Parkinson's disease and vitamins: a focus on vitamin B12

Parkinson's disease (PD) has been linked to a vast array of vitamins among which vitamin B12 (Vit B12) is the most relevant and often investigated specially in the context of intrajejunal levodopa infusion therapy. Vit B12 deficiency, itself, has been reported to cause acute parkinsonism. Nevertheless, concrete mechanisms through which B12 deficiency interacts with PD in terms of pathophysiology, clinical manifestation and progression remains unclear. Recent studies have suggested that Vit B12 deficiency along with the induced hyperhomocysteinemia are correlated with specific PD phenotypes characterized with early postural instability and falls and more rapid motor progression, cognitive impairment, visual hallucinations and autonomic dysfunction. Specific clinical features such as polyneuropathy have also been linked to Vit B12 deficiency specifically in context of intrajejunal levodopa therapy. In this review, we explore the link between Vit B12 and PD in terms of physiopathology regarding dysfunctional neural pathways, neuropathological processes as well as reviewing the major clinical traits of Vit B12 deficiency in PD and Levodopa-mediated neuropathy. Finally, we provide an overview of the therapeutic effect of Vit B12 supplementation in PD and posit a practical guideline for Vit B12 testing and supplementation.

Towards therapeutic electrophysiological neurofeedback in Parkinson's disease

Neurofeedback (NF) techniques support individuals to self-regulate specific features of brain activity, which has been shown to impact behavior and potentially ameliorate clinical symptoms. Electrophysiological NF (epNF) may be particularly impactful for patients with Parkinson's disease (PD), as evidence mounts to suggest a central role of pathological neural oscillations underlying symptoms in PD. Exaggerated beta oscillations (12-30 Hz) in the basal ganglia-cortical network are linked to motor symptoms (e.g., bradykinesia, rigidity), and beta is reduced by successful therapy with dopaminergic medication and Deep Brain Stimulation (DBS). PD patients also experience non-motor symptoms related to sleep, mood, motivation, and cognitive control. Although less is known about the mechanisms of non-motor symptoms in PD and how to successfully treat them, low frequency neural oscillations (1-12 Hz) in the basal ganglia-cortical network are particularly implicated in non-motor symptoms. Here, we review how cortical and subcortical epNF could be used to target motor and non-motor specific oscillations, and potentially serve as an adjunct therapy that enables PD patients to endogenously control their own pathological neural activities. Recent studies have demonstrated that epNF protocols can successfully support volitional control of cortical and subcortical beta rhythms. Importantly, this endogenous control of beta has been linked to changes in motor behavior. epNF for PD, as a casual intervention on neural signals, has the potential to increase understanding of the neurophysiology of movement, mood, and cognition and to identify new therapeutic approaches for motor and non-motor symptoms.

The clinical and neuroimaging differences between vascular parkinsonism and Parkinson's disease: a case-control study

BACKGROUND

Parkinson's disease (PD) and vascular parkinsonism (VaP) have highly overlapping phenotypes, and different prognosis. This study comprehensively investigated the clinical, brain MRI and transcranial sonography differences between VaP and PD.

METHODS

Forty-eight patients with PD, 27 patients with VaP, and 29 healthy controls were compared. All patients were assessed using the MDS-UPDRS, Berg Balance Scale (BBS), Ten-Meter Walking Test (10-MWT), Time Up and Go Test, and Non-Motor Symptoms Scale. Beck Depression Inventory, PD questionnaire- 39, international urine incontinence scale, cognitive assessment scales, MRI brain and transcranial colour-coded doppler. The study was registered on clinical-Trial.gov (NCT04308135) on 03/12/2020.

RESULTS

VaP patients showed significantly older age of onset, shorter disease duration, lower drug doses and levodopa responsiveness, higher On and Off axial scores, On and Off BBS, higher On scores for PIGD, rigidity, bradykinesia and total motor MDS-UPDRS, lower On and Off tremor, lower-half predominance, lower asymmetrical presentation and symmetric index than PD patients. VaP patients had worse non-motor symptoms Scale (NMSS) than controls except for perceptual problems/hallucinations but better symptoms than PD patients except for urinary dysfunction. Quality of life (QoL) was impaired in VaP patients and was correlated with motor function and NMSs. The VaP group had significantly higher white matter lesions and brain atrophy, with lower hyperechogenicity of the substantia nigra and more impaired cerebral vascular resistance and vasoreactivity than the PD group.

CONCLUSIONS

VaP has a characteristic motor and non-motor profile, with impaired QoL, white matter, and transcranial sonography abnormalities that differentiate it from PD. Further studies are warranted to explore the role of vascular lesions in the pathogenesis of VaP.

TRIAL REGISTRATION

The registered identifier NCT04308135 on clinical-Trial.gov. Registered on 03/12/2020.

Setting the clinical context to non-motor symptoms reflected by Park-pain, Park-sleep, and Park-autonomic subtypes of Parkinson's disease

Non-motor symptoms (NMS) of Parkinson's disease (PD) are well described in both clinical practice and the literature, enabling their management and enhancing our understanding of PD. NMS can dominate the clinical pictures and NMS subtypes have recently been proposed, initially based on clinical observations, and later confirmed in data driven analyses of large datasets and in biomarker-based studies. In this chapter, we provide an update on what is known about three common subtypes of NMS in PD. The pain (Park-pain), sleep dysfunction (Park-sleep), and autonomic dysfunction (Park-autonomic), providing an overview of their individual classification, clinical manifestation, pathophysiology, diagnosis, and potential treatments.

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.

The Park Sleep subtype in Parkinson's disease: from concept to clinic

INTRODUCTION

The heterogeneity of Parkinson's disease (PD) is evident from descriptions of non-motor (NMS) subtypes and Park Sleep, originally identified by Sauerbier et al. 2016, is one such clinical subtype associated with the predominant clinical presentation of sleep dysfunctions including excessive daytime sleepiness (EDS), along with insomnia.

