Parkinson Disease: The Relationship Between Non-motor Symptoms and Motor Phenotype

Altered functional connectivity of the primary motor cortex in tremor dominant and postural instability gait difficulty subtypes of early drug-naive Parkinson's disease patients

Background

The primary motor cortex (M1) is an important hub in the motor circuitry of Parkinson's disease (PD), but the subregions' function and their correlation to tremor dominant (TD) and postural instability and gait disturbance (PIGD) with PD remain unclear. This study aimed to determine whether the functional connectivity (FC) of the M1 subregions varied between the PD and PIGD subtypes.

Methods

We recruited 28 TD patients, 49 PIGD patients, and 42 healthy controls (HCs). M1 was divided into 12 regions of interest using the Human Brainnetome Atlas template to compare FC among these groups.

Results

Compared with HCs, TD and PIGD patients exhibited increased FC between the left upper limb region (A4UL_L) and the right caudate nucleus (CAU)/left putamen (PUT), between the right A4UL (A4UL_R) and the left anterior cingulate and paracingulate gyri (ACG)/bilateral cerebellum4_5 (CRBL4_5)/left PUT/right CAU/left supramarginal gyrus/left middle frontal gyrus (MFG), as well as decreased connectivity between the A4UL_L and the left postcentral gyrus and the bilateral cuneus, and between the A4UL_R and the right inferior occipital gyrus. TD patients showed increased FC between the right caudal dorsolateral area 6 (A6CDL_R) and the left ACG/right MFG, between the A4UL_L and the right CRBL6/right middle frontal gyrus, orbital part/bilateral inferior frontal gyrus, and orbital part (ORBinf), and between the A4UL_R and the left ORBinf/right MFG/right insula (INS). PIGD patients displayed increased connectivity between the A4UL_L and the left CRBL4_5. Compared with PIGD patients, TD patients exhibited increased connectivity between the A6CDL_R and the left ACG/right MFG and between the A4UL_R and the left ACG/left ORBinf/right INS/right MFG. Furthermore, in TD and PIGD groups, the FC strength between the A6CDL_R and right MFG was negatively correlated with PIGD scores, while the FC strength between the A4UL_R and left ORBinf/right INS was positively correlated with TD scores and tremor scores.

Conclusion

Our results demonstrated that early TD and PIGD patients share some common injury and compensatory mechanisms. TD patients occupied more resources in the MFG, ORBinf, INS, and ACG, which can be used as biomarkers to distinguish them from PIGD patients.

The complex syndrome of functional neurological disorder

BACKGROUND

Patients with functional neurological disorders (FND) often present with multiple motor, sensory, psychological and cognitive symptoms. In order to explore the relationship between these common symptoms, we performed a detailed clinical assessment of motor, non-motor symptoms, health-related quality of life (HRQoL) and disability in a large cohort of patients with motor FND. To understand the clinical heterogeneity, cluster analysis was used to search for subgroups within the cohort.

METHODS

One hundred fifty-two patients with a clinically established diagnosis of motor FND were assessed for motor symptom severity using the Simplified Functional Movement Disorder Rating Scale (S-FMDRS), the number of different motor phenotypes (i.e. tremor, dystonia, gait disorder, myoclonus, and weakness), gait severity and postural instability. All patients then evaluated each motor symptom type severity on a Likert scale and completed questionnaires for depression, anxiety, pain, fatigue, cognitive complaints and HRQoL.

RESULTS

Significant correlations were found among the self-reported and all objective motor symptoms severity measures. All self-reported measures including HRQoL correlated strongly with each other. S-FMDRS weakly correlated with HRQoL. Hierarchical cluster analysis supplemented with gap statistics revealed a homogenous patient sample which could not be separated into subgroups.

CONCLUSIONS

We interpret the lack of evidence of clusters along with a high degree of correlation between all self-reported and objective measures of motor or non-motor symptoms and HRQoL within current neurobiological models as evidence to support a unified pathophysiology of 'functional' symptoms. Our results support the unification of functional and somatic syndromes in classification schemes and for future mechanistic and therapeutic research.

Risk factors for developing dyskinesia among Parkinson's disease patients with wearing-off: J-FIRST

BACKGROUND

Dyskinesia frequently occurs during long-term treatment with levodopa in patients with Parkinson's disease (PD) and impacts quality of life. Few studies have examined risk factors for developing dyskinesia in PD patients exhibiting wearing-off. Therefore, we investigated the risk factors and impact of dyskinesia in PD patients exhibiting wearing-off.

METHODS

We investigated the risk factors and impact of dyskinesia in a 1-year observational study of Japanese PD patients exhibiting wearing-off (J-FIRST). Risk factors were assessed by logistic regression analyses in patients without dyskinesia at study entry. Mixed-effect models were used to evaluate the impact of dyskinesia on changes in Movement Disorder Society-Unified PD Rating Scale (MDS-UPDRS) Part I and PD Questionnaire (PDQ)-8 scores from one timepoint before dyskinesia was observed.

RESULTS

Of 996 patients analyzed, 450 had dyskinesia at baseline, 133 developed dyskinesia within 1 year, and 413 did not develop dyskinesia. Female sex (odds ratio [95% confidence interval]: 2.636 [1.645-4.223]) and administration of a dopamine agonist (1.840 [1.083-3.126]), a catechol-O-methyltransferase inhibitor (2.044 [1.285-3.250]), or zonisamide (1.869 [1.184-2.950]) were independent risk factors for dyskinesia onset. MDS-UPDRS Part I and PDQ-8 scores increased significantly after the onset of dyskinesia (least-squares mean change [standard error] at 52 weeks: 1.11 [0.52], P = 0.0336; 1.53 [0.48], P = 0.0014; respectively).

CONCLUSION

Female sex and administration of a dopamine agonist, a catechol-O-methyltransferase inhibitor, or zonisamide were risk factors for dyskinesia onset within 1 year in PD patients exhibiting wearing-off. Nonmotor symptoms and quality of life deteriorated after dyskinesia onset.

Non-motor effects of deep brain stimulation in Parkinson's disease motor subtypes

INTRODUCTION

Deep brain stimulation (DBS) is a well-established treatment for patients with Parkinson's disease (PD) improving quality of life, motor, and non-motor symptoms. However, non-motor effects in PD subtypes are understudied. We hypothesized that patients with 'postural instability and gait difficulty' (PIGD) experience more beneficial non-motor effects than 'tremor-dominant' patients undergoing DBS for PD.

METHODS

In this prospective, observational, international multicentre study with a 6-month follow-up, we assessed the Non-Motor Symptom Scale (NMSS) as primary and the following secondary outcomes: Unified PD Rating Scale-motor examination (UPDRS-III), Scales for Outcomes in PD (SCOPA)-activities of daily living (ADL) and -motor complications, PDQuestionnaire-8 (PDQ-8), and levodopa-equivalent daily dose (LEDD). We analysed within-group longitudinal changes with Wilcoxon signed-rank test and Benjamini-Hochberg correction for multiple comparisons. Additionally, we explored outcome between-group differences of motor subtypes with Mann-Whitney U-tests.

