Hallucinations in Parkinson disease

Does an association between cigarette smoking and Parkinson's Disease-related psychosis exist? Insights from a large non-demented cohort

BACKGROUND

Parkinson's Disease-related Psychosis (PDP) encompasses a spectrum of symptoms ranging from "minor" hallucinations to formed hallucinations and delusions. Notably, cognitive impairment has been recognized as the strongest risk factor for PDP. Several evidences suggest a possible role of cigarette smoking in both cognition and psychotic syndromes.

OBJECTIVES

To evaluate the possible independent association between cigarette smoking and PDP in a large cohort of non-demented PD patients.

METHODS

A cohort of non-demented PD patients was selected from the FRAGAMP study population. All participants underwent a standardised structured questionnaire to assess demographic, clinical and environmental exposure data. Clinical features were assessed using UPDRS, HY stage, AIMS, MMSE and Hamilton Rating Scale for Depression. Presence of psychotic symptoms was assessed using UPDRS-I.2 score. Diagnosis of PDP was made according to NINDS/NIMH criteria.

RESULTS

Four hundred eighty-five non-demented PD patients were enrolled [292 men (60.2%); mean age ± SD 65.6 ± 9.8]. Among them, 28 (5.8%) had PDP. Multivariate analysis, adjusting by HY stage, MMSE and LED, shown an independent association between PDP and "nightmares-abnormal movements during sleep" and current smoking [adjOR 7.39 (95%CI 1.45-37.69; P-value 0.016)].

CONCLUSIONS

Our findings provide interesting insights about the possible role of current smoking in facilitating the occurrence of psychotic symptoms in PD.

Effects of Gocovri (Amantadine) Extended-Release Capsules on Motor Aspects of Experiences of Daily Living in People with Parkinson's Disease and Dyskinesia

Introduction

Gocovri, a bedtime-administered delayed-release/extended-release capsule formulation of amantadine, is the only drug approved by the US Food and Drug Administration as levodopa-adjunctive therapy for the treatment of OFF episodes and/or dyskinesia in Parkinson’s disease (PD). Part II of the Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) assesses patient-perceived disability on experiences of daily living affected by PD motor symptoms. We analyzed Gocovri-related changes in MDS-UPDRS Part II ratings in two placebo-controlled clinical trials.

Methods

Baseline to week 12 changes in MDS-UPDRS Part II total and item scores were compared for Gocovri and placebo using pooled data from phase 3 trials (EASE LID and EASE LID 3).

Results

Baseline mean MDS-UPDRS Part II total score was 15.1 for Gocovri (n = 100) and 15.3 for placebo (n = 96) groups. At week 12, the least squares mean change from baseline was −3.4 for the Gocovri group and −1.4 for placebo (treatment difference, −2.0; 95% CI −3.3 to −0.7; P = 0.004). For Gocovri, change from baseline exceeded a published minimal clinically important difference threshold of 3.05. Gocovri-related treatment differences over placebo were driven primarily by improvement in the scale items of freezing (−0.4; P < 0.0001), tremor (−0.4; P = 0.002), getting out of bed/car/deep chair (−0.3; P = 0.002), and eating tasks (−0.2; P = 0.016).

Conclusion

In addition to improvement in dyskinesia, Gocovri-treated participants experienced improvement in motor aspects of experiences of daily living. Analyses suggest that Gocovri may specifically improve freezing, tremor, getting out of bed/car/deep chair, and eating tasks.

Trial Registration

ClinicalTrials.gov identifiers: NCT02136914, NCT02274766.

Face pareidolia is associated with right striatal dysfunction in drug-naïve patients with Parkinson's disease

BACKGROUND AND AIM

Some patients with Parkinson's disease (PD) present with pareidolia, an illusion of a meaningless stimulus as a familiar object known to the observer. Since the striatum is associated with processing of visual information, we investigated correlations of pareidolia with motor symptoms and striatal dopaminergic function.

METHOD

A noise pareidolia test, assessment of motor symptoms using MDS-UPDRS and ¹²³I-Ioflupane SPECT were performed in 58 drug-naïve PD patients. A number of images in which a participant noticed an illusory face (number of illusory responses) were compared with motor assessment scores and uptake of ¹²³I-ioflupane in the striatum.

RESULTS

Of the 58 participants, 22 had at least one illusory response. Mean scores for MDS-UPDRS part III (p<0.05), rigidity (p<0.05), and rigidity on the left side of the body (p<0.01) in patients with pareidolia were significantly higher than those in patients without pareidolia. Uptake of ¹²³I-ioflupane in the right caudate nucleus (p<0.05), anterior putamen (p<0.01), and posterior putamen (p<0.01) in patients with pareidolia was significantly lower than in patients without pareidolia. In the 22 patients with pareidolia, the number of illusory responses was significantly correlated with total scores for MDS-UPDRS part III (r=0.443, p<0.05) and subscores for bradykinesia (r=0.440, p<0.05) and bradykinesia on the left side of the body (r=0.564, p<0.01). The prevalence of pareidolia in left-dominant parkinsonism (16/30 patients) was higher than that in right-dominant parkinsonism (6/28 patients) (p<0.05 by chi-square test).

CONCLUSION

Pareidolia in PD patients is associated with dysfunction in the right striatum.

Polymorphisms of Dopamine Receptor Genes and Parkinson's Disease: Clinical Relevance and Future Perspectives

Parkinson’s disease (PD) is a neurodegenerative disease caused by loss of dopaminergic neurons in the midbrain. PD is clinically characterized by a variety of motor and nonmotor symptoms, and treatment relies on dopaminergic replacement. Beyond a common pathological hallmark, PD patients may present differences in both clinical progression and response to drug therapy that are partly affected by genetic factors. Despite extensive knowledge on genetic variability of dopaminergic receptors (DR), few studies have addressed their relevance as possible influencers of clinical heterogeneity in PD patients. In this review, we summarized available evidence regarding the role of genetic polymorphisms in DR as possible determinants of PD development, progression and treatment response. Moreover, we examined the role of DR in the modulation of peripheral immunity, in light of the emerging role of the peripheral immune system in PD pathophysiology. A better understanding of all these aspects represents an important step towards the development of precise and personalized disease-modifying therapies for PD.

White matter abnormalities of right hemisphere attention networks contribute to visual hallucinations in dementia with Lewy bodies

OBJECTIVE

Functional alterations of the visual attention networks in a setting of impaired visual information processing have a role in the genesis of visual hallucinations (VH) in dementia with Lewy bodies (DLB). This multimodal MRI study aims at exploring structural and functional basis of VH.

METHODS

23 DLB patients (10 with and 13 without VH) and 13 healthy controls were studied. They underwent MRI with T1-w sequences to measure cortical thickness, DTI for whole-brain and single tract microstructural properties and rs-fMRI of the default mode, dorsal and ventral attention, and visual networks.

RESULTS

In DLB with VH, whole-brain DTI revealed a lower fractional anisotropy and a greater mean diffusivity in the right frontal and temporo-parietal white matter tracts. Tracts dissection showed lower fractional anisotropy in the right inferior and superior (ventral part) longitudinal fasciculi (ILF and SLF) (p < .05, corrected), and greater mean diffusivity (p < .05). The extent of white matter microstructural alterations involving the right ILF and SLF correlated with the severity of VH (r = .55, p < .01; r = .42, p < .05, respectively), and with performance in the visual attention task (r = -.56 and r = -.61; p < .01, respectively). Cortical thickness in the projection areas of the right SLF was significantly reduced (p < .05). Patients with VH also showed an altered functional connectivity in the ventral attention network, connected by the ventral portion of the SLF (p < .05).