AREAS COVERED

A literature search was conducted using the PubMed, Medline, Embase, and Web of Science databases, accessed between 1 February 2023 and 28 March 2023. In this review, we describe the clinical subtype of Park Sleep and related 'tests' ranging from polysomnography to investigational neuromelanin MRI brain scans and some tissue-based biological markers.

EXPERT OPINION

Cholinergic, noradrenergic, and serotonergic systems are dominantly affected in PD. Park Sleep subtype is hypothesized to be associated primarily with serotonergic deficit, clinically manifesting as somnolence and narcoleptic events (sleep attacks), with or without rapid eye movement behavior disorder (RBD). In clinic, Park Sleep recognition may drive lifestyle changes (e.g. driving) along with therapy adjustments as Park Sleep patients may be sensitive to dopamine D3 active agonists, such as ropinirole and pramipexole. Specific dashboard scores based personalized management options need to be implemented and include pharmacological, non-pharmacological, and lifestyle linked advice.

Dysphagia in Parkinson Disease: Part I - Pathophysiology and Diagnostic Practices

Purpose of Review

Dysphagia affects the majority of individuals with Parkinson disease (PD) and is not typically diagnosed until later in disease progression. This review will cover the current understanding of PD pathophysiology, and provides an overview of dysphagia in PD including diagnostic practices, gaps in knowledge, and future directions.

Recent Findings

Many non-motor and other motor signs of PD appear in the prodrome prior to the manifestation of hall- mark signs and diagnosis. While dysphagia often presents already in the prodrome, it is not routinely addressed in standard neurology examinations.

Summary

Dysphagia in PD can result in compromised efficiency and safety of swallowing, which significantly contributes to malnutrition and dehydration, decrease quality of life, and increase mortality. The heterogeneous clinical presentation of PD complicates diagnostic procedures which often leads to delayed treatment. Research has advanced our knowledge of mechanisms underlying PD, but dysphagia is still largely understudied, especially in the prodromal stage.

Use of remote monitoring and integrated platform for the evaluation of sleep quality in adult-onset idiopathic cervical dystonia

BACKGROUND

Up to 70% of individuals diagnosed with adult-onset idiopathic focal cervical dystonia (AOIFCD) report difficulties with sleep. Larger cohort studies using wrist-worn accelerometer devices have emerged as an alternative to smaller polysomnography studies, in order to evaluate sleep architecture.

METHODS

To measure activity during the sleep/wake cycle, individuals wore a consumer-grade wrist device (Garmin vivosmart 4) continuously over 7 days on their non-dominant wrist, while completing a daily sleep diary and standardised sleep and non-motor questionnaires via a dedicated app. Sleep measures were derived from the captured raw triaxial acceleration and heart rate values using previously published validated algorithms.

RESULTS

Data were collected from 50 individuals diagnosed with AOIFCD and 47 age- and sex-matched controls. Those with AOIFCD self-reported significantly higher levels of excessive daytime sleepiness (p = 0.04) and impaired sleep quality (p = 0.03), while accelerometer measurements found the AOIFCD cohort to have significantly longer total sleep times (p = 0.004) and time spent in NREM sleep (p = 0.009), compared to controls. Overall, there was limited agreement between wearable-derived sleep parameters, and self-reported sleep diary and visual analogue scale records.

DISCUSSION

This study shows the potential feasibility of using consumer-grade wearable devices in estimating sleep measures at scale in dystonia cohorts. Those diagnosed with AOIFCD were observed to have altered sleep architecture, notably longer total sleep time and NREM sleep, compared to controls. These findings suggest that previously reported disruptions to brainstem circuitry and serotonin neurotransmission may contribute to both motor and sleep pathophysiology.

The Collicular-Pulvinar-Amygdala Axis and Adult-Onset Idiopathic Focal Dystonias

Adult-onset idiopathic focal dystonias (AOIFD) are the most common type of dystonia. It has varied expression including multiple motor (depending on body part affected) and non-motor symptoms (psychiatric, cognitive and sensory). The motor symptoms are usually the main reason for presentation and are most often treated with botulinum toxin. However, non-motor symptoms are the main predictors of quality of life and should be addressed appropriately, as well as treating the motor disorder. Rather than considering AOIFD as a movement disorder, a syndromic approach should be taken, one that accommodates all the symptoms. Dysfunction of the collicular-pulvinar-amygdala axis, with the superior colliculus as a central node, can explain the diverse expression of this syndrome.

Defining the unknowns for cell therapies in Parkinson's disease

First-in-human clinical trials have commenced to test the safety and efficacy of cell therapies for people with Parkinson's disease (PD). Proof of concept that this neural repair strategy is efficacious is based on decades of preclinical studies and clinical trials using primary foetal cells, as well as a significant literature exploring more novel stem cell-derived products. Although several measures of efficacy have been explored, including the successful in vitro differentiation of stem cells to dopamine neurons and consistent alleviation of motor dysfunction in rodent models, many unknowns still remain regarding the long-term clinical implications of this treatment strategy. Here, we consider some of these outstanding questions, including our understanding of the interaction between anti-Parkinsonian medication and the neural transplant, the impact of the cell therapy on cognitive or neuropsychiatric symptoms of PD, the role of neuroinflammation in the therapeutic process and the development of graft-induced dyskinesias. We identify questions that are currently pertinent to the field that require further exploration, and pave the way for a more holistic understanding of this neural repair strategy for treatment of PD.

