Risk factors for minor hallucinations in Parkinson's disease

Diagnostics and treatment of impulse control disorders, psychosis and delirium: systemic review-based recommendations - guideline "Parkinson's disease" of the German Society of Neurology

BACKGROUND AND OBJECTIVE

Impulse control disorders (ICD), psychosis and delirium are part of the spectrum of behavioural changes associated with Parkinson's disease (PD). The diagnostic and therapeutic management of these rather complex neuropsychiatric conditions has been updated in the clinical guideline by the German Society of Neurology (DGN).

METHODS

Recommendations are based on a systematic literature reviews, other relevant guidelines and expert opinion.

RESULTS

Patients receiving dopamine agonists (DA) therapy should be informed about the symptoms and risks of an ICD and should be routinely screened for ICD symptoms. In the presence of an ICD, DA should be reduced or discontinued and psychotherapeutic treatment may be considered. Non-oral therapies (levodopa/carbidopa intestinal gel infusion or deep brain stimulation) may also be an option for appropriate candidates. Psychosis in PD often has a gradual onset. Cognitive and affective disorders, psychiatric and medical comorbidities as well as polypharmacy are risk factors for a psychosis. Non-pharmacological treatments should be implemented as soon as possible and anti-parkinsonian medications should be adjusted/reduced if feasible. For psychosis associated with PD, quetiapine or clozapine should be used on an as-needed basis and for as short a time as is necessary, with safety monitoring. Delirium in PD may be underdiagnosed due to an overlap with chronic neuropsychiatric features of PD. Although transient by definition, delirium in PD can lead to permanent cognitive decline, motor impairment and increased mortality. Management of delirium includes pharmacological and non-pharmacological interventions.

CONCLUSION

The updated guideline encompasses the evidence-based diagnostic, non-pharmacological and pharmacological management of ICD, psychosis and delirium in PD.

Exploring the Spectrum of Visual Illusions and Other Minor Hallucinations in Patients with Parkinson's Disease in Lithuania

Background and Objectives: Parkinson's disease (PD) is associated with various non-motor symptoms, including minor hallucinations, comprising visual illusions and presence and passage hallucinations. Despite their occurrence, even in newly diagnosed PD patients, data regarding the prevalence and characteristics of minor hallucinations, visual illusions in particular, remain limited. The aim of this study was to address this knowledge gap by assessing the prevalence of minor hallucinations in PD patients, with a focus on visual illusions. Materials and Methods: In this prospective pilot study, we enrolled 35 PD patients without dementia and 35 age- and gender-matched PD-unaffected individuals. Cognitive function was assessed using the Montreal Cognitive Assessment, clinical data were collected, and all subjects were assessed via questionnaires regarding 20 types of visual illusions and other minor hallucinations. Results: The prevalence of minor hallucinations was significantly higher among PD patients compared to controls (45.7% vs. 11.4%, p = 0.003). PD patients reported visual illusions and presence hallucinations more frequently than the controls (37.1% vs. 8.6% and 22.9% vs. 2.9%, p = 0.009 and p = 0.028, respectively), with no significant difference in passage hallucinations (20% vs. 8.6%, p = 0.306). In the PD group, the most frequently observed visual illusions were complex visual illusions, kinetopsia, and pelopsia; the latter was also the most common visual illusion in the control group. PD patients experiencing visual illusions were more likely to report presence hallucinations compared to patients without visual illusions (53.8% vs. 4.5%, p = 0.002); no significant differences in other clinical characteristics were found. Conclusions: Minor hallucinations are a common phenomenon among PD patients without dementia, with a higher prevalence than among healthy controls. Visual illusions are the most prevalent type of minor hallucinations, affecting more than a third of PD patients, with complex visual illusions, kinetopsia, and pelopsia being the most frequently reported types.

Minor Phenomena in Parkinson's Disease-Prevalence, Associations, and Risk of Developing Psychosis

BACKGROUND

Minor phenomena, including passage phenomena, feeling of presence, and illusions, are common and may represent a prodromal form of psychosis in Parkinson's disease (PD). We examined the prevalence and clinical correlates of minor phenomena, and their potential role as a risk factor for PD psychosis.

METHODS

A novel questionnaire, the Psychosis and Mild Perceptual Disturbances Questionnaire for PD (PMPDQ), was completed by Fox Insight cohort participants with and without PD. Additional assessments included the Non-Motor Symptoms Questionnaire (NMSQuest), REM Sleep Behavior Disorder Single Question Screen (RBD1Q), Movement Disorder Society-Unified Parkinson Disease Rating Scale Part II, demographic features, and medication usage. For participants with PD, we used regression models to identify clinical associations and predictors of incident psychosis over one year of follow-up.

