Publications by authors named "Christian R Baumann"

Background And Objectives: Mesial temporal lobe epilepsy (mTLE) is generally associated with focal brain atrophy, but little knowledge exists on possible disease-related hypertrophy of brain structures. We hypothesized that repeated seizures or adaptive plasticity may lead to focal brain hypertrophy and aimed to investigate associated clinical correlates.

Methods: In this cohort study, we included patients with mTLE undergoing detailed epilepsy evaluations and matched healthy volunteers (HVs) from 2 tertiary centers (discovery and validation cohorts).

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Article Synopsis
  • Sleep changes are common in Alzheimer's and Parkinson's diseases, affecting brain health during deep sleep.
  • A new method called mouse closed-loop auditory stimulation (mCLAS) has been developed to enhance slow-wave activity during deep sleep in models of these diseases.
  • Initial findings show that mCLAS can improve sleep patterns in mice, with different effects seen in Alzheimer's versus Parkinson's models, suggesting potential for future sleep-based therapies in neurodegenerative conditions.
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  • This study investigates the metabolic and bioenergetic changes in the spinal cord of a transgenic mouse model of Parkinson's disease (M83) that overexpresses a mutated form of alpha-synuclein, comparing it to non-transgenic mice.!* -
  • Using advanced imaging techniques, the researchers found that the M83 mice had lower oxygen saturation levels in their spinal cords, but there were no significant changes in spinal cord volume or vascular organization despite the presence of phosphorylated alpha-synuclein.!* -
  • The study highlights the development of deep learning tools for analyzing spinal cord MRI data, and underscores the complexity of Parkinson's disease by showing reduced oxygen levels without related structural changes in the spinal cord.!
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  • Poor sleep quality may increase the risk and worsening of neurodegenerative diseases by disrupting the brain's ability to clear waste during sleep.
  • This study analyzed MRI images of 20 Parkinson’s disease patients and 17 healthy individuals to examine the relationship between enlarged perivascular spaces (a potential marker of sleep-related waste clearance) and sleep quality and motor symptoms.
  • The findings showed that in Parkinson's patients, more perivascular spaces were linked to deeper sleep issues and worsened motor symptoms, suggesting that poor sleep may hinder brain waste clearance, potentially exacerbating disease symptoms.
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Boosting slow-wave activity (SWA) by modulating slow waves through closed-loop auditory stimulation (CLAS) might provide a powerful non-pharmacological tool to investigate the link between sleep and neurodegeneration. Here, we established mouse CLAS (mCLAS)-mediated SWA enhancement and explored its effects on sleep deficits in neurodegeneration, by targeting the up-phase of slow waves in mouse models of Alzheimer's disease (AD, Tg2576) and Parkinson's disease (PD, M83). We found that tracking a 2 Hz component of slow waves leads to highest precision of non-rapid eye movement (NREM) sleep detection in mice, and that its combination with a 30° up-phase target produces a significant 15-30% SWA increase from baseline in wild-type (WT) and transgenic (TG) mice versus a mock stimulation group.

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Article Synopsis
  • Abnormal accumulation of alpha-synuclein (αSyn) and iron in the brain contributes significantly to Parkinson's disease, prompting researchers to visualize these elements in M83 (A53T) mouse models.
  • The study utilized THK-565, a fluorescent probe, alongside various imaging techniques like fluorescence and multispectral optoacoustic tomography (vMSOT) to detect αSyn inclusions and iron deposits in vivo and post-mortem.
  • Results showed that THK-565 effectively targets αSyn, indicating its higher retention in M83 mice brains compared to nontransgenic controls, and iron accumulation was confirmed through magnetic resonance imaging (SWI) and scanning transmission x-ray microscopy (STXM).
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Objective: Parkinsonian motor symptoms are linked to pathologically increased beta oscillations in the basal ganglia. Studies with externalised deep brain stimulation electrodes showed that Parkinson patients were able to rapidly gain control over these pathological basal ganglia signals through neurofeedback. Studies with fully implanted deep brain stimulation systems duplicating these promising results are required to grant transferability to daily application.

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Background: Enhancing slow waves, the electrophysiological (EEG) manifestation of non-rapid eye movement (NREM) sleep, could potentially benefit patients with Parkinson's disease (PD) by improving sleep quality and slowing disease progression. Phase-targeted auditory stimulation (PTAS) is an approach to enhance slow waves, which are detected in real-time in the surface EEG signal.

Objective: We aimed to test whether the local-field potential of the subthalamic nucleus (STN-LFP) can be used to detect frontal slow waves and assess the electrophysiological changes related to PTAS.

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Background: DBS of the subthalamic nucleus (STN) considerably ameliorates cardinal motor symptoms in PD. Reported STN-DBS effects on secondary dysarthric (speech) and dysphonic symptoms (voice), as originating from vocal tract motor dysfunctions, are however inconsistent with rather deleterious outcomes based on post-surgical assessments.

Objective: To parametrically and intra-operatively investigate the effects of deep brain stimulation (DBS) on perceptual and acoustic speech and voice quality in Parkinson's disease (PD) patients.

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Background: Freezing of Gait (FOG) is a motor symptom frequently observed in advanced Parkinson's disease. However, due to its paroxysmal nature and diverse presentation, assessing FOG in a clinical setting can be challenging. Before FOG can be fully investigated, it is critical that a reliable experimental setting is established in which FOG can be evoked in a standardized manner, but the efficacy of various gait tasks and triggers for eliciting FOG remains unclear.

