Delineating nonmotor symptoms in early Parkinson's disease and first-degree relatives

Non-motor symptoms in prodromal Parkinson's disease are linked to reduced quality of life

Isolated rapid eye movement (REM) sleep behavior disorder (iRBD) highlights an early α-synucleinopathy. This study compared health-related quality of life (hrQoL) in 62 individuals with iRBD with 19 healthy controls (HC) and 29 individuals with Parkinson's disease (PD) and identified factors linked to poorer hrQoL. HrQoL was significantly lower in individuals with iRBD (83.33 ± 16.96) compared to HC (92.29 ± 5.49, p = 0.027). Poorer hrQoL in individuals with iRBD was linked to severity of multiple non-motor symptoms, most prominently fatigue and depressive symptoms being significant predictors (p < 0.001, adjusted R2 = 0.81). This study highlights the importance of non-motor symptoms for hrQoL in prodromal PD.

Burden of non-motor symptoms of Parkinson's disease: cost-of-illness and quality-of-life estimates through a scoping review

INTRODUCTION

Parkinson's Disease (PD) is a progressive, chronic neurodegenerative disease, representing significant economic and social burdens. It is typically defined by motor symptoms (MSs), however, this does not reflect the full patient burden. Non-motor symptoms (NMSs) are increasingly recognized as central characteristics of PD. However, they still lack recognition in research. Therefore, this study aims to identify relevant NMSs, their prevalence, and the effect they have on Quality-of-Life (QoL) and Cost-of-Illness (COI). Secondly, it aims to identify gaps in the current body of knowledge and propose possible ways future research could bridge those gaps.

METHODS

The study employed a scoping review, identifying 60 records for inclusion, using PubMed and Web of Science. It included studies from Spain or Italy, including data on People with Parkinson's Disease. A comparative analysis was performed using Microsoft Excel.

RESULTS

It showed that the body of evidence relevant to NMSs, their prevalence, QoL, and COI is limited, or that estimates vary to an extent where interpretation is difficult.

CONCLUSION

Most studies suffer from generalization, representation, and standardization issues, stemming from their designs and methodological decisions. Although the findings of this study should be interpreted with caution, several recommendations are made for future research.

Characterizing pain in Parkinson's disease: types, predictors, and management implications

Background

Pain impacts quality of life (QoL) in Parkinson's disease (PD) patients, yet it is often overlooked. This study aims to comprehensively evaluate pain in PD, particularly focusing on differences between neuropathic pain (NP) and other types.

Methods

We conducted a cross-sectional study involving PD patients, assessing the prevalence and characteristics of pain. Various scales were employed to evaluate anxiety, depression, and QoL. We investigated associations between pain, demographic, and clinical variables to determine predictors and pain-related factors. Additionally, factors related to NP were explored.

Results

During the study period, a total of 109 patients were examined. Sixteen patients were excluded due to various reasons. The final analysis included 93 patients (34 females and 59 males). Pain was reported by 80.6% of PD patients, with no significant demographic or clinical differences between those with and without pain. However, longer disease duration predicted NP, and musculoskeletal pain was more prevalent in females. Anxiety was common in patients with central parkinsonian pain (CPP). Patients taking amantadine reported less radicular/ neuropathic pain (RNP), suggesting a therapeutic role.

Conclusions

Our findings underscore the high prevalence of pain in PD and its impact on QoL. NP appears to be associated with disease progression, while sex-specific differences highlight the need for personalized pain management strategies. The association between anxiety and CPP emphasizes the importance of addressing psychological factors in PD pain management. Further research on amantadine's benefits in reducing RNP is warranted, emphasizing the importance of tailored pain management strategies for PD patients.

[Fatigue in chronic physical diseases]

The term fatigue is used to describe states of unusual tiredness and exhaustion that can occur in connection with various chronic diseases, particularly cancer, multiple sclerosis, Parkinson's disease and rheumatoid arthritis. In contrast to states of exhaustion in healthy people, fatigue is characterized by the fact that it can last for long periods, is disproportionate to previous activities and does not subside after recovery phases. Fatigue is described as a multidimensional problem that encompasses physical, emotional and cognitive aspects and is associated with a high level of subjective suffering. Depending on the severity and course of the symptoms, fatigue is associated with a severely reduced quality of life and it impairs participation and coping with everyday life. It also makes professional reintegration and reemployment more difficult. Although we cannot yet fully explain the aetiology and pathogenesis, fatigue in physical illnesses must be understood based on a multifactorial biopsychosocial model. The possibilities of diagnostics and an overview of various measures for clarifying fatigue are presented. The challenges for medical care are also outlined and advice is given on how to deal with them in everyday clinical practice.

Research progress on the application of anti-gravity treadmill in the rehabilitation of Parkinson's disease patients: a mini review

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by motor and non-motor symptoms. It is the second most common chronic progressive neurodegenerative disease. PD still lacks a known cure or prophylactic medication. Current treatments primarily address symptoms without halting the progression of PD, and the side effects of dopaminergic therapy become more apparent over time. In contrast, physical therapy, with its lower risk of side effects and potential cardiovascular benefits, may provide greater benefits to patients. The Anti-Gravity Treadmill is an emerging rehabilitation therapy device with high safety, which minimizes patients' fear and allows them to focus more on a normal, correct gait, and has a promising clinical application. Based on this premise, this study aims to summarize and analyze the relevant studies on the application of the anti-gravity treadmill in PD patients, providing a reference for PD rehabilitation practice and establishing a theoretical basis for future research in this area.

The effect of dance on mental health and quality of life of people with Parkinson's disease: A systematic review and three-level meta-analysis

OBJECTIVES

Parkinson's disease (PD) is a neurodegenerative disease that affects millions of individuals worldwide. Dance has emerged as a comprehensive intervention for enhancing well-being in this population. This meta-analysis aimed to assess the effectiveness of dance on mental health and quality of life among individuals with PD.

METHODS

Three databases were searched in December 2022. Research papers comparing the effects of dance with a non-dance control on the quality of life or mental health of individuals with PD were included. Two authors independently screened the studies, extracted data, and assessed methodological quality of eligible studies. To address the interdependence of effect sizes within studies, the three-level meta-analysis approach was employed to analyze the data.

RESULTS

Thirteen trials involving a total of 496 participants were included, with 11 being subjected to statistical analysis. The results indicated that dance had a positive impact on mental health (g = 0.43, 95 % CI = [0.11, 0.75]) and quality of life (g = 0.46, 95 % CI = [-0.04, 0.95]) when compared to passive control groups. Moderator analyses revealed that non-partnered dance and dance interventions with lower total dosages were particularly beneficial for mental health.

CONCLUSION

Dance interventions are an effective lifestyle activity for enhancing mental health and quality of life in individuals with PD. A theoretical framework is proposed to explain the impact of dance on well-being from neurological, social, physical, and psychological perspectives.

Sexual dysfunction among patients with Parkinson's disease: A systematic review and meta-analysis

BACKGROUND

Previous studies have reported a higher prevalence of sexual dysfunction (SD) in patients with Parkinson's disease (PD). In the current study, we aimed to conduct a systematic review and meta-analysis to investigate the role of PD as a potential risk factor for SD in both genders.