RESULTS

Among participants with PD (n = 5950) and without PD (n = 1879), the prevalence of minor phenomena was 43.1% and 31.7% (P < .001). Of the 3760 participants with PD and no baseline psychosis, independent correlates of minor phenomena included positive responses on the NMSQuest apathy/attention/memory (OR 1.7, 95% CI 1.3-2.1, P < .001) or sexual function domain (OR 1.3, 95% CI 1.1-1.6, P = .01) and positive RBD1Q (OR 1.3, 95% CI 1.05-1.5, P = .01). Independent risk factors for incident PD psychosis included the presence of minor phenomena (HR 3.0, 95% CI 2.4-3.9, P < .001), positive response on the NMSQuest apathy/attention/memory domain (HR 1.8, 95% CI 1.3-2.6, P < .001), and positive RBD1Q (HR 1.5, 95% CI 1.1-1.9, P = .004).

CONCLUSIONS

Minor phenomena are common, associated with specific non-motor symptoms, and an independent predictor of incident psychosis in PD.

To be or not to be hallucinating: Implications of hypnagogic/hypnopompic experiences and lucid dreaming for brain disorders

The boundaries between waking and sleeping-when falling asleep (hypnagogic) or waking up (hypnopompic)-can be challenging for our ability to monitor and interpret reality. Without proper understanding, bizarre but relatively normal hypnagogic/hypnopompic experiences can be misinterpreted as psychotic hallucinations (occurring, by definition, in the fully awake state), potentially leading to stigma and misdiagnosis in clinical contexts and to misconception and bias in research contexts. This Perspective proposes that conceptual and practical understanding for differentiating hallucinations from hypnagogic/hypnopompic experiences may be offered by lucid dreaming, the state in which one is aware of dreaming while sleeping. I first introduce a possible systematization of the phenomenological range of hypnagogic/hypnopompic experiences that can occur in the transition from awake to REM dreaming (including hypnagogic perceptions, transition symptoms, sleep paralysis, false awakenings, and out-of-body experiences). I then outline how metacognitive strategies used by lucid dreamers to gain/confirm oneiric lucidity could be tested for better differentiating hypnagogic/hypnopompic experiences from hallucinations. The relevance of hypnagogic/hypnopompic experiences and lucid dreaming is analyzed for schizophrenia and narcolepsy, and discussed for neurodegenerative diseases, particularly Lewy-body disorders (i.e. Parkinson's disease, Parkinson's disease dementia, and dementia with Lewy bodies), offering testable hypotheses for empirical investigation. Finally, emotionally positive lucid dreams triggered or enhanced by training/induction strategies or by a pathological process may have intrinsic therapeutic value if properly recognized and guided. The overall intention is to raise awareness and foster further research about the possible diagnostic, prognostic, and therapeutic implications of hypnagogic/hypnopompic experiences and lucid dreaming for brain disorders.

Phantosmia in Parkinson's Disease: A Systematic Review of the Phenomenology of Olfactory Hallucinations

Olfactory dysfunction is a prevalent non-motor symptom in Parkinson's disease (PD), affecting approximately 65-90% of subjects. PD patients may also report odor perception in the absence of any external source, often referred to as olfactory hallucinations (OHs) or phantosmia. This study aims to explore the current understanding of OHs in PD and offer a comprehensive overview of their prevalence and characteristics. We conducted a systematic search of the literature published on PubMed from inception to July 2023 regarding OHs in PD, following PRISMA guidelines. From the 2875 studies identified through database searching, 29 studies fulfilled the necessary criteria and underwent data extraction. The frequency of OHs in PD patients varies widely, ranging from 0.5% to 18.2%, with female prevalence ranging from 36% to 75% of the patients. Olfactory experiences may vary widely, ranging from pleasant scents to unpleasant odors. Several studies have indicated the concurrent presence of other types of hallucinations alongside phantosmia, especially visual and auditory hallucinations. OHs in PD are a type of hallucination that has been largely overlooked. To gain a deeper understanding of OHs in PD patients, the next crucial step should involve the development and validation of a dedicated questionnaire.

Prevalence of hallucinations in Parkinson's patients: meta-analysis of International studies

BACKGROUND

Parkinson's disease (PD) is one of the common causes of disability in the elderly. This study aims to estimate the prevalence of hallucinations in Parkinson's patients in the world.

