Charles Bonnet Syndrome Adversely Affects Vision-Related Quality of Life in Patients with Glaucoma.

PURPOSE: To investigate the impact of Charles Bonnet syndrome (CBS) on vision-related quality of life (VRQoL) in patients with glaucoma. DESIGN: Cross-sectional cohort study. PARTICIPANTS: Twenty-four patients with CBS and 42 matched controls without CBS out of 337 patients with open-angle glaucoma (OAG) with visual field (VF) loss. METHODS: A matching technique was used to identify control patients with similar disease stage, best-corrected visual acuity (BCVA) and age to patients with CBS. Patients' VRQoL was determined using the National Eye Institute Visual Function Questionnaire 25 (NEI VFQ-25). Rasch-calibrated NEI VFQ-25 scores of the CBS group and the control group were compared. Uni- and multivariable regression analysis was used to evaluate the impact of different factors on VRQoL. MAIN OUTCOME MEASURES: Vision-related quality of life in patients with glaucoma with CBS and without CBS. RESULTS: Vision-related quality of life scores were significantly lower in the CBS group than in the control group on both the visual functioning scale with 39 points (95% confidence interval (CI): 30-48) vs. 52 points (95% CI: 46-58) (P = 0.013) and on the socioemotional scale with 45 points (95% CI: 37-53) vs. 58 points (95% CI: 51-65) (P = 0.015). Univariable regression analysis showed that integrated visual field mean deviation (IVF-MD) (r2 = 0.334, P < 0.001), BCVA in the better eye (r2 = 0.117, P = 0.003), and the presence of CBS (r2 = 0.078, P = 0.013) were significantly correlated to VRQoL scores on the visual functioning scale. Integrated visual field mean deviation (r2 = 0.281, P < 0.001), age (r2 = 0.048, P = 0.042), and the presence of CBS (r2 = 0.076, P = 0.015) were significantly correlated to VRQoL scores on the socioemotional scale. Multivariable regression analysis showed that IVF-MD and the presence of CBS accounted for nearly 40% of the VRQoL score on the visual functioning scale (R2 = 0.393, P < 0.001) and for 34% of the VRQoL score on the socioemotional scale (R2 = 0.339, P < 0.001). CONCLUSIONS: Charles Bonnet syndrome had a significant negative association to VRQoL in patients with glaucoma. Presence of CBS should be considered when evaluating VRQoL in patients with glaucoma. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Explanatory power by vagueness. Challenges to the strong prior hypothesis on hallucinations exemplified by the Charles-Bonnet-Syndrome.

Predictive processing models are often ascribed a certain generality in conceptually unifying the relationships between perception, action, and cognition or the potential to posit a 'grand unified theory' of the mind. The limitations of this unification can be seen when these models are applied to specific cognitive phenomena or phenomenal consciousness. Our article discusses these shortcomings for predictive processing models of hallucinations by the example of the Charles-Bonnet-Syndrome. This case study shows that the current predictive processing account omits essential characteristics of stimulus-independent perception in general, which has critical phenomenological implications. We argue that the most popular predictive processing model of hallucinatory conditions - the strong prior hypothesis - fails to fully account for the characteristics of nonveridical perceptual experiences associated with Charles-Bonnet-Syndrome. To fill this explanatory gap, we propose that the strong prior hypothesis needs to include reality monitoring to apply to more than just veridical percepts.

Charles Bonnet syndrome in patients with Stargardt disease: prevalence and risk factors.

