Boris Kotchoubey | University of Tubingen (original) (raw)

Papers by Boris Kotchoubey

Research paper thumbnail of The effect of mindfulness-based cognitive therapy on frontal α-asymmetry in recurrently depressed patients

International Journal of Psychophysiology, 2010

We asked the subjects to indicate their responses by pressing the button "idea" in order to diffe... more We asked the subjects to indicate their responses by pressing the button "idea" in order to differentiate thinking process into two stages-a problem-solving stage (before pressing the button "idea") and a check stage (after pressing the button "idea").

Research paper thumbnail of A Device for the Detection of Cognitive Brain Functions in Completely Paralyzed or Unresponsive Patients

Biomedical Engineering, 2005

Unresponsive patients with remaining cognitive abilities may be able to communicate with a brain-... more Unresponsive patients with remaining cognitive abilities may be able to communicate with a brain-computer interface (BCI) such as the Thought Translation Device (TTD). Before initiating TTD learning, which may imply considerable effort, it is important to classify the patients' state of awareness and their remaining cognitive abilities. A tool for detection of cognitive activity (DCA) in the completely paralyzed was developed and integrated into the TTD which is a psychophysiological system for direct brain communication. In the present version, DCA entails five event-related brain-potential (ERP) experiments and investigates the capability of a patient to discriminate, e.g., between semantically related and unrelated concepts and categories. ERPs serve as an indicator of the patients' cortical information processing. Data from five severely brain-injured patients in persistent vegetative state diagnosed as unresponsive and five healthy controls are presented to illustrate the methodology. Two patients showing the highest responsiveness were selected for TTD training. The DCA integrated in the TTD allows screening of cognitive abilities and direct brain communication in the patients' home.

Research paper thumbnail of Anwendungen der Selbstkontrolle langsamer kortikaler Potentiale

Verhaltenstherapie, 2000

Summary Applications for the Self-Control of Slow Cortical PotentialsIt is well established that ... more Summary Applications for the Self-Control of Slow Cortical PotentialsIt is well established that biofeedback and operant learning procedures can be used to enable humans to gain voluntary control over bodily functions such as heart rate, blood pressure, or muscle tension. Similarly, individuals can acquire control over their brain activity. In a typical training paradigm, visual feedback of slow cortical potential

Research paper thumbnail of Oddball (P300) Brain-Computer Interface: The Effect of Depressed Mood and Emotion on Performance

... reflects the authors' views. Funding agencies are not liable for any use that may be mad... more ... reflects the authors' views. Funding agencies are not liable for any use that may be made of the information contained herein. Contact: steve-daniel.lukito@student.uni-tuebingen.de Fig 2. (a) Emotional state after each ... selection. 1 blk duration is equal to 62.5 ms (a) (b) (b) (a) (b) ...

Research paper thumbnail of THE EFFECT OF MOTIVATION IN BCI PERFORMANCE

Research paper thumbnail of The Effect of Motivation on Brain-Computer Interface Performance

Research paper thumbnail of Sustained reduction of seizures in patients with intractable epilepsy after self-regulation training of slow cortical potentials - 10 years after

Frontiers in human neuroscience, 2014

The aim of this study was to determine whether the reduction of seizures in patients with intract... more The aim of this study was to determine whether the reduction of seizures in patients with intractable epilepsy after self-regulation of slow cortical potentials (SCPs) was maintained almost 10 years after the end of treatment. Originally, 41 patients received training with SCP-neurofeedback. A control group of 12 patients received respiratory feedback while another group of 11 patients had their anticonvulsant medications reviewed. Nineteen patients in the experimental group participated at least in parts of the long-term follow-up, but only two patients from each control group agreed to do so. The follow-up participants completed the same seizure diaries as in the original study. Patients of the experimental group also took part in three SCP-training sessions at the follow-up evaluation. Due to the small sample size, the results of participants in the control groups were not considered in the analysis. A significant decrease in seizure frequency was found about 10 years after the e...

Research paper thumbnail of What kind of consciousness is minimal?