METHODS

A systematic review of PubMed/Medline, ISI Web of Knowledge, and Google Scholar was conducted from 2017 to 2022. This study investigated the prevalence of hallucinations in Parkinson's patients. Point prevalence was analyzed with a 95% confidence interval. The variances of each study were calculated using the binomial distribution formula The researcher used Cochrane Q-test with a significance level of less than 0.1 to check the heterogeneity between studies and the change index assigned to heterogeneity I2. Due to the heterogeneity between the studies, the random effects model was used to combine the results of the studies. All statistical analyses were performed by STATA version 14 software using meta-analysis commands.

RESULTS

Reports indicated that the prevalence of hallucinations in Parkinson's patients in 32 studies was 28% (0.22-0.34 = 95%CI). The highest prevalence was 34% and 95% CI = 0.07- 0.61 in developing countries and 27% with CI = 0.33-0.21 in developed countries. Reports showed the prevalence in men was 30% (CI = 0.22-0.38) and in women 23% (95% CI = 0.14-0.31).

CONCLUSIONS

Considering the relatively high prevalence of hallucinations in these patients, checking up for the presence of hallucinations on every visit of Parkinson's patients is recommended, and providing appropriate treatment for that is necessary.

Minor hallucinations in Parkinson's disease with probable rapid eye movement sleep behavior disorder

Background

Rapid eye movement sleep behavior disorder (RBD) and minor hallucinations (MHs) are prevalent nonmotor symptoms in Parkinson's disease (PD). The purpose of this study was to explore the association of MHs in PD patients with probable RBD (pRBD).

Methods

This cross-sectional study included 291 patients diagnosed with PD. Patients who scored 6 or higher on the Rapid Eye Movement Behavior Disorder (RBD) Screening Questionnaire were defined as pRBD. A comprehensive evaluation was performed for all patients, including the collection of demographic information, clinical assessment, and MH features.

Results

Among the 291 PD patients, 69 (23.7%) had pRBD. MHs were observed in 35 (50.7%) patients with pRBD, significantly higher than 29.7% in patients without RBD (p = 0.015). The main type of MHs in pRBD was presence hallucinations with variable content. Patients with pRBD and MHs tended to be older, had a longer disease duration, and were more likely to take levodopa or dopamine-receptor agonists. Besides, the pRBD with MHs group had higher scores on the Nonmotor Symptoms Questionnaire (NMS-Quest) and Hamilton Anxiety Scale (HAMA). Binary logistic regression analysis revealed that longer disease duration and higher NMS-Quest scores were associated with MHs in PD patients with pRBD.

Conclusion

A high prevalence of MHs was observed in PD patients with pRBD. The main type of MHs in pRBD was presence hallucinations. MHs in PD with RBD are mainly associated with disease duration and severity of nonmotor symptoms. These findings provide new insights into the interaction between MHs and RBD.

Risk of Cognitive Impairment in Patients With Parkinson's Disease With Visual Hallucinations and Subjective Cognitive Complaints

BACKGROUND AND PURPOSE

Visual hallucinations (VH) and subjective cognitive complaints (SCC) are associated with cognitive impairment (CI) in Parkinson's disease. Our aims were to determine the association between VH and SCC and the risk of CI development in a cohort of patients with Parkinson's disease and normal cognition (PD-NC).

METHODS

Patients with PD-NC (total score of >80 on the Parkinson's Disease Cognitive Rating Scale [PD-CRS]) recruited from the Spanish COPPADIS cohort from January 2016 to November 2017 were followed up after 2 years. Subjects with a score of ≥1 on domain 5 and item 13 of the Non-Motor Symptoms Scale at baseline (V0) were considered as "with SCC" and "with VH," respectively. CI at the 2-year follow-up (plus or minus 1 month) (V2) was defined as a PD-CRS total score of <81.

RESULTS

At V0 (n=376, 58.2% males, age 61.14±8.73 years [mean±SD]), the frequencies of VH and SCC were 13.6% and 62.2%, respectively. VH were more frequent in patients with SCC than in those without: 18.8% (44/234) vs 4.9% (7/142), p<0.0001. At V2, 15.2% (57/376) of the patients had developed CI. VH presenting at V0 was associated with a higher risk of CI at V2 (odds ratio [OR]=2.68, 95% confidence interval=1.05-6.83, p=0.0.039) after controlling for the effects of age, disease duration, education, medication, motor and nonmotor status, mood, and PD-CRS total score at V0. Although SCC were not associated with CI at V2, presenting both VH and SCC at V0 increased the probability of having CI at V2 (OR=3.71, 95% confidence interval=1.36-10.17, p=0.011).

