Publications by authors named "Granert O"

Spatial learning and navigation are supported by distinct memory systems in the human brain such as the hippocampus-based navigational system and the striatum-cortex-based system involved in motor sequence, habit and reversal learning. Here, we studied the role of subthalamic circuits in hippocampus-associated spatial memory and striatal-associated spatial reversal learning formation in patients with Parkinson's disease, who underwent a deep brain stimulation of the subthalamic nucleus. Deep brain stimulation patients (Parkinson's disease-subthalamic nucleus: = 26) and healthy subjects ( = 15) were tested in a novel experimental spatial memory task based on the Morris water maze that assesses both hippocampal place memory as well as spatial reversal learning.

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Spatial navigation critically underlies hippocampal-entorhinal circuit function that is early affected in Alzheimer's disease (AD). There is growing evidence that AD pathophysiology dynamically interacts with the sleep/wake cycle impairing hippocampal memory. To elucidate sleep-dependent consolidation in a cohort of symptomatic AD patients (n = 12, 71.

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Objective: Spatial memory deficits are an early symptom in Alzheimer's disease (AD), reflecting the neurodegenerative processes in the neuronal navigation network such as in hippocampal and parietal cortical areas. As no effective treatment options are available, neuromodulatory interventions are increasingly evaluated. Against this backdrop, we investigated the neuromodulatory effect of anodal transcranial direct current stimulation (tDCS) on hippocampal place learning in patients with AD or mild cognitive impairment (MCI).

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Background: Questionable signs of dystonia are a common finding in patients with essential tremor (ET). Brain structural alterations in ET patients plus dystonic soft signs (ET + ds) in comparison to ET patients without dystonic soft signs (ET-ds) or patients with tremor associated with manifest dystonia (TAWD) have not been examined yet. Therefore, our study aims to explore alterations of brain grey matter in patients with ET + ds.

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Background: Three-dimensional (3D) human body estimation from common photographs is an evolving method in the field of computer vision. It has not yet been evaluated on postural disorders. We generated 3D models from 2-dimensional pictures of camptocormia patients to measure the bending angle of the trunk according to recommendations in the literature.

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Hypersexuality in medicated patients with PD is caused by an increased influence of motivational drive areas and a decreased influence of inhibitory control areas due to dopaminergic medication. In this pilot study, we test a newly developed paradigm investigating the influence of dopaminergic medication on brain activation elicited by sexual pictures with and without inhibitory contextual framing. Twenty PD patients with and without hypersexuality were examined with fMRI either OFF or ON standardized dopaminergic medication.

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Article Synopsis
  • The study aimed to explore if imagining handwriting and circle drawing activates the same brain regions as actually performing these tasks using fMRI.
  • Eighteen right-handed participants were tested on their handwriting and drawing movements in both sitting and lying positions, with kinematic data collected on aspects like speed and pressure.
  • Results showed that while there was significant overlap in brain activity during imagined and executed tasks, actual writing led to greater activation in specific motor control areas, suggesting that writing is more automated in healthy individuals.
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Background: Subthalamic nucleus deep brain stimulation (STN-DBS) effectively treats motor symptoms and quality of life (QoL) of advanced and fluctuating early Parkinson's disease. Little is known about the relation between electrode position and changes in symptom control and ultimately QoL.

Objectives: The relation between the stimulated part of the STN and clinical outcomes, including the motor score of the Unified Parkinson's Disease Rating Scale (UPDRS) and the quality-of-life questionnaire, was assessed in a subcohort of the EARLYSTIM study.

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Background And Objective: Cognitive impairment is among the most burdensome non-motor symptoms in Parkinson's disease (PD) and has been associated with hippocampal atrophy. Exercise has been reported to enhance neuroplasticity in the hippocampus in correlation with an improvement of cognitive function. We present data from the Training-PD study, which was designed to evaluate effects of an "" training protocol on neuronal plasticity in PD.

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Objective: Planning of voluntary object-related movements requires the estimation of the most probable object properties. We investigated how 14 writer's cramp (WC) patients compared to 14 controls use probabilistic weight cues in a serial grip-lift task.

Methods: In every grip-lift trial, an object of either light, medium or heavy weight had to be grasped and lifted after a visual cue gave a probabilistic prediction of the object weights (e.

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Background: While the concept of prodromal Parkinson's disease (PD) is well established, reliable markers for the diagnosis of this disease stage are still lacking. We investigated the functional connectivity of the putamina in a resting-state functional MRI analysis in persons with at least two prodromal factors for PD, which is considered a high risk for PD (HRPD) group, in comparison to PD patients and controls.

Methods: We included 16 PD patients, 20 healthy controls and 20 HRPD subjects.

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Background: Writer's cramp (WC), a task specific form of dystonia, is considered to be a motor network disorder, but abnormal sensory tactile processing has also been acknowledged. The sensory spatial discrimination threshold (SDT) can be determined with a spatial acuity test (JVP domes). In addition to increased SDT, patients with WC exhibited dysfunctional sensory processing in the sensory cortex, insula, basal ganglia and cerebellum in a functional magnetic resonance imaging (fMRI) study while performing the spatial acuity test.

