- Email: [email protected]
FC19.1 Intracortical recordings of pain related laser evoked potentials in the human cingulate cortex
Oral Communications / Clinical Neurophysiology 117 (2006) S49–S111
FC18.1 A home environment operated by a brain computer interface for patients suffering from neuromuscular diseases: The ASPICE project F. Cincotti 1, F. Aloise 1, F. Babiloni 1, M.G. Marciani 1, D. Morelli 2, S. Paolucci 2, G. Oriolo 3, A. Cherubini 3, F. Macrı` 3, F. Sciarra 4, F. Mangiola 4, A. Melpignano 5, F. Davide 5, D. Mattia 1 1
Fondazione Santa Lucia IRCCS, Clinical Neurophysiopathology Unit, Italy 2 Fondazione Santa Lucia IRCCS, Italy 3 La Sapienza University, Computer and Systems Science Department, Italy 4 UILDM Sezione Lazio, Italy 5 Telecom Italia Learning Services, Italy Background: Brain–Computer Interface (BCI) is a technology which allows a user to express his/her will (for communication or control purposes) regardless of the ability to have a voluntary control of his/her own muscles. Though being an aid for the motor disabled is often mentioned as the primary goal for BCIs, few systems are actually available as aids for a number of daily activities. Aim: The purpose of the ASPICE project is to give an actual application to the BCI technology, by developing a modular control system for house appliances that users can drive through a BCI. Methods: The core of the system is implemented by software running on a commercial personal computer. User input is fed through hardware/software interfaces matched with the individual’s residual abilities. The system uses the user’s input to control domotic devices – such as remotely controlled lights, TV sets, etc. – and a Sony AIBO robot. During the second year of the study, 15 patients affected by neuromuscular diseases have been included in the clinical validation, in order to provide assessment through patients’ feedback and guidelines for customized system installation. Results: The system has been implemented, and installed in a room of the hospital furnished like a real house. Preparing the environment for the experimentation required no structural intervention – almost all actuators are easily put in place. The system allows the neuro motor disabled persons to improve their ability to control the home environment and to communicate. The interface has shown to be intuitive enough to be utilized by those users who are not familiar with computer interfaces. The level of acceptation by the users was satisfactory. Conclusions: This study has proved that a system including BCI interfaces as front-end can be useful in a clinical context as an assistive device. doi:10.1016/j.clinph.2006.06.058
1 2
S71
University of Essex, Computer Science, UK University of Strathclyde, Bioengineering, UK
Background: Currently, Brain Computer Interfaces (BCI) are of limited practical use requiring prolonged user training. BCI usability can improve by developing methods for EEG feature selection that allow for a more intuitive link between user intention and device control and which can provide multiple degrees of freedom in command selection. Aims: This study compares the performance of using principal component analysis (PCA) and support vector machines (SVM) for multiple feature selection in classifying pre-movement EEG epochs with direction of movement associated with rapid wrist movements to different positions in space. Methods: EEG was recorded from 28 electrodes forming an array over the left sensorimotor cortex in normal subjects with approval of a Local Ethics Committee. Right wrist muscle EMG was also recorded. Subjects viewed a PC monitor randomly presenting a set of five spatially distinct target positions corresponding to neutral, flexed, extended, ulnar and radial deviations of the wrist. When presented with a new target subjects were required to move (or imagine move) their wrist to the target as fast as possible creating datasets of repeats of 20 different movement (or imagined movement) combinations. Continuous wavelet transform was used to extract spatio-temporal characteristics of the EEG signals relative to time of movement initiation or target appearance in case of imagined motion. Results: Using PCA, 10 principal components generated 95% correct classification of pre-movement EEG with actual direction of motion. During imagined movement classification success reduced to 67%. In contrast, SVM classification of the imagined movement data outperformed PCA with up to 87% correct classification for intended direction of movement. Conclusion: During imagined movement SVM outperforms PCA. However, SVM is computationally demanding. We conclude that a hybrid method combining merits of both PCA and SVM may have potential for use in BCI intention detection. doi:10.1016/j.clinph.2006.06.059