METHODS

We performed a comprehensive search on PubMed, Embase, Scopus, and Web of Science. All observational studies comparing the prevalence of SD in PD with the general population were included.

RESULTS

After screening 22 studies were included in our qualitative and statistical analysis. We included 13 studies that reported odds ratio (OR) and found a significant association between PD and SD (pooled OR = 3.5, 95% CI = 2.19-5.58). Five studies included only male patients and reported an OR of 3.34 (95% CI = 1.34-8.35; heterogeneity I2 = 81%, Tau2 = 0.79, p < 0.00), while seven studies included both sexes and reported an OR of 3.55 (95% CI = 1.89-6.66; heterogeneity I2 = 78%, Tau2 = 0.53, p < 0.00).

CONCLUSION

In conclusion, our study suggests a strong association between PD and SD in both men and women. Our analysis of 22 observational studies reveals that the prevalence of sexual dysfunction is significantly higher in patients with PD compared to the general population. These findings highlight the importance of addressing SD as part of the comprehensive management of patients with PD.

Pain in monogenic Parkinson's disease: a comprehensive review

Pain, a challenging symptom experienced by individuals diagnosed with Parkinson's disease (PD), still lacks a comprehensive understanding of its underlying pathophysiological mechanisms. A systematic investigation of its prevalence and impact on the quality of life in patients affected by monogenic forms of PD has yet to be undertaken. This comprehensive review aims to provide an overview of the association between pain and monogenic forms of PD, specifically focusing on pathogenic variants in SNCA, PRKN, PINK1, PARK7, LRRK2, GBA1, VPS35, ATP13A2, DNAJC6, FBXO7, and SYNJ1. Sixty-three articles discussing pain associated with monogenic PD were identified and analyzed. The included studies exhibited significant heterogeneity in design, sample size, and pain outcome measures. Nonetheless, the findings of this review suggest that patients with monogenic PD may experience specific types of pain depending on the pathogenic variant present, distinguishing them from non-carriers. For instance, individuals with SNCA pathogenic variants have reported painful dystonia, lower extremity pain, dorsal pain, and upper back pain. However, these observations are primarily based on case reports with unclear prevalence. Painful lower limb dystonia and lower back pain are prominent symptoms in PRKN carriers. A continual correlation has been noted between LRRK2 mutations and the emergence of pain, though the conflicting research outcomes pose challenges in reaching definitive conclusions. Individuals with PINK1 mutation carriers also frequently report experiencing pain. Pain has been frequently reported as an initial symptom and the most troublesome one in GBA1-PD patients compared to those with idiopathic PD. The evidence regarding pain in ATP13A2, PARK7, VPS35, DNAJC6, FBXO7, and SYNJ1pathogenic variants is limited and insufficient. The potential linkage between genetic profiles and pain outcomes holds promising clinical implications, allowing for the potential stratification of patients in clinical trials and the development of personalized treatments for pain in monogenic PD. In conclusion, this review underscores the need for further research to unravel the intricate relationship between pain and monogenic forms of PD. Standardized methodologies, larger sample sizes, and longitudinal studies are essential to elucidate the underlying mechanisms and develop targeted therapeutic interventions for pain management in individuals with monogenic PD.

Possible association between the lrrk2 gene and anxiety behavior: a systematic literature review

Alterations to the LRRK2 gene have been associated with Parkinson's disease and alcohol consumption in animals and humans. Furthermore, these disorders are strongly related to anxiety disorders (ADs). Thus, we investigated how the LRRK2 gene might influence anxiety in humans and mice. We elaborated a systematic review based on the PRISMA Statement of studies that investigated levels of anxiety in animal or human models with alterations in the LRRK2 gene. The search was conducted in the PubMed, Scopus, and Web of Science databases, and in reference lists with descriptors related to ADs and the LRRK2. From the 62 articles assessed for eligibility, 16 were included: 11 conducted in humans and seven, in mice. Lrrk2 KO mice and the LRRK2 G2019S, LRRK2 R1441G, and LRRK2 R1441C variants were addressed. Five articles reported an increase in anxiety levels concerning the LRRK2 variants. Decreased anxiety levels were observed in two articles, one focusing on the LRRK2 G2019S and the other, on the Lrrk2 KO mice. Eight other articles reported no differences in anxiety levels in individuals with Lrrk2 alterations compared to their healthy controls. This study discusses a possible influence between the LRRK2 gene and anxiety, adding information to the existing knowledge respecting the influence of genetics on anxiety.

The Subthalamic Nucleus Exclusively Evokes Dopamine Release in the Tail of the Striatum

A distinct population of dopamine neurons in the substantia nigra pars lateralis (SNL) has a unique projection to the most caudolateral (tail) region of the striatum. Here, using two electrochemical techniques to measure basal dopamine and electrically evoked dopamine release in anesthetized rats, we characterized this pathway, and compared it with the ‘classic’ nigrostriatal pathway from neighboring substantia nigra pars compacta (SNc) dopamine neurons to the dorsolateral striatum. We found that the tail striatum constitutes a distinct dopamine domain compared with the dorsolateral striatum, with consistently lower basal and evoked dopamine, and diverse dopamine release kinetics. Importantly, electrical stimulation of the SNL and SNc evoked dopamine release in entirely separate striatal regions; the tail and dorsolateral striatum, respectively. Furthermore, we showed that stimulation of the subthalamic nucleus (STN) evoked dopamine release exclusively in the tail striatum, likely via the SNL, consistent with previous anatomical evidence of STN afferents to SNL dopamine neurons. Our work identifies the STN as an important modulator of dopamine release in a novel dopamine pathway to the tail striatum, largely independent of the classic nigrostriatal pathway, which necessitates a revision of the basal ganglia circuitry with the STN positioned as a central integrator of striatal information.

Mapping brain structural differences and neuroreceptor correlates in Parkinson's disease visual hallucinations

Parkinson's psychosis (PDP) describes a spectrum of symptoms that may arise in Parkinson's disease (PD) including visual hallucinations (VH). Imaging studies investigating the neural correlates of PDP have been inconsistent in their findings, due to differences in study design and limitations of scale. Here we use empirical Bayes harmonisation to pool together structural imaging data from multiple research groups into a large-scale mega-analysis, allowing us to identify cortical regions and networks involved in VH and their relation to receptor binding. Differences of morphometrics analysed show a wider cortical involvement underlying VH than previously recognised, including primary visual cortex and surrounding regions, and the hippocampus, independent of its role in cognitive decline. Structural covariance analyses point to the involvement of the attentional control networks in PD-VH, while associations with receptor density maps suggest neurotransmitter loss may be linked to the cortical changes.