RESULTS

In 82 PIGD and 33 tremor-dominant patients included in this study, baseline NMSS total scores were worse in PIGD patients, both groups experienced postoperative improvements of the NMSS sleep/fatigue domain, and between-group differences in postoperative outcomes were favourable in the PIGD group for the NMSS total and miscellaneous domain scores.

CONCLUSIONS

This study provides evidence of a favourable outcome of total non-motor burden in PIGD compared to tremor-dominant patients undergoing DBS for PD. These differences of clinical efficacy on non-motor aspects should be considered when advising and monitoring patients with PD undergoing DBS.

Aberrant inter-network functional connectivity in drug-naive Parkinson's disease patients with tremor dominant and postural instability and gait difficulty

Background: Insight into neural mechanisms of tremor dominant (TD) and postural instability and gait disorder (PIGD) subtypes in Parkinson's disease (PD) is vital for understanding pathophysiological hypotheses underlying this phenotype. However, network disturbances and their correlation with motor subtypes of PD remain unclear. We aimed to investigate the alterations of intra- and inter-network functional connectivity (FC) in drug-naive PD patients with different motor subtypes. Methods: Resting-state functional magnetic resonance imaging was performed on 25 drug-naive PD patients with TD (PD-TD) and 40 drug-naive PD patients with PIGD (PD-PIGD), and 37 healthy controls (HCs) underwent. The following networks were extracted using independent component analysis: sensorimotor network (SMN), left executive control network (LECN), right executive control network, anterior salience network (aSN), posterior salience network (pSN), ventral attention network (VAN), dorsal attention network (DAN), default mode network (DMN), visual network, and auditory network (AN). We measured FC values within and between these networks. Results: There were no detectable variations in intra-network FC. PD-PIGD group demonstrated lower FC between aSN and pSN, as well as between VAN and DMN, in contrast to PD-TD group. Particularly, the FC strength between VAN and DMN was positively correlated with TD and tremor scores, and the best fitting classification models of TD and PIGD subtypes were based on the FC between aSN and pSN. Compared with HCs, both PD-TD and PD-PIGD patients displayed decreased FC between two SMN subnetworks, while PD-TD patients exhibited increased FC between the SMN subnetwork and pSN, and between LECN and VAN. Furthermore, PD-PIGD patients demonstrated decreased FC between the SMN subnetwork and AN. Conclusions: The altered FC between aSN and pSN can be an imaging marker to distinguish PD-TD from PD-PIGD. We for the first time disclosed that the PD-TD patients compensated by increasing attention resources and the PD-PIGD patients displayed reduced FC between SMN and AN. Our findings provide a basis for identification and precision treatment of PD motor subtypes.

Non-motor symptoms in multiple system atrophy: A comparative study with Parkinson's disease and progressive supranuclear palsy

Background

Non-motor symptoms (NMS) are compulsory clinical features for the clinical diagnosis of multiple system atrophy (MSA), some of which precede motor symptoms onset. To date, few studies have systematically investigated NMS in MSA and the timing of presenting NMS as the disease progresses. Clinically, MSA is difficult to be differentiated from Parkinson's disease (PD) and progressive supranuclear palsy (PSP), and the differences in NMS between MSA and PD/PSP remain unclear. The aim of this study was to compare the burden of NMS between MSA and PD/PSP and to delineate the timing of NMS presentation relative to the onset of motor symptoms in MSA.

Methods

A total of 61, 87, and 30 patients with MSA, PD, and PSP, respectively, were enrolled in this study. NMS was systematically assessed in all patients using the NMS scale (NMSS), and the onset of NMS relative to the onset of motor symptoms in MSA was investigated.

Results

MSA group had higher total NMSS scores (82.15 ± 46.10) than the PD (36.14 ± 30.78) and PSP (50.30 ± 55.05) groups (p < 0.001 overall). The number distribution pattern of the NMS was significantly different among the three parkinsonian disorders (p < 0.001 overall). In total, 85.2% of patients with MSA had more than 10 NMS, which was significantly higher than PD (28.7%) and PSP (33.3%). The frequency and scores of many NMSS subdomains and symptoms were higher in MSA than in PD and PSP (all p < 0.05). Multivariate logistic regression analysis revealed that patients with fainting, lack of motivation, swallowing, and loss of sexual interest could be attributed to MSA rather than PD or PSP, while patients with loss of concentration and forgetfulness were characteristic features of PD or PSP rather than MSA. REM-sleep behavior disorder (RBD), constipation, problems having sex, and loss of sexual interest preceded the motor symptoms onset of MSA by 2.81 ± 4.51, 1.54 ± 6.32, 1.35 ± 4.70, and 0.45 ± 3.61 years, respectively.

Conclusion

The NMS spectrum in MSA differs from that of PD and PSP. Patients with MSA have a higher NMS burden than patients with PD or PSP. RBD, constipation, problems having sex, and loss of sexual interest may become early diagnostic clinical markers of MSA.

Profiles of Motor-Cognitive Interference in Parkinson's Disease-The Trail-Walking-Test to Discriminate between Motor Phenotypes

Background and Aims. Most research on Parkinson’s disease (PD) focuses on describing symptoms and movement characteristics. Studies rarely focus on the early detection of PD and the search for suitable markers of a prodromal stage. Early detection is important, so treatments that may potentially change the course of the disease can be attempted early on. While gait disturbances are less pronounced in the early stages of the disease, the prevalence, and severity increase with disease progression. Therefore, postural instability and gait difficulties could be identified as sensitive biomarkers. The aim was to evaluate the discriminatory power of the Trail-Walking Test (TWT; Schott, 2015) as a potential diagnostic instrument to improve the predictive power of the clinical evaluation concerning the severity of the disease and record the different aspects of walking. Methods. A total of 20 older healthy (M = 72.4 years, SD = 5.53) adults and 43 older adults with PD and the motor phenotypes postural instability/gait difficulty (PIGD; M = 69.7 years, SD = 8.68) and tremor dominant (TD; M = 68.2 years, SD = 8.94) participated in the study. The participants performed a motor-cognitive dual task (DT) of increasing cognitive difficulty in which they had to walk a given path (condition 1), walk to numbers in ascending order (condition 2), and walk to numbers and letters alternately and in ascending order (condition 3). Results. With an increase in the cognitive load, the time to complete the tasks (seconds) became longer in all groups, F(1.23, 73.5) = 121, p < 0.001, ɳ2p = 0.670. PIGD showed the longest times in all conditions of the TWT, F(2, 60) = 8.15, p < 0.001, ɳ2p = 0.214. Mutual interferences in the cognitive and motor domain can be observed. However, clear group-specific patterns cannot be identified. A differentiation between the motor phenotypes of PD is especially feasible with the purely motor condition (TWT-M; AUC = 0.685, p = 0.44). Conclusions. PD patients with PIGD must be identified by valid, well-evaluated clinical tests that allow for a precise assessment of the disease’s individual fall risk, the severity of the disease, and the prognosis of progression. The TWT covers various aspects of mobility, examines the relationship between cognitive functions and walking, and enables differentiation of the motor phenotypes of PD.