FC19.1 Intracortical recordings of pain related laser evoked potentials in the human cingulate cortex L. Garcia-Larrea 1, M. Frot 1, M. Magnin 1, F. Maugiere 2 1
Inserm EMI 342-Central Integration of pain, France Neurological Hospital, Functional Neurophysiology Department, France
2
FC18.2 On feature selection for brain computer interfaces H. Lakany 1, P. Worrarjiran 2, G. Valsan 2, 2 B.A. Conway
The cingulate cortex (CC) is one of the most frequently reported sites of cerebral blood flow increase to pain (PET
S72
Oral Communications / Clinical Neurophysiology 117 (2006) S49–S111
and fMRI studies) but the CC areas in which pain-related activity changes have been found are widely distributed across studies. In most functional imaging and EEG modelling reports, the activated sites corresponded to the ‘midcingular’ region (Brodmann’s area 24 0 ). However, some imaging studies have also showed hemodynamic activations and deactivations of more anterior perigenual cingulate portions. In this study, we report laser evoked potentials (LEPs) recorded in the CC with intra-cerebral electrodes implanted in epileptic patients. Data were collected using a total number of 31 electrodes distributed along the whole rostro-caudal axis of the CC. LEPs were exclusively recorded in the middle part of the CC (area 24 0 ), within a rectangle bounded by vertical planes 6 mm anterior and 28 mm posterior to the vertical anterior commissure plane, and between horizontal planes 28–48 mm above the horizontal anterior commissure-posterior commissure line. The first typical cingulate LEP was biphasic, negative–positive, with mean latencies at 120.5 ± 17 and 194.2 ± 30 ms, respectively. A second biphasic LEP was recorded along 6 of the 8 electrodes implanted in the mid-cingulate at 234.4 ± 16 and 275.4 ± 30 ms for the negative and positive response, respectively. Our results suggest that only the mid-cingulate portion responds with a recordable evoked potential to phasic painful laser stimuli. The location of the CC response was consistent with most EEG modelling studies of scalp LEPs, and might reflect an attentional orienting reaction in close connection with motor responses to pain. The evoked potential technique only records faithfully time-locked EEG activities, but fails to reproduce responses that are not phase-locked to the stimulus, even if these latter are also induced by the stimulation. Other sub-regions of the CC could be the core of these ‘‘induced–not locked’’ activities which will need, to be extracted, more powerful analysis techniques such as time-frequency methods.
peripheral neuroanatomy. Our earlier neurophysiologic and brain imaging studies have shown both peripheral trigeminal and central dopaminergic dysfunction in AFP. Clinical examination may not be sufficient for the diagnosis of trigeminal neuropathy, and in trigeminal neuropathic pain (TNP), the sensory signs may spread outside the involved nerve distribution. Aim: To elucidate neuropathic mechanisms of AFP by comparing the results of neurophysiologic and psychophysical tests between patients with AFP and definite TNP. Methods: Twenty AFP patients (age mean 55.6, range 30–80 years) and 14 TNP patients (51.8, 32–76) participated. All patients underwent blink reflex (BR) testing with stimulation of the supraorbital nerve and the affected trigeminal distribution on both sides, habituation of the BR, and thermal quantitative sensory testing (QST) for cooling, warming, and heat pain. Results: The BR was abnormal in 15% of the AFP and in 64% of the TNP patients, always indicating unilateral trigeminal pathology (in 1 AFP and in 1 TNP patient, the findings suggested intracranial pathology). Deficient habituation of the BR was found in 35% of the AFP, and in 29% of the TNP patients. QST was abnormal in 55% of the AFP and in all TNP patients. Most frequent finding in both groups was hypoesthesia to innocuous thermal stimuli; only two AFP patients showed warm allodynia with deficient habituation of the BR. Five (25%) AFP patients had normal findings. Conclusions: Neurophysiologic and psychophysical tests show similar but less severe abnormalities in AFP patients compared to patients with definite TNP. Although AFP represents a heterogeneous entity, with a careful diagnostic work-up, a considerable proportion of AFP patients can be found to suffer from clinically under-diagnosed TNP. Current clinical diagnostic criteria for neuropathic pain may need reconsideration. doi:10.1016/j.clinph.2006.06.061
