Hippocampal resting-state connectivity is associated with posterior-cortical cognitive impairment in Parkinson's disease.

AIM: Frontal and posterior-cortical cognitive subtypes in Parkinson's disease (PD) present with executive/attention and memory/visuospatial deficits, respectively. As the posterior-cortical subtype is predicted to progress rapidly toward dementia, the present study aimed to explore biological markers of this group using resting-state functional magnetic resonance imaging (rs-fMRI). METHODS: K-means cluster analysis delineated subtypes (cognitively intact, frontal, posterior-cortical, and globally impaired) among 85 people with PD. A subset of PD participants (N = 42) and 20 healthy controls (HCs) underwent rs-fMRI. Connectivity of bilateral hippocampi with regions of interest was compared between posterior-cortical, cognitively intact, and HC participants using seed-based analysis, controlling for age. Exploratory correlations were performed between areas of interest from the group analysis and a series of cognitive tests. RESULTS: The posterior-cortical subtype (N = 19) showed weaker connectivity between the left hippocampus and right anterior temporal fusiform cortex compared to the cognitively intact (N = 11) group, p-false discovery rate (FDR) = .01, and weaker connectivity between bilateral hippocampi and most fusiform regions compared to HCs (N = 20). No differences were found between HCs and cognitively intact PD. Exploratory analyses revealed strongest associations between connectivity of the right anterior temporal fusiform cortex and left hippocampus with category fluency (p-FDR = .01). CONCLUSION: Results suggest that weakened connectivity between the hippocampus and fusiform region is a unique characteristic of posterior-cortical cognitive deficits in PD. Further exploration of hippocampal and fusiform functional integrity as a marker of cognitive decline in PD is warranted.

Feasibility and Acceptability of a Videoconferencing CBT Intervention for Anxiety in People with Parkinson's Disease.

OBJECTIVES: In people with Parkinson's disease (PwPD), non-motor symptoms such as anxiety are common and have negative impacts on their quality of life. There are currently few interventions that address anxiety in PwPD, and access to diagnosis and treatment is often limited for those living in rural areas. The aim of this study was to evaluate the feasibility and acceptability of a telehealth videoconferencing CBT intervention for anxiety in PwPD. METHODS: A pre- and post-test feasibility study (N = 10) was conducted and evaluated utilizing the RE-AIM framework (Reach, Effectiveness, Adoption, Implementation, and Maintenance). RESULTS: Lack of access to the internet and videoconferencing technology were identified as barriers to participation. Physical health issues also impacted recruitment and retention. Non-completers were significantly older and less likely to have a carer involved in the intervention. Clinician adoption of the intervention was low while participant acceptability of videoconferencing technology varied and required carer support. CONCLUSIONS: Providing access to technology and support to overcome technological issues, as well as telehealth training for clinicians, are recommended in future studies to improve recruitment, retention, and implementation. CLINICAL IMPLICATIONS: Identification of barriers and facilitators provides future studies with the knowledge to tailorize their program to better suit PwPD.

A physiotherapy group exercise and self-management approach to improve physical activity in people with mild-moderate Parkinson's disease: a randomized controlled trial.

BACKGROUND: Physical activity levels are low in people with Parkinson's disease (PD) and have proved difficult to increase with exercise programs alone. Intervention approaches that address both the capacity to engage in physical activity and self-management strategies to change and maintain exercise behaviours are needed to address this intractable issue. METHODS: This will be an assessor-blinded, randomized controlled trial performed in Brisbane, Australia. Ninety-two people with mild-moderate PD will be randomly allocated to two groups: usual care, and a physiotherapy-led group exercise program combined with self-management strategies. In the intervention group, twelve, 80-min sessions will be conducted over 4 weeks in groups of up to 4 participants. The intervention will consist of circuit training including treadmill walking to target aerobic fitness, and activities targeting strength, balance, and gait performance. In addition, each session will also incorporate strategies focusing on self-management and behaviour change, augmented by the provision of a fitness activity tracker. Outcome measures will be collected at baseline (T1), immediately post intervention (T2) and at 6 months follow-up (T3). The primary outcome measure is free-living physical activity (average daily step count over 7 days) at pre (T1) and post (T2) intervention measured using an activPAL™ device. Secondary outcome measures captured at all time points include time spent walking, sedentary and in moderate intensity exercise over 7 days; spatiotemporal gait performance (step length, gait speed, endurance); health-related quality of life; and outcome expectations and self-efficacy for exercise. DISCUSSION: Sustainability of gains in physical activity following exercise interventions is a challenge for most populations. Our incorporation of a chronic disease self-management approach into the exercise program including fitness tracking extends previous trials and has potential to significantly improve free-living physical activity in people with PD. TRIAL REGISTRATION: This study has been prospectively registered in Australian and New Zealand Clinical Trial Registry (ACTRN12617001057370), registered on 19/07/2017. Available from www.anzctr.org.au/ACTRN12617001057370.aspx .