Differential Effects of Subthalamic Nucleus and Globus Pallidus Internus Deep Brain Stimulation on Motor Subtypes in Parkinson's Disease

OBJECTIVE

We investigated the differences in motor symptom change outcomes after bilateral subthalamic nucleus (STN) and globus pallidus internus (GPi) deep brain stimulation (DBS) in well-defined motor subtypes of Parkinson's disease (PD) to improve clinical decision making.

METHODS

We included 114 patients who had undergone STN-DBS and 65 patients who had undergone GPi-DBS. The patients were classified as having akinetic-rigid type (ART), tremor-dominant type (TDT), and mixed type (MT) using the preoperative Movement Disorder Society Unified Parkinson's Disease Rating Scale part III (MDS-UPDRS-III) scores in the no-medication state. The outcome measures included the no-medication MDS-UPDRS-III scores and subscore changes at the last follow-up after surgery. The outcomes were compared among the different motor subtypes and between STN-DBS and GPi-DBS.

RESULTS

At the last follow-up (14.92 ± 8.35 months), the TDT patients had had a greater median overall motor improvement in the no-medication MDS-UPDRS-III scores compared with the ART patients (62.90% vs. 46.67%; P < 0.001), regardless of the stimulation target. The ART patients showed greater improvement after STN-DBS than after GPi-DBS (54.44% vs. 37.21%; P < 0.001), with improvements in rigidity, akinesia, and posture and gait disorders accounting for the difference.

CONCLUSIONS

Our results suggest that the different PD motor subtypes will have differential responses to STN-DBS and GPi-DBS, that TDT patients will experience greater improvement than ART patients, and that STN-DBS provides better effects for ART patients than does GPi-DBS. In addition, different motor symptoms among the different motor subtypes might respond differently to STN-DBS than to GPi-DBS. All these factors could reflect the heterogeneity of PD. Longer-term outcomes across the different motor subtypes and stimulation targets should be studied further.

The emerging postural instability phenotype in idiopathic Parkinson disease

Identification of individuals at high risk for rapid progression of motor and cognitive signs in Parkinson disease (PD) is clinically significant. Postural instability and gait dysfunction (PIGD) are associated with greater motor and cognitive deterioration. We examined the relationship between baseline clinical factors and the development of postural instability using 5-year longitudinal de-novo idiopathic data (n = 301) from the Parkinson’s Progressive Markers Initiative (PPMI). Logistic regression analysis revealed baseline features associated with future postural instability, and we designated this cohort the emerging postural instability (ePI) phenotype. We evaluated the resulting ePI phenotype rating scale validity in two held-out populations which showed a significantly higher risk of postural instability. Emerging PI phenotype was identified before onset of postural instability in 289 of 301 paired comparisons, with a median progression time of 972 days. Baseline cognitive performance was similar but declined more rapidly in ePI phenotype. We provide an ePI phenotype rating scale (ePIRS) for evaluation of individual risk at baseline for progression to postural instability.

Self-Reported Visual Complaints in People with Parkinson's Disease: A Systematic Review

BACKGROUND

Scientific research increasingly focuses on visual symptoms of people with Parkinson's disease (PD). However, this mostly involves functional measures, whereas self-reported data are equally important for guiding clinical care.

OBJECTIVE

This review provides an overview of the nature and prevalence of self-reported visual complaints by people with PD, compared to healthy controls.

METHODS

A systematic literature search was performed. Studies from three databases (PubMed, PsycInfo, and Web of Science) were screened for eligibility. Only studies that reported results of visual self-reports in people with idiopathic PD were included.

RESULTS

One hundred and thirty-nine eligible articles were analyzed. Visual complaints ranged from function-related complaints (e.g., blurred vision, double vision, increased sensitivity to light or changes in contrast sensitivity) to activity-related complaints (e.g., difficulty reading, reaching, or driving). Visual complaints were more prevalent in people with PD compared to healthy controls. The presence of visual complaints leads to a reduced quality of life (QoL). Increased prevalence and severity of visual complaints in people with PD are related to longer disease duration, higher disease severity, and off-state.

CONCLUSION

A large proportion of people with PD have visual complaints, which negatively affect QoL. Complaints are diverse in nature, and specific and active questioning by clinicians is advised to foster timely recognition, acknowledgement, and management of these complaints.

Parkinson's Disease Motor Subtypes Change with the Progression of the Disease: Results from the COPPADIS Cohort at 2-Year Follow-Up

BACKGROUND

Motor phenotype (MP) can be associated with a different prognosis in Parkinson's disease (PD), but it is not fixed and can change over time.

OBJECTIVE

Our aim was to analyze how the MP changed over time and to identify factors associated with the changes in PD patients from a multicenter Spanish PD cohort.

METHODS

PD patients who were recruited from January-2016 to November-2017 (baseline visit; V0) and evaluated again at a 2-year±30 days follow-up (V2) from 35 centers of Spain from the COPPADIS cohort, were included in this study.MP was calculated at both visits based on Jankovic classification in TD (tremor dominant), IND (indeterminate), or PIGD (postural instability and gait difficulty). Sociodemographic and clinical data were collected, including serum biomarkers.

RESULTS

Five hundred eleven patients (62.57±8.59 years old; 59.2%males) were included in the study. At V0, MP was: 47.4%(242/511) TD; 36.6%(187/511) PIGD; 16%(82/511) IND. Up to 38%(194/511) of the patients changed their phenotype from V0 to V2, being the most frequent from TD to IND (8.4%) and from TD to PIGD (6.7%). A worse cognitive status (OR = 0.966) and less autonomy for activities of daily living (OR  =  0.937) at V0 and a greater increase in the globalNMS burden (OR  =  1.011) from V0 to V2 were associated with changing from TD to another phenotype after 2-year follow-up.

CONCLUSION

The MP in PD can change over time. With disease progression, the percentage of cases with non-tremoric MP increases. PD patients who changed from TD to postural instability and gait difficulty increased NMS burden significantly.

A Cross-Sectional Comprehensive Assessment of the Profile and Burden of Non-motor Symptoms in Relation to Motor Phenotype in the Nigeria Parkinson Disease Registry Cohort

Background

Data on non-motor symptoms (NMS) in black Africans with Parkinson's disease (PD) are sparse.

Objective

To describe the profile of NMS in the Nigeria PD Registry (NPDR) cohort and explore the relationship between NMS and PD motor phenotype.

Methods

We conducted a cross-sectional study of the frequency and burden of NMS, based on the non-motor symptoms scale (NMSS) and the Chaudhuri method respectively in our cohort. Baseline demographics, disease characteristics (Hoehn and Yahr stage, MDS-UPDRS total score and Part III motor score), motor phenotype (based on Stebbin et al's algorithm), and levodopa equivalent daily dose (LEDD) were documented.

