Search

Abstract Background Brain-computer interfaces (BCI) use electroencephalography (EEG) to interpret user intention and control an output device accordingly. We describe a novel BCI method to use a signal from five EEG channels (comprising one primary channel with four additional channels used to calculate its Laplacian derivation) to provide two-dimensional (2-D) control of a cursor on a computer screen, with simple threshold-based binary classification of band power readings taken over pre-defined time windows during subject hand movement. Methods We tested the paradigm with four healthy subjects, none of whom had prior BCI experience. Each subject played a game wherein he or she attempted to move a cursor to a target within a grid while avoiding a trap. We also present supplementary results including one healthy subject using motor imagery, one primary lateral sclerosis (PLS) patient, and one healthy subject using a single EEG channel without Laplacian derivation. Results For the four healthy subjects using real hand movement, the system provided accurate cursor control with little or no required user training. The average accuracy of the cursor movement was 86.1% (SD 9.8%), which is significantly better than chance (p = 0.0015). The best subject achieved a control accuracy of 96%, with only one incorrect bit classification out of 47. The supplementary results showed that control can be achieved under the respective experimental conditions, but with reduced accuracy. Conclusion The binary method provides naïve subjects with real-time control of a cursor in 2-D using dichotomous classification of synchronous EEG band power readings from a small number of channels during hand movement. The primary strengths of our method are simplicity of hardware and software, and high accuracy when used by untrained subjects.

Purpose: To evaluate the diagnostic performance (DP) of the high-resolution contrast computed tomography (HR-contrast-CT) based Neck-Persistency-Net in distinguishing vital from non-vital persistent cervical lymph nodes (pcLNs) in patients with advanced head and neck squamous cell carcinoma (HNSCC) following primary concurrent chemoradiotherapy (CRT) with [18F]-fluorodeoxyglucose positron emission tomography and high-resolution contrast-enhanced computed tomography ([18F]FDG-PET-CT). Furthermore, the Neck-Persistency-Net's potential to justify omitting post-CRT neck dissection (ND) without risking treatment delays or preventing unnecessary surgery was explored., Methods: All HNSCC patients undergoing primary CRT followed by post-CRT-ND for pcLNs recorded in the institutional HNSCC registry were analyzed. The Neck-Persistency-Net DP was explored for three scenarios: balanced performance (BalPerf), optimized sensitivity (OptSens), and optimized specificity (OptSpec). Histopathology of post-CRT-ND served as a reference., Results: Among 68 included patients, 11 were female and 32 had vital pcLNs. The Neck-Persistency-Net demonstrated good DP with an area under the curve of 0.82. For BalPerf, both sensitivity and specificity were 78%; for OptSens (90%), specificity was 62%; for OptSpec (95%), sensitivity was 54%. Limiting post-CRT-ND to negative results would have delayed treatment in 27%, 40%, and 7% for BalPerf, OptSens and OptSpec, respectively, versus 23% for [18F]FDG-PET-CT. Conversely, restricting post-CRT-ND to positive results would have prevented unnecessary post-CRT-ND in 78%, 60%, and 95% for BalPerf, OptSens and OptSpec, respectively, versus 55% for [18F]FDG-PET-CT., Conclusion: The DP of the Neck-Persistency-Net was comparable to [18F]-FDG-PET-CT. Depending on the chosen decision boundary, the potential to justify the omission of post-CRT-ND without risking treatment delays in false negative findings or reliably prevent unnecessary surgery in false positive findings outperforms the [18F]-FDG-PET-CT., (© 2024. The Author(s).)