Levetiracetam for the treatment of mild cognitive impairment in Parkinson's disease: a double-blind controlled proof-of-concept trial protocol.

BACKGROUND: Mild memory impairment, termed amnestic mild cognitive impairment (aMCI), is associated with rapid progression towards dementia in Parkinson's disease (PD). Studies have shown hyperactivation of hippocampal DG/CA3 subfields during an episodic memory task as a biomarker of aMCI related to Alzheimer's disease. This project investigates the feasibility of a trial to establish the efficacy of a repurposed antiepileptic drug, levetiracetam, in low doses as a putative treatment to target DG/CA3 hyperactivation and improve episodic memory deficits in aMCI in PD. Based on previous work, it is hypothesized that levetiracetam will normalize DG/CA3 overactivation in PD-aMCI participants and improve memory performance. METHODS: Twenty-eight PD-aMCI participants, 28 PD participants without memory impairment (PD-nMI), and 28 healthy controls will be recruited. PD-aMCI participants will undertake a 12-week randomized, placebo-controlled, double-blind cross-over trial with a 14-day treatment of 125 mg levetiracetam or placebo twice daily, separated by a 4-week washout period. After each treatment period, participants will complete an episodic memory task designed to tax hippocampal subregion-specific function during high-resolution functional magnetic resonance imaging (fMRI). PD-nMI and healthy controls will undergo the fMRI protocol only, to compare baseline DG/CA3 subfield activity. RESULTS: Episodic memory task performance and functional activation in the DG/CA3 subfield during the fMRI task will be primary outcome measures. Global cognition, PD severity, and adverse events will be measured as secondary outcomes. Recruitment, eligibility, and study completion rates will be explored as feasibility outcomes. CONCLUSIONS: This study, the first of its kind, will establish hippocampal subregion functional impairment and proof of concept of levetiracetam as an early therapeutic option to reduce dementia risk in PD. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04643327 . Registered on 25 November 2020.

Pareidolias are a function of visuoperceptual impairment.

Pareidolias, or the misperception of ambiguous stimuli as meaningful objects, are complex visual illusions thought to be phenomenologically similar to Visual Hallucination (VH). VH are a major predictor of dementia in Parkinson's Disease (PD) and are included as a core clinical feature in Dementia with Lewy Bodies (DLB). A newly developed Noise Pareidolia Test (NPT) was proposed as a possible surrogate marker for VH in DLB patients as increased pareidolic responses correlated with informant-corroborated accounts of VH. This association could, however, be mediated by visuoperceptual impairment. To understand the drivers of performance on the NPT, we contrasted performances in patient groups that varied both in terms of visuoperceptual ability and rates of VH. N = 43 patients were studied of whom n = 13 had DLB or PD with Dementia (PDD); n = 13 had PD; n = 12 had typical, memory-onset Alzheimer's Disease (tAD); and n = 5 had Posterior Cortical Atrophy (PCA) due to Alzheimer's disease. All patient groups reported pareidolias. Within the Lewy body disorders (PD, DLB, PDD), there was no significant difference in pareidolic response rates between hallucinating and non-hallucinating patients. Visuoperceptual deficits and pareidolic responses were most frequent in the PCA group-none of whom reported VH. Regression analyses in the entire patient cohort indicated that pareidolias were strongly predicted by visuoperceptual impairment but not by the presence of VH. These findings suggest that pareidolias reflect the underlying visuoperceptual impairment of Lewy body disorders, rather than being a direct marker for VH.

Longitudinal follow up of data-driven cognitive subtypes in Parkinson's disease.

