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.

Neurofilament light predicts worse nonmotor symptoms and depression in Parkinson's disease.

BACKGROUND: The identification of biomarkers that reflect worse progression of nonmotor symptoms (NMS) in Parkinson's disease (PD) is currently an unmet need. The main aim of this study was to investigate whether cerebrospinal fluid (CSF) and serum neurofilament light (NfL), measured at baseline or longitudinally, can be used to predict the progression of NMS in patients with PD. METHODS: Baseline and longitudinal NfL levels were measured in the CSF and serum in 392 PD patients and 184 healthy controls from the Parkinson's Progression Marker Initiative. NMS were assessed using several scales, including, but not restricted to, the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part I, the Geriatric Depression Scale (GDS) and the State-Trait Anxiety Inventory (STAI). The relationship between baseline and longitudinal NfL levels with changes in NMS was assessed using linear mixed effects models (LME) in PD patients. In addition, we compared CSF and serum NfL levels between groups and assessed the relationship between NfL biomarkers with baseline NMS. Finally, to assess the specificity of our findings we ran the previous LME models using other biomarkers such as CSF amyloid-ß1-42, total tau, phosphorylated tau181 and total α-synuclein and we also ran the models in healthy controls. RESULTS: Baseline levels and longitudinal changes in serum and CSF NfL predicted worse longitudinal MDS-UPDRS-I and depression scores over time in PD (p < 0.01). This relationship remained significant only for CSF NfL when controlling for motor and cognitive status. Furthermore, longitudinal changes in serum and CSF NfL were associated with worse anxiety over time in PD patients (p < 0.05). In contrast to CSF NfL, serum NfL levels were slightly higher at baseline (p = 0.043) and showed significant longitudinal increases (p < 0.001) in PD patients compared to controls. There were no significant correlations between NfL levels (CSF or serum) with other NMS scales, baseline NMS variables, other biomarkers or in healthy controls. CONCLUSIONS: Our findings indicate that both serum and CSF NfL are associated with worse longitudinal NMS burden, particularly in relation to the progression of depression and anxiety. Serum NfL showed stronger associations with NMS suggesting it could potentially be used as a non-invasive marker of NMS progression for PD.

Increased basal forebrain volumes could prevent cognitive decline in LRRK2 Parkinson's disease.

BACKGROUND AND OBJECTIVES: It has been recently suggested that LRRK2 mutations are associated with a more benign clinical phenotype and a potentially more preserved cholinergic function in Parkinson's disease (PD). However, to our knowledge, no studies have tested whether the better clinical progression observed in LRRK2-PD patients is associated with more preserved volumes of a cholinergic brain area, the basal forebrain (BF). To address this hypothesis, here we compared BF volumes in LRRK2 carriers with and without PD with respect to idiopathic PD (iPD) patients and controls, and assessed whether they are associated with better clinical progression observed in LRRK2-PD compared to iPD. METHODS: Thirty-one symptomatic LRRK2-PD patients and 13 asymptomatic LRRK2 individuals were included from the Parkinson's Progression Markers Initiative. In addition, 31 patients with iPD and 13 healthy controls matched to the previous groups were also included. BF volumes were automatically extracted from baseline T1-weighted MRI scans using a stereotactic atlas of cholinergic nuclei. These volumes were then compared between groups and their relationship with longitudinal cognitive changes was evaluated using linear mixed effects models. Mediation analyses assessed whether BF volumes mediated differences in cognitive trajectories between groups. RESULTS: LRRK2-PD patients showed significantly higher BF volumes compared to iPD (P = 0.019) as did asymptomatic LRRK2 subjects compared to controls (P = 0.008). There were no other significant differences in cortical regions or subcortical volumes between these groups. BF volumes predicted longitudinal decline in several cognitive functions in iPD patients but not in LRRK2-PD, who did not show cognitive changes over a 4-year follow-up period. BF volumes were a significant mediator of the different cognitive trajectories between iPD and LRRK2-PD patients (95% CI 0.056-2.955). DISCUSSION: Our findings suggest that mutations in LRRK2 are associated with increased BF volumes, potentially reflecting a compensatory hypercholinergic state that could prevent cognitive decline in LRRK2-PD patients.

