Abnormal higher-order network interactions in Parkinson's disease visual hallucinations.

Visual hallucinations in Parkinson's disease can be viewed from a systems-level perspective, whereby dysfunctional communication between brain networks responsible for perception predisposes a person to hallucinate. To this end, abnormal functional interactions between higher-order and primary sensory networks have been implicated in the pathophysiology of visual hallucinations in Parkinson's disease, however the precise signatures remain to be determined. Dimensionality reduction techniques offer a novel means for simplifying the interpretation of multidimensional brain imaging data, identifying hierarchical patterns in the data that are driven by both within- and between-functional network changes.

A multicentre study on grey matter morphometric biomarkers for classifying early schizophrenia and parkinson's disease psychosis.

Psychotic symptoms occur in a majority of schizophrenia patients and in ~50% of all Parkinson's disease (PD) patients. Altered grey matter (GM) structure within several brain areas and networks may contribute to their pathogenesis. Little is known, however, about transdiagnostic similarities when psychotic symptoms occur in different disorders, such as in schizophrenia and PD.

Dementia in long-term Parkinson's disease patients: a multicentre retrospective study.

While several studies have investigated the clinical progression of cognitive decline in Parkinson's disease (PD) patients, there has been a paucity of data on specifically evaluating PD patients with a disease duration of over 20 years. This study retrospectively investigated the frequency of dementia in PD (PDD) patients with a disease duration of over 20 years assessed in research clinics across the UK and Australia. Data from 2327 PD patients meeting the United Kingdom Parkinson's Disease Society Brain Bank Criteria was pooled.

Subtle gait and balance impairments occur in idiopathic rapid eye movement sleep behavior disorder.

Background: Although motor abnormalities have been flagged as potentially the most sensitive and specific clinical features for predicting the future progression to Parkinson's disease, little work has been done to characterize gait and balance impairments in idiopathic rapid eye movement sleep behavior disorder (iRBD).

Objective: The objective of this study was to quantitatively determine any static balance as well as gait impairments across the 5 independent domains of gait in polysomnography-confirmed iRBD patients using normal, fast-paced, and dual-task walking conditions.

Methods: A total of 38 participants (24 iRBD, 14 healthy controls) completed the following 5 different walking trials across a pressure sensor carpet: (1) normal pace, (2) fast pace, (3) while counting backward from 100 by 1s, (4) while naming as many animals as possible, (5) while subtracting 7s from 100.

Evidence for subtypes of freezing of gait in Parkinson's disease.

Background: The purpose of this study is to identify and characterize subtypes of freezing of gait by using a novel questionnaire designed to delineate freezing patterns based on self-reported and behavioral gait assessment.

Methods: A total of 41 Parkinson's patients with freezing completed the Characterizing Freezing of Gait questionnaire that identifies situations that exacerbate freezing. This instrument underwent examination for construct validity and internal consistency, after which a data-driven clustering approach was employed to identify distinct patterns amongst individual responses.

Cognitive training for freezing of gait in Parkinson's disease: a randomized controlled trial.

The pathophysiological mechanism of freezing of gait (FoG) has been linked to executive dysfunction. Cognitive training (CT) is a non-pharmacological intervention which has been shown to improve executive functioning in Parkinson's disease (PD). This study aimed to explore whether targeted CT can reduce the severity of FoG in PD.

Alterations in white matter network topology contribute to freezing of gait in Parkinson's disease.

Freezing of gait (FOG) is a common symptom in advanced Parkinson's disease (PD). Despite current advances, the neural mechanisms underpinning this disturbance remain poorly understood. To this end, we investigated the structural organisation of the white matter connectome in PD freezers and PD non-freezers.

Exploring the Phenotype in Mild Cognitive Impairment to Aid the Prediction of Those at Risk of Transitioning to Parkinson Disease and Dementia With Lewy Bodies.

To date, only limited research has concurrently investigated the presence of rapid eye movement sleep behavior disorder (RBD) and other features associated with Parkinson disease (PD) and dementia with Lewy bodies (DLB) in people presenting with mild cognitive impairment (MCI). As a first step towards a longitudinal research project, the present study explored the relationships between MCI, RBD, and depression in 108 older adults who presented with subjective memory complaints but were not known to have a neurodegenerative condition. The present study found that RBD was a frequent feature in individuals with MCI (35%).

Mild Cognitive Impairment in Parkinson's Disease: Impact on Caregiver Outcomes.

Background: Recent attempts to standardise the definition of Mild Cognitive Impairment (MCI) in Parkinson's disease (PD) by the Movement Disorder Society Task Force has led to a greater understanding of this entity but to date, there has been a paucity of research regarding the impact of PD-MCI on caregiver outcomes.

Objective: The aim of this study was to utilise the newly established PD-MCI diagnostic criteria to investigate caregiver outcomes in relation to four specific aspects: (1) caregiver burden, (2) quality of life (QoL), (3) caregiving experience, and (4) psychological distress.

Methods: This study included a total of 166 patient-caregiver dyads.

Current Treatment Options for Alzheimer's Disease and Parkinson's Disease Dementia.

Alzheimer's disease (AD) and Parkinson's disease (PD) are the two most common neurodegenerative disorders encountered in clinical practice. Whilst dementia has long been synonymous with AD, it is becoming more widely accepted as part of the clinical spectrum in PD (PDD). Neuropsychiatric complications, including psychosis, mood and anxiety disorders, and sleep disorders also frequently co-exist with cognitive dysfunctions in AD and PDD patients.

The relationships between mild cognitive impairment and phenotype in Parkinson's disease.

Background: The concept of differing clinical phenotypes within Parkinson's disease (PD) is well represented in the literature. However, there is no consensus as to whether any particular disease phenotype is associated with an increased risk of mild cognitive impairment (MCI) using the newly proposed Movement Disorders Society diagnostic criteria for this feature.

Aims: To explore the expression of PD-MCI in relation to the heterogeneity of idiopathic PD.

Assessing the utility of the Movement Disorder Society Task Force Level 1 diagnostic criteria for mild cognitive impairment in Parkinson's disease.

Background: Using the Movement Disorder Society (MDS) Task Force Level 1 criteria, this study examined the classification of mild cognitive impairment in Parkinson's Disease (PD-MCI) derived from a range of cut-off scores that have previously been suggested by the MDS Task Force. Furthermore, differences in PD-MCI frequencies were examined when comparing performance on current neuropsychological testing to the normative sample, as opposed to decline from premorbid functioning, as evidence of cognitive impairment.

Method: Two hundred and thirty-four non-demented PD patients underwent neurological and neuropsychological assessment at the Parkinson's Disease Research Clinic at the Brain and Mind Research Institute, University of Sydney.

The major impact of freezing of gait on quality of life in Parkinson's disease.

Freezing of gait (FOG) is a disabling motor symptom experienced by a large proportion of patients with Parkinson's disease (PD). While it is known that FOG contributes to lower health-related quality of life (HRQoL), previous studies have not accounted for other important factors when measuring the specific impact of this symptom. The aim of this study was to examine FOG and HRQoL while controlling for other factors that are known to impact patient well-being, including cognition, motor severity, sleep disturbance and mood.