CONCLUSIONS

Our findings suggest that a combination of microstructural and functional alterations involving the attention networks in the right hemisphere may be important in the genesis of VH.

Gemfibrozil Protects Dopaminergic Neurons in a Mouse Model of Parkinson's Disease via PPARα-Dependent Astrocytic GDNF Pathway

Parkinson's disease (PD) is the most common neurodegenerative movement disorder in humans. Despite intense investigations, effective therapies are not yet available to halt the progression of PD. Gemfibrozil, a Food and Drug Administration-approved lipid-lowering drug, is known to decrease the risk of coronary heart disease by increasing the level of high-density lipoprotein cholesterol and decreasing the level of low-density lipoprotein cholesterol. This study underlines the importance of gemfibrozil in protecting dopaminergic neurons in an animal model of PD. Oral administration of the human equivalent dose of gemfibrozil protected tyrosine hydroxylase (TH)-positive dopaminergic neurons in the substantia nigra pars compacta and TH fibers in the striatum of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-insulted mice of both sexes. Accordingly, gemfibrozil also normalized striatal neurotransmitters and improved locomotor activities in MPTP-intoxicated mice. Gemfibrozil-mediated protection of the nigrostriatal and locomotor activities in WT but not PPARα-/- mice from MPTP intoxication suggests that gemfibrozil needs the involvement of peroxisome proliferator-activated receptor α (PPARα) in protecting dopaminergic neurons. While investigating further mechanisms, we found that gemfibrozil stimulated the transcription of glial-derived neurotrophic factor (GDNF) gene in astrocytes via PPARα and that gemfibrozil protected nigral neurons, normalized striatal fibers and neurotransmitters, and improved locomotor activities in MPTP-intoxicated Gfafcre mice, but not GdnfΔastro mice lacking GDNF in astrocytes. These findings highlight the importance of the PPARα-dependent astroglial GDNF pathway in gemfibrozil-mediated protection of dopaminergic neurons in an animal model of PD and suggest the possible therapeutic use of gemfibrozil in PD patients.SIGNIFICANCE STATEMENT Increasing the level of glial cell-derived neurotrophic factor (GDNF) in the brain is important for the protection of dopamine neurons in Parkinson's disease (PD). Although gene manipulation and GDNF protein infusion into the brain are available options, it seems from the therapeutic angle that the best option would be to stimulate/induce the production of GDNF in vivo in the brain of PD patients. Here, we delineate that gemfibrozil, a lipid-lowering drug, stimulates GDNF in astrocytes via peroxisome proliferator-activated receptor α (PPARα). Moreover, gemfibrozil protected nigral neurons, normalized striatal fibers and neurotransmitters, and improved locomotor activities from MPTP toxicity via the PPARα-dependent astroglial GDNF pathway. These studies highlight a new property of gemfibrozil and suggest its possible therapeutic use in PD patients.

Associations between probable REM sleep behavior disorder, olfactory disturbance, and clinical symptoms in Parkinson's disease: A multicenter cross-sectional study

BACKGROUND

Rapid eye movement sleep behavior disorder (RBD) and olfactory dysfunction are useful for early diagnosis of Parkinson's disease (PD). RBD and severe olfactory dysfunction are also regarded as risk factors for cognitive impairment in PD. This study aimed to assess the associations between RBD, olfactory function, and clinical symptoms in patients with PD.

METHODS

The participants were 404 patients with non-demented PD. Probable RBD (pRBD) was determined using the Japanese version of the RBD screening questionnaire (RBDSQ-J) and the RBD Single-Question Screen (RBD1Q). Olfactory function was evaluated using the odor identification test for Japanese. Clinical symptoms were evaluated using the Movement Disorder Society Revision of the Unified PD Rating Scale (MDS-UPDRS) parts I-IV.

RESULTS

In total, 134 (33.2%) patients indicated a history of pRBD as determined by the RBD1Q and 136 (33.7%) by the RBDSQ-J based on a cutoff value of 6 points. Moreover, 101 patients were diagnosed as pRBD by both questionnaires, 35 by the RBDSQ-J only, and 33 by the RBD1Q only. The MDS-UPDRS parts I-III scores were significantly higher and disease duration significantly longer in the pRBD group. pRBD was significantly associated with male gender and the MDS-UPDRS part I score. The olfactory identification function was significantly reduced in the pRBD group.

CONCLUSIONS

About 33% of the patients with PD had pRBD based on the questionnaires, and both motor and non-motor functions were significantly decreased in these patients. These results suggest that more extensive degeneration occurred in patients with non-demented PD with RBD.

Schizotypy in Parkinson's disease predicts dopamine-associated psychosis

Psychosis is the most common neuropsychiatric side-effect of dopaminergic therapy in Parkinson’s disease (PD). It is still unknown which factors determine individual proneness to psychotic symptoms. Schizotypy is a multifaceted personality trait related to psychosis-proneness and dopaminergic neurotransmission in healthy subjects. We investigated whether (1) PD patients exhibit lower schizotypy than controls and (2) dopamine-related neuropsychiatric side-effects can be predicted by higher schizotypy. In this cross-sectional study, we used the Oxford-Liverpool Inventory of Feelings and Experiences in 56 PD patients (12 women, mean ± sd age: 61 ± 11 years) receiving their usual dopaminergic medication and 32 age-matched healthy controls (n = 32; 18 women, mean ± sd age: 57 ± 6 years). We further compared schizotypy scores of patients with (n = 18, 32.1%) and without previously experienced psychosis. We found that patients exhibited lower schizotypy than controls. Further, patients with a history of psychosis exhibited higher schizotypy than patients without these symptoms. Using an information theoretic measure and a machine learning approach, we show that schizotypy yields the greatest predictive value for dopamine-associated hallucinations compared to other patient characteristics and disease related factors. Our results indicate an overlap between neural networks associated with schizotypy and the pathophysiology of PD and a relationship between schizotypy and psychotic side-effects of dopaminergic medication.

Treating hallucinations in Parkinson's disease

Introduction: Hallucinations in Parkinson's disease are common, can complicate medication management and significantly impact upon the quality of life of patients and their carers.Areas covered: This review aims to examine current evidence for the management of hallucinations in Parkinson's disease.Expert opinion: Treatment of hallucinations in Parkinson's disease should be both individualized and multifaceted. Screening, education, medication review and the avoidance of common triggers are important. For well-formed visual hallucinations, acetylcholinesterase inhibitors are recommended first-line. Refractory or severe symptoms may require the cautious use of atypical antipsychotics. Antidepressants may be beneficial in the appropriate setting. Unfortunately, current therapies for hallucinations offer only limited benefits and future research efforts are desperately required to improve the management of these challenging symptoms.

Hallucination, imagery, dreaming: reassembling stimulus-independent perceptions based on Edmund Parish's classic misperception framework

Within the broad field of human perception lies the category of stimulus-independent perceptions, which draws together experiences such as hallucinations, mental imagery and dreams. Traditional divisions between medical and psychological sciences have contributed to these experiences being investigated separately. This review aims to examine their similarities and differences at the levels of phenomenology and underlying brain function and thus reassemble them within a common framework. Using Edmund Parish's historical work as a guiding tool and the latest research findings in the cognitive, clinical and computational sciences, we consider how different perspectives may be reconciled and help generate novel hypotheses for future research. This article is part of the theme issue 'Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'.