Dance Intervention Using the Feldenkrais Method Improves Motor, and Non-Motor Symptoms and Gait in Parkinson's Disease: A 12-Month Study

Objective

The aim of this study was to assess the effects of dancing (using the Feldenkrais method) on motor and non-motor symptoms, quality of life (QoL), and objective parameters of gait at the time of intervention and at the end of the 1-year study period.

Methods

This was a single-arm study in which 12 subjects with Parkinson’s disease (PD) received dance intervention during a 6-month period. Objective motor scales, gait analysis, and questionnaires on non-motor symptoms were evaluated at baseline and at 3, 6, and 12 months.

Results

Dance intervention decreased motor scale (Unified Parkinson’s Disease Rating Scale and Tinetti scale) scores and improved gait disturbance (gait velocity and step length) without increasing levodopa equivalent dose. Furthermore, dancing decreased non-motor scale (Non-Motor Symptoms Scale and Montgomery-Asberg Depression Rating Scale) scores and improved QoL.

Conclusion

Our findings suggest that dance intervention can be a complementary management method for PD patients.

Cognition in children and young adults with myoclonus dystonia - A case control study

INTRODUCTION

In adult patients with myoclonus dystonia (MD), cognitive deficits regarding information processing speed and executive functioning have been demonstrated, but it is unclear whether cognition is also affected in young MD patients. The present study investigates cognition in young MD patients and the role of an SGCE mutation.

METHODS

In this case control study 20 young MD patients (9 children (5.75-12.58 years) and 11 adolescents/young adults (13.5-25.42 years)) were included and compared to an age-, IQ- and gender-matched healthy control group (n = 40). Within the patient group, we compared patients with (n = 12) and without (n = 8) an SGCE mutation (SGCE+/-). All participants completed neuropsychological tests for memory, attention/processing speed, executive functioning, social cognition and language.

RESULTS

Overall, patients performed in the (low) average range, comparable to healthy controls. Only on a semantic fluency test, patients scored significantly lower. SGCE + patients had lower emotion recognition scores (a social cognition test) compared to SGCE-patients.

CONCLUSION

We could not demonstrate cognitive deficits as found in adult MD patients in our younger group. Patients performed on the same level as healthy controls, with only a small difference in semantic fluency. We did not find executive deficits that were manifest in adult SGCE + patients, but we did find an association of an SGCE mutation and lower scores on a social cognition test. Similar to executive functioning, social cognition is a prefrontally regulated function, but had not been tested in adult MD. Hence, social cognition may precede executive problems in adulthood, suggesting growing into deficit.

Recent advances in the pathology of prodromal non-motor symptoms olfactory deficit and depression in Parkinson's disease: clues to early diagnosis and effective treatment

Parkinson’s disease (PD) is a progressive neurodegenerative disease characterized by movement dysfunction due to selective degeneration of dopaminergic neurons in the substantia nigra pars compacta. Non-motor symptoms of PD (e.g., sensory dysfunction, sleep disturbance, constipation, neuropsychiatric symptoms) precede motor symptoms, appear at all stages, and impact the quality of life, but they frequently go unrecognized and remain untreated. Even when identified, traditional dopamine replacement therapies have little effect. We discuss here the pathology of two PD-associated non-motor symptoms: olfactory dysfunction and depression. Olfactory dysfunction is one of the earliest non-motor symptoms in PD and predates the onset of motor symptoms. It is accompanied by early deposition of Lewy pathology and neurotransmitter alterations. Because of the correlation between olfactory dysfunction and an increased risk of progression to PD, olfactory testing can potentially be a specific diagnostic marker of PD in the prodromal stage. Depression is a prevalent PD-associated symptom and is often associated with reduced quality of life. Although the pathophysiology of depression in PD is unclear, studies suggest a causal relationship with abnormal neurotransmission and abnormal adult neurogenesis. Here, we summarize recent progress in the pathology of the non-motor symptoms of PD, aiming to provide better guidance for its effective management.

Extra-basal ganglia iron content and non-motor symptoms in drug-naïve, early Parkinson's disease

Background

Although iron dyshomeostasis is associated with Parkinson’s disease (PD) pathogenesis, the relationship between iron deposition and non-motor involvement in PD is not fully understood. In this study, we investigated basal ganglia and extra-basal ganglia system iron contents and their correlation with non-motor symptoms in drug-naïve, early-stage PD patients.

Methods

We enrolled 14 drug-naïve, early-stage PD patients and 12 age/sex-matched normal controls. All participants underwent brain magnetic resonance imaging to obtain the effective transverse relaxation rate (R2*) and quantitative susceptibility mapping (QSM). Deep brain structures, including the nucleus accumbens, caudate nucleus, putamen, globus pallidus, thalamus, hippocampus, and amygdala, were delineated using the FSL-FIRST; the substantia nigra, red nucleus, and dentate nucleus were segmented manually. Inter-group differences in R2* and QSM values, as well as their association with clinical parameters of PD, were investigated.

Results

Substantia nigra and putamen R2* values were significantly higher in PD patients than in normal controls, despite no significant difference in QSM values. Regarding the non-motor symptom scales, PD sleep scale score negatively correlated with R2* values in the red nucleus and right amygdala, Scales for Outcomes in Parkinson’s disease-Autonomic scores were positively correlated with R2* values in the right amygdala and left hippocampus, and cardiovascular sub-score of Non-Motor Symptoms Scale for PD was positively associated with the QSM value in the left hippocampus.

Conclusion

In this study, iron content in the extra-basal ganglia system was significantly correlated with non-motor symptoms, especially sleep problems and dysautonomia, even in early-stage PD.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10072-021-05223-0.

Clinical features associated with drooling in Parkinson's disease

INTRODUCTION

Drooling is characterized by an excessive pooling of saliva in the oral cavity. The exact pathophysiological mechanism of drooling in Parkinson's disease (PD) is not yet fully understood.

