other groups. The results suggest that participants with hallucinations compensate for perceptual deficits by relaxing perceptual criteria, at a cost of seeing things that are not there, and that visual cues regularize perception. This latter finding may provide a mechanism for understanding the interaction between environments and hallucinations.

Measures of visual hallucinations: Review and recommendations

BACKGROUND

Studies designed to investigate visual hallucinations (VH) require reliable and valid measures that can appropriately capture peoples' experiences. This review aimed to assess the psychometric rigour and usefulness of VH measures.

METHOD

A systematic literature search was carried out against inclusion criteria (e.g. more than one specific question on VH, measures for adults in clinical and non-clinical populations). Eighteen measures were identified and rated against an adapted evaluation grid, which included essential criteria such as clear purpose and definition, psychometric properties including reliability and validity, and appropriate exploration of visual hallucinations.

RESULTS

Measures could be categorised into 3 groups; those for general psychotic symptoms, those for all hallucinations, or those specifically for visual hallucinations. With one exception (the North East Visual Hallucinations Inventory), the measures were considered to be limited as they often targeted one population and hence lacked generalisability, or were limited in the characteristics of the visions that were described, or that psychometric properties were not adequately evaluated.

CONCLUSIONS

Measures of VH require further development. The need to establish a clearer definition of VH is essential to provide clarity and consistency within research and practice. Measures need to demonstrate good psychometric properties to indicate robustness whilst being sensitive to change to help in the evaluation of treatments. Other recommendations include developing cross-cultural measures and involving service users in item development.

What Is the Link Between Hallucinations, Dreams, and Hypnagogic-Hypnopompic Experiences?

By definition, hallucinations occur only in the full waking state. Yet similarities to sleep-related experiences such as hypnagogic and hypnopompic hallucinations, dreams and parasomnias, have been noted since antiquity. These observations have prompted researchers to suggest a common aetiology for these phenomena based on the neurobiology of rapid eye movement (REM) sleep. With our recent understanding of hallucinations in different population groups and at the neurobiological, cognitive and interpersonal levels, it is now possible to draw comparisons between the 2 sets of experiences as never before. In the current article, we make detailed comparisons between sleep-related experiences and hallucinations in Parkinson's disease, schizophrenia and eye disease, at the levels of phenomenology (content, sensory modalities involved, perceptual attributes) and of brain function (brain activations, resting-state networks, neurotransmitter action). Findings show that sleep-related experiences share considerable overlap with hallucinations at the level of subjective descriptions and underlying brain mechanisms. Key differences remain however: (1) Sleep-related perceptions are immersive and largely cut off from reality, whereas hallucinations are discrete and overlaid on veridical perceptions; and (2) Sleep-related perceptions involve only a subset of neural networks implicated in hallucinations, reflecting perceptual signals processed in a functionally and cognitively closed-loop circuit. In summary, both phenomena are non-veridical perceptions that share some phenomenological and neural similarities, but insufficient evidence exists to fully support the notion that the majority of hallucinations depend on REM processes or REM intrusions into waking consciousness.

Visual Hallucinations in Eye Disease and Lewy Body Disease

OBJECTIVES

Visual hallucinations (VH) most commonly occur in eye disease (ED), Parkinson disease (PD), and Lewy body dementia (LBD). The phenomenology of VH is likely to carry important information about the brain areas within the visual system generating them.

METHODS

Data from five controlled cross-sectional VH studies (164 controls, 135 ED, 156 PD, 79 [PDD 48 + DLB 31] LBD) were combined and analyzed. The prevalence, phenomenology, frequency, duration, and contents of VH were compared across diseases and sex.

RESULTS

Simple VH were most common in ED patients (ED 65% versus LBD 22% versus PD 9%, χ(2) = 31.43, df = 2, p < 0.001), whereas complex VH were more common in LBD (LBD 76% versus ED 38%, versus PD 28%, χ(2) = 96.80, df = 2, p < 0.001). The phenomenology of complex VH was different across diseases and sex. ED patients reported more "flowers" (ED 21% versus LBD 6% versus PD 0%, χ(2) = 10.04, df = 2, p = 0.005) and "body parts" (ED 40% versus LBD 17% versus PD 13%, χ(2) = 11.14, df = 2, p = 0.004); in contrast, LBD patients reported "people" (LBD 85% versus ED 67% versus PD 63%, χ(2) = 6.20, df = 2, p = 0.045) and "animals/insects" (LBD 50% versus PD 42% versus ED 21%, χ(2) = 9.76, df = 2, p = 0.008). Men reported more "machines" (13% versus 2%, χ(2) = 6.94, df = 1, p = 0.008), whereas women reported more "family members/children" (48% versus 29%, χ(2) = 5.10, df = 1, p = 0.024).