AIM: The dual syndrome hypothesis proposes that there are two cognitive subtypes in Parkinson's disease (PD): a frontal subtype with executive/attention impairment and gradual cognitive decline, and a posterior-cortical subtype with memory/visuospatial deficits and rapid cognitive decline. We aimed to compare the rate of global cognitive decline between subtypes derived using data-driven methods and explore their longitudinal performance within specific cognitive domains to better understand the prognosis of each subtype. METHOD: Frontal, posterior-cortical, globally impaired, and cognitively intact PD subtypes were identified at baseline using k-means clustering (N = 85), and 29 participants (34%) returned for follow-up assessments on average 4.87 years from baseline. Linear mixed effects models compared progression of subtypes on global cognition; psychological symptoms; parkinsonism; and the memory, attention, executive, language, and visuospatial cognitive domains. RESULTS: The frontal subtype was lost to attrition. While rate of change in parkinsonism, anxiety, and apathy differed between subtypes, there was no difference in the rate of global cognitive decline. However, the posterior-cortical subtype declined most rapidly in verbal memory, card sorting, trail making, and judgement of line orientation (JLO), while the cognitively intact group declined most rapidly on verbal memory and semantic fluency. The globally impaired subtype declined most rapidly in JLO, although this should be interpreted with caution due to high attrition. CONCLUSION: Despite limited sample size, the present study supports the differential progression of the posterior-cortical subtype compared to cognitively intact and globally impaired PD. These results encourage further, large-scale longitudinal investigations of cognitive subtypes in PD.

Global assessment, cognitive profile, and characteristics of mild cognitive impairment in Parkinson's disease.

BACKGROUND: Cognitive deficits are evident throughout the course of Parkinson's disease (PD), with 24% of patients experiencing subtle cognitive disturbances at the time of diagnosis, and with up to 80% of patients developing PD dementia (PDD) at advanced stages of the disease PD patients with mild cognitive impairment (MCI), an at-risk phenotype of PDD, present with heterogeneous clinical characteristics that complicate the management of PD. OBJECTIVES: This study aims to examine the characteristics of PD-MCI by using the Movement Disorder Society (MDS) diagnostic criteria and evaluate the validity of global cognitive scales in identifying PD-MCI. METHODS: Seventy-nine (79) PD patients completed neuropsychological assessments and a comprehensive cognitive battery. PD-MCI was classified according to the level 2 MDS task force criteria. Mini-Mental State Examination (sMMSE), Montreal Cognitive Assessment (MoCA) and Parkinson's Disease Cognitive Rating Scale (PDCRS) were examined against a level 2 dichotomised PD-MCI diagnosis. Characteristics of PD-MCI were evaluated using logistic regression analysis. RESULTS: Twenty-seven patients met criteria for PD-MCI (34%). The MoCA and PDCRS demonstrated high validity to screen for PD-MCI. Impairments in multiple cognitive domains were observed in 77.8% of PD-MCI patients. There were significantly more males in the PD-MCI group compared to PD patients without MCI (p < 0.01). CONCLUSIONS: PD patients with MCI exhibited impairments in the attention/working memory, executive function and memory domains. Heterogeneous cognitive characteristics in PD warrant further investigation into specific cognitive subtypes to advance understanding and effective evaluation of PD-MCI.

A Review of RRx-001: A Late-Stage Multi-Indication Inhibitor of NLRP3 Activation and Chronic Inflammation.

Chronic unresolving inflammation is emerging as a key underlying pathological feature of many if not most diseases ranging from autoimmune conditions to cardiometabolic and neurological disorders. Dysregulated immune and inflammasome activation is thought to be the central driver of unresolving inflammation, which in some ways provides a unified theory of disease pathology and progression. Inflammasomes are a group of large cytosolic protein complexes that, in response to infection- or stress-associated stimuli, oligomerize and assemble to generate a platform for driving inflammation. This occurs through proteolytic activation of caspase-1-mediated inflammatory responses, including cleavage and secretion of the proinflammatory cytokines interleukin (IL)-1ß and IL-18, and initiation of pyroptosis, an inflammatory form of cell death. Several inflammasomes have been characterized. The most well-studied is the nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome, so named because the NLRP3 protein in the complex, which is primarily present in immune and inflammatory cells following activation by inflammatory stimuli, belongs to the family of nucleotide-binding and oligomerization domain (Nod) receptor proteins. Several NLRP3 inflammasome inhibitors are in development, all with multi-indication activity. This review discusses the current status, known mechanisms of action, and disease-modifying therapeutic potential of RRx-001, a direct NLRP3 inflammasome inhibitor under investigation in several late-stage anticancer clinical trials, including a phase 3 trial for the treatment of third-line and beyond small cell lung cancer (SCLC), an indication with no treatment, in which RRx-001 is combined with reintroduced chemotherapy from the first line, carboplatin/cisplatin and etoposide (ClinicalTrials.gov Identifier: NCT03699956). Studies from multiple independent groups have now confirmed that RRx-001 is safe and well tolerated in humans. Additionally, emerging evidence in preclinical animal models suggests that RRx-001 could be effective in a wide range of diseases where immune and inflammasome activation drives disease pathology.