Brain injury, 2014

A comparison between unitary and non-unitary views on minimal consciousness. First, unitary (all-... more A comparison between unitary and non-unitary views on minimal consciousness. First, unitary (all-or-none) and non-unitary (gradual or continuous) models of consciousness are defined as they have been developed in both philosophy and neurophysiology. Then, the implications of these ideas to the notion the minimally conscious state (MCS) are discussed. Review and analysis of theoretical conceptions and empirical data. Both kinds of models are compatible with the actual definitions of MCS. Although unitary views may seem to contradict the description of the MCS in 'Neurology' 2002, the apparent contradiction can easily be solved. Most recent data, particularly those obtained using fMRI and concerning learning, emotional responsiveness and pain and suffering, speak for non-unitary models. Most evidence speaks for non-unitary models of minimal consciousness. If these models are correct, patients with MCS may have, in addition to temporal fluctuations, a lower level of consciousne...

Research paper thumbnail of Is there a mind? Electrophysiology of unconscious patients

News in physiological sciences : an international journal of physiology produced jointly by the International Union of Physiological Sciences and the American Physiological Society, 2002

Event related brain potentials (ERPs) provide information about cortical processing in severe neu... more Event related brain potentials (ERPs) provide information about cortical processing in severe neurological patients whose cognitive abilities cannot be expressed in their behavior. In coma, ERPs contribute to the prediction of the outcome. In a vegetative state, ERPs uncover the functional state of cortical processes. The significance of ERPs in the neurophysiological study of consciousness is discussed.

Research paper thumbnail of Task instructions modulate the attentional mode affecting the auditory MMN and the semantic N400

Frontiers in Human Neuroscience, 2014

Event-related potentials (ERPs) have been proven to be a useful tool to complement clinical asses... more Event-related potentials (ERPs) have been proven to be a useful tool to complement clinical assessment and to detect residual cognitive functions in patients with disorders of consciousness. These ERPs are often recorded using passive or unspecific instructions. Patient data obtained this way are then compared to data from healthy participants, which are usually recorded using active instructions. The present study investigates the effect of attentive modulations and particularly the effect of active vs. passive instruction on the ERP components mismatch negativity (MMN) and N400. A sample of 18 healthy participants listened to three auditory paradigms: an oddball, a word priming, and a sentence paradigm. Each paradigm was presented three times with different instructions: ignoring auditory stimuli, passive listening, and focused attention on the auditory stimuli. After each task, the participants indicated their subjective effort. The N400 decreased from the focused task to the passive task, and was extinct in the ignore task. The MMN exhibited higher amplitudes in the focused and passive task compared to the ignore task. The data indicate an effect of attention on the supratemporal component of the MMN. Subjective effort was equally high in the passive and focused tasks but reduced in the ignore task. We conclude that passive listening during EEG recording is stressful and attenuates ERPs, which renders the interpretation of the results obtained in such conditions difficult.

Research paper thumbnail of Mindfulness versus rumination and behavioral inhibition: A perspective from research on frontal brain asymmetry

Mindfulness represents an attribute of consciousness involving an intentional focus on the presen... more Mindfulness represents an attribute of consciousness involving an intentional focus on the presentmoment experience with a non-judgmental attitude. Due to this quality, it attenuates rumination, a maladaptive way of coping with negative mood characterized by a continuous, passive focus on particularly negative emotions. Only few studies have examined mindfulness and rumination in relation to basic notions of human motivation, such as the behavioral inhibition and activation systems (BIS/BAS), and the approach-withdrawal model of hemispheric asymmetry. We examined the indicated parameters and frontal brain asymmetry, assessed through the alpha band (8-13 Hz) in resting-state electroencephalogram. Alpha asymmetry represents a neurophysiologic marker of approach vs. withdrawal-related response dispositions. In line with previous findings, trait mindfulness and rumination were negatively related to each other. Further, rumination was positively and mindfulness negatively related to BIS, while neither parameter showed a consistent association with BAS. Frontal alpha asymmetry on the other hand was significantly associated with BAS, but not with BIS. Hence, rumination appears to be characterized by behavioral inhibition, but not by dispositions of active withdrawal. Mindfulness on the other hand is related to lower behavioral inhibition, but is not necessarily associated with behavioral activation or approach dispositions.