CONCLUSIONS

The phenomenology of VH is likely related to disease-specific dysfunctions within the visual system and to past, personal experiences.

Cognitive decline and quality of life in incident Parkinson's disease: The role of attention

Introduction

Parkinson's disease dementia (PDD) is associated with poorer quality of life (QoL). Prior to the onset of PDD, many patients experience progressive cognitive impairment. There is a paucity of longitudinal studies investigating the effects of cognitive decline on QoL. This study aimed to determine the longitudinal impact of cognitive change on QoL in an incident PD cohort.

Methods

Recently diagnosed patients with PD (n = 212) completed a schedule of neuropsychological assessments and QoL measures; these were repeated after 18 (n = 190) and 36 months (n = 158). Mild cognitive impairment (PD-MCI) was classified with reference to the Movement Disorder Society criteria. Principal component analysis was used to reduce 10 neuropsychological tests to three cognitive factors: attention, memory/executive function, and global cognition.

Results

Baseline PD-MCI was a significant contributor to QoL (β = 0.2, p < 0.01). For those subjects (9%) who developed dementia, cognitive function had a much greater impact on QoL (β = 10.3, p < 0.05). Multivariate modelling showed attentional deficits had the strongest predictive power (β = −2.3, p < 0.01); brief global tests only modestly predicted decline in QoL (β = −0.4, p < 0.01).

Conclusions

PD-MCI was associated with poorer QoL over three years follow up. Cognitive impairment had a greater impact on QoL in individuals who developed dementia over follow-up. Impaired attention was a significant determinant of QoL in PD. Interventions which improve concentration and attention in those with PD could potentially improve QoL.

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Rate of QoL decline was three times faster in PD-MCI subjects compared those with normal cognition.

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Cognitive decline predicted worsening of QoL over 36 months.

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Decline in attention was the strongest cognitive predictor of declining QoL.

Visual Priming and Visual Hallucinations in Parkinson's Disease. Evidence for Normal Top-Down Processes

BACKGROUND

Visual hallucinations (VH) are common in Parkinson's disease (PD) and are associated with increased morbidity and mortality. Current explanations for VH in PD suggest combined impairments in top-down attentional and bottom-up perceptual processes, which allow the passive "release" of stored images. Alternative models in other disorders have suggested that top-down factors may actively encourage hallucinations. In order to explore the interaction between top-down and bottom-up visual processing in PDVH, we developed novel experimental priming tasks in which top-down verbal cues were used to prime the bottom-up recognition of partial or ambiguous pictures.

METHOD

Two groups of PD participants with (PD + VH, n = 16), and without VH (PD - VH, n = 20) were compared to a group of healthy older adults (NC, n = 20) on 3 novel measures of visual priming.

RESULTS

All tasks showed significant priming effects. The PD + VH group was more impaired at accurately identifying silhouette and fragmented images compared to the PD - VH group. There were no differences in priming between the 2 PD groups.

CONCLUSIONS

The study showed that VH in PD are not associated with relatively greater top-down activation, and that the interaction between top-down and bottom-up processes is intact.

Patient and Informant Views on Visual Hallucinations in Parkinson Disease

OBJECTIVE

Visual hallucinations (VHs) are a very personal experience, and it is not clear whether information about them is best provided by informants or patients. Some patients may not share their hallucinatory experiences with caregivers to avoid distress or for fear of being labeled insane, and others do not have informants at all, which limits the use of informant-based questionnaires. The aim of this study was to compare patient and caregiver views about VHs in Parkinson disease (PD), using the North-East Visual Hallucinations Interview (NEVHI).

METHODS

Fifty-nine PD patient-informant pairs were included. PD patients and informants were interviewed separately about VHs using the NEVHI. Informants were additionally interviewed using the four-item version of the Neuropsychiatric Inventory. Inter-reliability and concurrent validity of the different measures were compared.

