Evidence from pupillometry, fMRI, and RNN modelling shows that gain neuromodulation mediates task-relevant perceptual switches.

Perceptual updating has been hypothesised to rely on a network reset modulated by bursts of ascending neuromodulatory neurotransmitters, such as noradrenaline, abruptly altering the brain's susceptibility to changing sensory activity. To test this hypothesis at a large-scale, we analysed an ambiguous figures task using pupillometry and functional magnetic resonance imaging (fMRI). Behaviourally, qualitative shifts in the perceptual interpretation of an ambiguous image were associated with peaks in pupil diameter, an indirect readout of phasic bursts in neuromodulatory tone.

Distinct brain atrophy progression subtypes underlie phenoconversion in isolated REM sleep behaviour disorder.

Background: Synucleinopathies include a spectrum of disorders varying in features and severity, including idiopathic/isolated REM sleep behaviour disorder (iRBD), Parkinson's disease (PD), and dementia with Lewy bodies (DLB). Distinct brain atrophy patterns may already be seen in iRBD; however, how brain atrophy begins and progresses remains unclear.

Methods: A multicentric cohort of 1276 participants (451 polysomnography-confirmed iRBD, 142 PD with probable RBD, 87 DLB, and 596 controls) underwent T1-weighted MRI and longitudinal clinical assessments.

Motor, affective, cognitive, and perceptual symptom changes over time in individuals with Parkinson's disease who develop freezing of gait.

Freezing of gait (FOG) affects up to 80% of individuals living with advanced Parkinson's disease and approximately 20% in early stages. Associated with motor, affective, cognitive, and sensory difficulties, FOG is challenging to treat due to its unknown etiology. Approaches and findings in research studies predicting FOG remain inconsistent.

Correction: Sensory focused exercise improves anxiety in Parkinson's disease: A randomized controlled trial.

[This corrects the article DOI: 10.1371/journal.pone.

Neural correlates of trait anxiety in sensory processing and distractor filtering.

Evidence suggests that trait anxiety relates to cognitive processing and behavior. However, the relationships between trait anxiety and sensory processing, goal-directed performance and sensorimotor function are unclear, particularly in a multimodal context. This study used electroencephalography to evaluate whether trait anxiety influenced visual and tactile event-related potentials (ERPs), as well as behavioral distractor cost, in a bimodal sensorimotor task.

Effect of dopamine on limbic network connectivity at rest in Parkinson's disease patients with freezing of gait.

Background: Freezing of gait (FOG) in Parkinson's disease (PD) has a poorly understood pathophysiology, which hinders treatment development. Recent work showed a dysfunctional fronto-striato-limbic circuitry at rest in PD freezers compared to non-freezers in the dopamine "OFF" state. While other studies found that dopaminergic replacement therapy alters functional brain organization in PD, the specific effect of dopamine medication on fronto-striato-limbic functional connectivity in freezers remains unclear.

The effects of trait and state anxiety on gait in healthy young adults.

Stable, personality-based (trait), and fluctuating, situational (state) anxiety have both been shown to consume attentional resources and reduce functional cognitive capacity, which may play a role in gait control. However, the role of attention in the relationship between trait and state anxiety has not yet been investigated formally. This study used a virtual reality-threat environment to evaluate whether changes in attention mediate the effects of state and trait anxiety on gait.

Emotional states affect steady state walking performance.

Gait is a large component and indicator of health. Many factors affect gait including age, disease, and even mood disorders. Few studies have looked at the influence of emotional states on gait.

Multi-Level Adversarial Spatio-Temporal Learning for Footstep Pressure Based FoG Detection.

Freezing of gait (FoG) is one of the most common symptoms of Parkinson's disease, which is a neurodegenerative disorder of the central nervous system impacting millions of people around the world. To address the pressing need to improve the quality of treatment for FoG, devising a computer-aided detection and quantification tool for FoG has been increasingly important. As a non-invasive technique for collecting motion patterns, the footstep pressure sequences obtained from pressure sensitive gait mats provide a great opportunity for evaluating FoG in the clinic and potentially in the home environment.