OBJECTIVE

To identify the relationship between drooling and other clinical features in people diagnosed with PD.

METHOD

Research on the topic was carried out on the PubMed and ScienceDirect electronic databases. Articles published between March 2015 and March 2020 were selected. Search terms and inclusion and exclusion criteria were previously defined. The articles included met those requirements.

RESULTS

Sixteen articles were included for analysis. The prevalence of drooling varies between 9.26 and 70% and can occur at any stage of the disease. Higher prevalence of drooling is related to disease duration, disease severity, older age, male, levodopa equivalent dose, hypomimia, dysphagia, dysarthria, cognition, sleep, non-dominant tremor, motor fluctuations, bradykinesia, more symmetric pattern, gastrointestinal and urinary problems, sexual dysfunction, obstipation, and orthostatic hypotension. However, it is not related to hallucinations, rapid eye movement sleep behavior disorder, akinetic-rigid PD, mixed, nor dyskinesias.

CONCLUSION

Drooling is not caused by a single factor; it is influenced and related to several clinical features. Some clinical factors participate in the onset of drooling while others are concomitant.

How specific are non-motor symptoms in the prodrome of Parkinson's disease compared to other movement disorders?

The clinical diagnosis of Parkinson's disease (PD) based on motor signs is often preceded by several non-motor symptoms that can indicate early prodromal neurodegenerative processes. Such prodromal symptoms can aid the early detection of PD, but their specificity for prodromal PD in comparison to prodromes of other movement disorders is still largely unclear. We here aim to give a first insight into the published evidence of prodromal non-motor symptoms in PD, dementia with Lewy bodies (DLB), multiple system atrophy (MSA), Huntington's disease (HD), progressive supranuclear palsy (PSP) and spinocerebellar ataxia (SCA). REM-sleep behavior disorder (RBD) and autonomic dysfunction have been observed in the prodromes of PD, MSA, DLB and SCA. Depression and cognitive decline have been reported for prodromal PD, DLB, HD, SCA, and PSP. Olfactory loss has only been described in prodromal PD/DLB. However, estimating the specificity of prodromal non-motor symptoms in PD is so far complicated by scarce prospective evidence and study limitations. Information on marker specificity is a prerequisite for an accurate early (differential) diagnosis of prodromal diseases, as well as specific recruitment for targeted neuroprotective interventions. We here would like to raise awareness of these issues and encourage further prospective research of prodromal non-motor symptoms in neurodegenerative movement disorders and other diseases.

Risk Factors for Falls in Patients with de novo Parkinson's Disease: A Focus on Motor and Non-Motor Symptoms

Objective

We aimed to identify risk factors for falls in patients with de novo Parkinson’s disease (PD).

Methods

Forty-six patients with de novo PD were retrospectively included in the study. We assessed details on the patients’ motor symptoms as well as non-motor symptoms using several representative scales for global cognition, depression, fatigue, and dysautonomia. Fallers and non-fallers were identified according to their history of falls during the preceding year.

Results

Twenty-two patients (45.8%) with de novo PD had a history of falls. Compared with the non-faller group, the faller group exhibited higher scores for postural instability/gait difficulty (PIGD), anxiety, fatigue, total dysautonomia, gastrointestinal dysfunction, and thermoregulatory dysfunction. Moreover, logistic regression analysis showed that falling was positively correlated with anxiety and gastrointestinal symptoms but negatively associated with the tremor scores.

Conclusion

Our findings suggest that falling in patients with de novo PD is significantly associated with PIGD/non-tremor symptoms, anxiety, and gastrointestinal dysfunction.

Various Motor and Non-Motor Symptoms in Early Multiple System Atrophy

BACKGROUND

Multiple system atrophy (MSA) patients pre-sent a variety of symptoms other than autonomic dysfunctions, parkinsonism, and cerebellar ataxia. The aim of this study was to evaluate the frequency of various motor and non-motor symptoms including so-called "red flags" in patients with early MSA and to determine whether the frequency of these symptoms was different between the parkinsonian (MSA-P) and cerebellar (MSA-C) subtypes.

METHODS

Sixty-one probable or possible MSA patients with disease duration of 3 years or less were included. Patients were classified into MSA-P, MSA-C, and MSA-PC. The frequency of 13 features including various motor and non-motor symptoms that commonly occur in MSA was assessed.

RESULTS

Dysarthria was the most prevalent feature (98.4%) followed by sexual dysfunction (95.1%). Probable REM sleep behavior disorder was present in 90.2%. The frequency of constipation (82.0%), dysphagia (68.9%), and snoring (70.5%) was also high. Stridor was present in 42.6% and more common in MSA-C than in MSA-P.

CONCLUSIONS

Increasing awareness of various motor and non-motor symptoms may assist clinicians to make an early, accurate diagnosis and to improve management of patients with MSA. We suggest that the diagnostic accuracy can be improved if these features are appropriately reflected in the new diagnostic criteria for MSA.

Sexual dysfunction in male patients with Parkinson's disease: related factors and impact on quality of life

BACKGROUND

Sexual dysfunction (SD) is a common, yet under-reported, non-motor symptom (NMS) of Parkinson's disease (PD). The present study investigated the sexual functions in PD male patients, its correlation with motor and other NMSs, and their impact on health-related quality of life (HRQoL).

METHODS

The sexual functions of 40 PD male patients were assessed using the International Index of Erectile Function (IIEF) and compared to 25 healthy age-matched controls. Patients were evaluated using the NMS Scale (NMSS) and the Arabic version of the Parkinson's-Disease Questionnaire (PDQ-39). We compared the sexual functions of younger (≤ 55 years) and elder (> 55 years) males and tested the correlations between sexual functions and motor, other NMSs, and HRQoL.