Results

Data are presented for 825 PD whose mean age at study was 63.7 ± 10.1 years, female sex-221 [26.8%] while median PD duration was 36 months. PD phenotypes included tremor-dominant 466 (56.5%), postural instability and gait disorder (PIGD) 259 (31.4%), and indeterminate 100 (12.1%). 82.6% were on treatment (median LEDD of 500 mg/24 hours). 804 (97.5%) endorsed at least 1 NMS. The median NMSS score was 26.0 while subscores for urinary and sexual function domains were significantly higher in males (P < 0.05). PIGD-PD had more frequent NMS and higher frequency of severe/very severe NMSS burden (P = 0.000 for both). Nocturia and fatigue were the most prevalent NMS overall and across motor subtypes. PIGD phenotype and total UPDRS scores were the independent determinants of NMSS scores (P = 0.000).

Conclusion

The profile and burden of NMS, and association with motor subtype in our black African cohort is largely similar to descriptions from other populations.

Stability of MDS-UPDRS Motor Subtypes Over Three Years in Early Parkinson's Disease

Background: Various classifications have been proposed to subtype Parkinson's disease (PD) based on their motor phenotypes. However, the stability of these subtypes has not been properly evaluated.

Objective: The goal of this study was to understand the distribution of PD motor subtypes, their stability over time, and baseline factors that predicted subtype stability.

Methods: Participants (n = 170) from two prospective cohorts were included: the Early PD Longitudinal Singapore (PALS) study and the National Neuroscience Institute Movement Disorders Database. Early PD patients were classified into tremor-dominant (TD), postural instability and gait difficulty (PIGD), and indeterminate subtypes according to the Movement Disorder Society's Unified PD Rating Scale (MDS-UPDRS) criteria and clinically evaluated for three consecutive years.

Results: At baseline, 60.6% patients were TD, 12.4% patients were indeterminate, and 27.1% patients were PIGD subtypes (p < 0.05). After 3 years, only 62% of patients in TD and 50% of patients in PIGD subtypes remained stable. The mean levodopa equivalent daily dose (LEDD) was higher in the PIGD subtype (276.92 ± 232.91 mg; p = 0.01). Lower LEDD [p < 0.05, odds ratio (OR) 0.99, 95% confidence interval (CI): 0.98–0.99] and higher TD/PIGD ratios (p < 0.05, OR 1.77, 95% CI: 1.29–2.43) were independent predictors of stability of TD subtype with an area under the curve (AUC) of 0.787 (95%CI: 0.669–0.876), sensitivity = 57.8%, and specificity = 89.7%.

Conclusion: Only 50–62% of PD motor subtypes as defined by MDS-UPDRS remained stable over 3 years. TD/PIGD ratio and baseline LEDD were independent predictors for TD subtype stability over 3 years.

The Trajectory of Motor Deterioration to Death in Parkinson's Disease

Background: Motor progression varies even among those with a single diagnosis such as Parkinson's disease (PD) and little is known about the trajectory of motor signs prior to death. Understanding deterioration patterns may help clinicians counsel patients and proactively plan interdisciplinary care, including palliative care. The objective of this study was to examine and describe Unified Parkinson's Disease Rating Scale motor score (UPDRS-III) trajectories at the end of life in PD. Methods: A retrospective chart review was performed for deceased PD patients who attended the Parkinson and Movement Disorders Program at the University of Alberta for at least 5 years between 1999 and 2018. UPDRS-III scores were recorded for all visits. Trajectory patterns were visualized with Loess curves stratified by sex and age at diagnosis. Piecewise linear models were used to individually model the UPDRS-III scores, and the trajectories obtained were clustered based on their features. Results: Among the 202 charts reviewed, 84 meeting inclusion criteria were analyzed. The UPDRS-III increased over time regardless of sex and age. Distinct trajectory variations present in PD (e.g., Consistent Deterioration, Stability-Deterioration, Improvement-Deterioration, Deterioration-Improvement-Deterioration) were identified. Twenty-five percent of the patients were classified as Undetermined/Irregular trajectories. In addition, regardless of trajectory type, many patients experienced a steep increase in UPDRS-III approaching death. Those with disease diagnosis after age 65 years had a shorter survival time, compared to PD patients with a younger age of onset. Conclusion: Our study identified dominant types of motor trajectory in PD that can help clinicians understand their patients' course of illness. This information can help counsel patients regarding the variability in motor deterioration and should alert physicians to recognize a terminal decline. Age of disease onset was correlated with survival time.

Ethnic Variation in the Manifestation of Parkinson's Disease: A Narrative Review

The global prevalence of Parkinson's disease is increasing, yet the characteristics, risk factors and genetics of PD in Black, Asian and Hispanic populations is little understood. In this paper we review the published literature on clinical variation in the symptoms and signs of Parkinson's disease in different ethnic groups and responses to treatment. We included any study that sampled patients with Parkinson's disease from distinct ethnic backgrounds. We conclude that whilst there is little published evidence for ethnic variation in the clinical features of Parkinson's disease, there are substantial limitations and gaps in the current literature, which mean that the evidence does necessarily not fit with clinical observation. Possible explanations for expected differences in manifestation include genetic determinants, the co-existence of cerebrovascular disease and/or Alzheimer's disease pathology, healthcare inequalities and socio-cultural factors.

Impact of motor subtype on non-motor symptoms and fall-related features in patients with early Parkinson's disease

AIM

Clinical implications for motor phenotypes of Parkinson's disease (PD) remain to be further elucidated, particularly at the early stages of the disease. We aimed to compare the non-motor and fall-related features between tremor-dominant (TD) and postural instability-gait difficulty (PIGD) subtypes in patients with early PD.

METHODS

PD was categorized into TD, intermediate and PIGD types, according to the literature. Not only motor symptoms, but also non-motor symptoms for global cognition, depression, anxiety, fatigue and dysautonomia, were measured in detail. In addition, fall-related features, including a previous history of falls, fear of fall measurement and gait freezing were assessed.

RESULTS

In patients with early PD (disease duration no more than 5 years), 35 patients with TD-type PD and 31 patients with PIGD-type PD were finally evaluated for the study. Compared with the TD group, the PIGD group showed higher fatigue, gastrointestinal dysfunction and fall-related parameter scores. Moreover, the PIGD scores were significantly correlated with all of those symptoms.

CONCLUSIONS

Our findings suggest that PIGD is significantly linked to fatigue, gastrointestinal dysfunction and fall-related features during the early stages of PD. Geriatr Gerontol Int 2021; 21: 416-420.

The correlation of non-motor symptoms and sleep on balance in Parkinson's disease patients with normal cognition and mild cognitive impairment

BACKGROUND

Parkinson's disease (PD) is characterized by non-motor symptoms (NMS) as well as by motor symptoms. Together with the impairment of cognitive functions, NMS and sleep also affect motor symptoms negatively. The aim of our study is to examine the correlation of NMS and sleep on balance in PD patients with normal cognition (PD-NC) and with mild cognitive impairment (PD-MCI).