CONCLUSIONS

VH were associated with the development of SCC and CI at the 2-year follow-up in patients with PD-NC.

Non-visual hallucinations in Parkinson's disease: a systematic review

BACKGROUND

Non-visual hallucinations in Parkinson's disease (PD) can be prevalent and distressing. Most existing research has however, focused on visual hallucinations as well as related risk factors. The current study thus conducted a systematic review to collate existing evidence on non-visual hallucinations in PD, focusing on their prevalence, phenomenology, and clinical-cognitive correlates.

METHODS

Ninety-one relevant studies were included from a systematic search across PsycINFO APA, PubMed, and Web of Science, for peer-reviewed publications in the English language, from 1970 to the present. These comprised a mix of case (30 studies; n = 56) and group design (62 studies; n = 7346) studies, divided into three somewhat overlapping collections to address our three research foci.

RESULTS

Prevalence estimates for hallucinations were: auditory 1.5-72.0%, olfactory 1.6-21.0%, somatic-tactile 0.4-22.5%, gustatory 1.0-15.0%, and sensed presence 0.9-73.3%. Phenomenological inquiries revealed descriptions of vivid, consuming events replete with elaborate detail, adversely affecting PD patients in different ways. Overt experiences of multisensory hallucinations were also highly variable (0.4-80%) but exceedingly common, reported by almost half of the 45 included prevalence studies. There was some evidence for modality-specific hallucination predictors, but this was largely tentative, pending robust replication.

CONCLUSIONS

Marked prevalence figures coupled with phenomenological descriptions implicating distress denote that non-visual and multisensory hallucinations in PD are of clinical significance. More direct research and clinical attention need to be devoted to the study and management of such hallucinatory experiences.

Combined multidisciplinary in/outpatient rehabilitation delays definite nursing home admission in advanced Parkinson's disease patients

Introduction

Advanced Parkinson's disease (aPD) patients have a high risk on definite nursing home admission. We analyzed the effectiveness of an in-and outpatient multidisciplinary rehabilitation, focusing on activities of daily living (ADL) and delaying definite nursing home admission.

Methods

This study included 24 aPD patients, who received a 6-week inpatient multidisciplinary rehabilitation program, including optimization of pharmacotherapy, which was followed by an individualized outpatient support program during 2 years (intervention group). A non-randomized matched control group (n = 19), received care as usual. Primary endpoints consisted of the Amsterdam Linear Disability Scale (ALDS) and percentage of patients being able to live independently at home after 2 years. Secondary endpoints included changes in medication (LEDD), motor performance (SCOPA-SPES), cognition (SCOPA-COG), hallucinations (NPI) and depression (BDI).

Results

Overall, 83% of patients were able to return home after the 6-week inpatient intervention, and 65% still lived at home at 2 years follow-up. Median ALDS scores after 2 years in the intervention group were significantly better, compared to the control group (p = 0.002). All secondary endpoints had improved significantly vs. baseline directly after the 6-week inpatient rehabilitation, which had disappeared at 2 years follow-up, with the exception of the daily dose of medication, which was significantly higher in the intervention group.

Conclusion

This 2-year follow-up study showed that a combined multidisciplinary in/outpatient rehabilitation program for aPD patients, was able to stabilize ADL functions, and finally delayed definite nursing home admissions in 65% of treated patients.

Trial registration

filenumber M10.091051; ABR code NL32699.042.10.

Characteristics of sleep structure in Parkinson's disease patients with hallucinations based on polysomnography

Hallucination is a common non-motor symptom in patients with Parkinson's disease (PD). Additionally, sleep disorders are associated with an increased risk of hallucinations in PD patients. This study aimed to examine the association between hallucination and objective sleep parameters in PD patients. We retrospectively recruited 278 PD patients who underwent polysomnography and clinical assessments and classified them into non-hallucination and hallucination groups. Hallucinations were observed in 77 older PD patients who had more severe motor symptoms and higher scores on the Non-Motor Symptoms Questionnaire (NMSQ), Hamilton Depression Scale (HAMD) and Hamilton Anxiety Scale (HAMA) but lower scores on the Montreal Cognitive Assessment (MOCA) and PD Sleep Scale (PDSS) than PD patients without hallucinations. Analysis of the polysomnographic variables in patients with hallucinations showed that they exhibited a decrease in total sleep time, sleep efficiency (SE), rapid eye movement (REM) sleep time and slow wave sleep (SWS, N3) time and percentage but a significant increase in wake time after sleep onset (WASO), periodic limb movement index (PLMI) scores, and stage 2 NREM (N2)percentage. Logistic regression analysis revealed that higher NMSQ scores, lower MOCA scores, lower SE, and a lower percentage of N3 sleep were associated with hallucinations in PD patients. Our results suggested that PD patients with hallucinations had worse sleep quality and differences in sleep architecture (measured by polysomnography).