RESULTS

Seventy percent of PD male patients reported erectile dysfunction. They showed significantly worse total (p < 0.001) and subscores of IIEF, compared to healthy controls. The total IIEF was inversely correlated to age of patients (p = 0.013), age at onset (p = 0.043), total, cognitive/mood, gastrointestinal and urinary domains of NMSS, and the cognitive domain of PDQ-39 (p = 0.013). Age was the main predictor (ß = - 0.581, p = 0.006) of SD. Elder patients showed worse sexual functions, stronger correlations to other NMSs, and more impact on HRQoL than younger patients.

CONCLUSION

Sexual functions are worse among PD male patients with age as the main predictor. SD was associated with worse cognitive/mood and urinary domains of NMSS and has a negative impact on the patients' HRQoL among elder males.

Prediagnostic motor and non-motor symptoms in progressive supranuclear palsy: The step-back PSP study

BACKGROUND

Improved knowledge of the prediagnostic phase of progressive supranuclear palsy (PSP) might provide information on when and how the disease starts, along with the opportunity to test therapies in disease stages with lesser neurodegeneration.

OBJECTIVE

To explore the symptoms in years preceding the PSP diagnosis.

METHODS

This is a single-center retrospective case-control study based on clinical charts review and a structured interview to PSP patients and their caregivers. Prediagnostic symptoms were defined as those present more than one year before the diagnosis. We explored 35 symptoms in the following domains: visual, dizziness, motor, mood/apathy, cognitive, behavioral, sleep, gastrointestinal/urinary and miscellaneous. Non-parametric statistics were applied, with significance set at <0.05 (FDR-corrected).

RESULTS

We included 150 subjects: 50 PSP patients (38% females, age 75.8) and an age- and sex-matched control group of 50 Parkinson's disease (PD) and 50 subjects (CS) without neurodegenerative disease. The frequencies of visual, motor, cognitive, behaviour and dizziness domains were significantly higher in PSP vs. PD, and so were the motor, mood/apathy, cognitive, behaviour and dizziness ones in PSP vs. CS. Over 50% of prediagnostic falls, apathy and anxiety, depression and memory-attention-executive symptoms, and over 30% of gait disturbances started more than three and up to ten years before the diagnosis. PSP patients had more consultations to ENT and ophthalmologists than PD patients.

CONCLUSION

PSP patients present a broad variety of motor and non-motor symptoms several years before the diagnosis. The definition of a prediagnostic PSP phase might be helpful to identify patients in early disease stages.

Stress and cortisol in Parkinson's disease

Stress is ubiquitous with many factors contributing to its effects, including psychological responses and associated biological factors, including cortisol related physiological responses, and inflammation. Also in Parkinson's disease there is growing evidence for the role of stress in some key symptoms, even stretching to the prodromal stage. Here we discuss the possible contributions of the range and nature of stress in PD and we aim to summarize the current knowledge about the role of stress-related responses on motor and non-motor symptoms, the underlying pathophysiology, and the potential implications for treatment.

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

Background

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

Objective

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

Methods

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

Results

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

Conclusions

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

Three weeks of SSRI administration enhances the visual perceptual threshold - a randomized placebo-controlled study

RATIONALE

The serotonergic system has been repeatedly linked to visual attention in general, but the effects of selective serotonin reuptake inhibitor (SSRI) on specific components of visual attention remain unknown. Changes in distinct perceptual and cognitive processes are not readily evident in most attention paradigms.

OBJECTIVE

In this study, we isolate basic components of visual attention to investigate potential effects of longer-term SSRI administration on non-emotional aspects of visual attention in healthy males.

METHODS

In a randomized double-blind placebo-controlled design, 32 young healthy males were tested on multiple attentional parameters, before and after a 3-week SSRI intervention with fluoxetine (40 mg daily) or placebo. Data were modeled with a computational theory of visual attention to derive independent estimates of five distinct components of visual attention.

RESULTS

The SSRI intervention selectively and significantly lowered the threshold for conscious visual perception. Specifically, we demonstrate that this improvement does not stem from a general increase in the speed of visual processing, as previously suggested, but specifically from a change in the perceptual threshold.

CONCLUSIONS

The study provides a novel description of the attentional dynamics affected by SSRI, while supporting previous findings on attentional effects of SSRI. Furthermore, it accentuates the utility of employing accuracy-based measures of attentional performance when conducting psychopharmacological research.

Diagnostic utility of gut α-synuclein in Parkinson's disease: A systematic review and meta-analysis

BACKGROUND

The accumulation of misfolded α-synuclein in the brain is associated with Parkinson's disease. However, the association between gut α-synuclein and PD and diagnostic value of α-synuclein in the gut still remain controversial.

METHODS

A literature search from inception to June 2018 was conducted, yielding 21 studies eligible for a systematic review and meta-analysis. We included studies that reported data on gut α-synuclein or phosphorylated α-synuclein in patients with PD and controls. The odds ratio(OR) was pooled using random-effect models, and heterogeneity was reported as I2. Studies were assessed for quality using the Newcastle-Ottawa Scale. Sensitivity and specificity analyses were performed using the summary receiver operating characteristics curve approach.

RESULTS

The database search yielded 395 results, of which 21 studies were deemed relevant. The PD group had a pooled OR of 10.01 (95% CI: 3.15-31.82, I2 = 72%) for gut α-synuclein compared with the control group. Sensitivity and specificity for distinguishing PD from controls were 0.568 and 0.819, respectively, for the colon, and 0.579 and 0.822, respectively, for phosphorylated α-synuclein.

CONCLUSION

Heterogeneity was high in most of the studies. This systematic review and meta-analysis confirmed a high degree of association between gut α-synuclein and PD, which suggested that gut α-synuclein is a potential therapeutic intervention. The measurement of gut α-synuclein alone could lead to the underdiagnosis of PD. Future research combining gut α-synuclein with other biochemical markers could improve the standardization of current assays.

