Christoph Kapeller

Christoph Kapeller
g.tec · R&D

PhD

About

63
Publications
14,932
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
848
Citations
Citations since 2016
28 Research Items
693 Citations
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120

Publications

Publications (63)
Article
Full-text available
The Eighth International Brain-Computer Interface (BCI) Meeting was held June 7-9, 2021 in a virtual format. The conference continued the BCI Meeting series' interactive nature with 21 workshops covering the breadth of topics in BCI (also called brain-machine interface) research. Some workshops provided detailed examinations of methods, hardware, o...
Preprint
Full-text available
Electrocorticogram (ECoG) well characterizes hand movement intentions and gestures. In the present work we aim to investigate the possibility to enhance hand pose classification, in a Rock-Paper-Scissor - and Rest - task, by introducing topological descriptors of time series data. We hypothesized that an innovative approach based on topological dat...
Article
Full-text available
Face recognition is impaired in patients with prosopagnosia, which may occur as a side effect of neurosurgical procedures. Face selective regions on the ventral temporal cortex have been localized with electrical cortical stimulation (ECS), electrocorticography (ECoG), and functional magnetic resonance imagining (fMRI). This is the first group stud...
Article
Full-text available
Normal and pathological networks related to seizure propagation have got attention to elucide complex seizure semiology and contribute to diagnosis and surgical monitoring in epilepsy treatment. Since focal and generalized epileptogenic syndromes abnormalities might involve multiple foci and large-scale networks, we applied electrophysiolpgy (cortc...
Article
Full-text available
Invasive brain-computer interfaces yield remarkable performance in a multitude of applications. For classification experiments, high-gamma bandpower features and linear discriminant analysis (LDA) are commonly used due to simplicity and robustness. However, LDA is inherently static and not suited to account for transient information that is typical...
Chapter
RATIONALE: Electrocorticography-based functional language mapping (ECoG-FLM) utilizes an ECoG signal paired with simultaneous language task presentation to create functional maps of the eloquent language cortex in patients selected for resective epilepsy or tumor surgery. At present, the concordance of functional maps derived by ECoG-FLM and electr...
Article
Full-text available
How do different parts of the brain work together to help us see, move, understand, and do other things? For many years, we have known that different brain regions perform different tasks that are important for vision. Some brain regions are responsible for seeing faces, colors, lines, movement, or other parts of the world. But mapping different br...
Article
Full-text available
Background: Electrical stimulation of the cortex using subdurally implanted electrodes can causally reveal structural connectivity by eliciting cortico-cortical evoked potentials (CCEPs). While many studies have demonstrated the potential value of CCEPs, the methods to evaluate them were often relatively subjective, did not consider potential arti...
Article
Full-text available
Objective: Several neuroimaging studies have demonstrated that the ventral temporal cortex contains specialized regions that process visual stimuli. This study investigated the spatial and temporal dynamics of electrocorticographic (ECoG) responses to different types and colors of visual stimulation that were presented to four human participants,...
Article
Full-text available
OBJECTIVE Recent neuroimaging studies suggest that intractable epilepsy involves pathological functional networks as well as strong epileptogenic foci. Combining cortico-cortical evoked potential (CCEP) recording and tractography is a useful strategy for mapping functional connectivity in normal and pathological networks. In this study, the authors...
Article
Full-text available
Significance Are some regions of the human brain exclusively engaged in a single specific mental process? Here we test this question in a neurosurgery patient implanted with electrodes for clinical reasons. When electrically stimulated in the fusiform face area while viewing objects, the patient reported illusory faces while the objects remained un...
Article
Full-text available
The development of technological applications that allow people to control and embody external devices within social interaction settings represents a major goal for current and future brain-computer interface (BCI) systems. Prior research has suggested that embodied systems may ameliorate BCI end-user's experience and accuracy in controlling exter...
Article
Full-text available
Background The identification of eloquent cortex, surrounding the seizure onset zone, is important for predictable surgical outcome in epilepsy patients. The symptoms during electrical cortical stimulation (ECS) lead to a functional map that includes motor, sensory, and other functions. In this study we test whether a prevenient high-gamma mapping...
Article
Objective: This paper discusses the invariance and variability in interaction error-related potentials (ErrPs), where a special focus is laid upon the factors of (1) the human mental processing required to assess interface actions (2) time (3) subjects. Approach: Three different experiments were designed as to vary primarily with respect to the...