Research paper thumbnail of Studentized continuous wavelet transform (t-CWT) in the analysis of individual ERPs: real and simulated EEG data

Frontiers in neuroscience, 2014

This study aimed at evaluating the performance of the Studentized Continuous Wavelet Transform (t... more This study aimed at evaluating the performance of the Studentized Continuous Wavelet Transform (t-CWT) as a method for the extraction and assessment of event-related brain potentials (ERP) in data from a single subject. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) of the t-CWT were assessed and compared to a variety of competing procedures using simulated EEG data at six low signal-to-noise ratios. Results show that the t-CWT combines high sensitivity and specificity with favorable PPV and NPV. Applying the t-CWT to authentic EEG data obtained from 14 healthy participants confirmed its high sensitivity. The t-CWT may thus be well suited for the assessment of weak ERPs in single-subject settings.

Research paper thumbnail of Brain potentials in human patients with extremely severe diffuse brain damage

Neuroscience Letters, 2001

To test higher cortical functions of neurological patients, oddball tasks are often used in which... more To test higher cortical functions of neurological patients, oddball tasks are often used in which a frequent and a rare stimulus are randomly presented and a P3 brain wave is recorded to the rare stimulus. We examined 33 patients with extremely severe brain injury. Three oddball conditions were used: with two sine tones (ST), with two complex tones (CT) and

Research paper thumbnail of Brain–Computer Communication: Unlocking the Locked In

Psychological Bulletin, 2001

With the increasing efficiency of life-support systems and better intensive care, more patients s... more With the increasing efficiency of life-support systems and better intensive care, more patients survive severe injuries of the brain and spinal cord. Many of these patients experience locked-in syndrome: The active mind is locked in a paralyzed body. Consequently, communication is extremely restricted or impossible. A muscle-independent communication channel overcomes this problem and is realized through a brain–computer interface, a

Research paper thumbnail of The thought translation device (TTD) for completely paralyzed patients

The thought translation device trains locked-in patients to self-regulate slow cortical potential... more The thought translation device trains locked-in patients to self-regulate slow cortical potentials (SCP's) of their electroencephalogram (EEG). After operant learning of SCP self-control, patients select letters, words or pictograms in a computerized language support program. Results of five respirated, locked-in-patients are described, demonstrating the usefulness of the thought translation device as an alternative communication channel in motivated totally paralyzed patients with amyotrophic lateral sclerosis.

Research paper thumbnail of Semantic processing in a coma patient

Electrical brain responses to words semantically related versus unrelated to their context were r... more Electrical brain responses to words semantically related versus unrelated to their context were recorded in a coma patient on days 6 (Glasgow Coma Scale, GCS = 6) and 22 (GCS = 9). Significant differences between related and unrelated words (which were completely matched in their physical features) were consistently observed in both examinations. This is the first evidence for semantic stimulus processing in coma.

Research paper thumbnail of Self-initiation of EEG-based communication in paralyzed patients

Electroencephalography and Clinical Neurophysiology/electromyography and Motor Control, 2001

Objectives: Severely paralyzed patients could learn to voluntarily generate slow cortical potenti... more Objectives: Severely paralyzed patients could learn to voluntarily generate slow cortical potential (SCP) shifts in their electroencephalogram and to use these signals to operate a communication device. To enhance the patients' autonomy, the present study describes the development of a permanently available communication system that can be turned on and off by locked-in patients without external assistance. A skill necessary

Research paper thumbnail of Recognition of affective prosody: Continuous wavelet measures of event-related brain potentials to emotional exclamations

Psychophysiology, 2004

The affective state of a speaker can be identified from the prosody of his or her speech. Voice q... more The affective state of a speaker can be identified from the prosody of his or her speech. Voice quality is the most important prosodic cue for emotion recognition from short verbal utterances and nonverbal exclamations, the latter conveying pure emotion, void of all semantic meaning. We adopted two context violation paradigmsFoddball and primingFto study the event-related brain potentials (ERP) reflecting this recognition process. We found a negative wave, the N300, in the ERPs to contextually incongruous exclamations, and interpreted this component as analogous to the well-known N400 response to semantically inappropriate words. The N300 appears to be a real-time psychophysiological measure of spontaneous emotion recognition from vocal cues, which could prove a useful tool for the examination of affective-prosody comprehension. In addition, we developed a new ERP component detection and estimation method that is based on the continuous wavelet transform (CWT), does not rely on visual inspection of the waveforms, and yields larger statistical difference effects than classical methods.