Cerebellum and cognition: Does the rodent cerebellum participate in cognitive functions?

There is a widespread, nearly complete consensus that the human and non-human primate cerebellum is engaged in non-motor, cognitive functions. This body of research has implicated the lateral portions of lobule VII (Crus I and Crus II) and the ventrolateral dentate nucleus. With rodents, however, it is not so clear. We review here approximately 40 years of experiments using a variety of cerebellar manipulations in rats and mice and measuring the effects on executive functions (working memory, inhibition, and cognitive flexibility), spatial navigation, discrimination learning, and goal-directed and stimulus-driven instrumental conditioning. Our conclusion is that there is a solid body of support for engagement of the rodent cerebellum in tests of cognitive flexibility and spatial navigation, and some support for engagement in working memory and certain types of discrimination learning. Future directions will involve determining the relevant cellular mechanisms, cerebellar regions, and precise cognitive functions of the rodent cerebellum.

Depressive symptoms may increase the risk of the future development of freezing of gait in patients with Parkinson's disease: Findings from a 5-year prospective study

INTRODUCTION

Prospective studies identifying predictors of freezing of gait (FOG) in Parkinson's disease (PD) are limited. We aim to explore which symptoms are associated with future development of FOG in non-freezers.

METHODS

Fifty-seven PD patients without FOG at baseline were re-evaluated after a mean of five years. At baseline, disease severity [Unified Parkinson's Disease Rating Scale (MDS-UPDRS)], gait under single and dual-tasking, balance, cognition and other non-motor symptoms were assessed. The new-FOG-questionnaire (NFOG-Q) determined FOG. Multivariate binary logistic regression determined independent predictors of FOG.

RESULTS

At follow-up, 26 subjects (46%) had FOG while 31 remained non-freezers. At baseline, non-freezers (FOG-) and future freezers (FOG+) were similar (p > 0.10) with respect to age, gender, disease duration, dopaminergic medications, and cognitive function. However, FOG + had significantly worse scores on the Geriatric Depression Scale (GDS) (FOG+:5.2 ± 3.7; FOG-:2.4 ± 2.0, p = 0.005), PDQ-39, the NMS-questionnaire, UPDRS-part I, UPDRS-part III (off), and the Berg Balance Scale. In binary logistic regression, GDS, gait speed and UPDRS-III (on vs. off) were the only significant independent predictors of future FOG (GDS: OR = 10.93, p = 0.003, ΔUPDRS-III: OR = 1.34, p = 0.006). Moreover, 80% of the subjects who had marked depressive symptoms at baseline (GDS≥5) developed FOG at follow-up. In contrast, only 27% of those with few depressive symptoms at baseline became freezers (p < 0.001).

CONCLUSIONS

Depressive symptoms apparently precede the development of FOG. While elucidation of the relationship between depression and FOG needs further study, our findings offer another perspective regarding the pathophysiology of FOG and may help clinicians to estimate the risk of developing this debilitating phenomenon.

Cerebellar BOLD signal during the acquisition of a new lexicon predicts its early consolidation

Cerebellar contributions to language are presently poorly understood, but it has been argued that the cerebellar role in motor learning can be extended to learning in cognitive and linguistic domains. Here, we used fMRI to investigate whether the cerebellum is recruited in mapping novel words onto existing semantic concepts. On separate days, participants performed a Basque vocabulary learning task and a control English synonym task in the MRI scanner. Learning-related BOLD activity was found in left inferior frontal gyrus, bilateral insula, pre-SMA, left superior parietal cortex, right caudate, the right cerebellar vermis and right cerebellar Crus II. The extent to which the cerebellar regions, but not the cerebral areas, were recruited during learning correlated positively with participants' off-line improvement in performance after the learning task. These data provide evidence for a cerebellar role in lexical learning, and suggest that the right cerebellum may contribute toward consolidation of lexico-semantic associations in the language network.

Caffeine consumption and the 4-year progression of de novo Parkinson's disease

INTRODUCTION

Higher caffeine consumption has been associated with reduced risk of Parkinson's disease (PD), and with a more benign progression of motor and non-motor symptoms (NMS). The present observational cohort study investigated motor and non-motor correlates of caffeine consumption in de novo PD.

METHODS

79 newly diagnosed, drug naïve PD patients have been included and followed up for 4 years. The total caffeine use was calculated with the Caffeine Consumption Questionnaire. Following study variables were recorded at baseline, and after 2 and 4 years: UPDRS part III, UPDRS part IV, l-dopa Equivalent Daily Dose (LEDD), NMS Questionnaire (NMSQuest), and the time occurring from PD diagnosis to the need for l-dopa treatment. Age, gender and disease duration were included as covariates in the statistical models.

RESULTS

The average daily caffeine consumption was 296.1 ± 157.2 mg. At Cox regression models, higher caffeine consumption was associated with a lower rate of starting l-Dopa treatment (HR = 0.630; 95%CI = 0.382-0.996). At the mixed-effects linear regression models considering the whole study period, each additional espresso cup per day (50 mg of caffeine) was more likely associated with 5-point lower UPDRS part III total score (Coef = -0.01; 95%CI = -0.02 to 0.00), with 50% reduced LEDD (Coef = -0.01; 95%CI = -0.15 to 0.00; p = 0.021), and with 5-point lower NMSQuest total score (Coef = -0.01; 95%CI = -0.01 to 0.00), but not with UPDRS part IV total score (Coef = -0.00; 95%CI = -0.00 to 0.00).

CONCLUSION

Caffeine consumption was associated with a reduced accrual of motor and non-motor disability during 4-year follow-up in de novo PD, highlighting the rationale for using adenosine A2A antagonists since the early phases of PD.