Neurogenic orthostatic hypotension in early stage Parkinson's disease: New insights from the first 105 patients of the BoProPark study

OBJECTIVES

The prevalence of neurogenic orthostatic hypotension (NOH, due to cardiovascular autonomic failure) at early stage of Parkinson's disease (PD) is unknown. The aims of this study are to prospectively evaluate in a cohort of PD patients recruited within 3 years from motor onset (1) cardiovascular autonomic functions by means of cardiovascular reflex tests (CRTs) and the occurrence of NOH; (2) the frequency of orthostatic symptoms with a validated questionnaire.

METHODS

We included the first 105 PD patients of the prospective "BoProPark" study. Each patient underwent CRTs (head up tilt test; Valsalva manoeuvre; deep breathing; cold face test and handgrip test) under continuous blood pressure monitoring according to standardized procedures and SCOPA-Aut questionnaire at baseline (T0) and after 16 months (T1). A group of 50 age- and sex-matched controls was used for comparison.

RESULTS

At T0 (mean age 61 ± 9 years, disease duration 19 ± 9 months) NOH was detected in 4/105 (3.8%) patients, whereas at T1 in 8/105 (7.6%). CRTs responses assessing sympathetic function were impaired at T0 in PD patients compared to controls and progressively worsened at T1. Only 1 patient at T0 and 3 at T1 with NOH reported orthostatic symptoms with low frequency, while the majority of patients reporting these symptoms did not have OH at testing.

CONCLUSIONS

Our prospective study shows that NOH is not common at early PD stage. Asymptomatic mild sympathetic impairment was observed at first evaluation and progressed with disease evolution. Secondary OH may account for the higher prevalence of OH in PD reported so far.

Heterogeneity of prodromal Parkinson symptoms in siblings of Parkinson disease patients

A prodromal phase of Parkinson's disease (PD) may precede motor manifestations by decades. PD patients' siblings are at higher risk for PD, but the prevalence and distribution of prodromal symptoms are unknown. The study objectives were (1) to assess motor and non-motor features estimating prodromal PD probability in PD siblings recruited within the European PROPAG-AGEING project; (2) to compare motor and non-motor symptoms to the well-established DeNoPa cohort. 340 PD siblings from three sites (Bologna, Seville, Kassel/Goettingen) underwent clinical and neurological evaluations of PD markers. The German part of the cohort was compared with German de novo PD patients (dnPDs) and healthy controls (CTRs) from DeNoPa. Fifteen (4.4%) siblings presented with subtle signs of motor impairment, with MDS-UPDRS-III scores not clinically different from CTRs. Symptoms of orthostatic hypotension were present in 47 siblings (13.8%), no different to CTRs (p = 0.072). No differences were found for olfaction and overall cognition; German-siblings performed worse than CTRs in visuospatial-executive and language tasks. 3/147 siblings had video-polysomnography-confirmed REM sleep behavior disorder (RBD), none was positive on the RBD Screening Questionnaire. 173/300 siblings had <1% probability of having prodromal PD; 100 between 1 and 10%, 26 siblings between 10 and 80%, one fulfilled the criteria for prodromal PD. According to the current analysis, we cannot confirm the increased risk of PD siblings for prodromal PD. Siblings showed a heterogeneous distribution of prodromal PD markers and probability. Additional parameters, including strong disease markers, should be investigated to verify if these results depend on validity and sensitivity of prodromal PD criteria, or if siblings' risk is not elevated.

Longitudinal Changes in Parkinson's Disease Symptoms with and Without Rapid Eye Movement Sleep Behavior Disorder: The Oxford Discovery Cohort Study

BACKGROUND

Parkinson's disease (PD) comorbid with rapid eye movement sleep behavior disorder (RBD) may show more severe motor and nonmotor symptoms, suggesting a distinct PD subtype.

OBJECTIVE

The aim of this study was to investigate the impact of RBD on the longitudinal change of motor and nonmotor symptoms in patients with PD.

METHODS

Patients with early PD (diagnosed within 3.5 years) recruited from 2010 to 2019 were followed every 18 months in the Oxford Parkinson's Disease Centre Discovery cohort. At each visit, we used standard questionnaires and measurements to assess demographic features and motor and nonmotor symptoms (including RBD, daytime sleepiness, mood, autonomic symptoms, cognition, and olfaction). Data were analyzed with linear mixed effects and Cox regression models. Possible RBD (pRBD) was longitudinally determined according to RBD Screening Questionnaire scores.

RESULTS

A total of 923 patients were recruited (mean age: 67.1 ± 9.59 years; 35.9% female), and 788 had follow-up assessment(s) (mean: 4.8 ± 1.98 years, range: 1.3-8.3). Among them, 33.3% were identified as pRBD (PD + pRBD). Patients with PD + pRBD had more severe baseline symptoms and showed faster progression on Movement Disorder Society-Unified Parkinson's Disease Rating Scale parts I and III, Purdue Pegboard test, and Beck Depression Inventory scores. Moreover, PD + pRBD was associated with an increased level of risk for mild cognitive impairment (hazard ratio [HR] = 1.36, 95% confidence interval [CI]: 1.01-1.83), freezing of gait (HR = 1.42, 95% CI: 1.10-1.86), and frequent falling (HR = 1.62, 95% CI: 1.02-2.60).

CONCLUSIONS

Patients with PD + pRBD progress faster on motor, mood, and cognitive symptoms, confirming a more aggressive PD subtype that can be identified at baseline and has major clinical implications. © 2021 International Parkinson and Movement Disorder Society.

Assessment of Motor Dysfunction with Virtual Reality in Patients Undergoing [123I]FP-CIT SPECT/CT Brain Imaging

[¹²³I]FP-CIT SPECT has been valuable for distinguishing Parkinson disease (PD) from essential tremor. However, its performance for quantitative assessment of motor dysfunction has not been established. A virtual reality (VR) application was developed and compared with [¹²³I]FP-CIT SPECT/CT for detection of severity of motor dysfunction. Forty-four patients (21 males, 23 females, age 64.5 ± 12.4) with abnormal [¹²³I]FP-CIT SPECT/CT underwent assessment of bradykinesia, activities of daily living, and tremor with VR. Support vector machines (SVM) machine learning models were applied to VR and SPECT data. Receiver operating characteristic (ROC) analysis demonstrated greater area under the curve (AUC) for VR (0.8418, 95% CI 0.6071–0.9617) compared with brain SPECT (0.5357, 95% CI 0.3373–0.7357, p = 0.029) for detection of motor dysfunction. Logistic regression identified VR as an independent predictor of motor dysfunction (Odds Ratio 326.4, SE 2.17, p = 0.008). SVM for prediction of the Unified Parkinson’s Disease Rating Scale Part III (UPDRS-III) demonstrated greater R-squared of 0.713 (p = 0.008) for VR, compared with 0.0764 (p = 0.361) for brain SPECT. This study demonstrates that VR can be safely used in patients prior to [¹²³I]FP-CIT SPECT imaging and may improve prediction of motor dysfunction. This test has the potential to provide a simple, objective, quantitative analysis of motor symptoms in PD patients.

Quality of life in Parkinson's disease: A systematic review and meta-analysis of comparative studies

BACKGROUND

Studies regarding the impact of Parkinson's disease (PD) on quality of life (QOL) have reported conflicting results, and the underlying QOL domains require further study. In order to understand the association between PD and QOL, we conducted this meta-analysis to systematically compare QOL between PD patients and healthy controls.