Research paper thumbnail of Psychobiology of Altered States of Consciousness

Vaitl, D., Birbaumer, N., Gruzelier, J., Jamieson, G. A., Kotchoubey, B., Kübler, A., ... & Weiss, T. (2005). Psychobiology of altered states of consciousness. Psychological bulletin, 131(1), 98-127., 2005

"The article reviews the current knowledge regarding altered states of consciousness (ASC) (a) oc... more "The article reviews the current knowledge regarding altered states of consciousness (ASC) (a) occurring
spontaneously, (b) evoked by physical and physiological stimulation, (c) induced by psychological
means, and (d) caused by diseases. The emphasis is laid on psychological and neurobiological ap-
proaches. The phenomenological analysis of the multiple ASC resulted in 4 dimensions by which they
can be characterized: activation, awareness span, self-awareness, and sensory dynamics. The neurophys-
iological approach revealed that the different states of consciousness are mainly brought about by a
compromised brain structure, transient changes in brain dynamics (disconnectivity), and neurochemical
and metabolic processes. Besides these severe alterations, environmental stimuli, mental practices, and
techniques of self-control can also temporarily alter brain functioning and conscious experience."

Research paper thumbnail of Brain-computer communication: Unlocking the locked in

Psychological Bulletin, 2001

With the increasing efficiency of life-support systems and better intensive care, more patients s... more With the increasing efficiency of life-support systems and better intensive care, more patients survive severe injuries of the brain and spinal cord. Many of these patients experience locked-in syndrome: The active mind is locked in a paralyzed body. Consequently, communication is extremely restricted or impossible. A muscle-independent communication channel overcomes this problem and is realized through a brain-computer interface, a direct connection between brain and computer. The number of technically elaborated brain-computer interfaces is in contrast with the number of systems used in the daily life of locked-in patients. It is hypothesized that a profound knowledge and consideration of psychological principles are necessary to make brain-computer interfaces feasible for locked-in patients.

Research paper thumbnail of The effect of mindfulness-based cognitive therapy on frontal α-asymmetry in recurrently depressed patients

International Journal of Psychophysiology, 2010

We asked the subjects to indicate their responses by pressing the button "idea" in order to diffe... more We asked the subjects to indicate their responses by pressing the button "idea" in order to differentiate thinking process into two stages-a problem-solving stage (before pressing the button "idea") and a check stage (after pressing the button "idea").

Research paper thumbnail of A Device for the Detection of Cognitive Brain Functions in Completely Paralyzed or Unresponsive Patients

Biomedical Engineering, 2005

Unresponsive patients with remaining cognitive abilities may be able to communicate with a brain-... more Unresponsive patients with remaining cognitive abilities may be able to communicate with a brain-computer interface (BCI) such as the Thought Translation Device (TTD). Before initiating TTD learning, which may imply considerable effort, it is important to classify the patients' state of awareness and their remaining cognitive abilities. A tool for detection of cognitive activity (DCA) in the completely paralyzed was developed and integrated into the TTD which is a psychophysiological system for direct brain communication. In the present version, DCA entails five event-related brain-potential (ERP) experiments and investigates the capability of a patient to discriminate, e.g., between semantically related and unrelated concepts and categories. ERPs serve as an indicator of the patients' cortical information processing. Data from five severely brain-injured patients in persistent vegetative state diagnosed as unresponsive and five healthy controls are presented to illustrate the methodology. Two patients showing the highest responsiveness were selected for TTD training. The DCA integrated in the TTD allows screening of cognitive abilities and direct brain communication in the patients' home.