Semantic fluency deficits and associated brain activity in Parkinson's disease with mild cognitive impairment.

People living with Parkinson's disease (PD) with poor verbal fluency have an increased risk of developing dementia. This study examines the neural mechanisms underpinning semantic fluency deficits in patients with PD with mild cognitive impairment (PD-MCI) compared to those without MCI (PD-NC) and control participants without PD (non-PD). Thirty-seven (37) participants with PD completed a cognitive assessment battery to identify MCI (13 PD-MCI). Twenty sex- and age-matched non-PD patients also participated. Participants were scanned (3T Siemens PRISMA) while performing semantic fluency, semantic switching, and automatic speech tasks. The number of responses and fMRI data for semantic generation and semantic switching were analyzed. Participants also completed a series of verbal fluency tests outside the scanner, including letter fluency. Participants with PD-MCI performed significantly worse than PD-NC and non-PD participants during semantic fluency and semantic switching tasks. PD-MCI patients showed greater activity in the right angular gyrus than PD-NC and non-PD patients during semantic switching. Increased right angular activity correlated with worse verbal fluency performance outside the scanner. Our study showed that the PD-MCI group performed worse on semantic fluency than either the PD-NC or non-PD groups. Increased right angular gyrus activity in participants with PD-MCI during semantic switching suggests early compensatory mechanisms, predicting the risk of future dementia in PD.

Caring for a loved one with Parkinson's disease: the role of coping styles and relationship quality.

OBJECTIVE: Informal carers play an essential role in the care of individuals with Parkinson's disease (PD). This role, however, is often fraught with difficulties, including emotional, physical, and financial. Coping styles and relationship quality have been hypothesized to influence the impact of stressors. The aim of this study is to examine the relationship between carers' coping style, relationship quality, and carer burden. DESIGN: Cross-sectional. PARTICIPANTS: Thirty-nine PD patient carer dyads were included in the study. MEASUREMENTS: Participants completed self-rated questionnaires including the Dyadic Adjustment Scale, Zarit Burden Interview, and Brief Coping Orientation to Problems Experienced Inventory. RESULTS: Correlational analyses found significant and positive correlation between carer burden and all three coping styles (problem-focused, emotion-focused, and dysfunctional). There was also a moderate association between carers' perceived relationship quality and satisfaction and carer burden. Regression analyses found that carer's gender, severity of PD, relationship quality, emotion-focused, and dysfunctional coping styles did not predict carer burden. Conversely, problem-focused coping style predicted carer burden. CONCLUSION: The results highlight that there is no perfect way to react and care for a loved one and serves as important information for practitioners who design and implement interventions.

Anxiety disorders are associated with verbal memory impairment in patients with Parkinson's disease without dementia.

INTRODUCTION: Preliminary evidence has demonstrated a link between anxiety and memory impairment in Parkinson's disease (PD). This study further investigated this association using the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria for anxiety disorders and a standardized cognitive test battery. METHODS: A convenience sample of 89 PD patients without dementia was recruited from neurology outpatient clinics. A cross-sectional design was applied. Participants completed two semi-structured interviews. The first interview diagnosed DSM-5 anxiety disorders, unspecified anxiety disorder, and no anxiety. The second interview applied a neurocognitive test battery comprising two tests for each domain. Logistic regression models compared cognitive characteristics associated with anxiety disorders to no anxiety. RESULTS: Clinically significant anxiety was associated with immediate verbal memory impairment compared to the no anxiety group (OR, 95% CI 0.52, 0.30-0.89; p = 0.018), controlling for sex and age. The anxiety disorders group demonstrated immediate (OR, 95% CI 0.46, 0.26-0.83; p = 0.010) and delayed (OR, 95% CI 0.63, 0.40-0.99; p = 0.047) verbal memory impairments compared to those without anxiety, controlling for sex and age. This association remained for immediate (OR, 95% CI 0.43, 0.22-0.84; p = 0.013), but not delayed verbal memory impairment (OR, 95% CI 0.65, 0.39-1.06; p = 0.081) when additionally controlling for disease severity, education and levodopa dose. CONCLUSION: These findings present first evidence that anxiety disorders are associated with verbal memory impairment in PD and have implications for the management and treatment of anxiety in PD.

