Karsten Witt

Karsten Witt
Carl von Ossietzky Universität Oldenburg

Prof. Dr.

About

207
Publications
21,817
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4,340
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Introduction
Karsten Witt is a neurologist, specializing in cognitive neurology, Parkinson's Disease and other Movement Disorders.
Additional affiliations
July 2017 - present
Carl von Ossietzky Universität Oldenburg
Position
  • CEO

Publications

Publications (207)
Article
Full-text available
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 pictu...
Article
Speech production relies on the interplay of different brain regions. Healthy aging leads to complex changes in speech processing and production. Here, we investigated how the whole-brain functional connectivity of healthy elderly individuals differs from that of young individuals. In total, 23 young (aged 24.6 ± 2.2 years) and 23 elderly (aged 64....
Article
Introduction: Deep brain stimulation (DBS) represents the treatment of choice for advanced stages of Parkinson's disease (PD). In addition to careful patient selection and precise lead placement, postoperative programming of DBS devices is considered the most important factor for the individual patient. Despite expert-based recommendations for adju...
Article
Full-text available
Dystonia is a debilitating disease with few treatment options. One effective option is deep brain stimulation (DBS) to the internal pallidum. While cervical and generalized forms of isolated dystonia have been targeted with a common approach to the posterior third of the nucleus, large-scale investigations regarding optimal stimulation sites and po...
Article
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Introduction Objective of this study was to examine if the Interlocking Finger Test (ILFT) is a suitable bedside screening test for visuospatial functions and/or dementia in Parkinson's disease (PD) patients aiming to facilitate the diagnosis of a dementia syndrome associated with posterior cortical and temporal lobe dysfunction according to the du...
Article
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Compared to functional magnetic resonance imaging (fMRI), functional near infrared spectroscopy (fNIRS) has several advantages that make it particularly interesting for neurofeedback (NFB). A pre-requisite for NFB applications is that with fNIRS, signals from the brain region of interest can be measured. This study focused on the supplementary moto...
Article
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Objective In this study we used functional magnetic resonance imaging (fMRI) to investigate whether motor imagery (MI) of handwriting and circle drawing activates a similar handwriting network as writing and drawing itself. Methods Eighteen healthy right-handed participants wrote the German word “ Wellen” and drew continuously circles in a sitting...
Article
Background: Parkinson's disease (PD) is associated with various non-motor symptoms, including cognitive deterioration. Objective: Here, we used data from the DEMPARK/LANDSCAPE cohort to describe the association between progression of cognitive profiles and the PD motor phenotypes: postural instability and gait disorder (PIGD), tremor-dominant (T...
Article
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Background: Meta-analyses indicate positive effects of cognitive training (CT) in patients with Parkinson's disease (PD), however, most previous studies had small sample sizes and did not evaluate long-term follow-up. Therefore, a multicenter randomized controlled, single-blinded trial (Train-ParC study) was conducted to examine CT effects in PD pa...
Article
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Dystonia, a debilitating neurological movement disorder, is characterized by involuntary muscle contractions and develops from a complex pathophysiology. Graph theoretical analysis approaches have been employed to investigate functional network changes in patients with different forms of dystonia. In this study, we aimed to characterize the abnorma...
Article
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Is the cognitive process of random number generation implemented via person-specific strategies corresponding to highly individual random generation behaviour? We examined random number sequences of 115 healthy participants and developed a method to quantify the similarity between two number sequences on the basis of Damerau and Levenshtein’s edit...
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Introduction: Large studies on cognitive profiles of patients with mild cognitive impair- ment (MCI) due to Alzheimer’s disease (AD-MCI) compared to Parkinson’s disease (PD- MCI) are rare. Methods: Data from two multicenter cohort studies in AD and PD were merged using a unified base rate approach for the MCI diagnosis. Cognitive profiles were comp...
Article
Recently, it was shown that patients with Parkinson's disease (PD) who exhibit an “Alzheimer's disease (AD)-like” pattern of brain atrophy are at greater risk for future cognitive decline. This study aimed to investigate whether this association is domain-specific and whether atrophy associated with brain aging also relates to cognitive impairment...