Visual hallucinations in Parkinson's disease are associated with thinning of the inner retina

Visual hallucinations (VH) are common in patients with Parkinson's disease (PD), yet the underlying pathophysiological mechanisms are still unclear. We aimed to explore the association of the presence of VH with inner retinal thinning and, secondarily, with visual acuity. To this end, we included 40 PD patients in this exploratory study, of whom 14 had VH, and 22 age- and sex-matched healthy controls. All participants were interviewed for the presence of VH by a neurologist specialized in movement disorders and underwent a thorough ophthalmologic examination, including measurement of the best-corrected visual acuity (BCVA) and optical coherence tomography to obtain macular scans of the combined ganglion cell layer and inner plexiform layer (GCL-IPL). Patients with VH had a thinner GCL-IPL than patients without VH, which persisted after correction for age, disease stage, levodopa equivalent daily dose (LED) and cognitive function. Furthermore, BCVA was lower in the PD group with VH than in the PD group without VH, although only a trend remained after correction for age, disease stage, LED and cognitive function. Taken together, in patients with PD, visual hallucinations appear to be associated with a thinning of the inner retinal layers and, possibly, with reduced visual acuity. Further research using a longitudinal design is necessary to confirm these findings and to establish the causality of these relationships.

Visual hallucinations and inferior longitudinal fasciculus in Parkinson's disease

INTRODUCTION

We investigated whether disruption of the inferior longitudinal fasciculus and inferior fronto-occipital fasciculus are associated with visual hallucinations in Parkinson's disease (PD).

METHODS

Sixty consecutive right-handed patients with PD with and without visual hallucinations were enrolled in this cross-sectional study. Diffusion tensor imaging was acquired by 3.0 T magnetic resonance imaging. We measured fractional anisotropy and mean diffusivity of the bilateral inferior longitudinal fasciculus and inferior fronto-occipital fasciculus using diffusion tensor tractography analysis software.

RESULTS

Seventeen patients with PD had visual hallucinations; these patients tended to have lower fractional anisotropy and higher mean diffusivity values in all fasciculi than did patients without visual hallucinations. A univariate logistic analysis showed that the presence of visual hallucinations was significantly associated with lower fractional anisotropy and higher mean diffusivity of the left inferior longitudinal fasciculus, and lower Mini-Mental State Examination (MMSE) scores. A multivariable logistic analysis adjusted by MMSE scores and disease duration showed a significant association between the presence of visual hallucinations and fractional anisotropy and mean diffusivity values of the left inferior longitudinal fasciculus.

CONCLUSIONS

Our results suggest that disruption of left inferior longitudinal fasciculus integrity is associated with visual hallucinations in patients with PD, independent of cognitive impairment and disease duration.

Increasing Contrast Improves Object Perception in Parkinson's Disease with Visual Hallucinations

Background

Deficits in basic vision are associated with visual hallucinations in Parkinson's disease. Of particular interest is contrast sensitivity loss in this disorder and its effect on object identification.

Objectives

Evaluate whether increased contrast improves object perception in persons with Parkinson's disease and visual hallucinations, without dementia.

Methods

We assessed 26 individuals with mild to moderate idiopathic Parkinson's disease, half of whom reported one or more episodes of hallucinations/unusual perceptual experiences in the past month, with a letter-identification task that determined the contrast level required to achieve 80% accuracy. Contrast sensitivity was further assessed with a chart that presented stimuli at multiple spatial frequencies. The groups were closely matched for demographic and clinical characteristics except for experience of hallucinations.

Results

Relative to participants without visual hallucinations, those with hallucinations had poorer spatial frequency contrast sensitivity and required significantly greater contrast to correctly identify the letters on the identification task. Specifically, participants with hallucinations required a mean contrast of 52.8%, whereas participants without hallucinations required 35.0%. When given sufficient contrast, the groups with and without hallucinations were equally accurate in letter identification.

Conclusions

Compared to those without hallucinations, individuals with Parkinson's disease and hallucinations without dementia showed poorer contrast sensitivity. Once contrast was individually enhanced, the groups were equally accurate at object identification. These findings suggest the potential of visual perception tests to predict, and perception-based interventions to reduce, hallucinations in Parkinson's disease.

Minor hallucinations reflect early gray matter loss and predict subjective cognitive decline in Parkinson's disease

BACKGROUND AND PURPOSE

Well-structured hallucinations in Parkinson's disease (PD) are associated with poor prognosis and dementia. However, the predictive value of minor psychotic phenomena in cognitive deterioration is not well known. Cross-sectional studies have shown that PD patients with minor hallucinations have more severe cortical atrophy than non-hallucinators, but baseline and longitudinal studies addressing the evolution of these brain differences are lacking. The impact of developing minor hallucinations on cognitive impairment and cortical atrophy progression in early PD was explored.

METHODS

One hundred and thirty-one de novo PD patients from the Parkinson's Progression Marker Initiative for whom brain magnetic resonance imaging scans were available were included. Cognitive outcome at 5 years was compared between patients with and without minor hallucinations during follow-up. Additionally, using gray matter volume (GMV) voxel-based morphometry, cross-sectional (at baseline) and longitudinal (1- and 2-year GMV loss) structural brain differences between groups were studied.

RESULTS

During follow-up, 35.1% of patients developed minor hallucinations. At 5 years, these patients showed an increased prevalence of subjective cognitive decline compared to non-hallucinators (44.1% vs. 13.9%; p < 0.001), but not formal cognitive impairment. Additionally, compared to non-hallucinators, they exhibited reduced GMV at baseline in visuoperceptive areas and increased GMV loss in left temporal areas (p < 0.05 corrected).

CONCLUSIONS

Minor hallucinations seem to be an early clinical marker of increased neurodegeneration and are associated with mid-term subjective cognitive decline. Longer follow-up analyses would be needed to further define if these findings could reflect a higher risk of future cognitive deterioration.

Selective blockade of the 5-HT3 receptor acutely alleviates dyskinesia and psychosis in the parkinsonian marmoset

In Parkinson's disease (PD), management of L-3,4-dihydroxyphenylalanine (l-DOPA)-related complications, such as l-DOPA induced dyskinesia and psychosis, remains inadequate, which poses a significant burden on the quality of life of patients. We have shown, in the hemi-parkinsonian rat model of PD, that the selective serotonin type 3 (5-HT₃) receptor antagonists ondansetron and granisetron decreased the severity of established dyskinesia, and ondansetron even attenuated the development of dyskinesia. Here, we seek to confirm these favourable data on dyskinesia and to explore the effect of ondansetron on the severity of psychosis-like behaviours (PLBs) in the gold standard model of PD, the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned non-human primate. We first determined the pharmacokinetic profile of ondansetron in the marmoset. Subsequently, six MPTP-lesioned marmosets were administered l-DOPA chronically until they exhibited stable and reproducible dyskinesia and PLBs upon each administration of l-DOPA. On behavioural assessment days, ondansetron (0.01, 0.1 and 1 mg/kg) or vehicle was administered in conjunction with l-DOPA, and the severity of dyskinesia, PLBs and parkinsonism was evaluated. Ondansetron 0.1 mg/kg alleviated global dyskinesia severity by 73% (P < 0.0001) and decreased duration of on-time with disabling dyskinesia by 88% (P = 0.0491). Ondansetron 0.1 mg/kg reduced the severity of global PLBs by 80% (P < 0.0001) and suppressed on-time with disabling PLBs (P = 0.0213). Ondansetron enhanced the anti-parkinsonian action of l-DOPA, reducing global parkinsonism by 53% compared to l-DOPA (P = 0.0004). These results suggest that selective blockade of the 5-HT₃ receptor with ondansetron may be an effective approach to alleviate l-DOPA-related complications.