Sodium selenate as a disease-modifying treatment for progressive supranuclear palsy: protocol for a phase 2, randomised, double-blind, placebo-controlled trial.

INTRODUCTION: Progressive supranuclear palsy (PSP) is a neurodegenerative disorder for which there are currently no disease-modifying therapies. The neuropathology of PSP is associated with the accumulation of hyperphosphorylated tau in the brain. We have previously shown that protein phosphatase 2 activity in the brain is upregulated by sodium selenate, which enhances dephosphorylation. Therefore, the objective of this study is to evaluate the efficacy and safety of sodium selenate as a disease-modifying therapy for PSP. METHODS AND ANALYSIS: This will be a multi-site, phase 2b, double-blind, placebo-controlled trial of sodium selenate. 70 patients will be recruited at six Australian academic hospitals and research institutes. Following the confirmation of eligibility at screening, participants will be randomised (1:1) to receive 52 weeks of active treatment (sodium selenate; 15 mg three times a day) or matching placebo. Regular safety and efficacy visits will be completed throughout the study period. The primary study outcome is change in an MRI volume composite (frontal lobe+midbrain-3rd ventricle) over the treatment period. Analysis will be with a general linear model (GLM) with the MRI composite at 52 weeks as the dependent variable, treatment group as an independent variable and baseline MRI composite as a covariate. Secondary outcomes are change in PSP rating scale, clinical global impression of change (clinician) and change in midbrain mean diffusivity. These outcomes will also be analysed with a GLM as above, with the corresponding baseline measure entered as a covariate. Secondary safety and tolerability outcomes are frequency of serious adverse events, frequency of down-titration occurrences and frequency of study discontinuation. Additional, as yet unplanned, exploratory outcomes will include analyses of other imaging, cognitive and biospecimen measures. ETHICS AND DISSEMINATION: The study was approved by the Alfred Health Ethics Committee (594/20). Each participant or their legally authorised representative and their study partner will provide written informed consent at trial commencement. The results of the study will be presented at national and international conferences and published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: Australian New Zealand Clinical Trials Registry (ACTRN12620001254987).

Characteristics of advanced Parkinson's disease patients seen in movement disorder clinics - Australian results from the cross-sectional OBSERVE study.

OBJECTIVES: To evaluate the proportion of Parkinson's disease (PD) patients identified as having advanced Parkinson's disease (APD) according to physician's judgement in Australia. METHODS: This cross-sectional, non-interventional observational study was performed in movement disorder clinics from 18 countries. Results from Australia are presented. Participants included consecutive adults with PD attending routine clinical visits, or inpatients, who could speak English. The primary outcome was the proportion of patients diagnosed with APD via physician judgement. RESULTS: 100 patients were recruited in Australia: 61.0% (95% CI 51.4-70.6%) diagnosed with APD by physician judgement. Patients were 66.6 ±â€¯8.5 years, 65% were male, were living at home (97%), and diagnosed with PD for median 10.7 years (0-30.5 years). Motor fluctuations were present in 68%. For those with APD, referral was predominantly to enable access to device assisted therapies (DAT) (49%), while for non-APD, referral was largely for diagnostic purposes (41%). Patients had a median follow-up at the movement disorder clinic of 4.8 years for those with APD, or 3.6 years for non-APD. While 62% were eligible for DAT, only two-thirds of these received them. The most commonly used DAT was deep brain stimulation (64.3%). There was fair agreement between physician's judgement and the APD criteria by Delphi method (Cohen's kappa) 0.325 (95% CI 0.150-0.500) in the Australian subset. CONCLUSIONS: The definition of APD requires refinement in order to facilitate greater agreement among movement disorder specialists. A third of APD patients eligible for DAT remain untreated. Better referral and education of patients with APD is needed.

Defining Atypical Anxiety in Parkinson's Disease.