doi:10.1016/j.clinph.2006.06.060
FC19.2 How does atypical facial pain differ from neuropathic trigeminal pain? S.K. Ja¨a¨skela¨inen 1, H. Forssell 2, O. Tenovuo 3, P. Silvoniemi 4 1
Turku University Hospital, Department of Clinical Neurophysiology, Finland 2 Turku University Hospital, Department of Oral Diseases, Finland 3 Turku University Hospital, Department of Neurology, Finland 4 Turku University Hospital, Finland Background: In atypical facial pain (AFP), the symptoms and subtle subjective sensory signs do not follow
FC19.3 Increased laser evoked potential amplitude after spinal cord stimulation in patients with cardiac syndrome X L. De Armas 1, D. Le Pera 1, A. Sestito 2, D. Restuccia 3, F. Infusino 2, G. Sgueglia 2, R. Miliucci 4, S. Mariani 3, F. Crea 2, P. Tonali 3, B. Cioni 5, M. Meglio 5, G.A. Lanza 2, M. Valeriani 4 1
IRCCS San Raffaele Pisana, Motor Rehabilitation, Italy Universita` Cattolica, Cardiology, Italy 3 Universita` Cattolica, Neurology, Italy 4 Ospedale Pediatrico Bambino Gesu`, IRCCS, Neurology, Italy 5 Universita` Cattolica, Neurosurgery, Italy 2
Background: Although spinal cord stimulation (SCS) has been successfully used in several painful syndromes for pain relief, its mechanism of action still remains obscure.
FC18.1 A home environment operated by a brain computer interface for patients suffering from neuromuscular diseases: The ASPICE project F. Cincotti 1, F. Aloise 1, F. Babiloni 1, M.G. Marciani 1, D. Morelli 2, S. Paolucci 2, G. Oriolo 3, A. Cherubini 3, F. Macrı` 3, F. Sciarra 4, F. Mangiola 4, A. Melpignano 5, F. Davide 5, D. Mattia 1 1
Fondazione Santa Lucia IRCCS, Clinical Neurophysiopathology Unit, Italy 2 Fondazione Santa Lucia IRCCS, Italy 3 La Sapienza University, Computer and Systems Science Department, Italy 4 UILDM Sezione Lazio, Italy 5 Telecom Italia Learning Services, Italy Background: Brain–Computer Interface (BCI) is a technology which allows a user to express his/her will (for communication or control purposes) regardless of the ability to have a voluntary control of his/her own muscles. Though being an aid for the motor disabled is often mentioned as the primary goal for BCIs, few systems are actually available as aids for a number of daily activities. Aim: The purpose of the ASPICE project is to give an actual application to the BCI technology, by developing a modular control system for house appliances that users can drive through a BCI. Methods: The core of the system is implemented by software running on a commercial personal computer. User input is fed through hardware/software interfaces matched with the individual’s residual abilities. The system uses the user’s input to control domotic devices – such as remotely controlled lights, TV sets, etc. – and a Sony AIBO robot. During the second year of the study, 15 patients affected by neuromuscular diseases have been included in the clinical validation, in order to provide assessment through patients’ feedback and guidelines for customized system installation. Results: The system has been implemented, and installed in a room of the hospital furnished like a real house. Preparing the environment for the experimentation required no structural intervention – almost all actuators are easily put in place. The system allows the neuro motor disabled persons to improve their ability to control the home environment and to communicate. The interface has shown to be intuitive enough to be utilized by those users who are not familiar with computer interfaces. The level of acceptation by the users was satisfactory. Conclusions: This study has proved that a system including BCI interfaces as front-end can be useful in a clinical context as an assistive device. doi:10.1016/j.clinph.2006.06.058
1 2
S71
University of Essex, Computer Science, UK University of Strathclyde, Bioengineering, UK