Multimodal Evaluation of Neurovascular Functionality in Early Parkinson's Disease

Parkinson's disease (PD) is a multisystem neurological condition affecting different neurotransmitter pathways characterized by aberrant functional connectivity (FC) and perfusion alteration. Since the FC, measuring neuronal activity, and cerebral blood flow (CBF) are closely related through the neurovascular coupling (NVC) mechanism, we aim to assess whether FC changes found in PD mirror perfusion ones. A multimodal MRI study was implemented by acquiring resting state functional MRI (rsfMRI) and arterial spin labeling (ASL) datasets on a group of 26 early PD (66.8 ± 8 years, 22 males, median [interquartile range] Hoehn and Yahr = 1.5 [1]) and 18 age- and sex-matched healthy controls (HCs). In addition, a T1-weighted MPRAGE was also acquired in the same scan session. After a standard preprocessing, resting state networks (RSNs) and CBF maps were extracted from rsfMRI and ASL dataset, respectively. Then, by means of a dual regression algorithm performed on RSNs, a cluster of FC differences between groups was obtained and used to mask CBF maps in the subsequent voxel-wise group comparison. Furthermore, a gray matter (GM) volumetric assessment was performed within the FC cluster in order to exclude tissue atrophy as a source of functional changes. Reduced FC for a PD patient with respect to HC group was found within a sensory-motor network (SMN, p_FWE = 0.01) and visual networks (VNs, primary p_FWE = 0.022 and lateral p_FWE = 0.01). The latter was accompanied by a decreased CBF (primary p_FWE = 0.037, lateral p_FWE = 0.014 VNs), while no GM atrophy was detected instead. The FC alteration found in the SMN of PD might be likely due to a dopaminergic denervation of the striatal pathways causing a functional disconnection. On the other hand, the changes in connectivity depicted in VNs might be related to an altered non-dopaminergic system, since perfusion was also reduced, revealing a compromised NVC. Finally, the absence of GM volume loss might imply that functional changes may potentially anticipate neurodegeneration. In this framework, FC and CBF might be proposed as early functional biomarkers providing meaningful insights in evaluating both disease progression and therapeutic/rehabilitation treatment outcome.

Clinical factors affecting evoked magnetic fields in patients with Parkinson's disease

Studies on evoked responses in Parkinson's disease (PD) may be useful for elucidating the etiology and quantitative evaluation of PD. However, in previous studies, the association between evoked responses and detailed motor symptoms or cognitive functions has not been clear. This study investigated the characteristics of the visual (VEF), auditory (AEF), and somatosensory (SEF) evoked magnetic fields in patients with Parkinson’s disease (PD), and the correlations between evoked fields and the patient’s clinical characteristics, motor symptoms, and cognitive functions. Twenty patients with PD and 10 healthy controls (HCs) were recruited as participants. We recorded VEF, AEF, and SEF, collected clinical characteristics, performed physical examinations, and administered 10 cognitive tests. We investigated differences in the latencies of the evoked fields between patients with PD and HCs. We also evaluated the correlation of the latencies with motor symptoms and cognitive functioning. There were significant differences between the two groups in 6 of the cognitive tests, all of which suggested mild cognitive impairment in patients with PD. The latencies of the VEF N75m, P100m, N145m, AEF P50m, P100m, and SEF P60m components were greater in the patients with PD than in the HCs. The latencies mainly correlated with medication and motor symptoms, less so with cognitive tests, with some elements of the correlations remaining significant after Bonferroni correction. In conclusion, the latencies of the VEF, AEF, and SEF were greater in PD patients than in HCs and were mainly correlated with medication and motor symptoms rather than cognitive functioning. Findings from this study suggest that evoked fields may reflect basal ganglia functioning and are candidates for assessing motor symptoms or the therapeutic effects of medication in patients with PD.

Clinical and Clinical-Pharmacogenetic Models for Prediction of the Most Common Psychiatric Complications Due to Dopaminergic Treatment in Parkinson's Disease

BACKGROUND

The most common psychiatric complications due to dopaminergic treatment in Parkinson's disease are visual hallucinations and impulse control disorders. Their development depends on clinical and genetic factors.

METHODS

We evaluated the simultaneous effect of 16 clinical and 34 genetic variables on the occurrence of visual hallucinations and impulse control disorders. Altogether, 214 Parkinson's disease patients were enrolled. Their demographic, clinical, and genotype data were obtained. Clinical and clinical-pharmacogenetic models were built by The Least Absolute Shrinkage and Selection Operator penalized logistic regression. The predictive capacity was evaluated with the cross-validated area under the receiver operating characteristic curve (AUC).

RESULTS

The clinical-pharmacogenetic index for prediction of visual hallucinations encompassed age at diagnosis (OR = 0.99), rapid eye movement (REM) sleep behavior disorder (OR = 2.27), depression (OR = 1.0002), IL6 rs1800795 (OR = 0.99), GPX1 s1050450 (OR = 1.07), COMT rs165815 (OR = 0.69), MAOB rs1799836 (OR = 0.97), DRD3 rs6280 (OR = 1.32), and BIRC5 rs8073069 (OR = 0.94). The clinical-pharmacogenetic index for prediction of impulse control disorders encompassed age at diagnosis (OR = 0.95), depression (OR = 1.75), beta-blockers (OR = 0.99), coffee consumption (OR = 0.97), NOS1 rs2682826 (OR = 1.15), SLC6A3 rs393795 (OR = 1.27), SLC22A1 rs628031 (OR = 1.19), DRD2 rs1799732 (OR = 0.88), DRD3 rs6280 (OR = 0.88), and NRG1 rs3924999 (OR = 0.96). The cross-validated AUCs of clinical and clinical-pharmacogenetic models for visual hallucinations were 0.60 and 0.59, respectively. The AUCs of clinical and clinical-pharmacogenetic models for impulse control disorders were 0.72 and 0.71, respectively. The AUCs show that the addition of selected genetic variables to the analysis does not contribute to better prediction of visual hallucinations and impulse control disorders.

CONCLUSIONS

Models could be improved by a larger cohort and by addition of other types of Parkinson's disease biomarkers to the analysis.

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.

Neuropsychiatric aspects of Parkinson disease psychopharmacology: Insights from circuit dynamics

Parkinson disease (PD) is a neurodegenerative disorder with a complex pathophysiology characterized by the progressive loss of dopaminergic neurons within the substantia nigra. Persons with PD experience several motoric and neuropsychiatric symptoms. Neuropsychiatric features of PD include depression, anxiety, psychosis, impulse control disorders, and apathy. In this chapter, we will utilize the National Institutes of Mental Health Research Domain Criteria (RDoC) to frame and integrate observations from two prevailing disease constructions: neurotransmitter anomalies and circuit physiology. When there is available evidence, we posit how unified translational observations may have clinical relevance and postulate importance outside of PD. Finally, we review the limited evidence available for pharmacologic management of these symptoms.