METHOD

The PubMed, PsycINFO, EMBASE, and Web of Science databases were systematically searched. Data were analyzed using the random-effects model.

RESULTS

Twenty studies covering 2707 PD patients and 150,661 healthy controls were included in the study. Compared with healthy controls, PD patients had significantly poorer QOL overall and in most domains with moderate to large effects sizes. Different QOL measures varied in their association with quality of life, with the Parkinson's Disease Questionnaire-39 (PDQ-39) having the largest effect size (standard mean difference, SMD = -1.384, 95% CI: -1.607, -1.162, Z = 12.189, P < 0.001), followed by the Europe Quality of Life Questionnaire-visual analogue scale (EQ-VAS) (SMD = -1.081, 95% CI: -1.578, -0.584, Z = -4.265, P < 0.001), Europe Quality of Life Questionnaire-5D (EQ-5D) (SMD = -0.889, 95% CI: -1.181, -0.596, Z = -5.962, P < 0.001), and the Short-form Health Survey (SF) scales (physical dimension: SMD = -0.826, 95% CI: -1.529, -0.123, Z = -2.303, P = 0.021; mental dimension: SMD = -0.376, 95% CI: -0.732, -0.019, Z = -2.064, P = 0.039).

CONCLUSION

PD patients had lower QOL compared with healthy controls in most domains, especially in physical function and mental health. Considering the negative impact of poor QOL on daily life and functional outcomes, effective measures should be developed to improve QOL in this population.

Olfactory Testing in Parkinson Disease and REM Behavior Disorder: A Machine Learning Approach

OBJECTIVE

We sought to identify an abbreviated test of impaired olfaction amenable for use in busy clinical environments in prodromal (isolated REM sleep behavior disorder [iRBD]) and manifest Parkinson disease (PD).

METHODS

Eight hundred ninety individuals with PD and 313 controls in the Discovery cohort study underwent Sniffin' Stick odor identification assessment. Random forests were initially trained to distinguish individuals with poor (functional anosmia/hyposmia) and good (normosmia/super-smeller) smell ability using all 16 Sniffin' Sticks. Models were retrained using the top 3 sticks ranked by order of predictor importance. One randomly selected 3-stick model was tested in a second independent PD dataset (n = 452) and in 2 iRBD datasets (Discovery n = 241, Marburg n = 37) before being compared to previously described abbreviated Sniffin' Stick combinations.

RESULTS

In differentiating poor from good smell ability, the overall area under the curve (AUC) value associated with the top 3 sticks (anise/licorice/banana) was 0.95 in the Development dataset (sensitivity 90%, specificity 92%, positive predictive value 92%, negative predictive value 90%). Internal and external validation confirmed AUCs ≥0.90. The combination of the 3-stick model determined poor smell, and an RBD screening questionnaire score of ≥5 separated those with iRBD from controls with a sensitivity, specificity, positive predictive value, and negative predictive value of 65%, 100%, 100%, and 30%.

CONCLUSIONS

Our 3-Sniffin'-Stick model holds potential utility as a brief screening test in the stratification of individuals with PD and iRBD according to olfactory dysfunction.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that a 3-Sniffin'-Stick model distinguishes individuals with poor and good smell ability and can be used to screen for individuals with iRBD.

[Non-motor symptoms of Parkinson's disease from pathophysiology to early diagnosis]

Parkinson's disease is the second most common neurodegenerative disease after Alzheimer's disease. The pathophysiology of Parkinson's disease is complex and imperfectly known. Primum movens is abnormal intra-neuronal accumulation of the protein α-synuclein, leading to metabolic disturbances and neurodegeneration. This abnormal accumulation of α-synuclein is also found in dementia with Lewy bodies and multiple system atrophy, which together with Parkinson's disease form the group of α-synucleinopathies. Well known by its motor signs (bradykinesia, rest tremor, cogwheel rigidity and gait disturbance), Parkinson's disease is above all a systemic disease composed of a myriad of non-motor symptoms (constipation, sense of smell disorders, rapid eye movement sleep behaviour disorders, genitourinary disorders…). These non-motor symptoms caused by accumulation and migration of α-synuclein deposits from the gut and the olfactory bulb to the central nervous system may precede motor signs by ten years and therefore be of interest for early diagnosis. Furthermore, non-motor symptoms have a poorer impact on quality of life than motor signs themselves. Therefore, understanding, recognition and management of non-motor symptoms are crucial in management of parkinsonian patient. In this paper, we offer an update on the main non-motor symptoms of Parkinson's disease, from their pathophysiology to their screening, ending with their management.

Pain in persons with mild-moderate Parkinson's disease: a cross-sectional study of pain severity and associated factors

The aims of this study were to determine pain severity in persons with mild-moderate Parkinson's disease compared with healthy age- and sex-matched controls, and identify related factors, that is, demographic, disease severity, and functioning, of pain severity in the Parkinson's disease group. A cross-sectional study design was adopted to assess pain severity in 100 persons with Parkinson's disease and 47 healthy controls. Bodily pain was assessed using item 21 of the Short Form 36, whereas pain severity was determined using the entire Short Form 36 Bodily Pain subscale (score ranging from 0 to 100). Self-report questionnaires and clinical tests were completed to determine factors, that is, demographic and disease severity characteristics as well as physical functioning indicators, related to pain severity. Based on fulfillment of assumptions of data normality, both univariate and multivariate regression analysis were carried out. Pain severity (P < 0.001) was significantly higher in persons with Parkinson's disease than healthy controls. Among persons with Parkinson's disease, the multivariate predictor model, explaining 34% of the variance in pain severity scores, identified three independently associated factors. Poorer balance performance, a shorter disease duration, and poorer health-related quality of life were independently associated with pain severity. Pain severity is higher in those living with Parkinson's disease than controls, and severity appears to be associated with disease characteristics and overall health. Further research is required to assess pain origin in Parkinson's disease with the aim of developing targeted interventions.

Impulse control disorders in Parkinson disease and RBD: A longitudinal study of severity

Objective

To describe the prevalence, natural history, and risk factors for impulse control behaviors (ICBs) among people with Parkinson disease (PD), those with REM sleep behavior disorder (RBD), and controls.

Methods

Participants with early PD (within 3.5 years of diagnosis), those with RBD, and controls were clinically phenotyped and screened for ICBs longitudinally (with the Questionnaire for Impulsivity in Parkinson's Disease). ICB-positive individuals were invited for a semistructured interview, repeated 1 year later. The severity of the ICB was assessed with the Parkinson's Impulse Control Scale. Multiple imputation and regression models were used to estimate ICB prevalence and associations.