RESULTS

VHs were more commonly reported by patients than informants. The inter-rater agreement between NEVHI-patient and NEVHI-informant was moderate for complex VHs (Cohen's kappa = 0.44; 95% confidence interval [CI]: 0.13-0.75; t = 3.43, df = 58, p = 0.001) and feeling of presence (Cohen's kappa = 0.35; 95% CI: 0.00-0.70; t = 2.75, df = 58, p = 0.006), but agreement was poor for illusions (Cohen's kappa = 0.25; 95% CI: -0.07-0.57; t = 2.36, df = 58, p = 0.018) and passage hallucinations (Cohen's kappa = 0.16; 95% CI: -0.04-0.36; t = 2.26, df = 58, p = 0.024).

CONCLUSION

When assessing VHs in PD patients, it is best to rely on patient information, because not all patients share the details of their hallucinations with their caregivers.

Visual hallucinations

Understanding of visual hallucinations is developing rapidly. Single-factor explanations based on specific pathologies have given way to complex multifactor models with wide potential applicability. Clinical studies of disorders with frequent hallucinations-dementia, delirium, eye disease and psychosis-show that dysfunction within many parts of the distributed ventral object perception system is associated with a range of perceptions from simple flashes and dots to complex formed figures and landscapes. Dissociations between these simple and complex hallucinations indicate at least two hallucinatory syndromes, though exact boundaries need clarification. Neural models of hallucinations variably emphasize the importance of constraints from top down dorsolateral frontal systems, bottom up occipital systems, interconnecting tracts, and thalamic and brainstem regulatory systems. No model has yet gained general acceptance. Both qualitative (a small number of necessary and sufficient constraints) and quantitative explanations (an accumulation of many nonspecific factors) fit existing data. Variable associations of hallucinations with emotional distress and thought disorders across and within pathologies may reflect the roles of cognitive and regulatory systems outside of the purely perceptual. Functional imaging demonstrates that hallucinations and veridical perceptions occur in the same brain areas, intimating a key role for the negotiating interface between top down and bottom up processes. Thus, hallucinations occur when a perception that incorporates a hallucinatory element can provide a better match between predicted and actual sensory input than does a purely veridical experience. Translational research that integrates understandings from clinical hallucinations and basic vision science is likely to be the key to better treatments. WIREs Cogn Sci 2010 1 781-786 For further resources related to this article, please visit the WIREs website.

Quality of life and mild cognitive impairment in early Parkinson's disease: does subtype matter?

We evaluated the association between mild cognitive impairment (MCI) subtypes and quality of life (QoL) in 219 newly diagnosed Parkinson's disease (PD) patients without dementia. Participants completed neuropsychological tests of attention, executive function, visuospatial function, memory, and language, and reported QoL using the Parkinson's Disease Questionnaire. Impairments were most common in executive function, memory and attention. MCI subtypes were classified according to Movement Disorder Society Task Force criteria. More severe cognitive impairment was associated with poorer quality of life (p = 0.01), but subtype of impairment was not (p > 0.10), suggesting that the nature of cognitive impairment is less significant than its severity.

Serum 25-hydroxyvitamin D and cognitive decline in the very old: the Newcastle 85+ Study

BACKGROUND AND PURPOSE

Studies investigating the association between 25-hydroxyvitamin D [25(OH)D] and cognition in the very old (85+) are lacking.

METHODS

Cross-sectional (baseline) and prospective data (up to 3 years follow-up) from 775 participants in the Newcastle 85+ Study were analysed for global (measured by the Standardized Mini-Mental State Examination) and attention-specific (measured by the attention battery of the Cognitive Drug Research test) cognitive performance in relation to season-specific 25(OH)D quartiles.

RESULTS

Those in the lowest and highest season-specific 25(OH)D quartiles had an increased risk of impaired prevalent (1.66, 95% confidence interval 1.06-2.60, P = 0.03; 1.62, 95% confidence interval 1.02-2.59, P = 0.04, respectively) but not incident global cognitive functioning or decline in functioning compared with those in the middle quartiles adjusted for sociodemographic, health and lifestyle confounders. Random effects models showed that participants belonging to the lowest and highest 25(OH)D quartiles, compared with those in the middle quartiles, had overall slower (log-transformed) attention reaction times for Choice Reaction Time (lowest, β = 0.023, P = 0.01; highest, β = 0.021, P = 0.02), Digit Vigilance Task (lowest, β = 0.009, P = 0.05; highest, β = 0.01, P = 0.02) and Power of Attention (lowest, β = 0.017, P = 0.02; highest, β = 0.022, P = 0.002) and greater Reaction Time Variability (lowest, β = 0.021, P = 0.02; highest, β = 0.02, P = 0.03). The increased risk of worse global cognition and attention amongst those in the highest quartile was not observed in non-users of vitamin D supplements/medication.