NMDA Receptor Antibodies and Neuropsychiatric Symptoms in Parkinson's Disease.

OBJECTIVE: N-methyl-d-aspartate receptor (NMDAR) encephalitis is an autoantibody-mediated neurological syndrome with prominent cognitive and neuropsychiatric symptoms. The clinical relevance of NMDAR antibodies outside the context of encephalitis was assessed in this study. METHODS: Plasma from patients with Parkinson's disease (PD) (N=108) and healthy control subjects (N=89) was screened at baseline for immunoglobulin A (IgA), IgM, and IgG NMDAR antibodies, phosphorylated tau 181 (p-tau181), and the neuroaxonal injury marker neurofilament light (NfL). Clinical assessment of the patients included measures of cognition (Mini-Mental State Examination [MMSE]) and neuropsychiatric symptoms (Hospital Anxiety and Depression Scale; Non-Motor Symptoms Scale for Parkinson's Disease). A subgroup of patients (N=61) was followed annually for up to 6 years. RESULTS: Ten (9%) patients with PD tested positive for NMDAR antibodies (IgA, N=5; IgM, N=6; IgG, N=0), and three (3%) healthy control subjects had IgM NMDAR antibodies; IgA NMDAR antibodies were detected significantly more commonly among patients with PD than healthy control subjects (χ2=4.23, df=1, p=0.04). Age, gender, and disease duration were not associated with NMDAR antibody positivity. Longitudinally, antibody-positive patients had significantly greater decline in annual MMSE scores when the analyses were adjusted for education, age, disease duration, p-tau181, NfL, and follow-up duration (adjusted R2=0.26, p=0.01). Neuropsychiatric symptoms were not associated with antibody status, and no associations were seen between NMDAR antibodies and p-tau181 or NfL levels. CONCLUSIONS: NMDAR antibodies were associated with greater cognitive impairment over time in patients with PD, independent of other pathological biomarkers, suggesting a potential contribution of these antibodies to cognitive decline in PD.

Viruses, parkinsonism and Parkinson's disease: the past, present and future.

Parkinsonism secondary to viral infections is not an uncommon occurrence and has been brought under the spotlight with the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. A variety of viruses have been described with a potential of inducing or contributing to the occurrence of parkinsonism and Parkinson's disease (PD), although the relationship between the two remains a matter of debate originating with the description of encephalitis lethargica in the aftermath of the Spanish flu in 1918. While some viral infections have been linked to an increased risk for the development of PD, others seem to have a causal link with the occurrence of parkinsonism. Here, we review the currently available evidence on viral-induced parkinsonism with a focus on potential pathophysiological mechanisms and clinical features. We also review the evidence on viral infections as a risk factor for developing PD and the link between SARS-CoV-2 and parkinsonism, which might have important implications for future research and treatments.

Late presentation of NMOSD as rapidly progressive leukoencephalopathy with atypical clinical and radiological findings.

Brain abnormalities in neuromyelitis optica spectrum disorder (NMOSD) are highly heterogeneous and often non-specific. Extensive white matter involvement has been described and frequently manifests with encephalopathy requiring prompt intervention. Rarely, this may represent the only manifestation at onset without concurrent suggestive features of the disease, thus making diagnosis challenging. NMOSD may potentially occur at any age, but it seems that this disorder has distinctive clinical features in the elderly. We describe a case of NMOSD presenting as rapidly progressive leukoencephalopathy with atypical clinical and magnetic resonance imaging (MRI) findings in a 69-year-old woman.

Subcutaneous Levodopa: A New Engine for the Vintage Molecule.

