Publications by authors named "Karen Ostergaard"

Background And Purpose: Most patients with isolated rapid eye movement sleep behaviour disorder (iRBD) progress to a parkinsonian alpha-synucleinopathy. However, time to phenoconversion shows great variation. The aim of this study was to investigate whether cholinergic and dopaminergic dysfunction in iRBD patients was associated with impending phenoconversion.

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Background: Using C-(R)-PK11195-PET, we found increased microglia activation in isolated REM sleep behavior disorder (iRBD) patients. Their role remains to be clarified.

Objectives: The objective is to assess relationships between activated microglia and progression of nigrostriatal dysfunction in iRBD.

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Background: Reduced cortical acetylcholinesterase activity, as measured by C-donepezil positron emission tomography (PET), has been reported in patients with isolated rapid eye movement (REM) sleep behavior disorder (iRBD). However, its progression and clinical implications have not been fully investigated. Here, we explored the relationship between longitudinal changes in brain acetylcholinesterase activity and cognitive function in iRBD.

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Article Synopsis
  • - Multiple system atrophy (MSA) is a severe disease with varying motor and autonomic symptoms, and previous studies have linked certain clinical factors to reduced survival rates.
  • - Researchers analyzed 210 MSA patients over 17 years to create a survival risk model using clinical factors like age at symptom onset and early autonomic failure.
  • - They developed a nomogram to predict individual survival probabilities over 7 years, which showed good accuracy and could enhance patient counseling and treatment strategies.
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The pleasurable urge to move to music (PLUMM) activates motor and reward areas of the brain and is thought to be driven by predictive processes. Dopamine in motor and limbic networks is implicated in beat-based timing and music-induced pleasure, suggesting a central role of basal ganglia (BG) dopaminergic systems in PLUMM. This study tested this hypothesis by comparing PLUMM in participants with Parkinson's disease (PD), age-matched controls, and young controls.

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Parkinson's disease (PD) is a neurodegenerative disorder, well-known for its motor symptoms; however, it also adversely affects cognitive functions, including language, a highly important human ability. PD pathology is associated, even in the early stage of the disease, with alterations in the functional connectivity within cortico-subcortical circuitry of the basal ganglia as well as within cortical networks. Here, we investigated functional cortical connectivity related to spoken language processing in early-stage PD patients.

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Objectives: In this study, we investigated the effects of bilateral and unilateral deep brain stimulation of the subthalamic nucleus (STN-DBS) in PD patients on neural responses associated with two aspects of spoken language processing: semantics of action-related verbs and morphosyntactic processing.

Materials And Methods: Using a passive unattended paradigm to present spoken linguistic stimuli, we recorded magnetoencephalographic (MEG) responses in three PD patients in four DBS conditions: left unilateral STN-DBS, right unilateral STN-DBS, bilateral STN-DBS, and no STN-DBS. To ensure that any observed effects of DBS on the neuromagnetic responses could be attributed to the linguistic context per se and were not merely induced by the electrical stimulation, we assessed the effects of STN-DBS on linguistic contrasts within each stimulation condition.

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During the prodromal period of Parkinson's disease and other α-synucleinopathy-related parkinsonisms, neurodegeneration is thought to progressively affect deep brain nuclei, such as the locus coeruleus, caudal raphe nucleus, substantia nigra, and the forebrain nucleus basalis of Meynert. Besides their involvement in the regulation of mood, sleep, behaviour, and memory functions, these nuclei also innervate parenchymal arterioles and capillaries throughout the cortex, possibly to ensure that oxygen supplies are adjusted according to the needs of neural activity. The aim of this study was to examine whether patients with isolated REM sleep behaviour disorder, a parasomnia considered to be a prodromal phenotype of α-synucleinopathies, reveal microvascular flow disturbances consistent with disrupted central blood flow control.

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Synucleinopathies are neurodegenerative diseases with both central and peripheral immune responses. However, whether the peripheral immune changes occur early in disease and their relation to brain events is yet unclear. Isolated rapid-eye-movement (REM) sleep behavior disorder (iRBD) can precede synucleinopathy-related parkinsonism and provides a prodromal phenotype to study early Parkinson's disease events.

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Introduction: In vivo PET studies in patients with isolated REM sleep behavior disorder (iRBD) have shown presence of neuroinflammation (microglial activation) in the substantia nigra, and reduced cortical acetylcholinesterase activity, suggestive of cholinergic dysfunction, that was more widespread in patients with poorer cognitive performances. This study aimed to explore whether reduced cortical acetylcholinesterase activity in iRBD is linked to microglial activation in the substantia innominata (SI), the major source of cholinergic input to the cortex.

Methods: We used C(R)-PK11195 and C-Donepezil PET to assess levels of activated microglia and cholinergic function, respectively, in 19 iRBD patients.

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Neuroinflammation (microglial activation) and subclinical nigrostriatal dysfunction have been reported in subjects at risk of Parkinsonism. Eight non-manifesting carriers (NMCs) of LRRK2 G2019S mutation had C-PK11195 and F-DOPA PET to assess microglial activation and striatal dopamine system integrity, respectively. Comparisons were made with healthy controls.