Seeing ophthalmologic problems in Parkinson disease: Results of a visual impairment questionnaire

Objective

To determine the prevalence and clinical effect of ophthalmologic symptoms in patients with Parkinson disease (PD), compared with controls, using a standardized questionnaire.

Methods

In this observational, cross-sectional, multicenter study, 848 patients with PD and 250 healthy controls completed the Visual Impairment in Parkinson's Disease Questionnaire (VIPD-Q). The VIPD-Q addressed 4 domains according to structures: (1) ocular surface; (2) intraocular; (3) oculomotor; and (4) optic nerve. The questionnaire also assessed the effect of ophthalmologic symptoms on daily activities.

Results

One or more ophthalmologic symptoms were reported by 82% (95% confidence interval [CI], 80–85) of patients, compared with 48% (95% CI, 42–54) of controls (p < 0.001). Patients with PD experienced more ophthalmologic symptoms across all domains than controls (p < 0.001), as reflected by a higher VIPD-Q total score among patients (median 10 [interquartile range (IQR) 13]) than controls (median 2 [IQR 5]; p < 0.001). Ophthalmologic symptoms interfered with daily activities in 68% (95% CI, 65–71) of patients, compared with 35% (95% CI, 29–41) of controls (p < 0.001).

Conclusion

Patients with PD have a higher prevalence of ophthalmologic symptoms than controls. Moreover, these frequently interfere with daily activities. A screening questionnaire such as the VIPD-Q may help with identifying ophthalmologic symptoms in PD, thereby enabling more timely treatment.

Neuropsychiatric Disorders in Parkinson's Disease: What Do We Know About the Role of Dopaminergic and Non-dopaminergic Systems?

Besides the hallmark motor symptoms (rest tremor, hypokinesia, rigidity, and postural instability), patients with Parkinson’s disease (PD) have non-motor symptoms, namely neuropsychiatric disorders. They are frequent and may influence the other symptoms of the disease. They have also a negative impact on the quality of life of patients and their caregivers. In this article, we will describe the clinical manifestations of the main PD-related behavioral disorders (depression, anxiety disorders, apathy, psychosis, and impulse control disorders). We will also provide an overview of the clinical and preclinical literature regarding the underlying mechanisms with a focus on the role of the dopaminergic and non-dopaminergic systems.

Spatial judgment in Parkinson's disease: Contributions of attentional and executive dysfunction

Spatial judgment is impaired in Parkinson's disease (PD), with previous research suggesting that disruptions in attention and executive function are likely contributors. If judgment of center places demands on frontal systems, performance on tests of attention/executive function may correlate with extent of bias in PD, and attentional disturbance may predict inconsistency in spatial judgment. The relation of spatial judgment to attention/executive function may differ for those with left-side versus right-side motor onset (LPD, RPD), reflecting effects of attentional lateralization. We assessed 42 RPD, 37 LPD, and 67 healthy control participants with a Landmark task (LM) in which a cursor moved horizontally from the right (right-LM) or left (left-LM). The task was to judge the center of the line. Participants also performed neuropsychological tests of attention and executive function. LM group differences were found on left-LM only, with both PD subgroups biased leftward of the control group (RPD p < .05; LPD p < .01; no RPD-LPD difference). For left-LM trials, extent of bias significantly correlated with performance on the cognitive tasks for PD but not for the control group. PD showed greater variability in perceived center than the control group; this variability correlated with performance on the cognitive tasks. The correlations between performance on the test of spatial judgment and the tests of attention/executive function suggest that frontal-based attentional dysfunction affects dynamic spatial judgment, both in extent of spatial bias and in consistency of response as indexed by intertrial variability. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Reality-monitoring deficits and visual hallucinations in schizophrenia

The presence of visual hallucinations in addition to auditory hallucinations (V + AH) is associated with poor prognosis in patients with schizophrenia. However, little consideration has been given to these symptoms and their underlying cognitive bases remain unclear. Based on cognitive models of hallucinations, we hypothesized that V + AH are underpinned by an impairment in reality-monitoring processes. The objective of the present study was to test whether reality-monitoring deficits were associated with V + AH in schizophrenia. This study examined reality-monitoring abilities in two groups of patients with schizophrenia: a group of patients with V + AH (n = 24) and a group of patients with AH only (n = 22). Patients with V + AH were significantly more likely to misremember imagined words as being perceived from an external source, compared to patients with AH only (p = 0.008, d = -0.82). In other words, V + AH patients display a larger externalization bias than patients with AH only. One explanation for these results could be that experiencing hallucinations in two sensory modalities may contribute to increased vividness of mental imagery and, in turn, lead to disruption in reality-monitoring processes. This study helps to refine our understanding of the cognitive processes underlying the presence of both auditory and visual hallucinations in patients with schizophrenia.

FDG-PET assessment and metabolic patterns in Lafora disease

PURPOSE

To describe cerebral glucose metabolism pattern as assessed by ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) in Lafora disease (LD), a rare, lethal form of progressive myoclonus epilepsy caused by biallelic mutations in EPM2A or NHLRC1.

METHODS

We retrospectively included patients with genetically confirmed LD who underwent FDG-PET scan referred to three Italian epilepsy centers. FDG-PET images were evaluated both visually and using SPM12 software. Subgroup analysis was performed on the basis of genetic and clinical features employing SPM. Moreover, we performed a systematic literature review of LD cases that underwent FDG-PET assessment.

RESULTS

Eight Italian patients (3M/5F, 3 EPM2A/5 NHLRC1) underwent FDG-PET examination after a mean of 6 years from disease onset (range 1-12 years). All patients showed bilateral hypometabolic areas, more diffuse and pronounced in advanced disease stages. Most frequently, the hypometabolic regions were the temporal (8/8), parietal (7/8), and frontal lobes (7/8), as well as the thalamus (6/8). In three cases, the FDG-PET repeated after a mean of 17 months (range 7-36 months) showed a metabolic worsening compared with the baseline examination. The SPM subgroup analysis found no significant differences based on genetics, whereas it showed a more significant temporoparietal hypometabolism in patients with visual symptoms compared with those without. In nine additional cases identified from eight publications, FDG-PET showed heterogeneous findings, ranging from diffusely decreased cerebral glucose metabolism to unremarkable examinations in two cases.

CONCLUSIONS

FDG-PET seems highly sensitive to evaluate LD at any stage and may correlate with disease progression. Areas of decreased glucose metabolism in LD are extensive, often involving multiple cortical and subcortical regions, with thalamus, temporal, frontal, and parietal lobes being the most severely affected. Prospective longitudinal collaborative studies are needed to validate our findings.