CONCLUSION

Low and high season-specific 25(OH)D quartiles were associated with prevalent cognitive impairment and poorer overall performance in attention-specific tasks over 3 years in the very old, but not with global cognitive decline or incident impairment.

Severity of mild cognitive impairment in early Parkinson's disease contributes to poorer quality of life

Background

Poor quality of life (QoL) is a feature of people with Parkinson's disease (PD) who develop dementia. The relationship between mild cognitive impairment in PD (PD-MCI) and QoL is less clear. To address this, we studied the impact of varying severities of cognitive impairment on QoL in a cohort of non-demented patients with early PD.

Method

Patients with newly diagnosed PD (n = 219) and age and sex matched healthy controls (n = 99) completed a schedule of neuropsychological tests, in addition to scales assessing QoL (PDQ-39), depression, sleep, neuropsychiatric symptoms and a clinical examination. The Movement Disorder Society criteria were used to define and classify PD-MCI.

Results

Participants with PD-MCI were significantly older than those with normal cognition, had more severe motor symptoms, scored higher for depression and had poorer quality of life. Logistic regression showed that mild cognitive impairment, independent of other factors, was an indicator of poorer QoL. Using cognitive performance 2.0 standard deviations (SD) below normative data as a cut-off to define PD-MCI, there was a significant difference in QoL scores between patients with PD-MCI and those classified as having normal cognition. Subjects with less severe mild cognitive impairment did not exhibit significant differences in QoL.

Conclusions

PD-MCI is a significant, independent factor contributing to poorer QoL in patients with newly diagnosed PD. Those classified with greatest impairment (2.0 SD below normal values) have lower QoL. This has implications for clinical practice and future interventions targeting cognitive impairments.

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Quality of life declines with increased severity of cognitive impairment in PD.

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Mild cognitive impairment in PD (PD-MCI) independently contributes to poorer QoL.

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PD-MCI at 2 standard deviations below controls had the greatest impact on QoL.

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The optimal operational cut-off for PD-MCI may be 2 standard deviations.

Visual hallucinations in the psychosis spectrum and comparative information from neurodegenerative disorders and eye disease

Much of the research on visual hallucinations (VHs) has been conducted in the context of eye disease and neurodegenerative conditions, but little is known about these phenomena in psychiatric and nonclinical populations. The purpose of this article is to bring together current knowledge regarding VHs in the psychosis phenotype and contrast this data with the literature drawn from neurodegenerative disorders and eye disease. The evidence challenges the traditional views that VHs are atypical or uncommon in psychosis. The weighted mean for VHs is 27% in schizophrenia, 15% in affective psychosis, and 7.3% in the general community. VHs are linked to a more severe psychopathological profile and less favorable outcome in psychosis and neurodegenerative conditions. VHs typically co-occur with auditory hallucinations, suggesting a common etiological cause. VHs in psychosis are also remarkably complex, negative in content, and are interpreted to have personal relevance. The cognitive mechanisms of VHs in psychosis have rarely been investigated, but existing studies point to source-monitoring deficits and distortions in top-down mechanisms, although evidence for visual processing deficits, which feature strongly in the organic literature, is lacking. Brain imaging studies point to the activation of visual cortex during hallucinations on a background of structural and connectivity changes within wider brain networks. The relationship between VHs in psychosis, eye disease, and neurodegeneration remains unclear, although the pattern of similarities and differences described in this review suggests that comparative studies may have potentially important clinical and theoretical implications.

Visual complaints and visual hallucinations in Parkinson's disease

BACKGROUND

Visual symptoms are common in Parkinson's disease (PD) and are frequently under-diagnosed. The detection of visual symptoms is important for differential diagnosis and patient management.

AIM

To establish the prevalence of recurrent visual complaints (RVC) and recurrent visual hallucinations (RVH) and to investigate their interaction in PD patients and controls.