Sleep-related hallucinations in patients with Parkinson's disease

Given that sleep-wake cycle dysfunction can cause hallucinations in Parkinson's disease patients, sleep-related hallucinations may be a different subtype from hallucinations that occur only during full wakefulness. However, few studies that distinguish the onset situations of hallucinations related to sleep from those that occur in full wakefulness have been conducted to investigate hallucinations in Parkinson's disease patients. Therefore, we conducted a multicenter observational study to investigate the prevalence of and factors associated with sleep-related hallucinations in patients with Parkinson's disease. Information on hallucinations was collected by using a questionnaire and face-to-face interviews. Of 100 consecutive patients with Parkinson's disease, 29 (29%) reported sleep-related hallucinations, and 16 (16%) reported hallucinations only in the full wakefulness. A longer duration of Parkinson's disease treatment (OR 1.35, 95% CI 1.07 to 1.72), higher Beck Depression Inventory-II scores (OR 1.07; 95% CI 1.01 to 1.14), and higher rapid eye movement sleep behavior disorder scores (OR 5.60; 95% CI 1.54 to 20.38) were independent factors associated with the presence of sleep-related hallucinations in a multivariable analysis. Sleep-related hallucinations, but not daytime hallucinations, were associated with probable rapid eye movement sleep behavior disorder. Phenomenological discrimination between sleep-related hallucinations and daytime hallucinations is important for elucidating the full pathology in Parkinson's disease and the mechanisms underlying hallucinations.

Emerging role of psychosis in Parkinson's disease: From clinical relevance to molecular mechanisms

Parkinson’s disease (PD) is the second most common neurodegenerative disease. Psychosis is one of the common psychiatric presentations in the natural course of PD. PD psychosis is an important non-motor symptom, which is strongly correlated with a poor prognosis. Increasing attention is being given to PD psychosis. In this opinion review, we summarized and analyzed the identification, screening, epidemiology, mechanisms, risk factors, and therapeutic approaches of PD psychosis based on the current clinical evidence. PD psychosis tends to have a negative effect on patients' quality of life and increases the burden of family caregiving. Screening and identification in the early stage of disease is crucial for establishing tailored therapeutic strategies and predicting the long-term outcome. Development of PD psychosis is believed to involve a combination of exogenous and endogenous mechanisms including imbalance of neurotransmitters, structural and network changes, genetic profiles, cognitive impairment, and antiparkinsonian medications. The therapeutic strategy for PD psychosis includes reducing or ceasing the use of dopaminergic drug, antipsychotics, cholinesterase inhibitors, and non-pharmacological interventions. Ongoing clinical trials are expected to provide new insights for tailoring therapy for PD psychosis. Future research based on novel biomarkers and genetic factors may help inform individualized therapeutic strategies.

Minor hallucinations in isolated rapid eye movement sleep behavior disorder indicative of early phenoconversion: A preliminary study

OBJECTIVES

Minor hallucinations (MH) are psychotic symptoms that can occur anywhere between prodromal to early Parkinson's disease and after onset of motor problems. MH include visual illusions, presence hallucinations, and passage hallucinations. Isolated rapid eye movement sleep behavior disorder (RBD) is a harbinger of neurodegenerative diseases. We conducted a retrospective cohort study to investigate the clinical characteristics of isolated RBD with MH and the risk of phenoconversion.

MATERIALS AND METHODS

We retrospectively analyzed the data of 36 patients with isolated RBD (four females; median age, 75.0 years). We defined cases reporting at least one minor hallucination as RBD with MH. Demographic data and cognitive function were compared between patients with and without MH, and Cox proportional hazards models estimated the risk of phenoconversion.