Article
Full-text available
To minimize functional morbidity associated with brain surgery, new preventive approaches (also referred to as "prehabilitation") by using motor-imagery-based computer interfaces (MI-BCIs) can be utilized. To achieve successful MI-BCI performance for prehabilitation purposes, the characteristics of an electrocorticographic (ECoG) signal that is ass...
Conference Paper
Full-text available
Electrical cortical stimulation (ECS) is often used in presurgical evaluation procedures for patients suffering from pharmacoresistant epilepsy. Real-time functional mapping (RTFM) is an alternative brain mapping methodology that can accompany traditional functional mapping approaches like ECS. In this paper, we present a combined RTFM/ECS system t...
Conference Paper
Brain waves contain fundamental information about cortical activity: signal power within certain frequency bands, which is exploited by a variety of Brain-Computer Interface applications. For real-time systems, these features must be estimated as quickly as possible while maintaining high signal fidelity. Here, we present a statistically optimal si...
Chapter
Brain-Computer Interfaces (BCIs) are powerful tools for enabling communication between people and the surrounding world by directly utilizing brain activity and avoiding motor pathways. Before moving into invasive implantation of BCIs, a key issue must be resolved—localization of the areas for implantation, which might vary depending on the chosen...
Article
Background: We developed a functional brain analysis system that enabled us to perform real-time task-related electrocorticography (ECoG) and evaluated its potential in clinical practice. We hypothesized that high gamma activity (HGA) mapping would provide better spatial and temporal resolution with high signal-to-noise ratios. Methods: Seven aw...
Article
Full-text available
OBJECTIVE Electrocortical stimulation (ECS) is the gold standard for functional brain mapping; however, precise functional mapping is still difficult in patients with language deficits. High gamma activity (HGA) between 80 and 140 Hz on electrocorticography is assumed to reflect localized cortical processing, whereas the cortico-cortical evoked pot...
Conference Paper
Full-text available
Introduction: There is evidence to suggest that surgically-implanted intracranial BCIs might be more efficient than scalp-based BCIs, especially for severely disabled patients. However, before moving into invasive implantation of BCIs, the important question must be addressed – localization of the areas for implantation, which might vary dependent...
Article
Full-text available
Precise localization of eloquent cortex in children may provide much needed surgical guidance and expand surgical epilepsy treatment options. It reduces the risk of postsurgical functional deficits and benefits children’s quality of life, educational capacity, and long-term employment potential. The ultimate goal of functional mapping for pediatric...
Article
Patients suffering from intractable epilepsy, who are candidates for surgical treatment, have to undergo several functional mapping procedures to make precisely diagnose for epileptogenic foci and eloquent brain regions. Since electrocorticography (ECoG) detects electric currents directly from the brain surface, it is expected to be the most reliab...
Conference Paper
Intention recognition through decoding brain activity could lead to a powerful and independent Brain-Computer-Interface (BCI) allowing for intuitive control of devices like robots. A common strategy for realizing such a system is the motor imagery (MI) BCI using electroencephalography (EEG). Changing to invasive recordings like electrocorticography...
Conference Paper
This study demonstrates the feasibility of high-gamma activity mapping for localization of somatosensory finger areas in the human brain. Identification of functional brain regions is important in surgical planning, such as for resections of epileptic foci or brain tumors. The mapping procedure is done using electrocorticography (ECoG), an invasive...
Article
Full-text available
To evaluate the use of the cortiQ-based mapping system (g.tec medication engineering GmbH, Austria) for real-time functional mapping (RTFM) and to compare it to results from electrical cortical stimulation mapping (ESM) and functional magnetic resonance imaging (fMRI). Electrocorticographic activity was recorded in 3 male patients with intractable...
Chapter
Full-text available
A brain-computer interface (BCI) analyzes brain activity in real-time to convey information or control an external device. BCI systems often consist of a biosignal amplifier for EEG data acquisition, parameter estimation, and classification to make decisions in real-time. Many BCIs are controlled via motor imagery (through imagined movements), whic...
Article
Full-text available
Recent advances in humanoid robot technologies have made it possible to inhabit a humanlike form located at a remote place. This allows the participant to interact with others in that space and experience the illusion that they are actually present in the remote space. Moreover, with these humanlike forms it may be possible to induce a full-body ow...
Article
Full-text available
