Revealing connectivity patterns of deep brain stimulation efficacy in Parkinson's disease.

The aim of this work was to study the effect of deep brain stimulation of the subthalamic nucleus (STN-DBS) on the subnetwork of subcortical and cortical motor regions and on the whole brain connectivity using the functional connectivity analysis in Parkinson's disease (PD). The high-density source space EEG was acquired and analyzed in 43 PD subjects in DBS on and DBS off stimulation states (off medication) during a cognitive-motor task. Increased high gamma band (50-100 Hz) connectivity within subcortical regions and between subcortical and cortical motor regions was significantly associated with the Movement Disorders Society - Unified Parkinson's Disease Rating Scale (MDS-UPDRS) III improvement after DBS.

Coupling between beta band and high frequency oscillations as a clinically useful biomarker for DBS.

Beta hypersynchrony was recently introduced into clinical practice in Parkinson's disease (PD) to identify the best stimulation contacts and for adaptive deep brain stimulation (aDBS) sensing. However, many other oscillopathies accompany the disease, and beta power sensing may not be optimal for all patients. The aim of this work was to study the potential clinical usefulness of beta power phase-amplitude coupling (PAC) with high frequency oscillations (HFOs).

Parkinson´s disease cardiovascular symptoms: A new complex functional and structural insight.

Background: The known impairments of the cardiovascular system in Parkinson´s disease (PD) are caused by autonomic dysfunction and manifested mainly in postural hypotension, chronotropic insufficiency, and reduced heart rate variability. Other dysfunctions, mainly stress response, arrhythmia occurrence, and heart morphology changes, are still the subject of research.

Objectives: To assess the heart rate and blood pressure reaction during exercise, advanced measurements of heart volumes and mass using cardiac magnetic resonance (CMR), and occurrence of arrhythmias in PD patients.

The effect of deep brain stimulation in Parkinson's disease reflected in EEG microstates.

Mechanisms of deep brain stimulation (DBS) on cortical networks were explored mainly by fMRI. Advanced analysis of high-density EEG is a source of additional information and may provide clinically useful biomarkers. The presented study evaluates EEG microstates in Parkinson's disease and the effect of DBS of the subthalamic nucleus (STN).

Cortical network organization reflects clinical response to subthalamic nucleus deep brain stimulation in Parkinson's disease.

The degree of response to subthalamic nucleus deep brain stimulation (STN-DBS) is individual and hardly predictable. We hypothesized that DBS-related changes in cortical network organization are related to the clinical effect. Network analysis based on graph theory was used to evaluate the high-density electroencephalography (HDEEG) recorded during a visual three-stimuli paradigm in 32 Parkinson's disease (PD) patients treated by STN-DBS in stimulation "off" and "on" states.

Altered Spatiotemporal Dynamics of the Resting Brain in Mild Cognitive Impairment with Lewy Bodies.

Background: Electrophysiological markers of prodromal dementia with Lewy bodies were described in the spectral domain. The sub-second temporal resolution may provide additional information.

Objective: To evaluate electroencephalography (EEG) microstates in patients with mild cognitive impairment with Lewy bodies and to assess the association between their temporal dynamics and the spectral marker.

Electrophysiological biomarkers for deep brain stimulation outcomes in movement disorders: state of the art and future challenges.

Several neurological diseases are accompanied by rhythmic oscillatory dysfunctions in various frequency ranges and disturbed cross-frequency relationships on regional, interregional, and whole brain levels. Knowledge of these disease-specific oscillopathies is important mainly in the context of deep brain stimulation (DBS) therapy. Electrophysiological biomarkers have been used as input signals for adaptive DBS (aDBS) as well as preoperative outcome predictors.

Resting-State Phase-Amplitude Coupling Between the Human Subthalamic Nucleus and Cortical Activity: A Simultaneous Intracranial and Scalp EEG Study.

It has been suggested that slow oscillations in the subthalamic nucleus (STN) reflect top-down inputs from the medial prefrontal cortex, thus implementing behavior control. It is unclear, however, whether the STN oscillations are related to cortical activity in a bottom-up manner. To assess resting-state subcortico-cortical interactions, we recorded simultaneous scalp electroencephalographic activity and local field potentials in the STN (LFP-STN) in 11 patients with Parkinson's disease implanted with deep brain stimulation electrodes in the on-medication state during rest.

Successful asymmetrical deep brain stimulation using right subthalamic and left pallidal electrodes in a patient with Parkinson's disease.

Purpose: Despite the best efforts of neurologists, the results of pharmacotherapy in the late stages of Parkinson's disease are often disappointing and accompanied by debilitating side effects. Under these circumstances, deep brain stimulation is a viable treatment option. The aim of the meticulous pre-surgical planning is not only precise electrode implantation, but also the avoidance of intraoperative vascular conflicts potentially causing intracerebral bleeding.

Suboptimal response to STN-DBS in Parkinson's disease can be identified via reaction times in a motor cognitive paradigm.

Although deep brain stimulation of the subthalamic nucleus (STN-DBS) in Parkinson's disease (PD) is generally a successful therapy, adverse events and insufficient clinical effect can complicate the treatment in some patients. We studied clinical parameters and cortical oscillations related to STN-DBS to identify patients with suboptimal responses. High-density EEG was recorded during a visual oddball three-stimuli paradigm in DBS "off" and "on" conditions in 32 PD patients with STN-DBS.

Impairment of brain functions in Parkinson's disease reflected by alterations in neural connectivity in EEG studies: A viewpoint.

Clinical symptoms of Parkinson's disease (PD) are accompanied by pathological phenomena detected locally in the basal ganglia (BG) as changes in local field potentials (LFPs) and also in cortical regions by electroencephalography (EEG). The literature published mainly between 2000 and 2017 was reviewed with an emphasis on approaches emerging after 2000, in particular on oscillatory dynamics, connectivity studies, and deep brain stimulation. Eighty-five articles were reviewed.