Higher Order Polynomial Transformer for Fine-Grained Freezing of Gait Detection.

Freezing of Gait (FoG) is a common symptom of Parkinson's disease (PD), manifesting as a brief, episodic absence, or marked reduction in walking, despite a patient's intention to move. Clinical assessment of FoG events from manual observations by experts is both time-consuming and highly subjective. Therefore, machine learning-based FoG identification methods would be desirable.

Modulating arousal to overcome gait impairments in Parkinson's disease: how the noradrenergic system may act as a double-edged sword.

In stressful or anxiety-provoking situations, most people with Parkinson's disease (PD) experience a general worsening of motor symptoms, including their gait impairments. However, a proportion of patients actually report benefits from experiencing-or even purposely inducing-stressful or high-arousal situations. Using data from a large-scale international survey study among 4324 people with PD and gait impairments within the online Fox Insight (USA) and ParkinsonNEXT (NL) cohorts, we demonstrate that individuals with PD deploy an array of mental state alteration strategies to cope with their gait impairment.

Exploring the Sensitivity of Prodromal Dementia with Lewy Bodies Research Criteria.

Dementia with Lewy bodies (DLB) is an insidious neurodegenerative disease characterised by a precipitous decline in cognition, sleep disturbances, motor impairment and psychiatric features. Recently, criteria for prodromal DLB (pDLB) including clinical features and biomarkers have been put forward to aid the classification and research of this ambiguous cohort of patients. Researchers can use these criteria to classify patients with mild cognitive impairment (MCI) with Lewy bodies (MCI-LB) as either possible (either one core clinical feature or one biomarker are present) or probable pDLB (at least two core clinical features, or one core clinical feature and at least one biomarker present).

The Ziegler Test Is Reliable and Valid for Measuring Freezing of Gait in People With Parkinson Disease.

Objective: The purpose of this study was to determine interrater and test-retest reliability of the Ziegler test to measure freezing of gait (FOG) severity in people with Parkinson disease. Secondary aims were to evaluate test validity and explore Ziegler test duration as a proxy FOG severity measure.

Methods: Physical therapists watched 36 videos of people with Parkinson disease and FOG perform the Ziegler test and rated FOG severity using the rating scale in real time.

An Adaptive Measure of Visuospatial Impairment in Dementia with Lewy Bodies.

Background: Dementia with Lewy bodies (DLB) is a common cause of dementia with poor prognosis and high hospitalization rates. DLB is frequently misdiagnosed, with clinical features that overlap significantly with other diseases including Parkinson's disease (PD). Clinical instruments that discriminate and track the progression of cognitive impairment in DLB are needed.

The influence of visual feedback on alleviating freezing of gait in Parkinson's disease is reduced by anxiety.

Background: Previous research has established that anxiety is associated with freezing of gait (FOG) in Parkinson's disease (PD). Although providing body-related visual feedback has been previously suggested to improve FOG, it remains unclear whether anxiety-induced FOG might be improved.

Research Question: The current study aimed to evaluate whether body-related visual feedback (VF) improves FOG consistently across low and high threat conditions.

The Contribution of Noradrenergic Activity to Anxiety-Induced Freezing of Gait.

Background: Freezing of gait is a complex paroxysmal phenomenon that is associated with a variety of sensorimotor, cognitive and affective deficits, and significantly impacts quality of life in patients with Parkinson's disease (PD). Despite a growing body of evidence that suggests anxiety may be a crucial contributor to freezing of gait, no research study to date has investigated neural underpinnings of anxiety-induced freezing of gait.

Objective: Here, we aimed to investigate how anxiety-inducing contexts might "set the stage for freezing," through the ascending arousal system, by examining an anxiety-inducing virtual reality gait paradigm inside functional magnetic resonance imaging (fMRI).

Dynamic network impairments underlie cognitive fluctuations in Lewy body dementia.

Cognitive fluctuations are a characteristic and distressing disturbance of attention and consciousness seen in patients with Dementia with Lewy bodies and Parkinson's disease dementia. It has been proposed that fluctuations result from disruption of key neuromodulatory systems supporting states of attention and wakefulness which are normally characterised by temporally variable and highly integrated functional network architectures. In this study, patients with DLB (n = 25) and age-matched controls (n = 49) were assessed using dynamic resting state fMRI.