METHODS

A total of 69 patients were included in our study. Using the Standardized Mini-Mental State Examination, participants were divided into 2 groups, PD-NC and PD-MCI. Patients were assessed with the Unified Parkinson's Disease Rating Scale (UPDRS), the Berg Balance Scale (BBS), the Tinetti Balance Assessment Tool (TBAT), the Non-Motor Symptoms Questionnaire (NMSQ), and the Parkinson's Disease Questionnaire (PDQ-39).

RESULTS

PD-MCI patients had statistically significant worse motor symptoms and more balance disorder compared to PD-NC (UPDRS: p = 0.009; BBS: p = 0.010; TBAT: p = 0.004). PD-MCI patients had greater severity of non-motor symptoms and worse sleep quality than the PD-NC group (NMSQ-total: p = 0.02; NMSQ-sleep total: p = 0.01). The evaluation has shown that with a diagnosis of MCI, NMS, and sleeping problems were correlated, and the correlation was associated with impairment of the balance function. While being more pronounced in the PD-MCI group, quality of life was affected in both groups (p < 0.05).

CONCLUSION

Our data demonstrate a negative effect on the balance function in patients with cognitive impairment suffering increased NMS and sleeping disorders. Treatment of these patients needs to concentrate on NMS and cognitive functions as much as on motor symptoms.

Sexual Disorders and Quality of Life in Parkinson's Disease

Introduction

Sexual disorders are the most neglected nonmotor symptoms in Parkinson's disease (PD). Although doctors seek greater priority to motor manifestations, which are the basis for the diagnosis of PD, the nonmotor symptoms deserve to be highlighted as much as the motor problems because of their strong presence and discomfort in the patients, causing the important impairment in the quality of life (QoL) of the individual with PD.

Aim

Provide the prevalence of sexual disorders among patients with PD and alert the medical profession to investigate and be familiar with problems related to QoL and sexual disorders in PD.

Methods

This is a large literature review on sexual disorders in PD and impaired QoL.

Main Outcome Measures

Sexual disorders in PD and prevalence between genders have been described in epidemiological studies. Neuroanatomy, pathophysiology, risk factors, QoL, and etiologies were reviewed.

Results

The estimate of the prevalence of sexual dysfunction in the form of compulsive sexual behavior in PD is higher in men by 5.2% than in women by 0.5%. This diagnosis is a determinant of intense and persistent suffering and is related to several health problems of a social, economic, personal, family, psychological, and occupational nature, which can even culminate in sexual abuse. It is most commonly associated with the use of drugs commonly used in PD therapy in 98.1% of cases. In addition to this serious public health problem, another common condition of sexual dysfunction occur with the decreased libido by loss of the neurotransmitter dopamine proper of the pathophysiology of PD.

Conclusion

The presence of sexual disorders in PD should be tracked and monitored because of its harmful consequences, whether due to increased sexual behavior or associated psychological distress, as well as the impacts on QoL. Early recognition and adequate treatment of PD in its fullness and richness of associated symptoms are essential for improving QoL.

Santa Rosa Malcher CM, Roberto da Silva Gonçalves Oliveira K, Fernandes Caldato MC, et al. Sexual Disorders and Quality of Life in Parkinson's Disease. Sex Med 2021;9:100280.

Investigation of non-motor symptoms, balance, muscle strength, and functional mobility in patients with parkinson's disease

PURPOSE

Although both motor symptoms and non-motor symptoms (NMSs) occur in patients with Parkinson's disease (PD), clinical practice focuses more on motor symptoms. The aim of this study was to examine balance, muscle strength, and mobility in relation with NMSs in patients with PD. The other aim of this study was to investigate the relationship between NMSs and muscle strength, balance, and functional mobility in PD.

MATERIALS AND METHODS

The study included 24 patients with PD (between Hoehn & Yahr Stage 1 and 3) and 20 healthy individuals of similar age and sex. The participants' balance was assessed with the Biodex Balance System (Biodex Medical Systems, Shirley, NY, USA), muscle strength assessments were conducted with a Biodex^® System 4 Dynamometer device, and functional mobility was assessed with the Timed Up and Go test (TUG). The non-motor symptoms scale was used for NMSs.

RESULTS

We found that lower extremity strength scores were lower and NMSs, balance, and mobility scores were greater in patients with PD in comparison to healthy controls (p < 0.05). The correlation analysis revealed that higher NMSs were related to reduced knee extension strength and cognitive dual task performance.

CONCLUSION

Although no relationship between NMSs and balance was observed, the relationship between the TUG + cognitive task and muscle strength suggests that NMSs should be carefully evaluated along with the motor symptoms, which deteriorate beginning with the early period.

The Role of Electrochemical Skin Conductance as a Screening Test of Cardiovascular Autonomic Neuropathy in Patients with Parkinson's Disease

Autonomic disorders have been recognized as an important non-motor feature in Parkinson's disease (PD). However, there is a paucity of information on the presence and severity of cardiovascular autonomic neuropathy (CAN) among different motor phenotypes. The aims of this study were to examine the feasibility of electrochemical skin conductance (ESC) measured by Sudoscan as a screening service for CAN in patients with PD and investigate the severity of CAN among different motor phenotypes. Design: This was a cross-sectional observational study that enrolled 63 patients with PD. Patients were divided into three phenotypes, postural instability/gait difficulty (PIGD), tremor-dominant (TD), and akinetic-rigid (AR), according to their motor symptoms. Cardiovascular autonomic function was measured, and the presence and severity of CAN was determined according to the composite autonomic scoring scale (CASS). Functional scores were measured by the Hoehn and Yahr (HY) stage and the Unified Parkinson's Disease Rating Scale (UPDRS). The median HY stage was 2.0 [1.5, 3.0]. Median UPDRS total score was 23.0 (17.5, 30.5), 10.0 (6.0, 11.0) and 14.0 (6.3, 23.8) in groups of PIGD, TD and AR, respectively (p = 0.001). Mean CASS was 1.7 ± 1.3, 0.6 ± 0.4, and 1.8 ± 1.5 in groups of PIGD, TD and AR, respectively (p = 0.204). Although the ESC was not strongly associated with the cardiovascular autonomic parameters, the CAN risk score provided by Sudoscan significantly correlated with parameters of cardiovascular autonomic function, including heart rate response to deep breathing (HR_DB), Valsalva ratio (VR), and baroreflex sensitivity (BRS). By receiver-operating characteristic (ROC) analysis, if a patient's CAN risk score is higher than 33.5 (%), it is recommended to be aware of the presence of CAN even in PD patients who are asymptomatic. The area under ROC curve was 0.704. Based on our results, CAN risk score may be used for screening of CAN in patients with PD before resorting to the more sophisticated and specific, but ultimately more time-consuming, complete autonomic function testing.