There are two main approaches to intraoperative monitoring in neurosurgery. One approach is related to fluorescent phenomena and the other is related to oscillatory neuronal activity. We developed novel techniques to visualize blood flow (BF) conditions in real time, based on indocyanine green videography (ICG-VG) and the electrophysiological pheno...
Conference Paper
Full-text available
Brain-Computer Interfaces (BCIs) are expected to become a game-changing modality for the communication and control of both devices and virtual environments in humans whose direct neuromotor response needs to be augmented, bypassed, or replaced. Recent developments in the area of BCI research suggest that subdural electrocorticography (ECoG)-based B...
Article
Full-text available
A brain-computer-interface (BCI) allows the user to control a device or software with brain activity. Many BCIs rely on visual stimuli with constant stimulation cycles that elicit steady-state visual evoked potentials (SSVEP) in the electroencephalogram (EEG). This EEG response can be generated with a LED or a computer screen flashing at a constant...
Article
For neurosurgery with an awake craniotomy, the critical issue is to set aside enough time to identify eloquent cortices by electrocortical stimulation (ECS). High gamma activity (HGA) ranging between 80 and 120 Hz on electrocorticogram (ECoG) is assumed to reflect localized cortical processing. In this report, we used realtime HGA mapping and funct...
Article
Full-text available
Decoding brain activity of corresponding highlevel tasks may lead to an independent and intuitively controlled Brain-Computer Interface (BCI). Most of today's BCI research focuses on analyzing the electroencephalogram (EEG) which provides only limited spatial and temporal resolution. Derived electrocorticographic (ECoG) signals allow the investigat...
Conference Paper
Full-text available
In a brain-computer interface (BCI), users perform specific mental tasks to convey messages or commands through direct measures of brain activity. Typically, users must perform each mental task for two or more seconds before their brain activity is distinct enough for accurate classification. In P300 BCIs, this usually entails silently counting spe...
Article
Full-text available
Planning for epilepsy surgery depends substantially on the localization of brain cortical areas responsible for sensory, motor, or cognitive functions, clinically also known as eloquent cortex. In this paper, we present the novel software package 'cortiQ' that allows clinicians to localize eloquent cortex, thus providing a safe margin for surgical...
Conference Paper
Full-text available
This work introduces a new system to allow persons with motor disabilities to control remote devices and communicate with their environment. This system consists of a real-time data processing computer that analyzes biosignals like the electroencephalogram (EEG), electromyogram (EMG), electrooculogram (EOG) and a second computer that controls a sma...
Article
A brain-computer interface (BCI) translates brain activity into commands to control devices or software. Common approaches are based on visual evoked potentials (VEP), extracted from the electroencephalogram (EEG) during visual stimulation. High information transfer rates (ITR) can be achieved using (i) steady-state VEP (SSVEP) or (ii) code-modulat...
Article
Planning for epilepsy surgery depends substantially on the localization of brain cortical areas responsible for sensory, motor, or cognitive functions, clinically also known as eloquent cortex. In this paper, we present the novel software package 'cortiQ' that allows clinicians to localize eloquent cortex, thus providing a safe margin for surgical...
Conference Paper
Full-text available
Severely disabled individuals often suffer from high care-giver dependence and are at risk of social exclusion. The prototype developed in the EU Project BrainAble (http://www.brainable.org/) offers access to common smart-home devices and popular Internet services, using electroencephalography (EEG) and non-EEG inputs. Here we describe our user-cen...
Chapter
Full-text available
This chapter provides a general introduction to brain–computer interfaces (BCIs). It outlines general principles of BCI systems and the need for general-purpose BCI software. It also gives an overview of the BCI2000 system and describes the target audience for BCI2000 generally and this book specifically.
Article
Full-text available
Brain-computer interfaces (BCI) are communication systems that allow people to send messages or commands without movement. BCIs rely on different types of signals in the electroencephalogram (EEG), typically P300s, steady-state visually evoked potentials (SSVEP), or event-related desynchronization. Early BCI systems were often evaluated with a sele...
Conference Paper
Early stages in the development of a Brain-and-Body-Computer Interface controlled robot avatar are presented. The robot is aimed at performing well-defined daily tasks upon the choice and on behalf of a user. We built on recent advances in neuroscience, robotics and machine learning to demonstrate that it is possible to control a robot, accurately...
Article
Full-text available
We present the prototype of a context-aware framework that allows users to control smart home devices and to access internet services via a Hybrid BCI system of an auto-calibrating sensorimotor rhythm (SMR) based BCI and another assistive device (Integra Mouse mouth joystick). While there is extensive literature that describes the merit of Hybrid B...