Introduction: Recent advances in the radiation therapy of prostate cancer have brought a shift toward moderate- and ultra-hypofractionated treatment schedules. Reducing safety margins can broaden the therapeutic window in stereotactic treatments and alleviate concerns for toxicity in high dose-per-fraction treatment schedules. Management of intrafractional motion is a necessity for stereotactic body radiation therapy (SBRT). It can be achieved by performing intrafractional image guidance and position corrections. We evaluate the suitability of such a novel prostate motion management system and its potential benefit for treatment accuracy., Methods: Intrafractional IGRT was performed for 22 patients during 149 treatment sessions using repeated orthogonal kV-XR imaging of implanted fiducial markers with the ExacTrac Dynamic (EXTD) system. Position measurements were taken four times during each arc of the applied volumetric modulated arc therapy (VMAT). Position correction was performed if translational deviation exceeded 2 mm in any direction., Results: Of 677 single EXTD measurements, 20.6% exceeded the predefined threshold of 2 mm 3D deviation. Without intrafractional corrections, 39.4% of all individual measurements would exceed the threshold. The 3D accuracy could thus significantly be improved, reducing mean 3D shifts from 1.97 (± 1.44) mm to 1.39 (± 1.01) mm by performing intrafractional IGRT. In total, 34% of all treatment sessions required correction of intrafractional position shifts., Conclusion: Monitoring of prostate motion using repeated intrafractional orthogonal kV-X-ray-based position measurements of implanted fiducial markers proved to be a reliable method to improve precision of stereotactic irradiations of the prostate. It can prevent unacceptable translation deviations in one third of all sessions., (© 2023. The Author(s).)

Clinical lymph node staging in head and neck carcinoma (HNC) is fraught with uncertainties. Established clinical algorithms are available for the problem of occult cervical metastases. Much less is known about clinical lymph node overstaging. We identified HNC patients clinically classified as lymph node positive (cN+), in whom surgical neck dissection (ND) specimens were histopathologically negative (pN0) and in addition the subgroup, in whom an originally planned postoperative radiotherapy (PORT) was omitted. We compared these patients with surgically treated patients with clinically and histopathologically negative neck (cN0/pN0), who had received selective ND. Using a fuzzy matching algorithm, we identified patients with closely similar patient and disease characteristics, who had received primary definitive radiotherapy (RT) with or without systemic therapy (RT ± ST). Of the 980 patients with HNC, 292 received a ND as part of primary treatment. In 128/292 patients with cN0 neck, ND was elective, and in 164 patients with clinically positive neck (cN+), ND was therapeutic. In 43/164 cN+ patients, ND was histopathologically negative (cN+/pN-). In 24 of these, initially planned PORT was omitted. Overall, survival did not differ from the cN0/pN0 and primary RT ± ST control groups. However, more RT ± ST patients had functional problems with nutrition ( p = 0.002). Based on these data, it can be estimated that lymph node overstaging is 26% (95% CI: 20% to 34%). In 15% (95% CI: 10% to 21%) of surgically treated cN+ HNC patients, treatment can be de-escalated without the affection of survival.

Acute myeloid leukemia (AML) carries a 10-100 fold lower mutational burden than other neoplastic entities. Mechanistic explanations for why a low number of mutations suffice to induce leukemogenesis are therefore required. Here we demonstrate that transgenic overexpression of the wild type sphingosine-1-phosphate receptor 3 (S1P 3 ) in murine hematopoietic stem cells is sufficient to induce a transplantable myeloid leukemia. In contrast, S1P 3 expression in more mature compartments does not cause malignant transformation. Treatment with the sphingosine phosphate receptor modulator Fingolimod, which prevents receptor signaling, normalized peripheral blood cell counts and reduced spleen sizes in S1P 3 expressing mice. Gene expression analyses in AML patients revealed elevated S1P 3 expression specifically in two molecular subclasses. Our data suggest a previously unrecognized contribution of wild type S1P 3 signaling to leukemogenesis that warrants the exploration of S1P 3 antagonists in preclinical AML models.