Oscillatory reactivity to effortful cognitive processing in the subthalamic nucleus and internal pallidum: a depth electrode EEG study.

This study investigates how complex motor-cognitive activities are processed in the subthalamic nucleus (STN) and internal globus pallidum (GPi), as adverse neuropsychiatric effects may accompany deep brain stimulation (DBS), mainly in Parkinson's disease (PD) and STN-DBS. Dystonia patients with GPi-DBS electrodes (n = 5) and PD subjects (n = 5) with STN-DBS electrodes performed two tasks: (1) copying letters; and (2) writing any letter other than that appearing on the monitor. The cognitive load of the second task was greater than that of the first.

Learning Curve in Anatomo-Electrophysiological Correlations in Subthalamic Nucleus Stimulation.

Aim: Advances in neuroradiological planning techniques in deep brain stimulation have put the need for intraoperative electrophysiological monitoring into doubt. Moreover intraoperative monitoring prolongs surgical time and there is potential association between the use of microelectrodes and increased incidence of hemorrhagic complications. The aim of this study was to analyze the correlation between the anatomically planned trajectory and the final subthalamic electrode placement after electrophysiological monitoring in patients with Parkinson"s disease and its change with the increasing experience of the surgical team.

The Role of Anterior Nuclei of the Thalamus: A Subcortical Gate in Memory Processing: An Intracerebral Recording Study.

Objective: To study the involvement of the anterior nuclei of the thalamus (ANT) as compared to the involvement of the hippocampus in the processes of encoding and recognition during visual and verbal memory tasks.

Methods: We studied intracerebral recordings in patients with pharmacoresistent epilepsy who underwent deep brain stimulation (DBS) of the ANT with depth electrodes implanted bilaterally in the ANT and compared the results with epilepsy surgery candidates with depth electrodes implanted bilaterally in the hippocampus. We recorded the event-related potentials (ERPs) elicited by the visual and verbal memory encoding and recognition tasks.

The modulatory role of subthalamic nucleus in cognitive functions - a viewpoint.

The modifications of electrophysiological activities of subthalamic nucleus (STN) by non-motor tasks, i.e. movement observation, emotional stimuli and impulse control, were reported repeatedly.

Complex motor-cognitive factors processed in the anterior nucleus of the thalamus: an intracerebral recording study.

Cognitive adverse effects were reported after the deep brain stimulation (DBS) of the anterior nucleus of the thalamus (AN) in epilepsy. As the AN may have an influence on widespread neocortical networks, we hypothesized that the AN, in addition to its participation in memory processing, may also participate in cognitive activities linked with the frontal neocortical structures. The aim of this study was to investigate whether the AN might participate in complex motor-cognitive activities.

Subthalamic nucleus involvement in executive functions with increased cognitive load: a subthalamic nucleus and anterior cingulate cortex depth recording study.

We studied the appearance of broadband oscillatory changes (ranging 2-45 Hz) induced by a cognitive task with two levels of complexity. The event-related de/synchronizations (ERD/S) in the subthalamic nucleus (STN) and in the anterior cingulate cortex (ACC) were evaluated in an executive function test. Four epilepsy surgery candidates with intracerebral electrodes implanted in the ACC and three Parkinson's disease patients with externalized deep brain stimulation electrodes implanted in the STN participated in the study.

DBS amplitude setting can improve aspects of quality of life in patients with Parkinson's disease.

The DBS STN is a non-curative treatment; its effect on the patient's quality of life (QoL) determines the therapeutic success of this procedure. We aimed to assess whether stimulation parameters setting may influence also some of the non-motor aspects of QoL. The QoL was assessed by PDQ-39 questionnaire.

The role of brain shift, patient age, and Parkinson's disease duration in the difference between anatomical and electrophysiological targets for subthalamic stimulation.

Introduction: Although microrecording is common in subthalamic stimulation, microelectrode monitoring prolongs surgical time and may increase the risk of haemorrhagic complications. The main reason for electrophysiological mapping is the discrepancy between the calculated anatomical and final electrophysiological targets. The aim of this paper is to describe the relationship between anatomical and electrophysiological targets defined as the best electrophysiological recordings from multiple parallel electrode tracts, explaining the target discrepancy with attention paid to the role of brain shift and patient- and disease-related factors.

Involvement of the subthalamic nucleus in cognitive functions -- a concept.

The involvement of the subthalamic nucleus (STN) in a broad spectrum of various non-motor functions - attention, executive functions, verbal learning and memory, verbal abstract reasoning, conflict resolution, and emotions - has been reported. The STN has an anatomically central position within the basal ganglia(BG)-thalamocortical motor, associative and limbic circuits. The STN might interfere with non-motor functions as an indirect modulator rather than a regulator.

Cognitive event-related potentials and oscillations in the subthalamic nucleus.

Background: The cognitive role of the subthalamic nucleus (STN) remains largely unknown.

Methods/results: A modified protocol with a dual task elicited local field event-related potentials (ERPs) within the STN. No generators of ERPs were elicited by the standard oddball protocol in the STN (at variance with recordings from the putamen, caudate and pallidum).

Cognitive activities in the subthalamic nucleus. Invasive studies.

Background: According to our studies, based on intracerebral recordings of cognitive Event Related Potentials (ERP), the cognitive activities in the the Basal Ganglia (BG) are organized in some way other than the well-known organization of the cortico-BG-thalamocortical circuits.

Purpose: The cognitive role of the subthalamic nucleus (STN) has been largely unknown. Direct connections with the cortex that bypass the circuitries might underlie the processing of specific cognitive functions in the STN.