The Pharmacology of Visual Hallucinations in Synucleinopathies

Visual hallucinations (VH) are commonly found in the course of synucleinopathies like Parkinson's disease and dementia with Lewy bodies. The incidence of VH in these conditions is so high that the absence of VH in the course of the disease should raise questions about the diagnosis. VH may take the form of early and simple phenomena or appear with late and complex presentations that include hallucinatory production and delusions. VH are an unmet treatment need. The review analyzes the past and recent hypotheses that are related to the underlying mechanisms of VH and then discusses their pharmacological modulation. Recent models for VH have been centered on the role played by the decoupling of the default mode network (DMN) when is released from the control of the fronto-parietal and salience networks. According to the proposed model, the process results in the perception of priors that are stored in the unconscious memory and the uncontrolled emergence of intrinsic narrative produced by the DMN. This DMN activity is triggered by the altered functioning of the thalamus and involves the dysregulated activity of the brain neurotransmitters. Historically, dopamine has been indicated as a major driver for the production of VH in synucleinopathies. In that context, nigrostriatal dysfunctions have been associated with the VH onset. The efficacy of antipsychotic compounds in VH treatment has further supported the notion of major involvement of dopamine in the production of the hallucinatory phenomena. However, more recent studies and growing evidence are also pointing toward an important role played by serotonergic and cholinergic dysfunctions. In that respect, in vivo and post-mortem studies have now proved that serotonergic impairment is often an early event in synucleinopathies. The prominent cholinergic impairment in DLB is also well established. Finally, glutamatergic and gamma aminobutyric acid (GABA)ergic modulations and changes in the overall balance between excitatory and inhibitory signaling are also contributing factors. The review provides an extensive overview of the pharmacology of VH and offers an up to date analysis of treatment options.

Aberrant functional connectivity of resting state networks related to misperceptions and intra-individual variability in Parkinson's disease

Patients with Parkinson's disease (PD) frequently suffer from visual misperceptions and hallucinations, which are difficult to objectify and quantify. We aimed to develop an image recognition task to objectify misperceptions and to assess performance fluctuations in PD patients with and without self-reported hallucinations. Thirty-two non-demented patients with Parkinson's disease (16 with and 16 without self-reported visual hallucinations) and 25 age-matched healthy controls (HC) were tested. Participants performed a dynamic image recognition task with real and scrambled images. We assessed misperception scores and intra-individual variability in recognition times. To gain insight into possible neural mechanisms related to misperceptions and performance fluctuations we correlated resting state network connectivity to the behavioral outcomes in a subsample of Parkinson's disease patients (N = 16). We found that PD patients with self-reported hallucinations (PD-VH) exhibited higher perceptual error rates, due to decreased perceptual sensitivity and not due to changed decision criteria. In addition, PD-VH patients exhibited higher intra-individual variability in recognition times than HC or PD-nonVH patients. Both, misperceptions and intra-individual variability were negatively correlated with resting state functional connectivity involving frontal and parietal brain regions, albeit in partly different subregions. Consistent with previous research suggesting that hallucinations arise from dysfunction in attentional networks, misperception scores correlated with reduced functional connectivity between the dorsal attention and salience network. Intra-individual variability correlated with decreased connectivity between somatomotor and right fronto-parietal networks. We conclude that our task can detect visual misperceptions that are more prevalent in PD-VH patients. In addition, fluctuating visual performance appear to be a signature of PD-VH patients, which might assist further studies of the underlying pathophysiological mechanisms and cognitive processes.

Difficulties and associated coping methods regarding visual hallucinations caused by dementia with Lewy bodies

Individuals who have dementia with Lewy bodies present various symptoms that differ from those associated with Alzheimer's disease. Of the several characteristic symptoms of dementia with Lewy bodies, visual hallucinations often appear in the early stages of the disease, and some hallucinations cause people with dementia with Lewy bodies to experience unique difficulties in their daily lives. The aim of this paper is to clarify the visual hallucination-related difficulties experienced by people with dementia with Lewy bodies as well as their coping methods. Participants were 10 people with dementia with Lewy bodies who were living at home, with input also obtained from their family members. Data were collected through semi-structured interviews, and a qualitative content analysis was consequently performed. The qualitative analysis showed four primary difficulties in the period before a patient realizes that their visual hallucinations are a symptom of an underlying disease; these included "feeling something strange is happening" and "restrictions on activities." Realizing that what they were experiencing was not real was a significant turning point for the participants, with some discovering this by discussing their apparitions with their families. It was consequently determined that, after an individual realizes that their hallucinations are indicative of a more serious condition, two further difficulties arise, including the "inability to discuss the visual hallucinations with friends and family." With regard to coping methods, some participants reported rearranging their living environments to hide areas where hallucinations commonly appeared. This paper suggests that care is needed to help people with dementia with Lewy bodies recognize that their visual hallucinations are a manifestation of their illness. In particular, psychological support should be made available to address the anxiety caused by the appearance of visual hallucinations and to help patients adjust their environments to reduce or prevent the appearance of such hallucinations.

Blindness, Psychosis, and the Visual Construction of the World

The relationship between visual loss and psychosis is complex: congenital visual loss appears to be protective against the development of a psychotic disorder, particularly schizophrenia. In later life, however, visual deprivation or visual loss can give rise to hallucinosis, disorders of visual insight such as blindsight or Anton syndrome, or, in the context of neurodegenerative disorders, more complex psychotic presentations. We draw on a computational psychiatric approach to consider the foundational role of vision in the construction of representations of the world and the effects of visual loss at different developmental stages. Using a Bayesian prediction error minimization model, we describe how congenital visual loss may be protective against the development of the kind of computational deficits postulated to underlie schizophrenia, by increasing the precision (and consequent stability) of higher-level (including supramodal) priors, focusing on visual loss-induced changes in NMDA receptor structure and function as a possible mechanistic substrate. In simple terms, we argue that when people cannot see from birth, they rely more heavily on the context they extract from the other senses, and the resulting model of the world is more impervious to the false inferences, made in the face of inevitably noisy perceptual input, that characterize schizophrenia. We show how a Bayesian prediction error minimization framework can also explain the relationship between later visual loss and other psychotic symptoms, as well as the effects of visual deprivation and hallucinogenic drugs, and outline experimentally testable hypotheses generated by this approach.

Visual hallucinations in psychosis

The Dutch version of the Visual Hallucination Questionnaire was used to assess lifetime visual hallucinations (VH) characteristics in 27 patients with psychosis. Our results confirmed substantial variance in many VH characteristics. Most patients reported multiple VH types. Complex VH were most prevalent, mainly consisting of people and animals, followed by simple, then geometric VH. Few patients experienced only simple VH. The VH generally had features resembling real perceptions. Insight was usually reduced. VH ranged from 'appropriate' and neutral to peculiar and delusion-associated. VH accompanied by fright and sound seem to be related to experiencing complex or multiple types of VH.

Auditory and visual hallucination prevalence in Parkinson's disease and dementia with Lewy bodies: a systematic review and meta-analysis

BACKGROUND

Non-motor features of Parkinson's disease (PD) and dementia with Lewy bodies (DLB), such as auditory hallucinations (AH), contribute to disease burden but are not well understood.

METHODS

Systematic review and random-effects meta-analyses of studies reporting AH associated with PD or DLB. Prevalence of visual hallucinations (VH) in identified studies meeting eligibility criteria were included in meta-analyses, facilitating comparison with AH. Synthesis of qualitative descriptions of AH was performed. PubMed, Web of Science and Scopus databases were searched for primary journal articles, written in English, published from 1970 to 2017. Studies reporting AH prevalence in PD or DLB were screened using PRISMA methods.

RESULTS

Searches identified 4542 unique studies for consideration, of which, 26 met inclusion criteria. AH pooled prevalence in PD was estimated to be 8.9% [95% confidence interval (CI) 5.3-14.5], while in DLB was estimated to be 30.8% (±23.4 to 39.3). Verbal hallucinations, perceived as originating outside the head, were the most common form of AH. Non-verbal AH were also common while musical AH were rare. VH were more prevalent, with an estimated pooled prevalence in PD of 28.2% (±19.1 to 39.5), while in DLB they were estimated to be 61.8% (±49.1 to 73.0). Meta-regression determined that the use of validated methodologies to identify hallucinations produced higher prevalence estimates.