Study Design: Exploratory case-control study., Introduction: Writer's cramp (WC) is a type of focal hand dystonia. The central nervous system plays a role in its pathophysiology, but abnormalities in the affected musculoskeletal components may also be relevant., Purpose of the Study: We compared the active range of motion (ROM) in patients with WC and healthy volunteers (HVs) and correlated the findings with disease duration and severity., Methods: Affected limb joints were measured with goniometers. Patients were assessed at least 3 months after their last botulinum toxin (botulinum neurotoxin) injection, and strength was clinically normal. t tests were used to compare the ROMs of WC with matched HVs. The Spearman correlation coefficient assessed the relationship of active ROMs to the disease duration and handwriting subscore of the Dystonia Disability Scale., Results: ROMs of D1 metacarpophalangeal (MCP) joint extension as well as D2 and D5 MCP flexion were significantly smaller in WC, and distal interphalangeal joint extension in D3 and D5 was significantly greater compared with HVs. There were negative correlations between D2 MCP flexion and disease duration and with Dystonia Disability Scale., Discussion: Abnormalities in ROMs in WC were found. Severity and disease duration correlated with reduced D2 MCP flexion. This may be related to intrinsic biomechanical abnormalities, co-contraction of muscles, or a combination of subclinical weakness and atrophy from repeated botulinum neurotoxin injections., Conclusions: Hand biomechanical properties should not be ignored in the pathophysiology of WC., Level of Evidence: 2c., Competing Interests: statement The authors declare that there are no relevant conflicts of interest., (Copyright © 2016 Hanley & Belfus. All rights reserved.)

Basic technical and economic examinations of Austrian mass waste landfills, concerning the recovery of secondary raw materials, have been carried out by the 'LAMIS - Landfill Mining Austria' pilot project for the first time in Austria. A main focus of the research - the subject of this article - was the first devotion of a pilot landfill to an integrated ecological and economic assessment so that its feasibility could be verified before a landfill mining project commenced. A Styrian mass waste landfill had been chosen for this purpose that had been put into operation in 1979 and received mechanically-biologically pre-treated municipal waste till 2012. The whole assessment procedure was divided into preliminary and main assessment phases to evaluate the general suitability of a landfill mining project with little financial and human resource expense. A portfolio chart, based on a questionnaire, was created for the preliminary assessment that, as a result, has provided a recommendation for subsequent investigation - the main assessment phase. In this case, specific economic criteria were assessed by net present value calculation, while ecological or socio-economic criteria were rated by utility analysis, transferring the result into a utility-net present value chart. In the case of the examined pilot landfill, assessing the landfill mining project produced a higher utility but a lower net present value than a landfill leaving-in for aftercare. Since no clearly preferable scenario could be identified this way, a cost-revenue analysis was carried out in addition that determined a dimensionless ratio: the 'utility - net present value quotient' of both scenarios. Comparing this quotient showed unmistakably that in the overall assessment, 'leaving the landfill in aftercare' was preferable to a 'landfill mining project' in that specific case., (© The Author(s) 2016.)

For the first time in Austria, fundamental technological and economic studies on recovering secondary raw materials from large landfills have been carried out, based on the 'LAMIS - Landfill Mining Austria' pilot project. A main focus of the research - and the subject of this article - was to develop an assessment or decision-making procedure that allows landfill owners to thoroughly examine the feasibility of a landfill mining project in advance. Currently there are no standard procedures that would sufficiently cover all the multiple-criteria requirements. The basic structure of the multiple attribute decision making process was used to narrow down on selection, conceptual design and assessment of suitable procedures. Along with a breakdown into preliminary and main assessment, the entire foundation required was created, such as definitions of requirements to an assessment method, selection and accurate description of the various assessment criteria and classification of the target system for the present 'landfill mining' vs. 'retaining the landfill in after-care' decision-making problem. Based on these studies, cost-utility analysis and the analytical-hierarchy process were selected from the range of multiple attribute decision-making procedures and examined in detail. Overall, both methods have their pros and cons with regard to their use for assessing landfill mining projects. Merging these methods or connecting them with single-criteria decision-making methods (like the net present value method) may turn out to be reasonable and constitute an appropriate assessment method., (© The Author(s) 2015.)