Depressive symptoms can amplify embarrassment in essential tremor

BACKGROUND

Embarrassment can be a considerable problem for patients with essential tremor (ET) and is a major motivator for treatment. Depression is also a common feature of ET; as many as 35 % of patients report moderate to severe depressive symptoms. Our goal was to assess the associations between these motor and psychosocial factors (tremor, depression, embarrassment) in ET, with a particular interest in more fully assessing the possible association between depression and embarrassment.

METHODS

Ninety one ET cases (age 70.4 ± 12.8 years) enrolled in a prospective, clinical-epidemiological study. Depressive symptoms were assessed with the Center for Epidemiological Studies Depression Scale (CESD-10, 0-30 [maximum]), embarrassment, with the Essential Tremor Embarrassment Assessment (ETEA, 0-70 [maximum]), and action tremor, with a detailed in-person neurological examination.

RESULTS

Higher CESD-10 score was significantly associated with higher ETEA score (p = 0.005), but not with increasing tremor severity (p = 0.94). In stratified analyses, cases with no or minimal depressive symptoms had the lowest ETEA scores, cases with moderate depressive symptoms had intermediate ETEA scores, and cases with severe depressive symptoms had the highest ETEA scores (p = 0.01). Furthermore, at each level of tremor severity, cases with more depressive symptoms had more embarrassment.

CONCLUSIONS

Depressive symptoms seem to be more than a secondary response to the tremor in ET; they seem to amplify the level of embarrassment and, in addition to their own importance, seem to be a driver of other important clinical outcomes. Earlier treatment of depressive symptoms in ET patients could lessen the burden of secondary embarrassment.

Clinical clusters and dopaminergic dysfunction in de-novo Parkinson disease

BACKGROUND

The heterogeneity of PD suggests the existence of different subtypes. While some motor clusters have been consistently identified, little is known about non-motor PD subtypes and motor-non-motor interplay. Research in this regard has produced somewhat contradictory results, which might be biased by the inclusion of treated patients.

PATIENTS AND METHODS

We performed a non-hierarchical cluster analysis using both motor and non-motor data on 398 newly diagnosed untreated PD patients enrolled in the Parkinson's Progressive Marker Initiative (PPMI) study. We further evaluated whether dopaminergic dysfunction, as measured by (123)[I]-FP-CIT SPECT scan, could explain, at least partially, the observed difference between the clusters.

RESULTS

Three clusters were identified. Group 1 was characterized by the lowest motor and non-motor burden, whereas group 2 and 3 had similar motor disability, but different non-motor involvement, especially with regards to apathy and hallucinations. (123)[I]-FP-CIT binding values paralleled motor disability burden among the 3 clusters, but further multivariate analyses also revealed a negative correlation with depression.

DISCUSSION

Our results confirm the motor as well as non-motor heterogeneity of PD, suggesting the existence of 3 different subtypes. Dopaminergic dysfunction only marginally explains the non-motor variability of PD. Identification of such clusters can have important implications for generating novel pathophysiological hypotheses and therapeutic strategies.

Serotonergic perturbations in dystonia disorders-a systematic review

Dystonia is a hyperkinetic movement disorder characterized by sustained or intermittent muscle contractions. Emerging data describe high prevalences of non-motor symptoms, including psychiatric co-morbidity, as part of the phenotype of dystonia. Basal ganglia serotonin and serotonin-dopamine interactions gain attention, as imbalances are known to be involved in extrapyramidal movement and psychiatric disorders. We systematically reviewed the literature for human and animal studies relating to serotonin and its role in dystonia. An association between dystonia and the serotonergic system was reported with decreased levels of 5-hydroxyindolacetic acid, the main metabolite of serotonin. A relation between dystonia and drugs affecting the serotonergic system was described in 89 cases in 49 papers. Psychiatric co-morbidity was frequently described, but likely underestimated as it was not systematically examined. Currently, there are no good (pharmaco)therapeutic options for most forms of dystonia or associated non-motor symptoms. Further research using selective serotonergic drugs in appropriate models of dystonia is required to establish the role of the serotonergic system in dystonia and to guide us to new therapeutic strategies.

Baseline predictors of worsening apathy in Parkinson's disease: A prospective longitudinal study

INTRODUCTION

Apathy is one of the most common behavioural disorders in Parkinson's disease (PD) and contributes significantly to a reduced quality of life in PD patients.

METHODS

We conducted a prospective longitudinal study of 89 mild PD patients over 18 months, measuring apathy symptoms at 6-monthly intervals using the Starkstein Apathy Scale, as well as measures of motor and non-motor symptoms, cognitive function, and functional disability at baseline. Mixed-effects models were used to characterise the individual trajectories of apathy symptom severity, and linear regression with stepwise elimination procedure was used to select significant baseline predictors.

RESULTS

Clinically significant levels of apathy were present in 42.7% of our sample at baseline, with symptom severity remaining relatively stable on average over the course of 18 months. Male gender, lower educational attainment, higher depression symptom severity, more severe functional disability, and the presence of dyskinesias at study entry predicted increasing apathy over the subsequent 18 months.

CONCLUSIONS

Patients with these factors are at risk for progression of apathy, which may be prevented by treating depression and functional disability. Further studies are needed to address both the specific neurobiological pathways and psychosocial factors underpinning apathy in PD.

Depression and anxiety are co-morbid but dissociable in mild Parkinson's disease: A prospective longitudinal study of patterns and predictors

BACKGROUND

Depression and anxiety are common in Parkinson's disease (PD) and contribute significantly to a reduced quality of life in PD patients. Though they often co-exist, it is unclear whether depression and anxiety result from a shared pathological process. We studied the longitudinal course and determinants of depression and anxiety in PD in order to understand which factors contribute to the development of these symptoms.