Article
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A correction to this paper has been published: https://doi.org/10.1007/s00415-021-10634-2
Article
Introduction The Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) is a renowned cognitive test battery, which has been extended in its German version to the CERAD-Plus including tests of executive functions and processing speed. The most commonly used total score (TS) is based on the restricted CERAD version and reflects the sum o...
Preprint
Full-text available
Dystonia is a debilitating disease with few conservative treatment options but many types of isolated dystonia can be effectively treated using deep brain stimulation (DBS) to the internal pallidum. While cervical and generalized forms of isolated dystonia have been targeted with a common approach to the posterior third of the nucleus, large-scale...
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Objective We aimed to estimate the incidence of cerebral sinus and venous thrombosis (CVT) within one month from first-dose administration and the frequency of vaccine-induced immune thrombotic thrombocytopenia (VITT) as the underlying mechanism after vaccination with BNT162b2, ChAdOx1, and mRNA-1273, in Germany. Methods A web-based questionnaire...
Article
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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 dysf...
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To identify robust and reproducible methods of cerebellar morphometry that can be used in future large-scale structural MRI studies, we investigated the replicability, repeatability, and long-term reproducibility of three fully automated software tools: FreeSurfer, CEREbellum Segmentation (CERES), and automatic cerebellum anatomical parcellation us...
Article
Background: Assessment of affective-behavioral states in patients with Parkinson's disease (PD) undergoing deep brain stimulation (DBS) is essential. Objective: To analyze well-established questionnaires as a pilot-study with the long term aim to develop a screening tool evaluating affective-behavioral dysfunction, including depression, anxiety,...
Article
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Objective: Depressive symptoms have a high prevalence in patients with Parkinson's disease (PD) and are associated with cognitive dysfunction. Especially in PD with mild cognitive impairment (MCI), a time-efficient and valid instrument for the assessment of depression primarily focusing on psychological symptoms and disregarding confounding somatic...
Article
Hintergrund Das Vorliegen von leichten kognitiven Störungen bei der Parkinson-Erkrankung ist aktuell der beste Prädiktor für die Entwicklung einer Demenz bei Morbus Parkinson. Expertengruppen der Movement Disorder Society haben für die Diagnose leichter kognitiver Störungen und Parkinson-Demenz standardisierte diagnostische Verfahren vorgeschlagen....
Conference Paper
Movement contains a large amount of cognitive, central-motor and musculoskeletal information that correlates directly with the general state of health. Approaches to automatic movement analysis, in particular to automatized gait analysis are of utmost relevance to offer modern technological support for health professionals. The purpose of this pape...
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Background: Meta-analyses have demonstrated cognitive training (CT) benefits in Parkinson's disease (PD) patients. However, the patients' cognitive status has only rarely been based on established criteria. Also, prediction analyses of CT success have only sparsely been conducted. Objective: To determine CT effects in PD patients with mild cogni...
Article
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Olfactory dysfunction (OD) is a prominent nonmotor symptom in Parkinson's disease (PD), and OD is a supportive diagnostic criterion for PD. Physicians often ask their patients if they have noticed a smell disorder. This study evaluates the diagnostic validity of OD self-assessment in PD. To this end, 64 PD patients and 33 age-matched healthy contro...
Preprint
Full-text available
To identify robust and reproducible methods of cerebellar morphometry that can be used in future large-scale structural MRI studies, we investigated the replicability, repeatability, and longterm reproducibility of three fully-automated software tools: FreeSurfer, CERES, and ACAPULCO. Replicability was defined as computational replicability, determ...
Article
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Brain activity during natural walking outdoors can be captured using mobile electroencephalography (EEG). However, EEG recorded during gait is confounded with artifacts from various sources, possibly obstructing the interpretation of brain activity patterns. Currently, there is no consensus on how the amount of artifact present in these recordings...
Article
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Objective To determine frequencies, interlaboratory reproducibility, clinical ratings, and prognostic implications of neural antibodies in a routine laboratory setting in patients with suspected neuropsychiatric autoimmune conditions.Methods Earliest available samples from 10,919 patients were tested for a broad panel of neural antibodies. Sera tha...