Background: Currently, Brain Computer Interfaces (BCI) are of limited practical use requiring prolonged user training. BCI usability can improve by developing methods for EEG feature selection that allow for a more intuitive link between user intention and device control and which can provide multiple degrees of freedom in command selection. Aims: This study compares the performance of using principal component analysis (PCA) and support vector machines (SVM) for multiple feature selection in classifying pre-movement EEG epochs with direction of movement associated with rapid wrist movements to different positions in space. Methods: EEG was recorded from 28 electrodes forming an array over the left sensorimotor cortex in normal subjects with approval of a Local Ethics Committee. Right wrist muscle EMG was also recorded. Subjects viewed a PC monitor randomly presenting a set of five spatially distinct target positions corresponding to neutral, flexed, extended, ulnar and radial deviations of the wrist. When presented with a new target subjects were required to move (or imagine move) their wrist to the target as fast as possible creating datasets of repeats of 20 different movement (or imagined movement) combinations. Continuous wavelet transform was used to extract spatio-temporal characteristics of the EEG signals relative to time of movement initiation or target appearance in case of imagined motion. Results: Using PCA, 10 principal components generated 95% correct classification of pre-movement EEG with actual direction of motion. During imagined movement classification success reduced to 67%. In contrast, SVM classification of the imagined movement data outperformed PCA with up to 87% correct classification for intended direction of movement. Conclusion: During imagined movement SVM outperforms PCA. However, SVM is computationally demanding. We conclude that a hybrid method combining merits of both PCA and SVM may have potential for use in BCI intention detection. doi:10.1016/j.clinph.2006.06.059
FC19.1 Intracortical recordings of pain related laser evoked potentials in the human cingulate cortex L. Garcia-Larrea 1, M. Frot 1, M. Magnin 1, F. Maugiere 2 1
Inserm EMI 342-Central Integration of pain, France Neurological Hospital, Functional Neurophysiology Department, France
2
FC18.2 On feature selection for brain computer interfaces H. Lakany 1, P. Worrarjiran 2, G. Valsan 2, 2 B.A. Conway
The cingulate cortex (CC) is one of the most frequently reported sites of cerebral blood flow increase to pain (PET
S72
Oral Communications / Clinical Neurophysiology 117 (2006) S49–S111
and fMRI studies) but the CC areas in which pain-related activity changes have been found are widely distributed across studies. In most functional imaging and EEG modelling reports, the activated sites corresponded to the ‘midcingular’ region (Brodmann’s area 24 0 ). However, some imaging studies have also showed hemodynamic activations and deactivations of more anterior perigenual cingulate portions. In this study, we report laser evoked potentials (LEPs) recorded in the CC with intra-cerebral electrodes implanted in epileptic patients. Data were collected using a total number of 31 electrodes distributed along the whole rostro-caudal axis of the CC. LEPs were exclusively recorded in the middle part of the CC (area 24 0 ), within a rectangle bounded by vertical planes 6 mm anterior and 28 mm posterior to the vertical anterior commissure plane, and between horizontal planes 28–48 mm above the horizontal anterior commissure-posterior commissure line. The first typical cingulate LEP was biphasic, negative–positive, with mean latencies at 120.5 ± 17 and 194.2 ± 30 ms, respectively. A second biphasic LEP was recorded along 6 of the 8 electrodes implanted in the mid-cingulate at 234.4 ± 16 and 275.4 ± 30 ms for the negative and positive response, respectively. Our results suggest that only the mid-cingulate portion responds with a recordable evoked potential to phasic painful laser stimuli. The location of the CC response was consistent with most EEG modelling studies of scalp LEPs, and might reflect an attentional orienting reaction in close connection with motor responses to pain. The evoked potential technique only records faithfully time-locked EEG activities, but fails to reproduce responses that are not phase-locked to the stimulus, even if these latter are also induced by the stimulation. Other sub-regions of the CC could be the core of these ‘‘induced–not locked’’ activities which will need, to be extracted, more powerful analysis techniques such as time-frequency methods.