METHODS

We conducted a prospective longitudinal study of 89 mild PD patients over 18 months, measuring depressive and anxiety symptoms at 6 monthly intervals using the Geriatric Depression Scale and Hospital Anxiety and Depression Scale--'Anxiety' subscale. Univariate and multivariate Generalised Estimating Equations were used to investigate the course of depression and anxiety and their association with demographic factors, motor measures, non-motor symptoms, and pharmacological factors.

RESULTS

Depression and anxiety were co-morbid in 13.5% of the sample. Depressive symptoms remained relatively stable while anxiety symptoms improved over the course of 18 months. Severity of depressive symptoms was associated with female gender, motor fluctuations, apathy, and anxiety, while severity of anxiety was associated with older age, higher educational attainment, shorter disease duration, younger age of disease onset, and excessive daytime sleepiness.

CONCLUSIONS

Although depression and anxiety are frequently co-morbid in PD, they were dissociable from each other. They had distinct trajectories and different longitudinal relationships with demographic, motor, and non-motor factors that were unique to each disorder.

Non-motor symptoms in essential tremor: A review of the current data and state of the field

BACKGROUND

The motor features of essential tremor (ET) include its hallmark element, kinetic tremor, yet non-motor features are increasingly being recognized as an accompanying part of what was previously viewed as a solely motor disorder. Given the evolving state of the ET field with respect to these non-motor features, the purpose of this manuscript is to critically review the current data.

METHODS

A PubMed search was conducted on July 1, 2015. The term "essential tremor" was crossed in sequential order with 13 additional search terms (e.g., "cognitive", "dementia", "depression"). The total number of unique hits was 322.

RESULTS

Numerous studies seem to substantiate the presence of a range of non-motor features occurring in excess in ET cases compared to age-matched controls. These comprise cognitive features (including a full spectrum from mild cognitive difficulty through to frank dementia), psychiatric (including depression, apathy, anxiety, and personality characteristics), sensory (hearing and possibly olfactory abnormalities), and other non-motor features (e.g., sleep dysregulation). Emerging evidence suggests that some of these features could be primary disease features that pre-date motor features of ET.

CONCLUSIONS

The presence of numerous non-motor features in ET is increasingly evident. The biological basis of these features deserves additional study.

Quitting smoking: an early non-motor feature of Parkinson's disease?

INTRODUCTION

Epidemiological studies report a 60-70% reduced risk of Parkinson's disease (PD) in smokers as compared to non-smokers. However, relationships between former smoking and PD have been poorly investigated.

METHODS

We recruited 116 de novo PD subjects, and investigated current, former and never smoking, and reasons for smoking cessation among former smokers. Two hundred and thirty-two controls were matched by Propensity Score.

RESULTS

PD subjects and controls were found to be current smokers (7.7 vs. 39.6%), former smokers (43.9 vs. 6.5%) and never smokers (48.2 vs. 53.9%). Logistic regression showed that current smokers were less likely to have PD (p < 0.001; OR: 0.22; 95% CI: 0.10-0.46), while former smokers were more likely to have PD (p < 0.001; OR: 7.6; 95% CI: 4.09-15.75), as compared to never smokers. Fifty-one PD patients reported quitting smoking before PD diagnosis (mean time since cessation 9.4 ± 7.3 years). Most important reasons to quit smoking in PD group were illness different from PD (26 subjects, 51.0%), knowledge of the harmful effects of smoking (24 subjects, 47.0%), and physician's advice (1 subject, 2.0%).

CONCLUSION

The reduced prevalence of current smokers among PD subjects as compared to healthy controls is consistent with previous findings, suggesting a possible neuroprotective effect of smoking. However, it could be due, at least in part, to the increased prevalence of former smokers among PD patients, that were more prone to quit smoking as compared to healthy controls. We suggest that smoking cessation could be an early preclinical condition occurring in PD.

Reduction of gastrointestinal symptoms in Parkinson's disease after a switch from oral therapy to rotigotine transdermal patch: a non-interventional prospective multicenter trial

INTRODUCTION

Gastrointestinal (GI) symptoms are common among patients with Parkinson's disease (PD), due to both the disease itself and anti-PD drugs. We hypothesized that transdermal drug administration may result in fewer GI problems. This prospective observational study (ClinicalTrials.gov: NCT01159691) investigated effect of switching to rotigotine transdermal patch from oral anti-PD medications in patients with PD and existing GI symptoms.

METHODS

Patients were enrolled if their physician was planning to switch them to rotigotine because of GI symptoms experienced while receiving oral anti-PD medications. Effectiveness assessments included a visual analog scale (VAS) measuring intensity of GI symptoms from 0 (no disorder) to 100 mm (extremely severe disorder), a questionnaire on the frequency and intensity of six individual GI complaints (heartburn, bloating, nausea, vomiting, abdominal pain, diarrhea), each rated 0-12 for a sum score of 0-72, and patient satisfaction regarding GI symptoms over approximately 6 weeks after switching.

RESULTS

Of 75 patients who received rotigotine, 58 had follow-up data available for final analysis. Intensity of GI complaints improved numerically on both the VAS (47.5 ± 24.4 mm [n = 65] at baseline, 19.7 ± 23.3 mm [n = 58] after around 6 weeks) and the sum score of GI complaints (11.2 ± 9.0 at baseline, 2.1 ± 4.4 [n = 58] after around 6 weeks). Fifty of 58 patients were "satisfied" or "very satisfied" regarding GI symptoms over around 6 weeks following switch to the patch.

CONCLUSION

This study suggests that a switch from oral anti-PD medications to rotigotine transdermal patch may improve existing GI symptoms among patients with PD. Additional controlled studies are needed to confirm this finding.