Motor/Nonmotor Symptoms and Progression in Patients with Parkinson's Disease: Prevalence and Risks in a Longitudinal Study

We previously assessed the prevalence and risks of motor/nonmotor symptoms in a large sample of Japanese patients with Parkinson's disease. In the present study, we longitudinally assessed the prevalence and risk of motor/nonmotor symptoms, changes in treatment, disease progression, and death in patients with Parkinson's disease. We enrolled 1,227 patients diagnosed and treated at our hospital in Tokyo at first evaluation. We were able to follow-up 445 patients until the second evaluation, 7.4 years later. Using Kaplan-Meier survival curves and the Cox proportional-hazards model in 1,227 patients, motor/nonmotor symptoms were analyzed in association with the following events: pain, wearing-off, camptocormia, psychosis, orthostatic hypotension, pneumonia, tube feeding, modified Hoehn and Yahr stages (H-Y) 3 and 4 of the on state, and death. The mean age (standard deviation) at the first evaluation was 67.2 (9.9) years, while the mean ages at onset and disease duration were 57.8 (11.7) years and 9.3 (6.6) years, respectively. The mean H-Y of the on state was 2.7 (1.1) at the first evaluation. Age at onset and duration of levodopa use decreased the hazard ratios (HRs) (0.968 and 0.910, respectively) for wearing-off. Female sex increased the HRs (1.414) for wearing-off and decreased the HRs for orthostatic hypotension (0.540) and pneumonia (0.510). Older age at onset increased the HR for psychosis (1.035), orthostatic hypotension (1.033), H-Y 3 (1.048) and 4 (1.071), pneumonia (1.123), tube feeding (1.140), and death (1.095). Early onset of orthostatic hypotension itself increased the HR for numerous events, especially for death (0.893). Our results indicated that age, sex, and some nonmotor symptoms may predict many Parkinson's disease-related events. In addition, these data may provide a useful reference for the clinical course of Parkinson's disease.

THE IMPACT OF BRAZILIAN SAMBA ON PARKINSON’S DISEASE: ANALYSIS BY THE DISEASE SUBTYPES

ABSTRACT Introduction: People with Parkinson's disease constantly have low levels of physical activity. Dancing has become increasingly important for treating the disease and can help improve non-motor symptoms. Objective: To analyze the influence of Brazilian samba on the non-motor symptoms of PD according to TD and PGID subtypes. Methods: A 12-week, non-randomized clinical trial, through comparison with a control group. The 23 individuals who agreed to participate in the activities formed the experimental group (EG) and the 24 individuals who opted not to participate in the Brazilian samba classes comprised the control group (CG). A questionnaire was applied, composed of validated instruments. Mini Mental State Examination – MMSE; HY – Disability Scale; Unified Parkinson's Disease Rating Scale – UPDRS 1 and total values; Parkinson's Disease Questionnaire – PDQ-39, Parkinson's Disease Sleep Scale – PDSS; Beck Depression Inventory – BDI; Fatigue Severity Scale – FSS and Magnitude of Perceived Changes. Results: After the twelve weeks of intervention, it was observed that the EG showed improvement in the scores of all the tests. The comparison between groups, however, indicated a significant difference in the post-UPDRS1 period in which the EG presented improvement in cognitive impairment, while the CG presented a deficit in these values. The results of the division between disease subtypes show a greater change in the values between individuals of the TD group, when comparing the EG with the CG. For the EG, the greatest difference between pre- and post- intervention was fatigue. Conclusion: There was a positive trend in all the variables studied after the application of the protocol. This demonstrates that interventions such as dance may have greater effects on non-motor symptoms, depending on the expected progression of the disease. The scarcity of studies that use this approach in their analyses may explain the lack of evidence in this symptomatology related to dance. Level of evidence II; Therapeutic studies – Investigating the results of treatment.

Parkinson patients without tremor show changed patterns of mechanical muscle oscillations during a specific bilateral motor task compared to controls

The pathophysiology of Parkinson's disease (PD) is still not understood. There are investigations which show a changed oscillatory behaviour of brain circuits or changes in variability of, e.g., gait parameters in PD. The aim of this study was to investigate whether or not the motor output differs between PD patients and healthy controls. Thereby, patients without tremor are investigated in the medication off state performing a special bilateral isometric motor task. The force and accelerations (ACC) were recorded as well as the Mechanomyography (MMG) of the biceps brachii, the brachioradialis and of the pectoralis major muscles using piezoelectric-sensors during the bilateral motor task at 60% of the maximal isometric contraction. The frequency, a specific power ratio, the amplitude variation and the slope of amplitudes were analysed. The results indicate that the oscillatory behaviour of motor output in PD patients without tremor deviates from controls: thereby, the 95%-confidence-intervals of power ratio and of amplitude variation of all signals are disjoint between PD and controls and show significant differences in group comparisons (power ratio: p = 0.000-0.004, r = 0.441-0.579; amplitude variation: p = 0.000-0.001, r = 0.37-0.67). The mean frequency shows a significant difference for ACC (p = 0.009, r = 0.43), but not for MMG. It remains open, whether this muscular output reflects changes of brain circuits and whether the results are reproducible and specific for PD.

Exercise and Neuroinflammation in Health and Disease

Neuroinflammation is a central pathological feature of several acute and chronic brain diseases, including Alzheimer disease (AD), Parkinson disease (PD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS). It induces microglia activation, mitochondrial dysfunction, the production of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), pro-inflammatory cytokines, and reactive oxygen species. Exercise, which plays an important role in maintaining and improving brain health, might be a highly effective intervention for preventing neuroinflammation-related diseases. Thus, since exercise can improve the neuroimmune response, we hypothesized that exercise would attenuate neuroinflammation-related diseases. In this review, we will highlight (1) the biological mechanisms that underlie AD, PD, ALS, and MS, including the neuroinflammation pathways associated with microglia activation, NF-κB, pro-inflammatory cytokines, mitochondrial dysfunction, and reactive oxygen species, and (2) the role of exercise in neuroinflammation-related neurodegenerative diseases.

Subtyping of Parkinson's Disease - Where Are We Up To?

Heterogenous clinical presentations of Parkinson's disease have aroused several attempts in its subtyping for the purpose of strategic implementation of treatment in order to maximise therapeutic effects. Apart from a priori classifications based purely on motor features, cluster analysis studies have achieved little success in receiving widespread adoption. A priori classifications demonstrate that their chosen factors, whether it be age or certain motor symptoms, do have an influence on subtypes. However, the cluster analysis approach is able to integrate these factors and other clinical features to produce subtypes. Differences in inclusion criteria from datasets, in variable selection and in methodology between cluster analysis studies have made it difficult to compare the subtypes. This has impeded such subtypes from clinical applications. This review analysed existing subtypes of Parkinson's disease, and suggested that future research should aim to discover subtypes that are robustly replicable across multiple datasets rather than focussing on one dataset at a time. Hopefully, through clinical applicable subtyping of Parkinson's disease would lead to translation of these subtypes into research and clinical use.