BACKGROUND: Anxiety is a major complication in Parkinson's disease (PD). Many PD patients experience clinically significant anxiety not meeting Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) anxiety disorder criteria. This atypical anxiety (anxiety disorder not otherwise specified [NOS]) is often under-recognized and its diagnosis is underdeveloped. OBJECTIVES: This study aimed to identify the demographic, psychiatric, and clinical characteristics of anxiety disorder NOS in PD. METHODS: A cross-sectional design studied a convenience sample of 184 PD patients without dementia recruited from neurology outpatient clinics. A semi-structured interview using DSM-IV criteria categorized PD patients into current anxiety disorder NOS (n = 28), DSM-IV anxiety disorders (n = 42) or no anxiety (n = 86) groups. Logistic regression modeling identified characteristics associated with the anxiety disorder NOS group compared to DSM-IV anxiety and no anxiety groups. RESULTS: The anxiety disorder NOS group was associated with motor complications of PD therapy, episodic, persistent and social anxiety symptoms, depression, non-motor experiences of daily living, poor quality of life, and female sex compared to the no anxiety group. Compared to DSM-IV anxiety, those with anxiety disorder NOS demonstrated greater global cognitive impairment, more severe motor complications of PD therapy, a greater severity and functional impact of dyskinesias, and greater complexity of motor fluctuations. Persistent, episodic, and social anxiety symptoms did not significantly differ between anxiety disorder NOS and DSM-IV anxiety groups. CONCLUSIONS: These findings suggest that PD-specific symptoms characterize anxiety in a subgroup of PD patients who do not fulfill DSM-IV criteria for anxiety disorders.

Neural correlates of attentional deficits in Parkinson's disease patients with mild cognitive impairment.

INTRODUCTION: Deficits in attentional processing observed in Parkinson's disease (PD) patients with mild cognitive impairment (MCI) increase risk of PD dementia. However, the neural basis of these attentional deficits are presently unknown. The present study aimed to explore the neural correlates of attention dysfunction in PD-MCI using the Attention Network Test (ANT) and functional Magnetic Resonance Imaging (fMRI). METHOD: Fifteen (15) PD-MCI patients, 26 PD patients without MCI (PD-NC) and 22 healthy controls (HC) were scanned (3T Siemens PRISMA) whilst performing the ANT. Reaction time, accuracy and fMRI BOLD activation were compared between groups for the three attentional task components of 1) alerting, 2) orienting, and 3) executive control. RESULTS: PD-MCI patients showed an overall slower reaction time compared to PD-NC and HC, and showed less interference of reaction time in the orienting effect than HC. fMRI data demonstrated greater activation in the bilateral cerebellum crus 1 during the alerting attention condition in both PD-MCI and PD-NC compared to HC. However, activation was supressed in the left postcentral gyrus in PD-MCI compared to PD-NC and HC. DISCUSSION: Alterations in the alerting attention functional network despite intact task performance in PD-MCI suggests that functional brain changes may precede cognitive changes in the attention domain. Furthermore, increased activation in the cerebellum may reflect an attentional compensatory mechanism unique to the PD pathology. Taken together, the findings suggest that PD has a complex effect on attentional ability that can, at least in part, be elucidated using functional neuroimaging.

Identifying subtypes of mild cognitive impairment in Parkinson's disease using cluster analysis.

INTRODUCTION: The concept of Mild Cognitive Impairment (MCI) in Parkinson's disease (PD) has shown the potential for identifying at-risk dementia patients. Identifying subtypes of MCI is likely to assist therapeutic discoveries and better clinical management of patients with PD (PWP). Recent cluster-based approaches have demonstrated dominance in memory and executive impairment in PD. The present study will further explore the role of memory and executive impairment and associated clinical features in non-demented PWP. METHOD: A K-means cluster analysis was performed on ten "frontal" and "posterior" cognitive variables derived from a dataset of 85 non-demented PWP. The resulting cluster structure was chosen based on quantitative, qualitative, theoretical, and clinical validity. Cluster profiles were then created through statistical analysis of cognitive and clinical/demographic variables. A descriptive analysis of each cluster's performance on a comprehensive PD-MCI diagnostic battery was also explored. RESULTS: The resulting cluster structure revealed four distinct cognitive phenotypes: (1) frontal-dominant impairment; (2) posterior-cortical-dominant impairment; (3) global impairment, and (4) cognitively intact. Demographic profiling revealed significant differences in the age, gender split, global cognitive ability, and motor symptoms between these clusters. However, there were no significant differences between the clusters on measures of depression, apathy, and anxiety. CONCLUSION: These results validate the existence of distinct cognitive phenotypes within PD-MCI and encourage future research into their clinical trajectory and neuroimaging correlates.