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Introduction: Motor complications (MCs) compromise therapy in many patients suffering from Parkinson's Disease. By achieving more physiologic stimulation of dopamine-receptors, the continuous dopamine stimulation hypothesis suggests that longer-acting levodopa formulations may improve outcome. The aim of this study was to compare the duration until onset of MCs and motor disease progression in patients during their treatment initiation with either an immediate (IR) or a combined rapid- and sustained-release (i.

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Objective: Target depth, defined by the z-coordinate in the dorsoventral axis relative to the anterior commissure-posterior commissure axial plane of the MR-guided focused ultrasound (MRgFUS) lesion, is considered to be critical for tremor improvement and the occurrence of side effects such as gait impairment. However, although different z-coordinates are used in the literature, there are no comparative studies available with information on optimal lesion placement. This study aimed to compare two different MRgFUS lesion targets (z = +2 mm vs z = 0 mm) regarding efficacy and safety outcomes.

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Objective: According to current practical guidelines, naps of the Mean Sleep Latency Test (MSLT) must be terminated 15 min after sleep onset, which requires ad hoc scoring. For clinical convenience, some sleep clinics use a simplified protocol with fixed nap lengths of 20min. Its diagnostic accuracy remains unknown.

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Background: Abnormal alpha-synuclein and iron accumulation in the brain play an important role in Parkinson's disease (PD). Herein, we aim at visualizing alpha-synuclein inclusions and iron deposition in the brains of M83 (A53T) mouse models of PD .

Methods: Fluorescently labelled pyrimidoindole-derivative THK-565 was characterized by using recombinant fibrils and brains from 10-11 months old M83 mice, which subsequently underwent concurrent wide-field fluorescence and volumetric multispectral optoacoustic tomography (vMSOT) imaging.

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In a retrospective analysis, we recently reported findings on the detrimental motor effects of interrupted physiotherapy following the COVID-19 pandemic in parkinsonian patients. Using an extended follow-up period, we investigated the beneficial effect of reinstated physiotherapy on patients' disease severity and reversal of interruption-induced motor deterioration. Compared to before the COVID-19 outbreak, we observed persistence of motor disease worsening despite full resumption of state-of-the-art physical therapy suggesting that motor deterioration after discontinuation of physical therapy could not be compensated for.

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Objective: Previous studies suggest that intermittent deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) affects physiological sleep architecture. Here, we investigated the impact of continuous ANT DBS on sleep in epilepsy patients in a multicenter crossover study in 10 patients.

Methods: We assessed sleep stage distribution, delta power, delta energy, and total sleep time in standardized 10/20 polysomnographic investigations before and 12 months after DBS lead implantation.

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Importance: Acute symptomatic seizures occurring within 7 days after ischemic stroke may be associated with an increased mortality and risk of epilepsy. It is unknown whether the type of acute symptomatic seizure influences this risk.

Objective: To compare mortality and risk of epilepsy following different types of acute symptomatic seizures.

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Background: Postural instability and falls are considered a major factor of impaired quality of life in patients with advanced Parkinson's disease (PD). The knowledge of the time at which postural instability occurs will help to provide the evidence required to introduce fall-prevention strategies at the right time in PD.

Objective: To investigate whether postural instability of patients with different age at disease onset is associated with age or with disease duration of PD.

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Introduction: Sleep insufficiency or decreased quality have been associated with Alzheimer's disease (AD) already in its preclinical stages. Whether such traits are also present in rodent models of the disease has been poorly addressed, somewhat disabling the preclinical exploration of sleep-based therapeutic interventions for AD.

Methods: We investigated age-dependent sleep-wake phenotype of a widely used mouse model of AD, the Tg2576 line.

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Background: Supplementary treatment options after pediatric severe traumatic brain injury (TBI) are needed to improve neurodevelopmental outcome. Evidence suggests enhancement of brain delta waves via auditory phase-targeted stimulation might support neuronal reorganization, however, this method has never been applied in analgosedated patients on the pediatric intensive care unit (PICU). Therefore, we conducted a feasibility study to investigate this approach: In a first recording phase, we examined feasibility of recording over time and in a second stimulation phase, we applied stimulation to address tolerability and efficacy.

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Study Objectives: Excessive daytime sleepiness (EDS) is a common and devastating symptom in Parkinson disease (PD), but surprisingly most studies showed that EDS is independent from nocturnal sleep disturbance measured with polysomnography. Quantitative electroencephalography (EEG) may reveal additional insights by measuring the EEG hallmarks of non-rapid eye movement (NREM) sleep, namely slow waves and spindles. Here, we tested the hypothesis that EDS in PD is associated with nocturnal sleep disturbance revealed by quantitative NREM sleep EEG markers.

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Background: For safety reasons, both magnetic resonance-guided high-intensity focused ultrasound (MRgHiFUS) thalamotomy and pallidotomy are currently approved exclusively for unilateral treatment, but axial symptoms like levodopa-induced orofacial dyskinesia require a bilateral approach.

Objectives: We report the first case of successful bilateral MRgHiFUS pallidotomy for peak-dose dyskinesia in a patient with Parkinson's disease (PD).

Methods: The treatment decision was based on the patient's reluctance toward brain implants and pump therapies and the fact that he had limited access to a deep brain stimulation center in his home country.

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