The management of Parkinson's disease (PD) continues to evolve with advancements in non-oral levodopa-based therapies aiming to provide continuous drug delivery (CDD). Such therapies address the challenges posed by the emergence of motor fluctuations, dyskinesias, and non-motor fluctuations (NMF) associated with oral levodopa administration and contributing to define the advanced stage of PD. The key focus of this review is placed on subcutaneous foslevodopa/foscarbidopa (Foslevodopa/foscarbidopa) infusion, showcasing its recent clinical availability and efficacy in providing continuous levodopa delivery. While providing an overview of the other non-oral levodopa-based CDD systems, such as intrajejunal levodopa-carbidopa infusion and levodopa-entacapone-carbidopa infusion, we highlight the current promising evidence for Foslevodopa/foscarbidopa to improve, for example, "on time" without troublesome dyskinesia and reducing "off time" in people with advanced PD. Additionally, Foslevodopa/foscarbidopa demonstrates potential in managing early morning off periods, sleep quality and other motor and non-motor symptoms. Moreover, other non-oral CDD options such as ND0612 and DIZ102/DIZ101 are discussed, with focus on their pharmacokinetics/pharmacodynamics, efficacy, and safety profiles. While these advancements present new therapeutic avenues, long-term observational studies are warranted to elucidate their impact on existing PD therapies. Overall, this review provides insights into the evolving landscape of non-oral CDD therapies and offers a pragmatic approach for their integration into clinical practice.

A general clinical overview of the non-motor symptoms in Parkinson's disease: Neuropsychiatric symptoms.

The heterogeneity of non-motor features observed in people with Parkinson's disease (PD) is often dominated by one or more symptoms belonging to the neuropsychiatric spectrum, such as cognitive impairment, psychosis, depression, anxiety, and apathy. Due to their high prevalence in people with PD (PwP) and their occurrence in every stage of the disease, from the prodromal to the advanced stage, it is not surprising that PD can be conceptualised as a complex neuropsychiatric disorder. Despite progress in understanding the pathophysiological mechanisms underlying the neuropsychiatric signs and symptoms in PD, and better identification and diagnosis of these symptoms, effective treatments are still a major unmet need. The impact of these symptoms on the quality of life of PwP and caregivers, as well as their contribution to the overall non-motor symptom burden can be greater than that of motor symptoms and require a personalised, holistic approach. In this chapter, we provide a general clinical overview of the major neuropsychiatric symptoms of PD.

The PD-Ballet study: study protocol for a randomised controlled single-blind hybrid type 2 clinical trial evaluating the effects of ballet dancing on motor and non-motor symptoms in Parkinson's disease.

BACKGROUND: To date, beneficial effects of multimodal exercise programmes on Parkinson's disease (PD) have focused on motor symptoms and little attention has been paid to the potential effects of such programmes on the non-motor symptoms of PD, which are now universally known as one of the key drivers of quality of life and a key unmet need. We aim to explore clinical effectiveness of a ballet-based dance programme in addressing non-motor and motor symptoms of Parkinson's disease across all stages of progression. METHODS: A randomised, single-blind, controlled trial of 160 people with Parkinson's across all motor stages (Participants will be stratified into three groups of motor advancement: Hoehn and Yahr (HY) stages I and II being Mild Group, HY Stage III being Moderate Group and HY Stages IV and V being Severe Group) will be randomly allocated to either an intervention or a control group using an independent randomisation body. The primary outcome is an improvement in non-motor symptoms as measured by the Movement Disorders Society Non-Motor Scale (MDS-NMS). The intervention protocol consists of 12 one-weekly dance sessions led by English National Ballet. Each session is followed by a 'tea and biscuit' social time. Control group follows standard clinical pathway and joins the 'tea and biscuit' to control for any positive effects of social interactions. All participants are assessed at baseline, immediately after completion of the intervention and 3-6 months later to explore any potential longitudinal effects. DISCUSSION: To our knowledge, no adequately powered study has explored the effects of a dance-based intervention on non-motor symptoms of Parkinson's disease, assessing these on both holistic and granular levels. We also aim to stratify participants in accordance with their motor state as assessed by. HY staging to explore specific effects on the symptoms at the initial, moderate and complex stages of the disease. If successful, this trial provides first evidence on clinical effectiveness of a ballet-based dance intervention for symptoms of Parkinson's disease, assessed in a robust, rigorous manner. TRIAL REGISTRATION: NCT04719468.

The pharmacological management of the behavioral aspects of Parkinson's disease: an update.