The CuePed Trial: How Does Environmental Complexity Impact Cue Effectiveness? A Comparison of Tonic and Phasic Visual Cueing in Simple and Complex Environments in a Parkinson's Disease Population with Freezing of Gait.

BACKGROUND: The optimal prescription of cueing for the treatment of freezing of gait (FoG) in Parkinson's disease (PD) is currently a difficult problem for clinicians due to the heterogeneity of cueing modalities, devices, and the limited comparative trial evidence. There has been a rise in the development of motion-sensitive, wearable cueing devices for the treatment of FoG in PD. These devices generally produce cues after signature gait or electroencephalographic antecedents of FoG episodes are detected (phasic cues). It is not known whether these devices offer benefit over simple (tonic) cueing devices. METHODS: We assembled 20 participants with PD and FoG and familiarized them with a belt-worn, laser-light cueing device (Agilitas™). The device was designed with 2 cueing modalities-gait-dependent or "phasic" cueing and gait-independent or "tonic" cueing. Participants used the device sequentially in the off, phasic, or tonic modes, across 2 tasks-a 2-minute walk and an obstacle course. RESULTS: A significant improvement in mean distance walked during the 2-minute walk test was observed for the tonic mode (127.3 m) compared with the off (111.4 m) and phasic (116.1 m) conditions. In contrast, there was a nonsignificant trend toward improvement in FoG frequency, duration, and course time when the device was switched from off to tonic and to phasic modes for the obstacle course. CONCLUSIONS: Parkinson's disease patients with FoG demonstrated an improvement in distance walked during the two-minute walk test when a cueing device was switched from off to phasic and to tonic modes of operation. However, this benefit was lost when patients negotiated an obstacle course.

Updates and advances in the treatment of Parkinson disease.

Parkinson disease (PD) is a complex neurodegenerative disorder that can present heterogeneously with a combination of motor and non-motor symptoms. α-synuclein, a neuronal protein, can undergo aberrant conformational change resulting in the intra-neuronal accumulation of toxic oligomers that form Lewy bodies, the pathological hallmark of PD. There is evidence that pathological α-synuclein exhibits prion-like behaviour in its mode of transmission through the nervous system. The choice of initial dopaminergic treatments should be individually tailored but long term outcomes appear to be equivalent. There is level A evidence supporting the benefit of three different device-assisted therapies in treating troublesome motor fluctuations and dyskinesias. Stem cell transplantation as currently being trialled is predominantly a symptomatic therapy targeting only limited regions of the brain affected by PD, and will need to be proven to be not only as effective but as safe as currently available device-assisted therapies. New modes of treatment including active immunisation against oligomeric α-synuclein and drugs that alter cellular metabolism show some promise. The inability to effectively treat a range of non-motor, non-dopaminergic symptoms remains a major therapeutic challenge.

Depression symptomatology correlates with event-related potentials in Parkinson's disease: An affective priming study.

BACKGROUND: Depression is a predominant non-motor symptom of Parkinson's disease (PD), which is often under recognised and undertreated. To improve identification of depression in PD it is imperative to examine objective brain-related markers. The present study addresses this gap by using electroencephalography (EEG) to evaluate the processing of emotionally valanced words in PD. METHODS: Fifty non-demented PD patients, unmedicated for depression or anxiety, completed an affective priming task while EEG was simultaneously recorded. Prime and target word pairs of negative or neutral valence were presented at a short 250 ms stimulus onset asynchrony. Participants were asked to evaluate the valence of the target word by button press. Depression was measured using an established rating scale. Repeated measures analysis of covariance and correlational analyses were performed to examine whether event-related potentials (ERP) varied as a function of depression scores. RESULTS: Key ERP findings reveal reduced responses in parietal midline P300, N400 and Late Positive Potential (LPP) difference waves between congruent and incongruent neutral targets in patients with higher depression scores. LIMITATIONS: Comparisons of ERPs were limited by insufficient classification of participants with and without clinical depression. A majority of PD patients who had high depression scores were excluded from the analysis as they were receiving antidepressant and/or anxiolytic medications which could interfere with ERP sensitivity. CONCLUSIONS: The present study suggests that the Pz-P300, N400 and LPP are ERP markers relates to emotional dysfunction in PD. These findings thus advance current knowledge regarding the neurophysiological markers of a common neuropsychiatric deficit in PD.