CONCLUSIONS

AH and VH present in a substantial proportion of PD and DLB cases, with VH reported more frequently in both conditions. Both AH and VH are more prevalent in DLB than PD. There is a need for standardised use of validated methods to detect and monitor hallucinations.

Minor hallucinations in Parkinson disease: A subtle symptom with major clinical implications

OBJECTIVE

Psychosis is one of the most debilitating complications of Parkinson disease (PD). Although research on PD psychosis has been focused on the study of well-structured visual hallucinations (VH), currently accepted National Institute of Neurological Disorders and Stroke-National Institute of Mental Health diagnostic criteria emphasize minor hallucinations (MH) as the most common psychotic phenomena in PD. The objective of this review is to comprehensively describe the clinical and research advances on the understanding of MH and to provide future directions for obtaining further insights into their potential major implications for PD management and prognosis.

METHODS

A PubMed search was done in November 2018 to identify articles on minor psychotic phenomena in PD.

RESULTS

MH often precede the onset of well-structured VH and are associated with other nonmotor symptoms such as REM sleep behavior disorder and depression. The pattern of functional brain connectivity changes associated with MH involve visual-processing areas and attention control networks, which overlap with abnormalities described in patients with well-structured VH. The dysfunction of cortical networks in patients with MH may be an early indicator of a more widespread form of the disease.

CONCLUSION

Although called "minor," MH may have major clinical and prognostic implications. Further research is needed to establish whether MH are associated with a higher risk of disabling psychotic complications, cognitive deterioration, or a more accelerated disease progression. Understanding the early neurobiological underpinnings of MH may provide the background for future studies to identify the progressive dysfunction of neural circuits leading to more severe forms of psychosis in PD.

Hallucinations, somatic-functional disorders of PD-DLB as expressions of thalamic dysfunction

Hallucinations, delusions, and functional neurological manifestations (conversion and somatic symptom disorders) of Parkinson's disease (PD) and dementia with Lewy bodies increase in frequency with disease progression, predict the onset of cognitive decline, and eventually blend with and are concealed by dementia. These symptoms share the absence of reality constraints and can be considered comparable elements of the PD-dementia with Lewy bodies psychosis. We propose that PD-dementia with Lewy bodies psychotic disorders depend on thalamic dysfunction promoting a theta burst mode and subsequent thalamocortical dysrhythmia with focal cortical coherence to theta electroencephalogram rhythms. This theta electroencephalogram activity, also called fast-theta or pre-alpha, has been shown to predict cognitive decline and fluctuations in Parkinson's disease with dementia and dementia with Lewy bodies. These electroencephalogram alterations are now considered a predictive marker for progression to dementia. The resulting thalamocortical dysrhythmia inhibits the frontal attentional network and favors the decoupling of the default mode network. As the default mode network is involved in integration of self-referential information into conscious perception, unconstrained default mode network activity, as revealed by recent imaging studies, leads to random formation of connections that link strong autobiographical correlates to trivial stimuli, thereby producing hallucinations, delusions, and functional neurological disorders. The thalamocortical dysrhythmia default mode network decoupling hypothesis provides the rationale for the design and testing of novel therapeutic pharmacological and nonpharmacological interventions in the context of PD, PD with dementia, and dementia with Lewy bodies. © 2019 International Parkinson and Movement Disorder Society.

Targeting neurons in the gastrointestinal tract to treat Parkinson's disease

Background

Parkinson's disease (PD) is associated with α-synuclein (αS) aggregation within the enteric nervous system (ENS) and constipation. Squalamine displaces proteins that are electrostatically bound to intracellular membranes and through this mechanism suppresses aggregation of αS monomers into neurotoxic oligomers.

Objective

We sought to evaluate the safety of ENT-01 oral tablets (a synthetic squalamine salt), its pharmacokinetics, and its effect on bowel function in PD patients with constipation.

Methods

In Stage 1, 10 patients received escalating single doses from 25 to 200 mg/day or maximum tolerated dose (MTD). In Stage 2, 34 patients received daily doses escalating from 75 to a maximum of 250 mg/day, a dose that induced change in bowel function or MTD, followed by a fixed dose for 7 days, and a 2-week washout. Primary efficacy endpoint was defined as an increase of 1 complete spontaneous bowel movement (CSBM)/week, or 3 CSBM/week over the baseline period, as defined by FDA guidelines for prokinetic agents. Safety was also assessed.

Results

Over 80% of patients achieved the primary efficacy endpoint, with the mean number of CSBM/week increasing from 1.2 at baseline to 3.6 during fixed dosing (p = 1.2 × 10⁻⁷). Common adverse events included nausea in 21/44 (47%) and diarrhea in 18/44 (40%) patients. Systemic absorption was <0.3%.

Conclusions

Orally administered ENT-01 was safe and significantly improved bowel function in PD, suggesting that the ENS is not irreversibly damaged in PD. Minimal systemic absorption suggests that improvements result from local stimulation of the ENS. A double-blind, placebo-controlled study is now ongoing.

Towards seeing the visual impairments in Parkinson's disease: protocol for a multicentre observational, cross-sectional study

Background

Visual disorders are common in Parkinson’s disease (PD) but their exact frequency and severity are unknown. Good visual functioning is crucial for patients with PD, because of their need to compensate for loss of automated motor control and their postural instability, forcing patients to guide their movements visually. Here, we describe the study design of a cross-sectional, multi-centre study aiming to: (1) validate the Visual Impairment screening questionnaire (VIPD-Q, which aims to identify PD patients who should be referred to an ophthalmologist for further assessment); (2) study the prevalence of visual disorders in PD; (3) study the severity and clinical impact of different types of visual disorders in PD; and (4) explore treatment options for ophthalmologic disorders in PD, as a basis for future guideline development.

Methods

This study consists of two phases. In phase one, 750 PD patients and 250 healthy controls will be recruited to complete the VIPD-Q. In phase two, a subgroup of responders (n = 100) (with the highest and lowest scores on the VIPD-Q) will be invited for an extensive neurological and ophthalmological assessment. The in-depth ophthalmologic examination will serve as the “gold standard” for validating the VIPD-Q. Moreover, these assessments will be used to study associations between visual disorders and clinical presentation, in order to gain more insight in their clinical impact.

Discussion

Our study will heighten the awareness of visual problems in PD and offers a robust starting point to systematically approach this subject. In current daily practice, the association between visual problems and PD is far from obvious to both patients and clinicians. Consequently, patients may not adequately report visual problems themselves, while clinicians miss potentially treatable visual disorders. Routinely asking patients to complete a simple screening questionnaire could be an easy solution leading to timely identification of visual problems, tailored treatment, restored mobility, greater independence and improved quality of life.

Trial registration

Dutch Trial Registration, NL7421, Registered on 4 December 2018 – Retrospectively registered.

Electronic supplementary material

The online version of this article (10.1186/s12883-019-1365-8) contains supplementary material, which is available to authorized users.