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Introduction: Decision-making impairments in Parkinson's disease (PD) have frequently been measured using the Iowa Gambling Task (IGT), though results have been inconsistent. At present, task performance has primarily been evaluated based on the total IGT score, and there is a need for further analysis of the strategy of older individuals with PD and healthy control (HC) participants in IGT.

Objective: The present study aims to explore possible impairments in IGT performance in individuals with PD compared to healthy controls using strategy analysis, extending previous results on this subject, and to discuss potential effects of medication on task performance.

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Treatment with deep brain stimulation for Parkinson's disease, leads to a rapid improvement in mobility, which may challenge patients and spouses when adjusting to everyday life. An intervention, developed to support the adjustment to everyday life with DBS, demonstrated that individualized meetings with a specialized nurse was experienced as important and fruitful by both patient and spouses.  The aim was to gain a deeper understanding of how the meetings contributed to the adjustment process.

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Assessing the brain activity related to language comprehension is required in a range of situations. Particularly in cases when subjects' cooperation with instructions cannot be guaranteed (e.g.

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Background: Flortaucipir PET, a marker of tau tangles, has shown lower than expected cortical uptake in Parkinson's disease (PD), than would be predicted from neuropathologic estimates of Alzheimer's disease co-pathology. Instead, the most characteristic finding of flortaucipir imaging in PD is decreased uptake in the substantia nigra, reflecting reduction in its "off-target" binding to neuromelanin. We have previously reported these observations in cross-sectional studies.

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Background: Parkinson's disease is characterized by pathological α-synuclein accumulation and cell death, which has been hypothesized to originate in peripheral nerve terminals and subsequently spread via autonomic nerves. Supporting this, most Parkinson's disease patients experience autonomic non-motor symptoms such as constipation, often years prior to diagnosis.

Objective: We aimed to study gastrointestinal transit time, colonic volume, and peristaltic movements in idiopathic REM Sleep Behavior Disorder patients, a prodromal marker of Parkinson's disease or Dementia with Lewy bodies.

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Deep Brain Stimulation requires extensive postoperative testing of stimulation parameters to achieve optimal outcomes. Testing is typically not guided by neuroanatomical information on electrode contact locations. To address this, we present an automated reconstruction of electrode locations relative to the treatment target, the subthalamic nucleus, comparing different targeting methods: atlas-, manual-, or tractography-based subthalamic nucleus segmentation.

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Objective: Differentiating Parkinson's disease (PD) from atypical parkinsonian disorders (APD) such as Multiple System Atrophy, parkinsonian type (MSA-p) or Progressive Supranuclear Palsy (PSP-RS) can be challenging. Early signs of postural Instability and gait disability (PIGD) are considered clues that may signal presence of APD. However, it remains unknown which PIGD test - or combination of tests - can best distinguish PD from APD.

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This article evaluates the feasibility of a nursing intervention when adjusting to deep brain stimulation for Parkinson disease. Eight couples were included in the study. Main activities of the intervention were a diary and individualized meetings between nurses, patients, and spouses with a focus on everyday life and expectations to deep brain stimulation.

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Background: The majority of patients diagnosed with idiopathic rapid eye movement sleep behaviour disorder (iRBD) progress over time to a Lewy-type α-synucleinopathy such as Parkinson's disease or dementia with Lewy bodies. This in vivo molecular imaging study aimed to investigate if extrastriatal monoaminergic systems are affected in iRBD patients and if this coincides with neuroinflammation.

Methods: We studied twenty-one polysomnography-confirmed iRBD patients with F-DOPA and C-PK11195 positron emission tomography (PET) to investigate extrastriatal monoaminergic function and microglial activation.

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Cerebellar ataxia, areflexia, pes cavus, optic atrophy and sensorineural hearing impairment (CAPOS) is a rare clinically distinct syndrome caused by a single dominant missense mutation, c.2452G>A, p.Glu818Lys, in ATP1A3, encoding the neuron-specific alpha subunit of the Na+/K+-ATPase α3.

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Background And Objectives: Parkinson's disease (PD) patients experience several non-motor symptoms from the gastrointestinal tract that may partly be caused by parasympathetic deficiency. The pancreas is densely innervated by the vagus nerve, which mediates early meal-induced secretion of pancreatic polypeptide (PP). Early secretion after sham feeding has been validated as a marker of vagal integrity.

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Degeneration of noradrenergic neurons may underlie the disabling nonmotor symptoms in patients with Parkinson disease (PD). Quantification of the loss of noradrenergic neurons by means of neuroimaging has been limited by the lack of radioligands that are selective for noradrenergic neurotransmission. The radioligand ()-C-2-(α-(2-methoxyphenoxy)benzyl)morpholine (C-MeNER) is a highly selective inhibitor of noradrenaline transporters, and PET studies suggest that this radioligand is suitable for quantitative neuroimaging of noradrenergic deficits in human brain in vivo.

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