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Essential tremor (ET) occurs with steeply increasing prevalence in the elderly, and apart from disease duration, age is independently associated with an increase of tremor amplitude and a decrease of frequency. White matter hyperintensities (WMHs) are a common finding in the elderly, and their role in the pathophysiology of ET is unknown. The aims of this study were to examine whether ET patients differ in their total or region-specific WMH volumes from healthy controls and to determine the impact of WMH on tremor characteristics.

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Objective: To examine whether hippocampal volume loss is primarily associated with cognitive status or pathologic β-amyloid 1-42 (Aβ42) levels, this study compared hippocampal subfield volumes between patients with Parkinson disease (PD) with mild cognitive impairment (PD-MCI) and without cognitive impairment (PD-CN) and between patients with low and high Aβ42 levels, in addition exploring the relationship among hippocampal subfield volumes, CSF biomarkers (Aβ42, phosphorylated and total tau), neuropsychological tests, and activities of daily living.

Methods: Forty-five patients with PD without dementia underwent CSF analyses and MRI as well as comprehensive motor and neuropsychological examinations. Hippocampal segmentation was conducted using FreeSurfer image analysis suite 6.

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Objective:  To validate transcranial sonography (TCS) as a novel imaging tool for the assessment of medial temporal lobe (MTL) atrophy (MTA).

Materials And Methods:  Participants with Alzheimer's disease (AD, n = 30) and age-sex-matched controls (n = 30) underwent TCS and MRI. On TCS, MTL structures (choroidal fissure (CF) and temporal horn (TH)) were measured and combined to create an MTA score in sonography (MTA-S).

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Introduction: A stooped posture is a main clinical feature of Parkinson's disease (PD). The assessment of posture is important to measure treatment effects. The aim of this study was to investigate the reliability of a standardized postural rating tool, to calculate minimal detectable change scores and to assess the role of gender and age.

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Background: Motor and cognitive deficits and consequently mobility problems are common in geriatric patients. The currently available methods for diagnosis and for the evaluation of treatment in this vulnerable cohort are limited. The aims of the ComOn (COgnitive and Motor interactions in the Older populatioN) study are (i) to define quantitative markers with clinical relevance for motor and cognitive deficits, (ii) to investigate the interaction between both motor and cognitive deficits and (iii) to assess health status as well as treatment outcome of 1000 geriatric inpatients in hospitals of Kiel (Germany), Brescia (Italy), Porto (Portugal), Curitiba (Brazil) and Bochum (Germany).

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Postural abnormalities are common in Parkinson's disease (PD) and increasing with disease progression. While many studies focus on balance and gait, postural alignment is only infrequently studied. The aim of the present study was to examine the immediate and long-term effects of medication and deep brain stimulation (DBS) in the subthalamic nucleus on postural alignment in PD.

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Purpose: Allodynia refers to pain evoked by physiologically innocuous stimuli. It is a disabling symptom of neuropathic pain following a lesion within the peripheral or central nervous system. In fact, two different pathophysiological mechanisms of cold allodynia (ie, hypersensitivity to innocuous cold) have been proposed.

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Day-to-day life involves the perception of events that resemble one another. For the sufficient encoding and correct retrieval of similar information, the hippocampus provides two essential cognitive processes. Pattern separation refers to the differentiation of similar input information, whereas pattern completion reactivates memory representations based on noisy or degraded stimuli.

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Deep brain stimulation (DBS) is an established treatment for various movement disorders. There is little data available about the potential damage to brain parenchyma through DBS treatment. The objective of this study was to investigate the occurrence of signal changes on magnetic resonance imaging (MRI) in patients treated with DBS.

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Background: Hypokinetic dysarthria is highly prevalent in idiopathic Parkinson disease (PD), and effectiveness of high-intensity voice treatment is well established. However, the neural correlates remain largely unknown.

Objective: We aimed to specify cerebral pathophysiology of hypokinetic dysarthria and treatment-induced changes using functional magnetic resonance imaging (fMRI).

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Introduction: Camptocormia is characterized by a pathological forward flexion of the trunk, which is reversible when lying and worsened by standing and walking. So far there is no consensus on how to measure the angle of flexion, and studies therefore give differing results. Harmonization is needed for both research and clinical practice.

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Writer's cramp (WC) is a focal task-specific dystonia characterized by sustained or intermittent muscle contractions while writing, particularly with the dominant hand. Since structural lesions rarely cause WC, it has been assumed that the disease might be caused by a functional maladaptation within the sensory-motor system. Therefore, our objective was to examine the differences between patients suffering from WC and a healthy control (HC) group with regard to the effective connectivity that describes causal influences one brain region exerts over another within the motor network.

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Previous research found increased brain responses of men with sexual interest in children (i.e., pedophiles) not only to pictures of naked children but also to pictures of child faces.

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