Research paper thumbnail of Anwendungen der Selbstkontrolle langsamer kortikaler Potentiale

Verhaltenstherapie, 2000

Summary Applications for the Self-Control of Slow Cortical PotentialsIt is well established that ... more Summary Applications for the Self-Control of Slow Cortical PotentialsIt is well established that biofeedback and operant learning procedures can be used to enable humans to gain voluntary control over bodily functions such as heart rate, blood pressure, or muscle tension. Similarly, individuals can acquire control over their brain activity. In a typical training paradigm, visual feedback of slow cortical potential

Research paper thumbnail of Oddball (P300) Brain-Computer Interface: The Effect of Depressed Mood and Emotion on Performance

... reflects the authors' views. Funding agencies are not liable for any use that may be mad... more ... reflects the authors' views. Funding agencies are not liable for any use that may be made of the information contained herein. Contact: steve-daniel.lukito@student.uni-tuebingen.de Fig 2. (a) Emotional state after each ... selection. 1 blk duration is equal to 62.5 ms (a) (b) (b) (a) (b) ...

Research paper thumbnail of THE EFFECT OF MOTIVATION IN BCI PERFORMANCE

Research paper thumbnail of The Effect of Motivation on Brain-Computer Interface Performance

Research paper thumbnail of Sustained reduction of seizures in patients with intractable epilepsy after self-regulation training of slow cortical potentials - 10 years after

Frontiers in human neuroscience, 2014

The aim of this study was to determine whether the reduction of seizures in patients with intract... more The aim of this study was to determine whether the reduction of seizures in patients with intractable epilepsy after self-regulation of slow cortical potentials (SCPs) was maintained almost 10 years after the end of treatment. Originally, 41 patients received training with SCP-neurofeedback. A control group of 12 patients received respiratory feedback while another group of 11 patients had their anticonvulsant medications reviewed. Nineteen patients in the experimental group participated at least in parts of the long-term follow-up, but only two patients from each control group agreed to do so. The follow-up participants completed the same seizure diaries as in the original study. Patients of the experimental group also took part in three SCP-training sessions at the follow-up evaluation. Due to the small sample size, the results of participants in the control groups were not considered in the analysis. A significant decrease in seizure frequency was found about 10 years after the e...

Research paper thumbnail of What kind of consciousness is minimal?

Brain injury, 2014

A comparison between unitary and non-unitary views on minimal consciousness. First, unitary (all-... more A comparison between unitary and non-unitary views on minimal consciousness. First, unitary (all-or-none) and non-unitary (gradual or continuous) models of consciousness are defined as they have been developed in both philosophy and neurophysiology. Then, the implications of these ideas to the notion the minimally conscious state (MCS) are discussed. Review and analysis of theoretical conceptions and empirical data. Both kinds of models are compatible with the actual definitions of MCS. Although unitary views may seem to contradict the description of the MCS in 'Neurology' 2002, the apparent contradiction can easily be solved. Most recent data, particularly those obtained using fMRI and concerning learning, emotional responsiveness and pain and suffering, speak for non-unitary models. Most evidence speaks for non-unitary models of minimal consciousness. If these models are correct, patients with MCS may have, in addition to temporal fluctuations, a lower level of consciousne...

Research paper thumbnail of Is there a mind? Electrophysiology of unconscious patients

News in physiological sciences : an international journal of physiology produced jointly by the International Union of Physiological Sciences and the American Physiological Society, 2002

Event related brain potentials (ERPs) provide information about cortical processing in severe neu... more Event related brain potentials (ERPs) provide information about cortical processing in severe neurological patients whose cognitive abilities cannot be expressed in their behavior. In coma, ERPs contribute to the prediction of the outcome. In a vegetative state, ERPs uncover the functional state of cortical processes. The significance of ERPs in the neurophysiological study of consciousness is discussed.

Research paper thumbnail of Task instructions modulate the attentional mode affecting the auditory MMN and the semantic N400

Frontiers in Human Neuroscience, 2014

Event-related potentials (ERPs) have been proven to be a useful tool to complement clinical asses... more Event-related potentials (ERPs) have been proven to be a useful tool to complement clinical assessment and to detect residual cognitive functions in patients with disorders of consciousness. These ERPs are often recorded using passive or unspecific instructions. Patient data obtained this way are then compared to data from healthy participants, which are usually recorded using active instructions. The present study investigates the effect of attentive modulations and particularly the effect of active vs. passive instruction on the ERP components mismatch negativity (MMN) and N400. A sample of 18 healthy participants listened to three auditory paradigms: an oddball, a word priming, and a sentence paradigm. Each paradigm was presented three times with different instructions: ignoring auditory stimuli, passive listening, and focused attention on the auditory stimuli. After each task, the participants indicated their subjective effort. The N400 decreased from the focused task to the passive task, and was extinct in the ignore task. The MMN exhibited higher amplitudes in the focused and passive task compared to the ignore task. The data indicate an effect of attention on the supratemporal component of the MMN. Subjective effort was equally high in the passive and focused tasks but reduced in the ignore task. We conclude that passive listening during EEG recording is stressful and attenuates ERPs, which renders the interpretation of the results obtained in such conditions difficult.