AIMS: To describe the prevalence of the Charles Bonnet syndrome (CBS) and search for potential CBS risk factors in a Dutch Stargardt disease (STGD1) cohort. METHODS: Eighty-three patients with STGD1 were screened for CBS. They underwent a full eye examination. All patients completed the social functioning domain of the 36-Item Short Form Health Survey questionnaire. Participants suspected of CBS were interviewed to further evaluate their visual hallucinations. RESULTS: CBS prevalence was 8.4%. Six out of seven patients with CBS were women. CBS was not associated with age (p=0.279, Mann-Whitney). Patients with CBS had a significant lower social functioning score (p<0.05, Mann-Whitney). All seven patients with CBS were in the category of vision impairment (visual acuity <6/12, but ≥3/60). Moreover, first hallucinations manifested after a drop in visual acuity. The retinal atrophic area of the worst eye tended to be lower in the CBS group (range 0.11-9.86 mm2) as compared with controls (range 0-180 mm2). There was no relation between the position of the scotoma and the location of the visual hallucinations. CONCLUSION: The relative high CBS prevalence in STGD1 suggests that CBS may be more prevalent in younger ophthalmic patients than currently presumed. In this specific group of patients, we established social isolation and acquired vision impairment as risk factors for CBS. There was a female preponderance among patients with CBS. Age and retinal pigment epithelium atrophy were not identified as significant risk factors. We should actively diagnose CBS in patients of any age who fulfil the criteria for the category vision impairment, especially in cases where social isolation is suspected.

Charles Bonnet Syndrome Associated With Recurrent Hypertensive Crisis.

Charles Bonnet syndrome (CBS) is a disorder of visual hallucinations in psychologically normal patients with ocular disease or damage to visual pathways. The etiology of CBS is not fully understood. It is associated with various triggers, with age-related macular degeneration the most common; other triggers are systemic diseases such as stroke, multiple sclerosis, and anemia as well as lighting issues, fatigue, and medical or surgical eye treatments. Visual disturbances such as decreased visual acuity, visual field deficits, or visual hallucinations are common in association with hypertensive encephalopathy. We describe a patient with episodic CBS triggered by recurrent hypertensive crises, which resolved with blood pressure management in the hospital setting.

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.

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.

Charles Bonnet Syndrome in Patients with Open-Angle Glaucoma: Prevalence and Correlation to Visual Field Loss.

PURPOSE: To determine the prevalence and characteristics of Charles Bonnet Syndrome (CBS) and its relation to visual field loss (VFL) in patients with open-angle glaucoma (OAG). DESIGN: Prospective, cross-sectional study. PARTICIPANTS: Adult patients (n = 337) with manifest OAG with verified VFL and without significant macular disease or extraocular conditions known to cause visual hallucinations. METHODS: Patients attending the glaucoma outpatient department of the Skåne University hospital, Malmö, Sweden, between April 1, 2018, and December 31, 2018, were consecutively evaluated for inclusion. Potentially eligible patients admitting to having complex visual hallucinations were interviewed to explore the characteristics of their hallucinatory experiences. Recent automated visual field examinations were available for all participants, and swept-source OCT was performed in participants with CBS to rule out previously undiagnosed macular pathology. The correlation between potential risk factors and CBS was evaluated with logistic regression analysis. MAIN OUTCOME MEASURE: Prevalence of CBS in patients with OAG. RESULTS: Charles Bonnet Syndrome was found in 7.1% (95% confidence interval [CI], 4.7-10.6) of patients with OAG. Participants with CBS were more likely to have at least 1 eye with a visual field index (VFI) of ≤30% compared with those without CBS (71% vs. 34.2%; P = 0.001). Although the best-corrected visual acuity (BCVA) in the worse eye was significantly lower in participants with CBS (decimal equivalent of Snellen BCVA: 0.25 vs. 0.6, P = 0.003), 33% of these participants had a BCVA of ≥0.5 in the worse eye. In multivariable analysis, CBS was correlated to the VFI of the better eye (odds ratio, 0.984; 95% CI, 0.969-0.998, P = 0.030) and the BCVA of the worse-seeing eye (odds ratio, 0.210; 95% CI, 0.046-0.952, P = 0.043). CONCLUSIONS: Charles Bonnet Syndrome was not a rare condition in patients with glaucoma. Patients with a combination of advanced VFL and low BCVA had the highest risk of CBS; however, 1 of 3 patients with CBS had a BCVA of ≥0.5 in both eyes. These findings emphasize the importance of being attentive to symptoms of CBS in patients with glaucomatous VFL even when visual acuity is preserved.

Charles Bonnet Syndrome Prevalence in a Younger Ophtalmology Outpatient Population.