METHODS

This cross-sectional study included 88 PD patients and 90 controls. RVC and RVH were assessed with a visual symptom questionnaire and the North-East-Visual-Hallucinations-Interview (NEVHI).

RESULTS

Double vision (PD vs.

CONTROLS

18.2% vs. 1.3%; p < 0.001), misjudging objects when walking (PD vs.

CONTROLS

12.5% vs. 1.3%; p < 0.01), words moving whilst reading (PD vs.

CONTROLS

17.0% vs. 1.3%; p < 0.001) and freezing in narrow spaces (PD vs.

CONTROLS

30.7% vs. 0%; p < 0.001) were almost exclusively found in PD patients. The same was true for recurrent complex visual hallucinations and illusions (PD vs.

CONTROLS

both 17.0% vs. 0%; p < 0.001). Multiple RVC (43.2% vs. 15.8%) and multiple RVH (29.5% vs. 5.6%) were also more common in PD patients (both p < 0.001). RVC did not predict recurrent complex visual hallucinations; but double vision (p = 0.018, R(2) = 0.302) and misjudging objects (p = 0.002, R(2) = 0.302) predicted passage hallucinations. Misjudging objects also predicted the feeling of presence (p = 0.010, R(2) = 0.321).

CONCLUSIONS

Multiple and recurrent visual symptoms are common in PD. RVC emerged as risk factors predictive of the minor forms of hallucinations, but not recurrent complex visual hallucinations.

Complex visual hallucinations and attentional performance in eye disease and dementia: a test of the Perception and Attention Deficit model

OBJECTIVE

This study aimed to test the prediction from the Perception and Attention Deficit model of complex visual hallucinations (CVH) that impairments in visual attention and perception are key risk factors for complex hallucinations in eye disease and dementia.

METHODS

Two studies ran concurrently to investigate the relationship between CVH and impairments in perception (picture naming using the Graded Naming Test) and attention (Stroop task plus a novel Imagery task). The studies were in two populations-older patients with dementia (n = 28) and older people with eye disease (n = 50) with a shared control group (n = 37). The same methodology was used in both studies, and the North East Visual Hallucinations Inventory was used to identify CVH.

RESULTS

A reliable relationship was found for older patients with dementia between impaired perceptual and attentional performance and CVH. A reliable relationship was not found in the population of people with eye disease.

CONCLUSIONS

The results add to previous research that object perception and attentional deficits are associated with CVH in dementia, but that risk factors for CVH in eye disease are inconsistent, suggesting that dynamic rather than static impairments in attentional processes may be key in this population.

Psychotherapy and brain plasticity

In this paper, I will review why psychotherapy is relevant to the question of how consciousness relates to brain plasticity. A great deal of the research and theorizing on consciousness and the brain, including my own on hallucinations for example (Collerton and Perry, 2011) has focused upon specific changes in conscious content which can be related to temporal changes in restricted brain systems. I will argue that psychotherapy, in contrast, allows only a focus on holistic aspects of consciousness; an emphasis which may usefully complement what can be learnt from more specific methodologies.

Advances in the treatment of visual hallucinations in neurodegenerative diseases

Treatment of visual hallucinations in neurodegenerative disorders is not well advanced. The complexity of underlying mechanisms presents a number of potential avenues for developing treatments, but also suggests that any single one may be of limited efficacy. Reducing medication, with the careful introduction of antidementia medication if needed, is the mainstay of current management. Antipsychotic medication leads to excessive morbidity and mortality and should only be used in cases of high distress that do not otherwise respond. Education, reduction of risk factors and psychological treatments have limited evidence of efficacy, but are unlikely to cause harm.

The assessment of cognition in visually impaired older adults

BACKGROUND

visual and cognitive impairments are common in later life. Yet there are very few cognitive screening tests for the visually impaired.

OBJECTIVE

to screen for cognitive impairment in the visually impaired.

METHODS

case-control study including 150 elderly participants with visual impairment (n = 74) and a control group without visual impairment (n = 76) using vision-independent cognitive tests and cognitive screening tests (MMSE and clock drawing tests (CDT)) which are in part vision dependent.

RESULTS

the scoring of the two groups did not differ in the vision-independent cognitive tests. Visually impaired patients performed poorer than controls in the vision-dependent items of the MMSE (T = 7.3; df: 148; P < 0.001) and in CDT (T = 3.1; df: 145; P = 0.003). No group difference was found when vision-independent items were added to MMSE and CDT. The test score gain by the use of vision-independent items correlated with the severity of visual impairment (P < 0.002).

