Visual Hallucinations in Eye Disease and Lewy Body Disease

Abstract

Objective: Visual hallucinations (VH) most commonly occur in eye disease (ED), Parkinson's 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 analysed. The prevalence, phenomenology, frequency, duration, and contents of VH were compared across diseases and gender. Results: Simple VH were most common in ED patients (ED 65% METHODS Study Selection and Data CollectionThere have been several studies(2-5, 8, 24) using NEVHI(3) since its original publication in 2008. Only controlled cross-sectional NEVHI studies with ED, PD, PDD, and DLB samples using similar methodology were included in this study. Three(3, 4, 8) of them had two sample groups (patients, controls), while the other two had three sample groups (controls, ED, DLB;(2) controls, PD, PDD (5) Committee, United Kingdom. All procedures related to the study were explained to the participants and a written informed consent was obtained prior to participation. All data were merged into a single database including 164 individuals in the comparison group and 383 patients (135 ED, 156 PD, 48 PDD, 31 DLB, 13 with combination of ED/PD/PDD/DLB). The latter 13 patients were excluded from further analysis. A sub-analysis of VH phenomenology did not reveal any differences between DLB and PDD patients, which were subsequently considered as one LBD group. PD and LBD patients were only included if they had no visual field defects on neurological examination. AssessmentsAn interview was used to gather demographic data in all studies. Best near visual acuity was examined 6 members/children), "body parts", "animals/insects", "machines", and "letters/numbers/musical notes".(7, 13, 15) Prevalence, phenomenology, frequency, duration and severity of VH were compared between the (i) comparison group and patients and (ii) different patient groups (ED, PD, LBD). The phenomenology of Complex VH was also compared between gender. Statistical analysisStatistical analysis was undertaken using the Statistical Package for Social Sciences (SPSS Version 20).Normal distribution of data was examined using the Shapiro-Wilk test. Means and standard deviations (SD) were calculated. Data were analysed using parametric tests (one-way analysis of variance (ANOVA)). Multiple comparisons were assessed with Post-hoc Bonferroni tests. Frequencies were compared using the chi-square (χ 2 ) test and Fisher's exact test when expected frequency in either group was < 5. The effect of gender, disease and interaction of gender × disease on contents of complex VH was tested using a two-way ANOVA (Effect sizes are reported using partial η 2 ), whilst logistic regression was used to ascertain whether the VH phenomenology could significantly predict the disease. The homogeneity of variance of the interaction model was tested using Levene's test, while go...

Psychometric Properties and Characteristics of the North‐East Visual Hallucinations Interview in Parkinson's Disease

“…The majority of patients indicated that their VH began more than 1 year before evaluation and persisted for less than 1 minute, which is consistent with previous research . Also in line with previous studies, the majority of patients with complex VH reported that VH consisted of human figures and animals, whereas patients with simple VH reported seeing flashes, floaters, or movement in the periphery . Similar to Urwyler et al, the majority of the patients indicated that their VH were pleasant, and very few patients experienced frightening or irritating VH.…”

“…1 Also in line with previous studies, the majority of patients with complex VH reported that VH consisted of human figures and animals, whereas patients with simple VH reported seeing flashes, floaters, or movement in the periphery. 14,17,32 Similar to Urwyler et al, 14 the majority of the patients indicated that their VH were pleasant, and very few patients experienced frightening or irritating VH. Although complex VH often co-occur with simple VH in PD, 14,16,22,33 in the current study, only 2 participants reported more than 1 type of VH (i.e., simple or complex), whereas 92% reported 1 type of VH.…”

“…16 Simple VH consist of low-complexity visual features (e.g., flashes, swirls, patterns), whereas complex VH contain clearly defined images (e.g., animals, people, faces). 1,17 Assessing this phenomenology is important, because simple and complex VH may be associated with different pathophysiologic mechanisms 18 and thus may be valuable in terms of diagnostic and prognostic assessment. 19 One of the more promising measures of VH is the North-East Visual Hallucinations Interview (NEVHI).…”

Reduced occipital GABA in Parkinson disease with visual hallucinations

“…Visual hallucinations are common in Parkinson disease (PD), 1 particularly as the disease advances, and range from relatively simple flashes of light or color to more complex hallucinations that are typically well-formed images. 2 A number of models 3 , 4 have been proposed to explain the origin of complex recurrent visual hallucinations. Unifying elements across the models include breakdown in communication between cortical regions involved in visual processing, and alteration in the weighting of internal vs external input.…”

Visual hallucinations in neurological and ophthalmological disease: pathophysiology and management

“…dementia VH in dementia tend to be of people/children, animals or objects. 76 Around 50% of patients are significantly distressed by their experiences, with fear and anger being the most common responses. 77 As core defining features of DLB, they are likely to be present at the point of diagnosis, contrasting with AD where VH occur in later stages of cognitive decline, 5 to 6 years after the onset of dementia.…”