Alteration of Tremor Dominant and Postural Instability Gait Difficulty Subtypes During the Progression of Parkinson's Disease: Analysis of the PPMI Cohort

Background: Classifying PD into tremor dominant (TD) and postural instability gait difficulty (PIGD) subtypes may have several limitations, such as its diagnostic inconsistency and inability to reflect disease stage. In this study, we investigated the patterns of progression and dopaminergic denervation, by prospective evaluation at regular time intervals. Methods: 325 PD dopamine replacement drug-naïve patients (age 61.2 ± 9.7, M:F = 215:110) were enrolled. Patients were grouped into TD, indeterminant, and PIGD subtypes. Clinical parameters and I-123 FP-CIT SPECT images of each groups were analyzed and compared at baseline, 1, 2, and 4 years of follow up periods. Results: Baseline I-123 FP-CIT uptakes of the striatum were significantly higher in the TD group compared with the indeterminant group and PIGD group (p < 0.01). H & Y stage and MDS-UPDRS part III scores of the indeterminant group were significantly worse at baseline, compared with the TD and PIGD groups (p < 0.001 and p < 0.01, respectively), and MDS-UPDRS part II scores of the indeterminant group were significantly worse than the PIGD group (p < 0.001). There were no other significant differences of age, gender, weight, duration of PD, SCOPA-AUT, MOCA, usage of dopamine agonists, and levodopa equivalent daily doses at baseline. After 4 years of follow up, there were no differences of I-123 FP-CIT uptakes or clinical parameters, except for the MDS-UPDRS part II between the TD and indeterminant group (p < 0.05). The motor-subtypes were reevaluated at the 4 years period, and the proportion of patients grouped to the PIGD subtype increased. In the reevaluated PIGD group, MDS-UPDRS part II score (p < 0.001), SCOPA-AUT (p < 0.001), the proportion of patients who developed levodopa induced dyskinesia were higher than the reevaluated TD group, and the striatal I-123 FP-CIT uptakes were significantly lower (p < 0.01). Conclusion: There are no significant differences of symptoms and dopaminergic innervation between the TD and PIGD group after a certain period of follow up. Significant portion of patients switched from the TD subtype to the PIGD subtype during disease progression, and had a worse clinical prognosis.

Tremor-Dominant in Parkinson Disease: The Relevance to Iron Metabolism and Inflammation

Background: Tremor is one of the most predominant symptoms of patients with Parkinson disease (PD), but the underlying mechanisms for tremor relating to iron and its metabolism-related proteins and the inflammatory factors in cerebrospinal fluid (CSF) and serum have not been fully elucidated. Methods: A total of 135 PD patients were divided into a tremor-dominant (PD-TD) group (N = 74) and a postural instability and gait difficulty-dominant (PD-PIGD) group (N = 39) based on the ratio of mean tremor score to the mean bradykinesia/rigid score of the Unified Parkinson's Disease Rating Scale (UPDRS) III. Age and sex-matched healthy controls were recruited (N = 35). Demographic variables were evaluated; iron and its metabolism-related proteins and the inflammatory mediators in both CSF and serum were measured in these groups. The relevance of iron metabolism, inflammation and PD-TD were analyzed. Results: (1) The PD-TD group had significantly decreased L-ferritin, increased iron levels in CSF and increased ferritin levels in the serum compared with the PD-PIGD and control groups (P < 0.05). (2) The PD-TD group had significantly enhanced IL-6 levels in both CSF and serum compared with the PD-PIGD and control groups (P < 0.05). (3) In CSF, the IL-6 level was increased as the iron level was elevated in the PD-TD group (r = 0.308, P = 0.022). In serum, the IL-6 level was increased as the ferritin level was elevated in the PD-TD group (r = 0.410, P = 0.004). Conclusion: The interplay between disturbed iron metabolism and relevant inflammation might modulate clinical phenotypes of PD.

Prevalence and duration of non-motor symptoms in prodromal Parkinson's disease

Background and purpose

The prevalence and duration of non‐motor symptoms (NMS) in prodromal Parkinson's disease (PD) has not been extensively studied. The aim of this study was to determine the prevalence and duration of prodromal NMS (pNMS) in a cohort of patients with recently diagnosed PD.

Methods

We evaluated the prevalence and duration of pNMS in patients with early PD (n = 154). NMS were screened for using the Non‐Motor Symptom Questionnaire (NMSQuest). We subtracted the duration of the presence of each individual NMS reported from the duration of the earliest motor symptom. NMS whose duration preceded the duration of motor symptoms were considered a pNMS. Individual pNMS were then grouped into relevant pNMS clusters based on the NMSQuest domains. Motor subtypes were defined as tremor dominant, postural instability gait difficulty (PIGD) and indeterminate type according to the Movement Disorder Society Unified Parkinson's Disease Rating Scale revision.

Results

Prodromal NMS were experienced by 90.3% of patients with PD and the median number experienced was 4 (interquartile range, 2–7). A gender difference existed in the pNMS experienced, with males reporting more sexual dysfunction, forgetfulness and dream re‐enactment, whereas females reported more unexplained weight change and anxiety. There was a significant association between any prodromal gastrointestinal symptoms [odds ratio (OR), 2.30; 95% confidence interval (CI), 1.08–4.89, P = 0.03] and urinary symptoms (OR, 2.54; 95% CI, 1.19–5.35, P = 0.016) and the PIGD phenotype. Further analysis revealed that total pNMS were not significantly associated with the PIGD phenotype (OR, 1.10; 95% CI, 0.99–1.21, P = 0.068).

Conclusions

Prodromal NMS are common and a gender difference in pNMS experienced in prodromal PD may exist. The PIGD phenotype had a higher prevalence of prodromal gastrointestinal and urinary tract symptoms.

Prodromal Parkinsonism and Neurodegenerative Risk Stratification in REM Sleep Behavior Disorder

Objectives

Rapid eye movement (REM) sleep behavior disorder (RBD) is the most specific marker of prodromal alpha-synucleinopathies. We sought to delineate the baseline clinical characteristics of RBD and evaluate risk stratification models.

Methods

Clinical assessments were performed in 171 RBD, 296 control, and 119 untreated Parkinson's (PD) participants. Putative risk measures were assessed as predictors of prodromal neurodegeneration, and Movement Disorders Society (MDS) criteria for prodromal PD were applied. Participants were screened for common leucine-rich repeat kinase 2 (LRRK2)/glucocerebrosidase gene (GBA) gene mutations.

Results

Compared to controls, participants with RBD had higher rates of solvent exposure, head injury, smoking, obesity, and antidepressant use. GBA mutations were more common in RBD, but no LRRK2 mutations were found. RBD participants performed significantly worse than controls on Unified Parkinson's Disease Rating Scale (UPDRS)-III, timed "get-up-and-go", Flamingo test, Sniffin Sticks, and cognitive tests and had worse measures of constipation, quality of life (QOL), and orthostatic hypotension. For all these measures except UPDRS-III, RBD and PD participants were equally impaired. Depression, anxiety, and apathy were worse in RBD compared to PD participants. Stratification of people with RBD according to antidepressant use, obesity, and age altered the odds ratio (OR) of hyposmia compared to controls from 3.4 to 45.5. 74% (95% confidence interval [CI] 66%, 80%) of RBD participants met the MDS criteria for probable prodromal Parkinson's compared to 0.3% (95% CI 0.009%, 2%) of controls.

Conclusions

RBD are impaired across a range of clinical measures consistent with prodromal PD and suggestive of a more severe nonmotor subtype. Clinical risk stratification has the potential to select higher risk patients for neuroprotective interventions.