CONCLUSION

visually impaired patients benefit from cognitive tests, which do not rely on vision. The more visually impaired the greater the benefit.

An Exploratory Study of the Effectiveness of Memory Aids for Older People Living in Supported Accommodation

There is increasing evidence that electronic and other aids can support older people’s memory. In an effectiveness study, we explored whether assistive technologies could benefit 200 potential beneficiaries in a naturalistic setting. We first interviewed 50 participants to assess needs and preferences for memory aids, then researched, developed and trialled specific aids, and finally administered a follow-up questionnaire assessing future use of aids. Matching aids to needs was not easy. Relatively few people were interested in trailing aids. Simpler aids were most successful. Participants were curious about electronic aids, but found them too complicated and not adapted enough to their needs. Assistance from other people was necessary to prompt use of all types of aids. Future effectiveness studies should focus on longer trials with greater training and support for participants, a wider range of technologies, and more promotion of possible benefits.

Specific attentional impairments and complex visual hallucinations in eye disease

OBJECTIVE

To test the prediction by the Perception and Attention Deficit (PAD) model of complex visual hallucinations that cognitive impairment, specifically in visual attention, is a key risk factor for complex hallucinations in eye disease.

METHODS

Two studies of elderly patients with acquired eye disease investigated the relationship between complex visual hallucinations (CVH) and impairments in general cognition and verbal attention (Study 1) and between CVH, selective visual attention and visual object perception (Study 2). The North East Visual Hallucinations Inventory was used to classify CVH.

RESULTS

In Study 1, there was no relationship between CVH (n=10/39) and performance on cognitive screening or verbal attention tasks. In Study 2, participants with CVH (n=11/31) showed poorer performance on a modified Stroop task (p<0.05), a novel imagery-based attentional task (p<0.05) and picture (p<0.05) but not silhouette naming (p=0.13) tasks. Performance on these tasks correctly classified 83% of the participants as hallucinators or non-hallucinators.

CONCLUSIONS

The results suggest that, consistent with the PAD model, complex visual hallucinations in people with acquired eye disease are associated with visual attention impairment.

A semi-structured interview to assess visual hallucinations in older people

OBJECTIVE

Visual hallucinations are under-reported by patients and are often undiscovered by health professionals. There is no gold standard available to assess hallucinations. Our objective was to develop a reliable, valid, semi-structured interview for identifying and assessing visual hallucinations in older people with eye disease and cognitive impairment.

METHODS

We piloted the North-East Visual Hallucinations Interview (NEVHI) in 80 older people with visual and/or cognitive impairment (patient group) and 34 older people without known risks of hallucinations (control group). The informants of 11 patients were interviewed separately. We established face validity, content validity, criterion validity, inter-rater agreement and the internal consistency of the NEVHI, and assessed the factor structure for questions evaluating emotions, cognitions, and behaviours associated with hallucinations.

RESULTS

Recurrent visual hallucinations were common in the patient group (68.8%) and absent in controls (0%). The criterion, face and content validities were good and the internal consistency of screening questions for hallucinations was high (Cronbach alpha: 0.71). The inter-rater agreements for simple and complex hallucinations were good (Kappa 0.72 and 0.83, respectively). Four factors associated with experiencing hallucinations (perceived control, pleasantness, distress and awareness) were identified and explained a total variance of 73%. Informants gave more 'don't know answers' than patients throughout the interview (p = 0.008), especially to questions evaluating cognitions and emotions associated with hallucinations (p = 0.02).

CONCLUSIONS

NEVHI is a comprehensive assessment tool, helpful to identify the presence of visual hallucinations and to quantify cognitions, emotions and behaviours associated with hallucinations.

A comparison of computerized and pencil-and-paper tasks in assessing cognitive function in community-dwelling older people in the Newcastle 85+ Pilot Study

OBJECTIVES

To compare the acceptability and feasibility of computerized and pencil-and-paper tests of cognitive function in 85-year-old people.

DESIGN

Group comparison of participants randomly allocated to pencil-and-paper (Wechsler Adult Intelligence and Memory Scales) or computerized (Cognitive Drug Research) tests of verbal memory and attention.