INTRODUCTION: Behavioural symptoms are common manifestations of Parkinson's disease and include depression, anxiety, impulse control disorders, hallucinations, psychosis, and cognitive dysfunction. They remain inadequately addressed in many patients despite their relevance for quality of life and disability. This applies also to impulse control disorders where the most common approach in recent literature is to refrain from using dopamine agonists without consideration about their potential benefit on motor complications. AREAS COVERED: We conducted a narrative review searching for articles on behavioral symptoms in Parkinson disease and selected those which included involved neurotransmitters such as dopamine, noradrenaline, serotonin, acetylcholine. We specifically focused our search on open-label and randomized double-blind studies and biomarkers which could best characterize these clinical manifestations. EXPERT OPINION: Management of Parkinson disease behavioural manifestations lacks clear guidelines and standardized protocols beside general suggestions of dose adjustments in dopamine replacement therapy and use of antidepressants or antipsychotic drugs with little consideration of patients' age, sex, comorbidities, and motor status. We suggest a pragmatic approach which includes education of affected patients and caring people, dealing with complex cases by experienced multidisciplinary teams, use of cognitive behavioural therapy, and psychological counselling to complement drug treatment.

Chaudhuri's Dashboard of Vitals in Parkinson's syndrome: an unmet need underpinned by real life clinical tests.

We have recently published the notion of the "vitals" of Parkinson's, a conglomeration of signs and symptoms, largely nonmotor, that must not be missed and yet often not considered in neurological consultations, with considerable societal and personal detrimental consequences. This "dashboard," termed the Chaudhuri's vitals of Parkinson's, are summarized as 5 key vital symptoms or signs and comprise of (a) motor, (b) nonmotor, (c) visual, gut, and oral health, (d) bone health and falls, and finally (e) comorbidities, comedication, and dopamine agonist side effects, such as impulse control disorders. Additionally, not addressing the vitals also may reflect inadequate management strategies, leading to worsening quality of life and diminished wellness, a new concept for people with Parkinson's. In this paper, we discuss possible, simple to use, and clinically relevant tests that can be used to monitor the status of these vitals, so that these can be incorporated into clinical practice. We also use the term Parkinson's syndrome to describe Parkinson's disease, as the term "disease" is now abandoned in many countries, such as the U.K., reflecting the heterogeneity of Parkinson's, which is now considered by many as a syndrome.

Clinical trials for cognition in Parkinson's disease: Where are we and how can we do better?

BACKGROUND: Cognitive impairment is common in Parkinson's disease (PD) and has a substantial impact on quality of life. Despite numerous trials targeting various PD features, we still lack effective treatments for cognition beyond cholinesterase inhibitors. OBJECTIVE: To identify the gaps in recent clinical trials with cognitive outcomes in PD and consider areas for improvement. METHODS: We examined recent clinical trials with cognitive outcomes in PD registered on ClinicalTrials.gov, excluding trials without cognitive outcomes, non-interventional studies, and in atypical Parkinsonian disorders. Included trials were categorized by treatment approach (investigational medicinal product, behavioral, physical activity, device-based). Details of trial design and outcomes were collected. RESULTS: 178 trials at different stages of trial completion were considered. 46 trials were completed, 25 had available results. Mean follow-up duration was 29.9 weeks. Most common cognitive measure was Montreal Cognitive Assessment. Most were performed in North America or Europe. Majority of the participants identified as non-Hispanic and White. Only eight trials showed improvement in cognition, none showed improvement beyond four months. These included trials of international medicinal products, cognitive and physical interventions and devices. GRADE certainty levels ranged from Moderate to Very Low. Only mevidalen had a Moderate certainty for potential clinical effectiveness. CONCLUSIONS: Amongst a large number of trials for cognition in PD, only a small proportion were completed. Few showed significant improvement, with no proven long-lasting effects. Trial design, lack of enrichment for at-risk groups, short follow-up duration, insensitive outcome measures likely contribute to lack of detectable benefit and should be considered in future trials.

The Gut Dysmotility Questionnaire for Parkinson's disease: Insights into development and pretest studies.