Research paper thumbnail of Mindfulness versus rumination and behavioral inhibition: A perspective from research on frontal brain asymmetry

Mindfulness represents an attribute of consciousness involving an intentional focus on the presen... more Mindfulness represents an attribute of consciousness involving an intentional focus on the presentmoment experience with a non-judgmental attitude. Due to this quality, it attenuates rumination, a maladaptive way of coping with negative mood characterized by a continuous, passive focus on particularly negative emotions. Only few studies have examined mindfulness and rumination in relation to basic notions of human motivation, such as the behavioral inhibition and activation systems (BIS/BAS), and the approach-withdrawal model of hemispheric asymmetry. We examined the indicated parameters and frontal brain asymmetry, assessed through the alpha band (8-13 Hz) in resting-state electroencephalogram. Alpha asymmetry represents a neurophysiologic marker of approach vs. withdrawal-related response dispositions. In line with previous findings, trait mindfulness and rumination were negatively related to each other. Further, rumination was positively and mindfulness negatively related to BIS, while neither parameter showed a consistent association with BAS. Frontal alpha asymmetry on the other hand was significantly associated with BAS, but not with BIS. Hence, rumination appears to be characterized by behavioral inhibition, but not by dispositions of active withdrawal. Mindfulness on the other hand is related to lower behavioral inhibition, but is not necessarily associated with behavioral activation or approach dispositions.

Research paper thumbnail of Studentized continuous wavelet transform (t-CWT) in the analysis of individual ERPs: real and simulated EEG data

Frontiers in neuroscience, 2014

This study aimed at evaluating the performance of the Studentized Continuous Wavelet Transform (t... more This study aimed at evaluating the performance of the Studentized Continuous Wavelet Transform (t-CWT) as a method for the extraction and assessment of event-related brain potentials (ERP) in data from a single subject. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) of the t-CWT were assessed and compared to a variety of competing procedures using simulated EEG data at six low signal-to-noise ratios. Results show that the t-CWT combines high sensitivity and specificity with favorable PPV and NPV. Applying the t-CWT to authentic EEG data obtained from 14 healthy participants confirmed its high sensitivity. The t-CWT may thus be well suited for the assessment of weak ERPs in single-subject settings.

Research paper thumbnail of Brain potentials in human patients with extremely severe diffuse brain damage

Neuroscience Letters, 2001

To test higher cortical functions of neurological patients, oddball tasks are often used in which... more To test higher cortical functions of neurological patients, oddball tasks are often used in which a frequent and a rare stimulus are randomly presented and a P3 brain wave is recorded to the rare stimulus. We examined 33 patients with extremely severe brain injury. Three oddball conditions were used: with two sine tones (ST), with two complex tones (CT) and

Research paper thumbnail of Brain–Computer Communication: Unlocking the Locked In

Psychological Bulletin, 2001

With the increasing efficiency of life-support systems and better intensive care, more patients s... more With the increasing efficiency of life-support systems and better intensive care, more patients survive severe injuries of the brain and spinal cord. Many of these patients experience locked-in syndrome: The active mind is locked in a paralyzed body. Consequently, communication is extremely restricted or impossible. A muscle-independent communication channel overcomes this problem and is realized through a brain–computer interface, a

Research paper thumbnail of The thought translation device (TTD) for completely paralyzed patients

The thought translation device trains locked-in patients to self-regulate slow cortical potential... more The thought translation device trains locked-in patients to self-regulate slow cortical potentials (SCP's) of their electroencephalogram (EEG). After operant learning of SCP self-control, patients select letters, words or pictograms in a computerized language support program. Results of five respirated, locked-in-patients are described, demonstrating the usefulness of the thought translation device as an alternative communication channel in motivated totally paralyzed patients with amyotrophic lateral sclerosis.