Beyond Trauma: A Multiple Pathways Approach to Auditory Hallucinations in Clinical and Nonclinical Populations

That trauma can play a significant role in the onset and maintenance of voice-hearing is one of the most striking and important developments in the recent study of psychosis. Yet the finding that trauma increases the risk for hallucination and for psychosis is quite different from the claim that trauma is necessary for either to occur. Trauma is often but not always associated with voice-hearing in populations with psychosis; voice-hearing is sometimes associated with willful training and cultivation in nonclinical populations. This article uses ethnographic data among other data to explore the possibility of multiple pathways to voice-hearing for clinical and nonclinical individuals whose voices are not due to known etiological factors such as drugs, sensory deprivation, epilepsy, and so forth. We suggest that trauma sometimes plays a major role in hallucinations, sometimes a minor role, and sometimes no role at all. Our work also finds seemingly distinct phenomenological patterns for voice-hearing, which may reflect the different salience of trauma for those who hear voices.

Meta-analytic Evidence for the Plurality of Mechanisms in Transdiagnostic Structural MRI Studies of Hallucination Status

BACKGROUND

Hallucinations are transmodal and transdiagnostic phenomena, occurring across sensory modalities and presenting in psychiatric, neurodegenerative, neurological, and non-clinical populations. Despite their cross-category occurrence, little empirical work has directly compared between-group neural correlates of hallucinations.

METHODS

We performed whole-brain voxelwise meta-analyses of hallucination status across diagnoses using anisotropic effect-size seed-based d mapping (AES-SDM), and conducted a comprehensive systematic review in PubMed and Web of Science until May 2018 on other structural correlates of hallucinations, including cortical thickness and gyrification.

FINDINGS

3214 abstracts were identified. Patients with psychiatric disorders and hallucinations (eight studies) exhibited reduced gray matter (GM) in the left insula, right inferior frontal gyrus, left anterior cingulate/paracingulate gyrus, left middle temporal gyrus, and increased in the bilateral fusiform gyrus, while patients with neurodegenerative disorders with hallucinations (eight studies) showed GM decreases in the left lingual gyrus, right supramarginal gyrus/parietal operculum, left parahippocampal gyrus, left fusiform gyrus, right thalamus, and right lateral occipital gyrus. Group differences between psychiatric and neurodegenerative hallucination meta-analyses were formally confirmed using Monte Carlo randomizations to determine statistical significance, and a jackknife sensitivity analysis established the reproducibility of results across nearly all study combinations. For other structural measures (28 studies), the most consistent findings associated with hallucination status were reduced cortical thickness in temporal gyri in schizophrenia and altered hippocampal volume in Parkinson's disease and dementia. Additionally, increased severity of hallucinations in schizophrenia correlated with GM reductions within the left superior temporal gyrus, right middle temporal gyrus, bilateral supramarginal and angular gyri.

INTERPRETATION

Distinct patterns of neuroanatomical alteration characterize hallucination status in patients with psychiatric and neurodegenerative diseases, suggesting a plurality of anatomical signatures. This approach has implications for treatment, theoretical frameworks, and generates refutable predictions for hallucinations in other diseases and their occurrence within the general population.

FUNDING

None.

Cinnamic Acid Protects the Nigrostriatum in a Mouse Model of Parkinson's Disease via Peroxisome Proliferator-Activated Receptorα

Parkinson's disease (PD) is the second most common devastating human neurodegenerative disorder and despite intense investigation, no effective therapy is available for PD. Cinnamic acid, a naturally occurring aromatic fatty acid of low toxicity, is a precursor for the synthesis of a huge number of plant substances. This study highlights the neuroprotective effect of cinnamic acid in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. Oral administration of cinnamic acid protected tyrosine hydroxylase (TH)-positive dopaminergic neurons in the substantia nigra pars compacta (SNpc) and TH fibers in the striatum of MPTP-insulted mice. Accordingly, oral cinnamic acid also normalized striatal neurotransmitters and improved locomotor activities in MPTP-intoxicated mice. While investigating mechanisms, we found that cinnamic acid induced the activation of peroxisome proliferator-activated receptor α (PPARα), but not PPARβ, in primary mouse astrocytes. Cinnamic acid mediated protection of the nigrostriatal system and locomotor activities in WT and PPARβ (-/-), but not PPARα (-/-) mice from MPTP intoxication suggests that cinnamic acid requires the involvement of PPARα in protecting dopaminergic neurons in this model of PD. This study delineates a new function of cinnamic acid in protecting dopaminergic neurons via PPARα that could be beneficial for PD.

Association between changes in visual evoked magnetic fields and non-motor features in Parkinson's disease

Visual dysfunction can be caused by several abnormalities, including dysfunctions in the visual cortex and retina. Our aim was to investigate changes in visual evoked brain responses in the primary visual cortex associated with Parkinson’s disease (PD). Sixteen healthy control subjects and ten patients with PD participated in this study. We assessed the visual evoked magnetic field (VEF) using magnetoencephalography (MEG). Checkerboard pattern reversal (CPR) and monotonous grating pattern (MGP) stimulations were used. Magnetic resonance imaging (MRI) was performed to analyze brain volume and generate a tractogram. Cognitive and olfactory function, and Unified Parkinson’s Disease Rating Scale (UPDRS) scores were evaluated in patients with PD. Four components of the VEF (1M, 2M, 3M, 4M) were observed following stimulation. For both stimuli, results from the 1M and 2M components were significantly greater and the latency of the 1M component was increased markedly in the PD group compared with the healthy control group. In the PD group, 1M latency correlated with the UPDRS score of 1 for both stimuli, and a correlation was observed between olfactory function and the UPDRS score of 3 for the CPR stimulation alone. We suggest that the conduction delay observed following visual stimulation occurs peripherally rather than in the primary visual cortex. Degeneration of selective elements of the visual system in the retina, possibly midget cells, may be involved.

Pimavanserin for Parkinson's Disease psychosis: Effects stratified by baseline cognition and use of cognitive-enhancing medications

BACKGROUND

PD psychosis is often associated with cognitive impairment, including dementia, and involves dopaminergic, serotonergic, and cholinergic mechanisms.

OBJECTIVE

To evaluate the differential effect of the antipsychotic pimavanserin, a selective serotonin 2A receptor inverse agonist, in PD psychosis patients with versus without cognitive impairment and in those receiving versus not receiving cognitive-enhancing medications.

METHODS

Data from the pivotal randomized clinical trial of pimavanserin for PD psychosis were stratified by (1) screening MMSE score as cognitively impaired (21-24) versus unimpaired (≥25) and (2) concomitant use versus nonuse of cognitive-enhancing medications. The primary outcome measure was change in the PD-adapted Scale for the Assessment of Positive Symptoms.

RESULTS

Mean (pimavanserin vs. placebo) change from baseline was larger in the cognitively impaired (n = 50; -6.62 vs. -0.91; P = 0.002) versus the cognitively unimpaired (n = 135; -5.50 vs. -3.23; p = 0.046) group. The comparable change was -6.04 versus -2.18 (P = 0.012) and -5.66 versus -3.15 (P = 0.041) in patients treated (n = 69) and not treated (n = 116) with concomitant cognitive-enhancing medication. Pimavanserin was similarly tolerated across all cognitive groups with no additional safety concerns identified. Overall adverse event rates were comparable across the concomitant cognitive-enhancing medication groups; however, rates of serious adverse events and discontinuations attributed to adverse events were increased in patients taking cholinesterase inhibitors.

CONCLUSIONS

The antipsychotic effect of pimavanserin is robust in PD patients with cognitive impairment and may be enhanced by concomitant cognitive-enhancing medication use. Future prospective studies are needed to confirm these preliminary findings. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.