Objective: A total of 48% of patients with Parkinson's disease (PD) present symptoms of gastrointestinal dysfunction, particularly constipation. Furthermore, gastrointestinal tract (GIT)-related non-motor symptoms (NMSs) appear at all stages of PD, can be prodromal by many years and have a relevant impact on the quality of life. There is a lack of GIT-focused validated tools specific to PD to assess their occurrence, progress, and response to treatment. The aim of this study was to develop and evaluate a novel, disease- and symptom-specific, self-completed questionnaire, titled Gut Dysmotility Questionnaire (GDQ), for screening and monitoring gastrointestinal dysmotility of the lower GIT in patients with PD. Methods: In phase 1, a systematic literature review and multidisciplinary expert discussions were conducted. In phase 2, cognitive pretest studies comprising standard pretests, interviews, and evaluation questionnaires were performed in patients with PD (n = 21), age- and sex-matched healthy controls (HC) (n = 30), and neurologists (n = 11). Incorporating these results, a second round of cognitive pretests was performed investigating further patients with PD (n = 10), age- and sex-matched HC (n = 10), and neurologists (n = 5). The questionnaire was adapted resulting in the final GDQ, which underwent cross-cultural adaptation to the English language. Results: We report significantly higher GDQ total scores and higher scores in five out of eight domains indicating a higher prevalence of gastrointestinal dysmotility in patients with PD than in HC (p < 0.05). Cognitive pretesting improved the preliminary GDQ so that the final GDQ was rated as relevant (100/100%), comprehensive (100/90%), easy to understand concerning questions and answer options (100/90%), and of appropriate length (80/100%) by neurologists and patients with PD, respectively. The GDQ demonstrated excellent internal consistency (Cronbach's alpha value of 0.94). Evidence for good construct validity is given by moderate to high correlations of the GDQ total score and its domains by intercorrelations (r s = 0.67-0.91; p < 0.001) and with validated general NMS measures as well as with specific items that assess gastrointestinal symptoms. Interpretation: The GDQ is a novel, easy, and quick 18-item self-assessment questionnaire to screen for and monitor gastrointestinal dysmotility with a focus on constipation in patients with PD. It has shown high acceptance and efficacy as well as good construct validity in cognitive pretests.

Safety and tolerability of long-term apomorphine infusion in advanced Parkinson's disease: an Indian multi-center (APO-IND) experience.

Advanced Parkinson's Disease (APD) is complicated by the emergence of motor and non-motor fluctuations, which are initially predictable and eventually become unpredictable, in part due to erratic gastric absorption and short half of oral levodopa. Attempts to manage such fluctuations with oral dopaminergic drugs often lead to disabling dyskinesias. Continuous Subcutaneous Apomorphine Infusion (CSAI), despite being approved for the treatment of APD since 1993, was approved in India only in 2019. We studied the safety, tolerability and efficacy of CSAI in Indian patients with APD in a registry design to raise local awareness of this important treatment. We conducted a prospective registry-based observational audit at 10 centers across different states of India. Patients with APD, not responding to or with significant side effects from oral dopaminergic therapy, were assessed at baseline and at month 6 and 12 following CSAI infusion. Fifty-one patients completed the study, CSAI significantly reduced the functional impact of dyskinesia (p < 0.01 at 6 months and p < 0.001 at 12 months). There was a significant improvement in the OFF-state from baseline (p < 0.01 at 6 months and p < 0.001 at 12 months) No discernible side effects were observed apart from mild site reaction (n = 7), nausea (n = 7) skin nodules (n = 2). CSAI demonstrated safety, efficacy, tolerability and improved quality of life in patients with APD, as shown in previous studies. Our study highlighted current existing inequalities in treatment availability, lack of awareness, knowledge gap, affordability and cost remains a concern regarding apomorphine use in Indian PD population.

Treatment paradigms in Parkinson's Disease and Covid-19.

People with Parkinson's Disease (PwP) may be at higher risk for complications from the Coronavirus Disease 2019 (Covid-19) due to older age and to the multi-faceted nature of Parkinson's Disease (PD) per se, presenting with a variety of motor and non-motor symptoms. Those on advanced therapies may be particularly vulnerable. Taking the above into consideration, along with the potential multi-systemic impact of Covid-19 on affected patients and the complications of hospitalization, we are providing an evidence-based guidance to ensure a high standard of care for PwP affected by Covid-19 with varying severity of the condition. Adherence to the dopaminergic medication of PwP, without abrupt modifications in dosage and frequency, is of utmost importance, while potential interactions with newly introduced drugs should always be considered. Treating physicians should be cautious to acknowledge and timely address any potential complications, while consultation by a neurologist, preferably with special knowledge on movement disorders, is advised for patients admitted in non-neurological wards. Non-pharmacological approaches, including the patient's mobilization, falls prevention, good sleep hygiene, emotional support, and adequate nutritional and fluid intake, are essential and the role of telemedicine services should be strengthened and encouraged.