Research paper thumbnail of Semantic processing in a coma patient

Electrical brain responses to words semantically related versus unrelated to their context were r... more Electrical brain responses to words semantically related versus unrelated to their context were recorded in a coma patient on days 6 (Glasgow Coma Scale, GCS = 6) and 22 (GCS = 9). Significant differences between related and unrelated words (which were completely matched in their physical features) were consistently observed in both examinations. This is the first evidence for semantic stimulus processing in coma.

Research paper thumbnail of Self-initiation of EEG-based communication in paralyzed patients

Electroencephalography and Clinical Neurophysiology/electromyography and Motor Control, 2001

Objectives: Severely paralyzed patients could learn to voluntarily generate slow cortical potenti... more Objectives: Severely paralyzed patients could learn to voluntarily generate slow cortical potential (SCP) shifts in their electroencephalogram and to use these signals to operate a communication device. To enhance the patients' autonomy, the present study describes the development of a permanently available communication system that can be turned on and off by locked-in patients without external assistance. A skill necessary

Research paper thumbnail of Recognition of affective prosody: Continuous wavelet measures of event-related brain potentials to emotional exclamations

Psychophysiology, 2004

The affective state of a speaker can be identified from the prosody of his or her speech. Voice q... more The affective state of a speaker can be identified from the prosody of his or her speech. Voice quality is the most important prosodic cue for emotion recognition from short verbal utterances and nonverbal exclamations, the latter conveying pure emotion, void of all semantic meaning. We adopted two context violation paradigmsFoddball and primingFto study the event-related brain potentials (ERP) reflecting this recognition process. We found a negative wave, the N300, in the ERPs to contextually incongruous exclamations, and interpreted this component as analogous to the well-known N400 response to semantically inappropriate words. The N300 appears to be a real-time psychophysiological measure of spontaneous emotion recognition from vocal cues, which could prove a useful tool for the examination of affective-prosody comprehension. In addition, we developed a new ERP component detection and estimation method that is based on the continuous wavelet transform (CWT), does not rely on visual inspection of the waveforms, and yields larger statistical difference effects than classical methods.

Research paper thumbnail of Psychobiology of Altered States of Consciousness

Vaitl, D., Birbaumer, N., Gruzelier, J., Jamieson, G. A., Kotchoubey, B., Kübler, A., ... & Weiss, T. (2005). Psychobiology of altered states of consciousness. Psychological bulletin, 131(1), 98-127., 2005

"The article reviews the current knowledge regarding altered states of consciousness (ASC) (a) oc... more "The article reviews the current knowledge regarding altered states of consciousness (ASC) (a) occurring
spontaneously, (b) evoked by physical and physiological stimulation, (c) induced by psychological
means, and (d) caused by diseases. The emphasis is laid on psychological and neurobiological ap-
proaches. The phenomenological analysis of the multiple ASC resulted in 4 dimensions by which they
can be characterized: activation, awareness span, self-awareness, and sensory dynamics. The neurophys-
iological approach revealed that the different states of consciousness are mainly brought about by a
compromised brain structure, transient changes in brain dynamics (disconnectivity), and neurochemical
and metabolic processes. Besides these severe alterations, environmental stimuli, mental practices, and
techniques of self-control can also temporarily alter brain functioning and conscious experience."

Research paper thumbnail of Brain-computer communication: Unlocking the locked in

Psychological Bulletin, 2001

With the increasing efficiency of life-support systems and better intensive care, more patients s... more With the increasing efficiency of life-support systems and better intensive care, more patients survive severe injuries of the brain and spinal cord. Many of these patients experience locked-in syndrome: The active mind is locked in a paralyzed body. Consequently, communication is extremely restricted or impossible. A muscle-independent communication channel overcomes this problem and is realized through a brain-computer interface, a direct connection between brain and computer. The number of technically elaborated brain-computer interfaces is in contrast with the number of systems used in the daily life of locked-in patients. It is hypothesized that a profound knowledge and consideration of psychological principles are necessary to make brain-computer interfaces feasible for locked-in patients.