Results

Data from 921 cases of PD at baseline, 768 cases at 18 months, and 531 cases at 36 months were included, with 21% to 25% screening positive for ICBs at each visit. Interviews of ICB screen–positive individuals revealed that 10% met formal criteria for impulse control disorders (ICD), while 33% had subsyndromal ICD (ICB symptoms without reaching the formal diagnostic criteria for ICD). When these data were combined through the use of multiple imputation, the prevalence of PD-ICB was estimated at 19.1% (95% confidence interval 10.1–28.2). On follow-up, 24% of cases of subsyndromal ICD had developed full symptoms of an ICD. PD-ICD was associated with dopamine agonist use, motor complications, and apathy but not PD-RBD. ICD prevalence in the RBD group (1%) was similar to that in controls (0.7%).

Conclusions

ICBs occur in 19.1% of patients with early PD, many persisting or worsening over time. RBD is not associated with increased ICD risk. Psychosocial drivers, including mood and support networks, affect severity.

α-Synuclein and astrocytes: tracing the pathways from homeostasis to neurodegeneration in Lewy body disease

α-Synuclein is a soluble protein that is present in abundance in the brain, though its normal function in the healthy brain is poorly defined. Intraneuronal inclusions of α-synuclein, commonly referred to as Lewy pathology, are pathological hallmarks of a spectrum of neurodegenerative disorders referred to as α-synucleinopathies. Though α-synuclein is expressed predominantly in neurons, α-synuclein aggregates in astrocytes are a common feature in these neurodegenerative diseases. How and why α-synuclein ends up in the astrocytes and the consequences of this dysfunctional proteostasis in immune cells is a major area of research that can have far-reaching implications for future immunobiotherapies in α-synucleinopathies. Accumulation of aggregated α-synuclein can disrupt astrocyte function in general and, more importantly, can contribute to neurodegeneration in α-synucleinopathies through various pathways. Here, we summarize our current knowledge on how astrocytic α-synucleinopathy affects CNS function in health and disease and propose a model of neuroglial connectome altered by α-synuclein proteostasis that might be amenable to immune-based therapies.

Sensory neuropathy and nociception in rodent models of Parkinson's disease

Parkinson's disease (PD) often manifests with prodromal pain and sensory losses whose etiologies are not well understood. Multiple genetic and toxicity-based rodent models of PD partly recapitulate the histopathology and motor function deficits. Although far less studied, there is some evidence that rodents, similar to humans, develop sensory manifestations of the disease, which may precede motor disturbances and help to elucidate the underlying mechanisms of PD-associated pain at the molecular and neuron circuit levels. The present Review summarizes nociception and other sensory functions in frequently used rodent PD models within the context of the complex phenotypes. In terms of mechanisms, it appears that the acute loss of dopaminergic neurons in systemic toxicity models (MPTP, rotenone) primarily causes nociceptive hyperexcitability, presumably owing to a loss of inhibitory control, whereas genetic models primarily result in a progressive loss of heat perception, reflecting sensory fiber neuropathies. At the molecular level, neither α-synuclein deposits alone nor failure of mitophagy alone appear to be strong enough to result in axonal or synaptic pathology of nociceptive neurons that manifest at the behavioral level, and peripheral sensory loss may mask central ‘pain’ in behavioral tests. Hence, allostatic combinations or additional challenges and novel behavioral assessments are needed to better evaluate PD-associated sensory neuropathies and pain in rodents.

Summary: Rodent models of Parkinson's disease partially develop prodromal somatosensory and olfactory dysfunctions reminiscent of sensory neuropathies in patients and reveal mechanistic insight, but data are incomplete and fragmented.

Analysis of repetitive element expression in the blood and skin of patients with Parkinson's disease identifies differential expression of satellite elements

Repetitive elements (RE) constitute the majority of the human genome and have a range of functions both structural and regulatory on genomic function and gene expression. RE overexpression has been observed in several neurodegenerative diseases, consistent with the observation of aberrant expression of RE posing a mutagenic threat. Despite reports that associate RE expression with PD no study has comprehensively analysed the role of these elements in the disease. This study presents the first genome-wide analysis of RE expression in PD to date. Analysis of RNA-sequencing data of 12 PD patients and 12 healthy controls identified tissue-specific expression differences and more significantly, differential expression of four satellite elements; two simple satellite III (repName = CATTC_n and _GAATG_n) a high-copy satellite II (HSATII) and a centromeric satellite (ALR_Alpha) in the blood of PD patients. In support of the growing body of recent evidence associating REs with neurodegenerative disease, this study highlights the potential importance of characterization of RE expression in such diseases.

Parkinson's Disease Is Associated with Risk of Sexual Dysfunction in Men but Not in Women: A Systematic Review and Meta-Analysis

BACKGROUND

Mounting evidence has emerged suggesting that patients with Parkinson's disease (PD) are susceptible to sexual dysfunction (SD).

AIM

To better clarify the relationship between PD and SD.

METHODS

PubMed, Embase, Cochrane Library database, and PsychINFO database were systematically searched for pertinent studies evaluating sexual function in the patients with PD. This systematic review and meta-analysis have been registered on PROSPERO (ID: CRD42018108714; http://www.crd.york.ac.uk/PROSPERO).

OUTCOMES

The association between PD and SD was assessed using relative risk (RR) with 95% CI. The quality of evidence was ranked by the GRADE profiler.

RESULTS

11 observational studies met the predefined criteria for inclusion, enrolling 30,150 subjects from both the PD group and healthy control group (mean age 54.6-75.1 years). Synthesis results revealed that PD was associated with an elevated risk of SD in males (7 studies; 1.79; 95% CI = 1.26-2.54, P = .001; heterogeneity: I2 = 73.2%, P < .001). However, when restricted to female subjects, the combined RR from 3 eligible studies suggested a lack of significant association between PD and SD (RR = 1.3, 95% CI = 0.64-2.61, P = .469; heterogeneity: I2 = 80.0%, P = .007). The GRADE profiler indicated the overall quality of the evidence was low in studies including males and very low in studies including females.

CLINICAL IMPLICATIONS

The current meta-analysis indicated that men with PD were more likely to experience SD than those without PD. In female subjects, however, PD seemed to not be associated with a high prevalence of SD compared with healthy controls. Based on these findings, patients with PD should be routinely assessed for sexual functioning, especially males.

STRENGTHS & LIMITATIONS

This is the first systematic review and meta-analysis of the association between PD and the risks of SD in both males and females. However, substantial heterogeneities were detected across the included studies.

CONCLUSION

A hazardous effect of PD for developing SD was detected in men but not in women. As a result, sexual function assessment and appropriate therapy are recommended for men with PD in clinical practice. Zhao S, Wang J, Xie Q, et al. Parkinson's Disease Is Associated with Risk of Sexual Dysfunction in Men but Not in Women: A Systematic Review and Meta-Analysis J Sex Med 2019;16:434-446.

Risk factors for possible REM sleep behavior disorder: A CLSA population-based cohort study

OBJECTIVE

To assess sociodemographic, socioeconomic, and clinical correlates of idiopathic REM sleep behavior disorder (RBD) in a 30,097-person national cohort.