SETTING

The Newcastle 85+ Pilot Study was the precursor to the Newcastle 85+ Study a United Kingdom Medical Research Council/Biotechnology and Biological Sciences Research Council cohort study of health and aging in the oldest-old age group.

PARTICIPANTS

Eighty-one community-dwelling individuals aged 85.

MEASUREMENTS

Participant and researcher acceptability, completion rates, time taken, validity as cognitive measures, and psychometric utility.

RESULTS

Participants randomized to computerized tests were less likely to rate the cognitive function tests as difficult (odds ratio (OR)=0.16, 95% confidence interval (CI)=0.07-0.39), stressful (OR=0.18, 95% CI=0.07-0.45), or unacceptable (OR=0.18, 95% CI=0.08-0.48) than those randomized to pencil-and-paper tests. Researchers were also less likely to rate participants as being distressed in the computer test group (OR=0.19, 95% CI=0.07-0.46). Pencil-and-paper tasks took participants less time to complete (mean+/-standard deviation 18+/-4 minutes vs 26+/-4 minutes) but had fewer participants who could complete all tasks (91% vs 100%). Both types of task were equally good measures of cognitive function.

CONCLUSION

Computerized and pencil-and-paper tests are both feasible and useful means of assessing cognitive function in the oldest-old age group. Computerized tests are more acceptable to participants and administrators.

Why people see things that are not there: a novel Perception and Attention Deficit model for recurrent complex visual hallucinations

As many as two million people in the United Kingdom repeatedly see people, animals, and objects that have no objective reality. Hallucinations on the border of sleep, dementing illnesses, delirium, eye disease, and schizophrenia account for 90% of these. The remainder have rarer disorders. We review existing models of recurrent complex visual hallucinations (RCVH) in the awake person, including cortical irritation, cortical hyperexcitability and cortical release, top-down activation, misperception, dream intrusion, and interactive models. We provide evidence that these can neither fully account for the phenomenology of RCVH, nor for variations in the frequency of RCVH in different disorders. We propose a novel Perception and Attention Deficit (PAD) model for RCVH. A combination of impaired attentional binding and poor sensory activation of a correct proto-object, in conjunction with a relatively intact scene representation, bias perception to allow the intrusion of a hallucinatory proto-object into a scene perception. Incorporation of this image into a context-specific hallucinatory scene representation accounts for repetitive hallucinations. We suggest that these impairments are underpinned by disturbances in a lateral frontal cortex-ventral visual stream system. We show how the frequency of RCVH in different diseases is related to the coexistence of attentional and visual perceptual impairments; how attentional and perceptual processes can account for their phenomenology; and that diseases and other states with high rates of RCVH have cholinergic dysfunction in both frontal cortex and the ventral visual stream. Several tests of the model are indicated, together with a number of treatment options that it generates.

Characteristics of visual hallucinations in Parkinson disease dementia and dementia with lewy bodies

OBJECTIVE

Parkinson disease dementia (PDD) and dementia with Lewy bodies (DLB) have overlapping clinical and pathologic features. Recurrent visual hallucinations (RVH) are common in both disorders. The authors have compared details of hallucination characteristics and associated neuropsychiatric features in DLB and PDD.

METHODS

This is a descriptive, cross-sectional study using the Institute of Psychiatry Visual Hallucinations Interview (IP-VHI) to explore self-reported frequency, duration, and phenomenology of RVH in PDD and DLB. The caregivers' ratings of hallucinations and other neuropsychiatric features were elicited with the Neuropsychiatric Inventory (NPI).

RESULTS

Fifty-six patients (35 PDD; 21 DLB) with RVH were assessed. Hallucination characteristics were similar in both disorders. Simple hallucinations were rare. Most patients experienced complex hallucinations daily, normally lasting minutes. They commonly saw people or animals and the experiences were usually perceived as unpleasant. NPI anxiety scores were higher in PDD. Neuropsychiatric symptoms coexisting with hallucinations were apathy, sleep disturbance, and anxiety.

CONCLUSIONS

Patients with mild to moderate dementia can provide detailed information about their hallucinations. Characteristics of RVH were similar in PDD and DLB, and phenomenology suggests the involvement of dorsal and ventral visual pathways in their generation. The coexistence of RVH with anxiety, apathy, and sleep disturbance is likely to impair patients' quality of life and may have treatment implications.