Narrow doorways alter brain connectivity and step patterns in isolated REM sleep behaviour disorder.

Background: Motor impairments in those with isolated REM sleep behaviour disorder (iRBD) significantly increases the likelihood of developing Lewy body disease (e.g. Parkinson's disease and Dementia with Lewy Bodies).

A Video Self-Modeling Intervention Using Virtual Reality Plus Physical Practice for Freezing of Gait in Parkinson Disease: Feasibility and Acceptability Study.

Background: Despite optimal medical and surgical intervention, freezing of gait commonly occurs in people with Parkinson disease. Action observation via video self-modeling, combined with physical practice, has potential as a noninvasive intervention to reduce freezing of gait.

Objective: The aim of this study is to determine the feasibility and acceptability of a home-based, personalized video self-modeling intervention delivered via a virtual reality head-mounted display (HMD) to reduce freezing of gait in people with Parkinson disease.

Measuring anxiety in Lewy Body Disease - Which scale to choose?

Background: Anxiety is among the most prevalent mood disorders in Lewy Body Disease (LBD) (i.e., Parkinson's disease (PD), Dementia with Lewy bodies DLB), and those at-risk for developing LBD (e.

Graph Fusion Network-Based Multimodal Learning for Freezing of Gait Detection.

Freezing of gait (FoG) is identified as a sudden and brief episode of movement cessation despite the intention to continue walking. It is one of the most disabling symptoms of Parkinson's disease (PD) and often leads to falls and injuries. Many computer-aided FoG detection methods have been proposed to use data collected from unimodal sources, such as motion sensors, pressure sensors, and video cameras.

Biomarkers of conversion to α-synucleinopathy in isolated rapid-eye-movement sleep behaviour disorder.

Patients with isolated rapid-eye-movement sleep behaviour disorder (RBD) are commonly regarded as being in the early stages of a progressive neurodegenerative disease involving α-synuclein pathology, such as Parkinson's disease, dementia with Lewy bodies, or multiple system atrophy. Abnormal α-synuclein deposition occurs early in the neurodegenerative process across the central and peripheral nervous systems and might precede the appearance of motor symptoms and cognitive decline by several decades. These findings provide the rationale to develop reliable biomarkers that can better predict conversion to clinically manifest α-synucleinopathies.

Validating a Seated Virtual Reality Threat Paradigm for Inducing Anxiety and Freezing of Gait in Parkinson's Disease.

Background: Although prior research has established that freezing of gait (FOG) in Parkinson's disease (PD) is associated with anxiety, only one study to date has directly manipulated anxiety levels to induce FOG.

Objective: The current study aimed to replicate these previous findings and evaluate whether a seated version of a 'threat' virtual reality (VR) paradigm could induce anxiety and provoke FOG.

Methods: Twenty-four PD patients with FOG were assessed across various threat conditions in both a walking VR paradigm (Experiment 1) and a seated VR paradigm (Experiment 2).

Evaluating a novel behavioral paradigm for visual hallucinations in Dementia with Lewy bodies.

The aim of this study was to evaluate the utility of the Bistable Percept Paradigm (BPP), a computerised behavioural task that has previously been utilised for the assessment of visual hallucinations in Parkinson's Disease, in a Dementia with Lewy bodies (DLB) cohort. Dementia with Lewy bodies patients demonstrated poorer performance than healthy controls (HC) on the BPP with significantly more misperceptions and a greater failure to detect bistable percepts correctly compared to HC. Further, the number of misperceptions was also correlated with the severity of hallucinations.

Heart Rate Changes Prior to Freezing of Gait Episodes Are Related to Anxiety.

Background: Freezing of gait (FOG) in Parkinson's disease (PD) has been shown to be more frequent in stressful situations, implicating anxiety. Heart rate (HR) has been shown to increase prior to a FOG episode supporting the notion that elevated stress levels may trigger FOG. However, no studies to date have investigated whether elevated HR precedes all subtypes of FOG or only those episodes that are driven by anxiety.