METHODS

Participants 45 to 85 years of age in Canada were collected as part of the Canadian Longitudinal Study on Aging. Possible RBD (pRBD) was screened with the REM Sleep Behavior Disorder Single-Question Screen, a questionnaire with 94% specificity and 87% sensitivity. To improve diagnostic accuracy, those screening positive for apnea or non-REM parasomnia (young-onset pRBD) and those self-reporting dementia or Parkinson disease were excluded. A series of sociodemographic, lifestyle, and mental health variables were analyzed cross-sectionally. Potential correlates were assessed via multivariable logistic regression.

RESULTS

Of 30,097 participants, 958 (3.2%) were identified as having pRBD. Male sex (odds ratio [OR] 2.09, 95% confidence interval [CI] 1.78-2.44) and lower education (OR 0.95, 95% CI 0.92-0.98) were associated with pRBD. Participants with pRBD had smoked more (pack-years OR 1.01, 95% CI 1.00-1.01) and were more likely to be moderate to heavy drinkers (OR 1.25, 95% CI 1.04-1.51). There was a strong association between pRBD and self-reported antidepressant treatment for depression (OR 2.77, 95% CI 2.23-3.45), psychological distress (OR 1.61, 95% CI 1.44-1.80), mental illness (OR 2.09, 95% CI 1.75-2.49), and posttraumatic stress disorder (OR 2.68, 95% CI 1.97-3.65).

CONCLUSIONS

Our study replicated previous reported associations between pRBD and smoking, low education, and male sex and found previously unreported links with alcohol use and psychological distress. Risk factors for pRBD differ from those previously defined for neurodegenerative synucleinopathies.

Sardinian Folk Dance for Individuals with Parkinson's Disease: A Randomized Controlled Pilot Trial

OBJECTIVES

Among different exercise models proposed for individuals with Parkinson's disease (IwPD), the popularity of traditional forms of dance is increasing. The aim of this study was to evaluate the effects of Sardinian folk dance (Ballu Sardu, BS) on functional performance and motor and nonmotor symptoms in IwPD.

DESIGN

Single-blind, randomized controlled pilot trial.

SETTINGS

Outpatient health clinic.

SUBJECTS AND INTERVENTIONS

Twenty IwPD (13M, 7F; 67.4 ± 6.1 years) were randomly assigned to BS (n = 10) or usual care (n = 10). The dance program consisted of two sessions/week, 90-min/class, for 12 weeks.

OUTCOME MEASURES

Motor and nonmotor symptoms, as well as functional performance, were evaluated using different questionnaires and tests such as the Unified Parkinson's Disease Rating Scale Part-III (UPDRS-III), 6-min walking test (6MWT), Berg Balance Scale (BBS), Timed Up-and-Go (TUG) test, Five Times Sit-to-Stand Test (FTSST), Back Scratch Test (BST), Sit-and-Reach Test (SRT), instrumented gait analysis, Parkinson's Disease Fatigue Scale (PFS-16), Beck Depression Inventory, Starkstein Apathy Scale (SAS), and Montreal Cognitive Assessment (MOCA) scale.

RESULTS

Repeated-measures analysis of variance revealed significant Time × Group interactions for UPDRS-III and functional variables such as the 6MWT, BBS, FTSST, TUG (all, p < 0.001), BST (p = 0.04), and gait analysis parameters (stride length, p = 0.031; gait speed, p = 0.049; and gait fatigue index (GFI), p = 0.005). For nonmotor symptoms, significant Time × Group interactions for depression (p < 0.001), apathy (p = 0.016), and MOCA scores (p = 0.012) were observed. Of note, for GFI and SAS, the BS group only showed a trend toward improvement, while the condition of the controls worsened significantly. No between-group differences were observed for SRT and PFS-16.

CONCLUSIONS

BS is an enjoyable activity, which has been proved to be superior to usual care alone in inducing changes in different motor and nonmotor symptoms associated with PD. Results show that BS can be considered a safe tool for contrasting impairments observed in IwPD due to the intrinsic nature of the neurodegenerative disease.

Characteristics of apathy in treatment-naïve patients with Parkinson's disease

INTRODUCTION

Although apathy is a common psychiatric symptom of Parkinson's disease (PD), there are many unknown aspects of its pathology. This study aimed to investigate the characteristics of apathy in treatment-naïve patients with early-stage PD.

METHODS

Fifty treatment-naïve patients with early-stage PD were divided into 1 of 2 groups-apathetic or non-apathetic-based on Starkstein Apathy Scale (AS) scores. Cognitive function, depressive symptoms, olfactory function, and motor severity were compared between the two groups using validated assessment scales. Multiple linear regression was performed to assess the association between AS scores and clinical parameters.

RESULTS

Apathy (AS score ≥16) was observed in 13 (26%) patients. Assessment scale scores (Beck Depression Inventory-Second Edition [p < .004]; modified Hoehn & Yahr stage [p = .039]; Unified Parkinson's Disease Rating Scale part III [p < .001]) were significantly higher in apathetic patients than in non-apathetic patients. Significant association between these scale scores and AS score was also evident (all p ≤ .001). There were no significant differences in the test scores derived from several other validated scales.

CONCLUSION

Apathy was observed in 26% of treatment-naïve patients with early-stage PD. Significant association between apathy and motor severity was found, suggesting that dysfunction of the dopaminergic pathway is involved in the pathology of apathy.

Investigation of non-motor symptoms in first-degree relatives of patients with Parkinson's disease

OBJECTIVE

Non-motor symptoms (NMS) are important prodromal characteristics of Parkinson's disease (PD). However, the incidence of NMS in first-degree relatives, such as siblings of PD patients, is still unknown.

METHODS

A total of 98 PD patients of the Affiliated Hospital of Yangzhou University were recruited; 210 siblings of these patients were included in a first-degree relatives (FDR) group and 250 healthy individuals were included in a control group. Various scales were used to assess NMS, including depression, anxiety, cognitive function, sleep status, constipation, daytime sleepiness, Rapid-Eye-Movement Sleep Behavior Disorder (RBD), and Restless Legs Syndrome (RLS).

RESULTS

NMS were more common in the PD group than the control group. The incidence of anxiety (OR = 3.434, 95%CI: 2.058-5.731, P < 0.001), depression (OR = 2.438, 95%CI: 1.289-4.609, P = 0.005), and RBD (OR = 4.120, 95%CI: 1.897-8.945, P < 0.001) was higher in the FDR group than the control group. There were non-significant differences in constipation, cognitive impairment, sleep disorder, daytime sleepiness, and RLS between the two groups. The incidence of RLS in FDR of PD with an age of onset <60 years was higher than in the controls (OR = 2.273, 95%CI: 1.107-4.667, P = 0.023).

CONCLUSIONS

Siblings of PD are more likely to suffer from anxiety, depression and RBD than the general population. RLS is more common in siblings of PD with onset age<60 than in the general population. It is speculated that PD patients and their siblings have common pathogenic genetic factors and early living environment for neurodegeneration.

Sleep-wake disturbances in the premotor and early stage of Parkinson's disease

PURPOSE OF REVIEW

Review of recent literature pertaining to frequency, associations, mechanisms, and overall significance of sleep--wake disturbances (SWD) in the premotor and early phase of Parkinson's disease.