Systematic review and meta-analysis show that dementia with Lewy bodies is a visual-perceptual and attentional-executive dementia

To resolve differences in the literature, we have systematically reviewed 21 controlled comparisons of the cognitive performance of patients with dementia with Lewy bodies (DLB) These were identified by end May 2002 by Medline and PsycInfo searches, checking reference lists and contacting authors. Nine had comparisons between DLB patients (total n = 180) and age-matched controls (n = 172). Sixteen had comparisons between DLB (n = 312) and Alzheimer's disease (AD, n = 380). Three compared DLB (n = 48) with Parkinson's disease (PD, n = 65). Two raters independently scored the methodological quality. This was variable with a lack of high-quality studies (median rating 3 on a 0-7 scale, Kw = 0.41). There was a significant heterogeneity in results with marked discrepancies between studies. In a meta-analysis, DLB patients were more cognitively impaired than were AD or PD patients (95% CI of inverse variance weighted average of effect size relative to controls DLB 2.0-2.2; AD 1.4-1.6; PD 0.7-1.0). To permit an analysis of impairments in specific cognitive areas, the cognitive abilities underpinning the wide variety of tasks used were classified by a group of experienced neuropsychologists. Reducing overlapping task classifications using factor analysis showed large effect sizes relative to controls, AD and PD on two factors (combined variance 30%): attentional/executive impairment (effect sizes 1.1-2.9) and visual-perceptual impairment (0.7-3.6). There were small differences on two other factors (combined variance 39%): general verbal/non-verbal impairment (-0.12 to -0.5) and relative verbal memory impairment (-0.33 to 0.21). The cognitive performance is also more variable in DLB than in controls or in AD, but not PD (ratio of DLB to comparator standard deviations estimated from linear regression: DLB/controls 2.5-3.6; DLB/AD 2.1-2.6; DLB/PD 0.8-1.0). The greater variability of patients with DLB is seen only on tasks needing timed or motor responses, visual learning, executive or attentional abilities, or with visual content. Further stratification indicated that recent consensus diagnostic criteria, clinical diagnoses, and milder dementia were all associated with a more distinctive cognitive profile. The uniquely profound visual-perceptual and attentional-executive impairments that characterize DLB are consistent with the most frequent locations of Lewy bodies in frontal, cingulate, and inferior temporal cortex and may be related to the characteristic visual hallucinations and clinical fluctuations of this disease. These findings need to be confirmed in prospective, longitudinal, clinicopathological studies.

Dementia with Lewy bodies

The objective was to summarize recent findings about the clinical features, diagnosis and investigation of dementia with Lewy (DLB) bodies, together with its neuropathology, neurochemistry and genetics. Dementia with Lewy bodies (DLB) is a primary, neurodegenerative dementia sharing clinical and pathological characteristics with both Parkinson's disease (PD) and Alzheimer's disease (AD). Antiubiquitin immunocytochemical staining, developed in the early 1990s, allowed the frequency and distribution of cortical LBs to be defined. More recently, alpha-synuclein antibodies have revealed extensive neuritic pathology in DLB demonstrating a neurobiological link with other "synucleinopathies" including PD and multiple system atrophy (MSA). The most significant correlates of cognitive failure in DLB appear to be with cortical LB and Lewy neurites (LNs) rather than Alzheimer type pathology. Clinical diagnostic criteria for DLB, published in 1996, have been subjected to several validation studies against autopsy findings. These conclude that although diagnostic specificity is high (range 79- 100%, mean 92%), sensitivity is lower (range 0- 83 %, mean, 49%). Improved methods of case detection are therefore required. Fluctuating impairments in attention, visual recognition and construction are more indicative of DLB than AD. Relative preservation of medial temporal lobe volume on structural MRI and the use of SPECT tracers for regional blood flow and the dopamine transporter are the most reliable current biomarkers for DLB. There are no genetic or CSF tests recommended for the diagnosis of DLB at present. Between 15 and 20% of all elderly demented cases reaching autopsy have DLB, making it the most common cause of degenerative dementia after AD. Exquisite, not infrequently fatal, sensitivity to neuroleptic drugs and encouraging reports of the effects of cholinesterase inhibitors on cognitive, psychiatric and neurological features, mean that an accurate diagnosis of DLB is more than merely of academic interest. Dementia developing late in the course of PD shares many of the same clinical and pathological characteristics.