Article
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Geriatric medicine is a rapidly evolving field that addresses diagnostic, therapeutic and care aspects of older adults. Some disabilities and disorders affecting cognition (e.g. dementia), motor function (e.g. stroke, Parkinson’s disease, neuropathies), mood (e.g. depression), behavior (e.g. delirium) and chronic pain disorders are particularly fre...
Article
Introduction: The rate of intracranial hemorrhage (ICH) after deep brain stimulation (DBS) is between 1.5 and 6.1%, with prolonged deficits occurring in 0.4-2.5% of the patients. This retrospective study investigates whether the prophylactic administration of tranexamic acid (TA) to patients with abnormal platelet function detected preoperatively...
Article
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The tongue performs movements in all directions to subserve its diverse functions in chewing, swallowing, and speech production. Using task-based functional MRI in a group of 17 healthy young participants, we studied (1) potential differences in the cerebral control of frontal (protrusion), horizontal (side to side), and vertical (elevation) tongue...
Preprint
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Most work in the neurosciences collapses data from multiple subjects to obtain robust statistical results. This research agenda ignores that even in healthy subjects brain structure and function are known to be highly variable. Recently, Finn and colleagues showed that the brain's functional organisation is unique to each individual and can yield h...
Article
Background Idarucizumab is a monoclonal antibody fragment with high affinity for dabigatran reversing its anticoagulant effects within minutes. Thereby, patients with acute ischemic stroke who are on dabigatran treatment may become eligible for thrombolysis with recombinant tissue-type plasminogen activator (rt-PA). In patients on dabigatran with i...
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Background IgG-class autoantibodies to N-Methyl-D-Aspartate (NMDA)-type glutamate receptors define a novel entity of autoimmune encephalitis. Studies examining the prevalence of NMDA IgA/IgM antibodies in patients with Parkinson disease with/without dementia produced conflicting results. We measured NMDA antibodies in a large, well phenotyped sampl...
Article
It has often been claimed that orthodox thinking about personal identity undermines the moral authority of advance directives in dementia by implying that the signer of the directive is numerically different from the severely demented patient. This is the ‘identity problem’. I introduce the problem, outline some well‐known solutions, and explain wh...
Preprint
Full-text available
The tongue performs movements in all directions to subserve its diverse functions in chewing, swallowing, and speech production. The aims of the present study were twofold: using task-based functional MRI in a group of 17 healthy young participants, we studied (1) potential differences in the cerebral control of frontal, horizontal, and vertical to...
Article
Full-text available
Background: Several studies examined the influence of subthalamic nucleus-deep brain stimulation (STN-DBS) on quality of life (QoL) in patients with Parkinson's disease (PD). However, it is unclear whether this effect differs between age groups and disease durations and whether it stays consistent over time. Objectives: We assessed the influence...
Article
Introduction: Late-onset essential tremor is characterised by shorter life expectancy and more advanced aging parameters and may therefore be an 'aging-related' tremor. Brainstem functions involved in pupillary responses are hypothesized to reflect such earlier aging. The pupillary light response (PLR) and a task evoked pupillary response (TEPR) w...
Article
Background: Programming algorithms have never been tested for outcome. The EARLYSTIM study showed superior outcomes of deep brain stimulation of the subthalamic nucleus (STN-DBS) over best medical treatment in early Parkinson's disease (PD). Patients were programmed according to common guidelines but customized for each patient. Methods: Stimula...
Article
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Deep brain stimulation of the internal globus pallidus is a highly effective and established therapy for primary generalized and cervical dystonia, but therapeutic success is compromised by a non-responder rate of up to 25%, even in carefully-selected groups. Variability in electrode placement and inappropriate stimulation settings may account for...
Article
Background: Data on pediatric DBS is still limited because of small numbers in single center series and lack of systematic multi-center trials. Objectives: We evaluate short- and long-term adverse events (AEs) of patients undergoing deep brain stimulation (DBS) during childhood and adolescence. Methods: Data collected by the German registry on...
Article
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Introduction: 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....