RESULTS

We included 10 (27.8%) patients with MH and 26 (72.2%) without MH. Patients with MH were older, had less dopamine transporter accumulation, more severe autonomic dysfunction, more depressive symptoms, and lower verbal fluency and symbol coding test scores than patients without MH. After follow-up (median, 2.50 years), 13.9% (5/36) of all patients developed phenoconversion (Parkinson's disease, two patients; dementia with Lewy bodies, three patients). The rate of phenoconversion was significantly higher in patients with MH (40.0% vs. 3.8%, p = .005). The Cox proportional hazards model adjusted for age, sex, and disease duration revealed that MH was a significant risk factor for phenoconversion (hazard ratio, 14.72; 95% confidence interval, 1.35-160.5).

CONCLUSIONS

Minor hallucinations may be utilized as early clinical markers for prodromal estimation of neurodegenerative diseases.

Clinical Characteristics of Minor Hallucinations in Chinese Parkinson's Disease Patients

Background

Psychotic symptoms are common in Parkinson's disease (PD). However, the clinical characteristics of PD psychosis (PDP) have been rarely reported in Chinese PD patients. We aimed to categorize PDP in a PD cohort and its relationship to other clinical characteristics.

Methods

A total of 149 Chinese PD patients were consecutively enrolled, and idiopathic PD patients were recruited in the study. The symptoms of PDP were assessed with the enhanced Scale for the Assessment of Positive Symptoms in PD. Then, the patients were classified into a PD-control group, isolated minor hallucination (MH) group, and complex MH group, and clinical and demographic data of different groups were compared.

Results

Parkinson's disease psychosis was present in 40.3% (60/149) of our patients. The most common PDPs were MHs, present in 32.9% (49 of 149) of the cohort. Compared to patients without MHs, patients with MHs were older, had a longer disease duration, a higher levodopa equivalent daily dose, more severe motor symptoms, dyskinesia, a higher rate of rapid eye movement sleep behavior disorders, frontal lobe function impairments, and a higher percentage of cognitive impairment. Logistic regression analysis showed that advanced Hoehn-Yahr stage [odds ratio (OR): 2.697, p = 0.007)] and frontal lobe function impairment (OR: 0.684, p = 0.003) were independent risk factors for MHs.

Conclusion

MHs were frequent non-motor symptoms in PD patients. It was associated with increased motor and non-motor symptom burdens and reduced quality of life. MHs have been called “minor,” but they have major clinical and prognostic implications and need early screening.

[Hallucinations in Patients with Idiopathic Parkinson's Disease]

Patients with idiopathic Parkinson's disease develop symptoms of the hallucination-psychosis spectrum in more than 20%. Most common are visual hallucinations. The pathogenesis of hallucinations mainly depends on disease duration, the distribution and extent of alpha-synuclein pathology, and modulating effects of the dopaminergic therapy. When managing PD hallucinations both anti-delirogenic actions and medication management are important. However, decrease in dopaminergic medication may lead to critical worsening of akinesia. If appropriate neuroleptic medication - essentially quetiapin or clozapin - can be considered. Instead, anti-dopaminergic neuroleptics should not be used owing to their pro-akinetic side-effects. Here, we provide therapy recommendations to manage PD hallucinations based on an up-to-date targeted review of the literature and expert-based empirical evidence.

Prevalence and Risk Factors for Minor Hallucinations in Patients with Parkinson's Disease

Purpose

As the most frequent and earliest type of psychotic phenomenon in Parkinson's disease (PD), minor hallucination (MH) can occur before the onset of motor symptoms. This sensation may be an early predictor of severe psychotic and cognitive states and is often overlooked in clinics. This study was aimed at providing a comprehensive and in-depth understanding of MHs. Patients and Methods. Demographic information was obtained from 262 patients with PD, and a series of clinical assessment questionnaires were provided. According to the result of the Movement Disorders Society Unified Parkinson's Disease Rating Scale Part I, the patients were classified into the MH and nonhallucination (NH) groups.

Results

MHs were the most common psychotic symptom with 38.9% prevalence. The most frequent MH was visual illusion, especially object misidentification. Three minor phenomena were somewhat consistent in terms of external factors, temporal factors, and content. Disease duration, daily levodopa equivalent dose, and percentage of levodopa and dopamine-receptor agonist use were remarkably greater in the MH group than in the NH group. After covariate control, the MH group had worse life quality and more severe nonmotor symptoms, including poor sleep quality and rapid eye movement sleep behavior disorder (RBD), than the NH group. The binary logistic regression model showed that RBD, sleep quality, and health-related life quality were associated with MHs.

Conclusion

A high prevalence of MHs was observed in patients with PD. Further studies are needed to confirm and expand the identified clinical factors related to MH, which have potential prognostic and therapeutic implication.