Impact of sleep-related symptoms on clinical motor subtypes and disability in Parkinson's disease: a multicentre cross-sectional study

OBJECTIVES

To investigate the impact of sleep disturbances on Parkinson's disease (PD) clinical motor subtypes and disease-related disability in a multicentre setting.

METHODS

We report a cross-sectional relationship between sleep-related symptoms and clinical motor subtypes (tremor dominant (TD); intermediate; postural instability and gait disturbances (PIGDs)) identified in a multicentre study, including 436 patients with PD and 401 age-matched controls. PD-related sleep problems (PD-SP), excessive daytime sleepiness (EDS) and probable REM sleep behaviour disorder (pRBD) were evaluated using the PD sleep scale (PDSS)-2, Epworth Sleepiness Scale (ESS) and RBD screening questionnaire-Japanese version (RBDSQ-J), respectively.

RESULTS

PD-SP (PDSS-2 ≥18; 35.1% vs 7.0%), EDS (ESS ≥10; 37.8% vs 15.5%) and pRBD (RBDSQ-J ≥5; 35.1% vs 7.7%) were more common in patients with PD than in controls. The prevalence of restless legs syndrome did not differ between patients with PD and controls (3.4% vs 2.7%). After adjusting for age, sex, disease duration and Movement Disorder Society-Unified PD Rating Scale (MDS-UPDRS) part III score, the PIGD group had higher PDSS-2 and ESS scores than the TD group. The RBDSQ-J scores did not differ among the TD, intermediate and PIGD groups. A stepwise regression model predicting the MDS-UPDRS part II score identified the Hoehn and Yahr stage, followed by the number of sleep-related symptoms (PD-SP, EDS and pRBD), disease duration, MDS-UPDRS part III score, PIGD subtype, depression and MDS-UPDRS part IV score as significant predictors.

CONCLUSION

Our study found a significant relationship between sleep disturbances and clinical motor subtypes. An increased number of sleep-related symptoms had an impact on disease-related disability.

Predictors of onset of psychosis in patients with Parkinson's disease: Who gets it early?

INTRODUCTION

Psychosis is one of the common non-motor symptoms of PD, which substantially worsens the quality of life. Hence, it is important to identify factors that are associated with early onset of psychosis in PD. In order to identify those factors, the current study aims to compare various demographic and clinical features of PD patients with early and late onset psychosis.

METHODOLOGY

In this prospective case-control study, 51 consecutive patients with PD having psychosis (PDP) were recruited. Median of the latency of onset of psychotic symptoms from the onset of motor symptoms was calculated (5.5 years) and after doing a median split, the cohort of PDP was divided into early onset PDP (EOP, n = 25) and late onset PDP (LOP, n = 26). Both the groups were compared for several demographic and clinical characteristics.

RESULTS

Compared to those with LOP, patients with EOP had poor scores on frontal assessment battery (13.8 ± 2.0 vs 15.3 ± 1.8, p = 0.007), more frequently had Rapid Eye movement sleep Behavior Disorder (RBD) (80% vs 46.2%, p = 0.02), Postural Instability with Gait Difficulty (PIGD) phenotype (72% vs 26.9%, p = 0.002), and excessive daytime sleepiness (Epworth Sleepiness Scale: 8.04 ± 3.7 vs 3.9 ± 3.1). Patients with LOP were older (63.4 ± 7.0 years vs 56.5 ± 8.1 years, p = 0.002) and had higher Levodopa equivalent dose/day (LEDD: 819.1 ± 365.8 vs 608.5 ± 356.3, p = 0.04) compared to those with EOP.

CONCLUSION

Presence of RBD, excessive daytime sleepiness, frontal lobe dysfunction, and PIGD phenotype of PD may be associated with early onset of psychosis in PD. Higher LEDD may not trigger early occurrence of psychosis in PD.

Do cognition and other non-motor symptoms decline similarly among patients with Parkinson's disease motor subtypes? Findings from a 5-year prospective study

Among patients with Parkinson's disease (PD), a wide range of motor and non-motor symptoms (NMS) are evident. PD is often divided into tremor dominant (TD) and postural instability gait difficulty (PIGD) motor subtypes. We evaluated the effect of disease duration and aimed to characterize whether there are differences in the deterioration of cognitive function and other NMS between the PIGD and TD subtypes. Sixty-three subjects were re-evaluated at the follow-up visit about 5 years after baseline examination. Cognitive function and other NMS were assessed. At follow-up, the PIGD and TD groups were similar with respect to medications, comorbidities and disease-related symptoms. There was a significant time effect for all measures, indicating deterioration and worsening in both groups. However, cognitive scores, particularly those related to executive function, became significantly worse in the PIGD with a more moderate decrease in the TD group. For example, the computerized global cognitive score declined in the PIGD group from 94.21 ± 11.88 to 83.91 ± 13.76, p < 0.001. This decline was significantly larger (p = 0.03) than the decrease observed in the TD group (96.56 ± 10.29 to 92.21 ± 14.20, p = 0.047). A significant group × time interaction effect was found for the change in global cognitive score (p = 0.047), the executive function index (p = 0.002) and accuracy on a motor-cognitive catch game (p = 0.008). In contrast, several NMS including depression, health-related quality of life and fear of falling deteriorated in parallel in both subtypes, with no interaction effect. The present findings highlight the difference in the natural history of the disease between the two PD "motor" subtypes. While the PIGD group demonstrated a significant cognitive decline, especially in executive functions, a more favorable course was observed in the TD subtype. This behavior was not seen in regards to the other NMS.

The role of neurotransmitters in the development of Parkinson's disease-related psychosis

Psychotic symptoms are common, disabling non-motor features of Parkinson's disease (PD). Despite noted heterogeneity in clinical features, natural history and therapy response, current dogma posits that psychosis generally progresses in a stereotypic manner through a cascade of events that begins with minor hallucinations and evolves to severe hallucinations and delusions. Further, the occurrence of psychotic symptoms is believed to indicate a poor prognosis. Here we propose a classification scheme that outlines the pathogenesis of psychosis as it relates to dysfunction of several neurotransmitter systems. We hypothesize that several subtypes exist, and that PD psychosis is not consistently indicative of a progressive cascade and poor prognosis. The literature was reviewed from 1990 to 2017. An overview of the features of PD psychosis is followed by a review of data indicating the existence of neurotransmitter-related subtypes of psychosis. We found that ample evidence exists to demonstrate the presence of multiple subtypes of PD psychosis, which are traced to dysfunction of the following neurotransmitter systems: dopamine, serotonin and acetylcholine. Dysfunction of each of these systems is recognizable through their clinical features and correlates, and the varied long-term prognoses. Identifying which neurotransmitter system is dysfunctional may help to develop targeted therapies. PD psychosis has various subtypes that differ in clinical features, underlying pathology and pathophysiology, treatment response and prognosis. A novel classification scheme is presented that describes the clinical subtypes with different outcomes, which could lead to the development of targeted therapies. Future research should focus on testing the viability of this classification.