New approaches to treatments for sleep, pain and autonomic failure in Parkinson's disease - Pharmacological therapies.

Non-motor symptoms (NMSs) are highly prevalent throughout the course of Parkinson's disease (PD). Pain, autonomic dysfunction and sleep disturbances remain at the forefront of the most common NMSs; their treatment is challenging and their effect on the quality of life of both patients and caregivers detrimental. Yet, the landscape of clinical trials in PD is still dominated by therapeutic strategies seeking to ameliorate motor symptoms; subsequently, effective strategies to successfully treat NMSs remain a huge unmet need. Wider awareness among industry and researchers is thus essential to give rise to development and delivery of high-quality, large-scale clinical trials in enriched populations of patients with PD-related pain, autonomic dysfunction and sleep. In this review, we discuss recent developments in the field of pharmacological treatment strategies designed or re-purposed to target three key NMSs: pain, autonomic dysfunction and sleep disturbances. We focus on emerging evidence from recent clinical trials and outline some exciting and intriguing findings that call for further investigations. This article is part of the Special Issue on 'New therapeutic approaches to Parkinson's disease'.

The pathophysiology of sexual dysfunction in Parkinson's disease: An overview.

Sexual dysfunction is a common, poorly recognized, poorly discussed (often because of cultural perceptions and sensitivities), bothersome and neglected aspect of the range of non-motor symptoms of Parkinson's disease (PD). The spectrum of sexual dysfunction in PD ranges from hyposexuality-based disturbances to hypersexuality-dominated behaviors in the context of drug-induced impulse control disorder. The pathophysiological mechanisms underlying PD-related sexual dysfunction, specifically for hyposexual disorders, are thus heterogeneous and still not fully understood. However, central and peripheral neural mechanisms secondary to the hallmark pathological alterations of the disease (alpha-synuclein deposition and nigrostriatal degeneration) and to the associated network and neurotransmitter dysfunctions, together with the effects of dopaminergic therapies, seem to play an important role in the development of sexual disturbances. In this chapter, we therefore review the neuroanatomical and neurophysiological basis of sexual function in humans, and we provide insights on the pathophysiological mechanisms of hyposexuality and hypersexuality in PD.

Disentangling the PIGD classification for the prediction of cognitive impairment in de novo Parkinson's disease.

BACKGROUND: Postural Instability and Gait difficulties (PIGD) subtype has been associated with worse cognitive performance in Parkinson's disease (PD). OBJECTIVE: To investigate whether PIGD subtype classification or PIGD-related clinical features predict the development of cognitive decline in de novo PD patients. METHODS: Data from 422 PD patients with de novo PD were obtained from the PPMI database. At follow-up (up to 6 years), patients were categorized as having cognitive impairment or not. Multivariate Cox survival analysis was carried out including motor subtype and individual MDS-UPDRS items defining PIGD phenotype as predictors. Previously validated clinical predictors of cognitive impairment were included in the model as covariates. Occurrence of cognitive impairment at follow-up was used as the time-to-event and Kaplan-Meier curve was generated. RESULTS: At baseline, 76 patients were classified as PIGD, 299 tremor-dominant and 47 as indeterminate. Development of cognitive impairment was not associated with PIGD subtype (p = 0.252). When individual MDS-UPDRS items were interrogated in the model, postural instability proved to be an independent predictor of cognitive impairment (HR = 2.045; 95%CI: 1.068-3.918; p = 0.031), while gait difficulties were not associated with cognitive decline (p = 0.870). CONCLUSIONS: Our findings suggest that postural instability, as assessed by MDS-UPDRS III, may serve as a possible indicator of the risk of developing cognitive impairment in de novo PD patients rather than the PIGD phenotype.