peripheral neuroanatomy. Our earlier neurophysiologic and brain imaging studies have shown both peripheral trigeminal and central dopaminergic dysfunction in AFP. Clinical examination may not be sufficient for the diagnosis of trigeminal neuropathy, and in trigeminal neuropathic pain (TNP), the sensory signs may spread outside the involved nerve distribution. Aim: To elucidate neuropathic mechanisms of AFP by comparing the results of neurophysiologic and psychophysical tests between patients with AFP and definite TNP. Methods: Twenty AFP patients (age mean 55.6, range 30–80 years) and 14 TNP patients (51.8, 32–76) participated. All patients underwent blink reflex (BR) testing with stimulation of the supraorbital nerve and the affected trigeminal distribution on both sides, habituation of the BR, and thermal quantitative sensory testing (QST) for cooling, warming, and heat pain. Results: The BR was abnormal in 15% of the AFP and in 64% of the TNP patients, always indicating unilateral trigeminal pathology (in 1 AFP and in 1 TNP patient, the findings suggested intracranial pathology). Deficient habituation of the BR was found in 35% of the AFP, and in 29% of the TNP patients. QST was abnormal in 55% of the AFP and in all TNP patients. Most frequent finding in both groups was hypoesthesia to innocuous thermal stimuli; only two AFP patients showed warm allodynia with deficient habituation of the BR. Five (25%) AFP patients had normal findings. Conclusions: Neurophysiologic and psychophysical tests show similar but less severe abnormalities in AFP patients compared to patients with definite TNP. Although AFP represents a heterogeneous entity, with a careful diagnostic work-up, a considerable proportion of AFP patients can be found to suffer from clinically under-diagnosed TNP. Current clinical diagnostic criteria for neuropathic pain may need reconsideration. doi:10.1016/j.clinph.2006.06.061
doi:10.1016/j.clinph.2006.06.060
FC19.2 How does atypical facial pain differ from neuropathic trigeminal pain? S.K. Ja¨a¨skela¨inen 1, H. Forssell 2, O. Tenovuo 3, P. Silvoniemi 4 1
Turku University Hospital, Department of Clinical Neurophysiology, Finland 2 Turku University Hospital, Department of Oral Diseases, Finland 3 Turku University Hospital, Department of Neurology, Finland 4 Turku University Hospital, Finland Background: In atypical facial pain (AFP), the symptoms and subtle subjective sensory signs do not follow
FC19.3 Increased laser evoked potential amplitude after spinal cord stimulation in patients with cardiac syndrome X L. De Armas 1, D. Le Pera 1, A. Sestito 2, D. Restuccia 3, F. Infusino 2, G. Sgueglia 2, R. Miliucci 4, S. Mariani 3, F. Crea 2, P. Tonali 3, B. Cioni 5, M. Meglio 5, G.A. Lanza 2, M. Valeriani 4 1
IRCCS San Raffaele Pisana, Motor Rehabilitation, Italy Universita` Cattolica, Cardiology, Italy 3 Universita` Cattolica, Neurology, Italy 4 Ospedale Pediatrico Bambino Gesu`, IRCCS, Neurology, Italy 5 Universita` Cattolica, Neurosurgery, Italy 2
Background: Although spinal cord stimulation (SCS) has been successfully used in several painful syndromes for pain relief, its mechanism of action still remains obscure.