Article
Background: Hypokinetic dysarthria is highly prevalent in idiopathic Parkinson’s disease (PD) and effectivity 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 m...
Article
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Objectives Parkinson’s disease (PD) is the second most common neurodegenerative disorder and is further associated with progressive cognitive decline. In respect to motor phenotype, there is some evidence that akinetic-rigid PD is associated with a faster rate of cognitive decline in general and a greater risk of developing dementia. The objective...
Article
Background Previous studies described long term effects of transcranial alternating current stimulation (tACS) on alpha (α) frequency (Helfrich et al., 2014; Müller et al., 2015; Varlet et al., 2017).tACS was hence proposed as a tool to synchronize and modulate regional biological neuronal oscillations. Objective Our objective was to validate tACS...
Article
Introduction: The deep brain stimulation (DBS) withdrawal syndrome (DBS-WDS) is a rare, life-threatening complication in Parkinson's disease (PD) patients with long disease duration and stimulation when stimulation is terminated for extended periods mostly due to infection of the DBS-hardware. Methods, results: In five patients explantation beca...
Article
Background: Apathy is a frequent symptom in Parkinson's disease (PD), substantially aggravating the course of PD. Regarding the accumulating evidence of the key role of apathy in PD, time-efficient assessments are useful for fostering progress in research and treatment. The Apathy Evaluation Scale (AES) is widely used for the assessment of apathy...
Article
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Previous studies demonstrated the influence of the post-learning period on procedural motor memory consolidation. In an early period after the acquisition, motor skills are vulnerable to modifications during wakefulness. Indeed, specific interventions such as world-list learning within this early phase of motor memory consolidation seem to enhance...
Article
Background: Although subthalamic stimulation is a recognised treatment for motor complications in Parkinson's disease, reports on behavioural outcomes are controversial, which represents a major challenge when counselling candidates for subthalamic stimulation. We aimed to assess changes in behaviour in patients with Parkinson's disease receiving...
Article
Background: Nonrechargeable deep brain stimulation impulse generators (IGs) with low or empty battery status require surgical IG exchange several years after initial implantation. The aim of this study was to investigate complication rates after IG exchange surgery and identify risk factors. Methods: We retrospectively analyzed complications fol...
Article
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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 objectiv...
Article
Postural instability is one of the most disabling and risky symptoms of advanced Parkinson's disease (PD). The purpose of this study was to investigate whether and how this is mediated by a centrally impaired spatial orientation. Therefore, we performed a spatial orientation study in 21 PD patients (mean age: 68 years, SD: 8.5, 9 women) in a medica...
Article
Objective: Nonrechargeable deep brain stimulation (DBS) generators must be replaced when the battery capacity is exhausted. Battery life depends on many factors and differs between generator models. A new nonrechargeable generator model replaced the previous model in 2008. Our clinical impression is that the earlier model had a longer battery life...
Article
Background This study focuses on the interaction of procedural and declarative memory contents and its effect on off-line consolidation over wakefulness on a neurophysiological level using fMRI. The finding that disconnecting declarative from implicit procedural motor contents allows off-line consolidation of motor performance over wakefulness but...
Article
Zusammenfassung Etwa 12.500 Menschen/Jahr erhalten in Deutschland die Diagnose Morbus Parkinson und sehen sich mit Einschränkung, Stigma und Invalidität konfrontiert. Obwohl sich die Lebenserwartung der Erkrankten deutlich gebessert hat, ist die Diagnose daher weiterhin mit Angst verbunden. Medikamentöse Therapie und aktivierende Behandlungsmethode...
Article
Background: Empathy describes the ability to infer and share emotional experiences of other people and is a central component of normal social functioning. Impaired empathy might be a non-motor symptom in Parkinson's disease (PD). Objective: To examine empathic abilities and their relationship to clinical and cognitive functioning in PD patients...
Article
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Background and Purpose This study investigates the prevalence of delirium in acute stroke patients on a primary stroke unit (SU) analyzing associated risk factors and clinical outcomes. Method Prospective, 4‐month observational study from 2015 to 2016 on patients aged ≥18 years with stroke at a German university hospital's SU. The presence of deli...