RECENT FINDINGS

SWD are frequent in Parkinson's disease and their prevalence increases with disease progression. Recent studies confirm previous findings that SWD can appear as initial manifestation of Parkinson's disease even decades before motor signs appear and highlight their clinical associations in these early stages. More intriguingly, new evidence underpins their role as risk factors, predictors, or even as driving force for the neurodegenerative process. As our understanding of sleep--wake neurobiology increases, new hypotheses emerge concerning the pathophysiology of SWD in early Parkinson's disease stages involving dopaminergic and nondopaminergic mechanisms.

SUMMARY

SWD are predictors for the development of parkinsonian syndromes including Parkinson's disease. This may offer the opportunity of developing new preventive strategies and interventions at an early stage of this neurodegenerative disease.

Variation in Recent Onset Parkinson's Disease: Implications for Prodromal Detection

BACKGROUND

The detection of prodromal Parkinson's disease (PD) is desirable to test drugs with neuroprotective potential, but will be affected by known disease variations.

OBJECTIVE

To assess the prevalence of four key non-motor prodromal PD markers, and evaluate the sensitivity of case detection when non-motor screening tools for prodromal PD are implemented in an early clinical PD cohort.

METHODS

Hyposmia (University of Pennsylvania smell identification test ≤15th centile or Sniffin' Sticks at or ≤10th centile corrected for age and sex), rapid-eye movement sleep behaviour disorder (RBD questionnaire >4), constipation (<1 daily spontaneous bowel motion) and depression (Leeds >6) were recorded in recent onset PD cases, and proposed non-motor screening criteria applied.

RESULTS

In 1,719 PD cases, mean age 68.6 years (SD 8.1), 65.5% male, mean disease duration 1.3 years (SD 0.9), 72.2% were hyposmic, 43.3% had RBD, 22.1% depression, and 21.5% constipation. 11.6% of cases had no key non-motor features, 38.8% one, 32.1% two, 15.5% three, and 2.0% all four. Increasing numbers of non-motor features were associated with younger age (p = 0.019), higher motor scores (p < 0.001), more postural instability gait difficulty (PIGD) (p < 0.001), greater cognitive impairment (p < 0.001) and higher total non-motor burden (p < 0.001). Cases with hyposmia alone were younger (p < 0.001), had less severe cognitive (p = 0.006) and other non-motor features (p < 0.001). All screening criteria selected younger patients (p = 0.001, p < 0.001), three of four greater overall non-motor burden (p = 0.005, p < 0.001), and inclusion of RBD more cognitive impairment (p = 0.003, p = 0.001) and PIGD (p = 0.004, p = 0.001).

CONCLUSIONS

Varying sensitivity levels, and age and phenotype selectivity, are found when different non-motor screening methods to detect prodromal PD are applied to an early clinical PD cohort.

Cognitive changes in prodromal Parkinson's disease: A review

Although other nonmotor phenomena representing possible prodromal symptoms of Parkinson's disease have been described in some detail, the occurrence and characteristics of cognitive decline in this early phase of the disease are less well understood. The aim of this review is to summarize the current state of research on cognitive changes in prodromal PD. Only a small number of longitudinal studies have been conducted that examined cognitive function in individuals with a subsequent PD diagnosis. However, when we consider data from at-risk groups, the evidence suggests that cognitive decline may occur in a substantial number of individuals who have the potential for developing PD. In terms of specific cognitive domains, executive function in particular and, less frequently, memory scores are reduced. Prospective longitudinal studies are thus needed to clarify whether cognitive, and specifically executive, decline might be added to the prodromal nonmotor symptom complex that may precede motor manifestations of PD by years and may help to update the risk scores used for early identification of PD. © 2017 International Parkinson and Movement Disorder Society.

When movement disorders hurt: Addressing pain in hyperkinetic disorders

Pain is an important nonmotor symptom in movement disorders. Dystonia is a hyperkinetic movement disorder characterized by involuntary, sustained or intermittent muscle contractions causing abnormal movements, postures or both. Contrary to common views the nonmotor symptoms are present in dystonia patients. Pain is a prevailing feature of cervical dystonia (CD), the most common form of focal dystonia. The mechanism of pain in CD remains mostly unknown, but there are growing evidence that it could not be only the consequence of muscle hyperactivity. We have shown that botulinum toxin (BoNT) produced pain relief before muscle relaxation and that effect on pain relief lasted longer than the effect on motor improvement. More and more data suggest that pain relief could be attributed to the direct effect of BoNT type A on central nervous system. Pain, depression, and anxiety have been shown to be significant determinants of QoL in focal dystonia patients. Routine clinical examination in patients with dystonia should include evaluation of motor as well as non-motor symptoms. Selective rating assessment should be used in clinical practice to quantify pain. Specific assessment of pain is important to determine the effect of BoNT as the most effective treatment in focal dystonia.

Meta-analysis on the prevalence of REM sleep behavior disorder symptoms in Parkinson's disease

Background

Our study was aimed to evaluate the risk of a selected non-motor symptom, namely rapid eye movement behavior disorder (RBD) symptoms, among patients with newly diagnosed Parkinson disease compared with health controls.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for meta-analysis and Cochrane manual were followed. Studies on RBD symptoms and PD were searched using PubMed, Embase, Web of Science and Cochrane library databases. All studies were published before August 3^rd, 2016. Eligible studies were those that reported a prevalence of RBD symptoms among newly diagnosed PD and health control. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated by random-effected models. Heterogeneity across studies was assessed using Cochran Q and I² statistics.

Results

We identified eight studies including 2462 PD patients and 3818 health controls. The overall prevalence of RBD symptoms in PD was 582/2462 (23.6%) compared to 131/3818 (3.4%) in control. And the pooled OR was 5.69 (95% CI 3.60 to 9.00; p = 0.001) with a moderate heterogeneity I² = 70.5%. After excluding the study of low weight, the overall polled OR was 3.54 (95% CI 2.77 to 4.52; p < 0.00001) and the heterogeneity was completely eliminated (I² = 0%).

Conclusions

RBD symptoms are common non-motor symptoms of PD, and people with PD are at a higher risk of developing RBD. Further studies are needed to understand the natural history of RBD symptoms in PD and its etiological and clinical implications.

Discussing sexuality with patients with Parkinson's disease: a survey among Dutch neurologists

Sexual functioning is often impaired in patients with Parkinson’s disease (PD) and may affect quality of life of patients and their spouse. However, little is known about the practice patterns of neurologists with regard to discussing sexuality in this field. The aim of this cross-sectional study was to evaluate to what extent neurologists discuss sexuality with PD patients. A 22-item questionnaire was sent to 139 neurologists specializing in PD. The survey contained questions about their attitudes, knowledge, and practice patterns with respect to sexual dysfunction (SD) in patients with PD. The response rate of the survey was 66.9%. Most participants (56.8%) stated that they address sexuality in less than half of their PD patients. High age of patients (42.0%), insufficient consultation time (37.5%), and a lack of patients’ initiative to raise the topic themselves (36.4%) were frequently reported barriers towards discussing sexuality. The majority of participants considered that discussing sexuality is a responsibility that lay with neurologists (85.2%), nurses (73.9%), and patients (72.7%). One quarter of the neurologists reported to have insufficient or no knowledge on SD. The majority of participants regarded screening for SD important or slightly important (85.2%). A large proportion of Dutch neurologists specializing in PD do not routinely discuss sexuality with their PD patients. Sexual healthcare in PD patients may benefit from time-efficient tools and agreements on who is responsible for discussing SD. Furthermore, recommendations in PD guidelines on screening and managing SD should be adapted to fit everyday practice.