BACKGROUND: In the literature, most of the studies on Charles Bonnet Syndrome (CBS) were performed on older populations. This study aims to determine the prevalence and epidemiology of CBS and the nature of the hallucinations of the younger group of patients from an ophthalmology outpatient clinic of a university hospital. SUBJECTS AND METHODS: Twenty-eight patients were randomly chosen from the outpatient ophthalmology clinic of a university hospital, and those who agreed to participate in the study were included. First, the patients were asked if they had ever seen visions that other people cannot when they were fully awake. The patients who were experiencing this symptom were given sociodemographic questionnaire and Psychiatry Institute Visual Hallucination Questionnaire, and asked to explain their hallucinations in detail. To exclude a psychiatric disorder, the participants were made a psychiatric interview as well. RESULTS: The study included 19 female (67.9%) and 9 male (32.1%) participants. Five patients (17.9%) were diagnosed with CBS. Average age of the patients diagnosed with CBS was 39.4 (min.31-max.48). Three of the 5 patients (60%) with CBS noted negative emotions (fear, wince and bewilderment) about their hallucinations. CONCLUSIONS: The prevalence of CBS (17.9%) we've found is compatible with the medical literature. CBS may also be accompanied by "relatively milder" ophthalmologic problems (myopia, astigmatism, etc.). The hallucinations which CBS patients experience could be quite distressing, and the individuals might have hard times to reveal their complaints because of the apprehension of stigmatization. To inquire this symptom during clinical examination may be the first step to help these individuals.

High-Density EEG in a Charles Bonnet Syndrome Patient during and without Visual Hallucinations: A Case-Report Study.

Charles Bonnet syndrome (CBS) is a rare clinical condition characterized by complex visual hallucinations in people with loss of vision. So far, the neurobiological mechanisms underlying the hallucinations remain elusive. This case-report study aims at investigating electrical activity changes in a CBS patient during visual hallucinations, as compared to a resting-state period (without hallucinations). Prior to the EEG, the patient underwent neuropsychological, ophthalmologic, and neurological examinations. Spectral and connectivity, graph analyses and signal diversity were applied to high-density EEG data. Visual hallucinations (as compared to resting-state) were characterized by a significant reduction of power in the frontal areas, paralleled by an increase in the midline posterior regions in delta and theta bands and by an increase of alpha power in the occipital and midline posterior regions. We next observed a reduction of theta connectivity in the frontal and right posterior areas, which at a network level was complemented by a disruption of small-worldness (lower local and global efficiency) and by an increase of network modularity. Finally, we found a higher signal complexity especially when considering the frontal areas in the alpha band. The emergence of hallucinations may stem from these changes in the visual cortex and in core cortical regions encompassing both the default mode and the fronto-parietal attentional networks.

Atypical Charles Bonnet syndrome secondary to frontal meningioma: a case report.

BACKGROUND: Charles Bonnet Syndrome (CBS) is a rare clinical entity that is classically composed of visual hallucinations in the context of an altered optic pathway with preservation of reality judgment. This case aims to present the association of visual hallucinations with complex alterations of the nervous structures adjacent to the visual pathway and an atypical clinical presentation, thus explaining the possible mechanisms involved in the generation of these symptoms. CASE PRESENTATION: A 43-year-old man presents seeking care due to visual hallucinations with partial preservation of reality judgment and symptoms compatible with a major depressive disorder, including irritability and diminished hygiene habits. He has a history of complete gradual loss of vision and hyposmia. Due to poor treatment response during hospitalization, an MRI was obtained, which showed a frontal tumor lesion with meningioma characteristics adjacent to the olfactory groove and compression of the optic chiasm. He underwent surgical resection of the lesion, which remitted the psychotic symptoms, but preserving the visual limitation and depressive symptoms. CONCLUSIONS: The presence of visual hallucinations, without other psychotic features as delusions, is a focus of attention for basic structural pathologies in the central nervous system. Affection at any level of the visual pathway can cause CBS. When finding atypical symptoms, a more in-depth evaluation should be made to allow optimization of the diagnosis and treatment.