Classification and Characteristics of Pain Associated with Parkinson's Disease

Neuropsychiatric symptoms and pain are among the most common nonmotor symptoms of Parkinson's disease (PD). The correlation between pain and PD has been recognized since its classic descriptions. Pain occurs in about 60% of PD patients, two to three times more frequent in this population than in age matched healthy individuals. It is an early and potentially disabling symptom that can precede motor symptoms by several years. The lower back and lower extremities are the most commonly affected areas. The most used classification for pain in PD defines musculoskeletal, dystonic, central, or neuropathic/radicular forms. Its different clinical characteristics, variable relationship with motor symptoms, and inconsistent response to dopaminergic drugs suggest that the mechanism underlying pain in PD is complex and multifaceted, involving the peripheral nervous system, generation and amplification of pain by motor symptoms, and neurodegeneration of areas related to pain modulation. Although pain in DP is common and a significant source of disability, its clinical characteristics, pathophysiology, classification, and management remain to be defined.

The prediagnostic phase of Parkinson's disease

The field of prediagnostic Parkinson's disease (PD) is fast moving with an expanding range of clinical and laboratory biomarkers, and multiple strategies seeking to discover those in the earliest stages or those 'at risk'. It is widely believed that the highest likelihood of securing neuroprotective benefit from drugs will be in these subjects, preceding current point of diagnosis of PD. In this review, we outline current knowledge of the prediagnostic phase of PD, including an up-to-date review of risk factors (genetic and environmental), their relative influence, and clinical features that occur prior to diagnosis. We discuss imaging markers across a range of modalities, and the emerging literature on fluid and peripheral tissue biomarkers. We then explore current initiatives to identify individuals at risk or in the earliest stages that might be candidates for future clinical trials, what we are learning from these initiatives, and how these studies will bring the field closer to realistically commencing primary or secondary preventive trials for PD. Further progress in this field hinges on greater clinical and biological description, and understanding of the prediagnostic, peridiagnostic and immediate postdiagnostic stages of PD. Identifying subjects 3-5 years before they are currently diagnosed may be an ideal group for neuroprotective trials. At the very least, these initiatives will help clarify the stage before and around diagnosis, enabling the field to push into unchartered territory at the earliest stages of disease.

Abnormal sexuality in Parkinson's disease: fact or fancy?

PURPOSE

Patients with Parkinson's disease (PD) variably report sexual dysfunctions. We assessed sexuality in PD by comparing sexual function between a large group of patients with idiopathic PD and a group of subjects without PD.

METHODS

We recruited 121 patients with mild-to-moderate PD (aged 40-80years) from four Italian Movement Disorder Clinics and 123 non-Parkinsonian controls (NPC) (aged 40-80years). Sexual function was assessed with four scales: the Brief Index of Sexual Functioning (BISF-M for men; BISF-W for women), the International Index of Erectile Function (IIEF), and the Female Sexual Function Index (FSFI). Both groups also underwent assessment with the Beck Depression Inventory (BDI) and the Mini Mental State Examination (MMSE), and patients were assessed with the Parkinson's Disease Questionnaire-8 (PDQ-8).

RESULTS

No differences in total score were found between PD and NPC for any sexual function scale (BISF-M, BISF-W, IIEF, FSFI: p>0.05). However, the Orgasm/Pleasure Domain (BISF, D5) was significantly lower in male patients than in controls.

CONCLUSION

Our findings fail to confirm previous findings that PD is associated with a significant sexual impairment. NPC and patients with PD have comparable sexual function in both sexes. Thus, rather than dismissing sexual dysfunction as a normal parkinsonian symptom, physicians should refer patients to sexual medicine specialists who can investigate and discuss problems fully, diagnose possible comorbidities, and suggest appropriate treatments.

Microbiota-gut-brain signalling in Parkinson's disease: Implications for non-motor symptoms

Parkinson's disease is the second most common neurodegenerative disorder, affecting 1-2% of the population over 65 years of age. The primary neuropathology is the loss of midbrain dopaminergic neurons, resulting in characteristic motor deficits, upon which the clinical diagnosis is based. However, a number of significant non-motor symptoms (NMS) are also evident that appear to have a greater impact on the quality of life of these patients. In recent years, it has become increasingly apparent that neurobiological processes can be modified by the bi-directional communication that occurs along the brain-gut axis. The microbiota plays a key role in this communication throughout different routes in both physiological and pathological conditions. Thus, there has been an increasing interest in investigating how microbiota changes within the gastrointestinal tract may be implicated in health and disease including PD. Interestingly α-synuclein-aggregates, the cardinal neuropathological feature in PD, are present in both the submucosal and myenteric plexuses of the enteric nervous system, prior to their appearance in the brain, indicating a possible gut to brain route of "prion-like" spread. In this review we highlight the potential importance of gut to brain signalling in PD with particular focus on the role of the microbiota as major player in this communication.

Non-motor symptoms in Parkinson's disease

With the growing awareness of the presence of non-motor symptoms in Parkinson's disease (PD) has come the realization that these non-motor features play a tremendously important, and sometimes dominant, role in the management and even the diagnosis of the disorder. Despite this, a reluctance to formally address and treat the non-motor symptoms of PD remains and quality of life for PD patients suffers. This review provides an overview of the impact non-motor symptoms have on persons with PD, along with a brief description of some of the more common non-motor features of PD.

Impacts of dance on non-motor symptoms, participation, and quality of life in Parkinson disease and healthy older adults

Evidence indicates exercise is beneficial for motor and non-motor function in older adults and people with chronic diseases including Parkinson disease (PD). Dance may be a relevant form of exercise in PD and older adults due to social factors and accessibility. People with PD experience motor and non-motor symptoms, but treatments, interventions, and assessments often focus more on motor symptoms. Similar non-motor symptoms also occur in older adults. While it is well-known that dance may improve motor outcomes, it is less clear how dance affects non-motor symptoms. This review aims to describe the effects of dance interventions on non-motor symptoms in older adults and PD, highlights limitations of the literature, and identifies opportunities for future research. Overall, intervention parameters, study designs, and outcome measures differ widely, limiting comparisons across studies. Results are mixed in both populations, but evidence supports the potential for dance to improve mood, cognition, and quality of life in PD and healthy older adults. Participation and non-motor symptoms like sleep disturbances, pain, and fatigue have not been measured in older adults. Additional well-designed studies comparing dance and exercise interventions are needed to clarify the effects of dance on non-motor function and establish recommendations for these populations.