The underlying pathophysiologic mechanism for complex motor stereotypies in children is unknown, with hypotheses ranging from an arousal to a motor control disorder. Movement-related cortical potentials (MRCPs), representing the activation of cerebral areas involved in the generation of movements, precede and accompany self-initiated voluntary movements. The goal of this study was to compare cerebral activity associated with stereotypies to that seen with voluntary movements in children with primary complex motor stereotypies. Electroencephalographic (EEG) activity synchronized with video recording was recorded in 10 children diagnosed with primary motor stereotypies and 7 controls. EEG activity related to stereotypies and self-paced arm movements were analyzed for presence or absence of early or late MRCP, a steep negativity beginning about 1 second before the onset of a voluntary movement. Early MRCPs preceded self-paced arm movements in 8 of 10 children with motor stereotypies and in 6 of 7 controls. Observed MRCPs did not differ between groups. No MRCP was identified before the appearance of a complex motor stereotypy. Unlike voluntary movements, stereotypies are not preceded by MRCPs. This indicates that premotor areas are likely not involved in the preparation of these complex movements and suggests that stereotypies are initiated by mechanisms different from voluntary movements. Further studies are required to determine the site of the motor control abnormality within cortico-striatal-thalamo-cortical pathways and to identify whether similar findings would be found in children with secondary stereotypies., (© 2013 International Parkinson and Movement Disorder Society.)

Background: Brain-computer interfaces (BCI) use electroencephalography (EEG) to interpret user intention and control an output device accordingly. We describe a novel BCI method to use a signal from five EEG channels (comprising one primary channel with four additional channels used to calculate its Laplacian derivation) to provide two-dimensional (2-D) control of a cursor on a computer screen, with simple threshold-based binary classification of band power readings taken over pre-defined time windows during subject hand movement., Methods: We tested the paradigm with four healthy subjects, none of whom had prior BCI experience. Each subject played a game wherein he or she attempted to move a cursor to a target within a grid while avoiding a trap. We also present supplementary results including one healthy subject using motor imagery, one primary lateral sclerosis (PLS) patient, and one healthy subject using a single EEG channel without Laplacian derivation., Results: For the four healthy subjects using real hand movement, the system provided accurate cursor control with little or no required user training. The average accuracy of the cursor movement was 86.1% (SD 9.8%), which is significantly better than chance (p = 0.0015). The best subject achieved a control accuracy of 96%, with only one incorrect bit classification out of 47. The supplementary results showed that control can be achieved under the respective experimental conditions, but with reduced accuracy., Conclusion: The binary method provides naïve subjects with real-time control of a cursor in 2-D using dichotomous classification of synchronous EEG band power readings from a small number of channels during hand movement. The primary strengths of our method are simplicity of hardware and software, and high accuracy when used by untrained subjects.

Objective: We sought to investigate the activity of bilateral parietal and premotor areas during a Go/No Go paradigm involving praxis movements of the dominant hand., Methods: A sentence was presented which instructed subjects on what movement to make (S1; for example, "Show me how to use a hammer."). After an 8-s delay, "Go" or "No Go" (S2) was presented. If Go, they were instructed to make the movement described in the S1 instruction sentence as quickly as possible, and continuously until the "Rest" cue was presented 3 s later. If No Go, subjects were to simply relax until the next instruction sentence. Event-related potentials (ERP) and event-related desynchronization (ERD) in the beta band (18-22 Hz) were evaluated for three time bins: after S1, after S2, and from -2.5 to -1.5 s before the S2 period., Results: Bilateral premotor ERP was greater than bilateral parietal ERP after the S2 Go compared with the No Go. Additionally, left premotor ERP was greater than that from the right premotor area. There was predominant left parietal ERD immediately after S1 for both Go and No Go, which was sustained for the duration of the interval between S1 and S2. For both S2 stimuli, predominant left parietal ERD was again seen when compared to that from the left premotor or right parietal area. However, the left parietal ERD was greater for Go than No Go., Conclusion: The results suggest a dominant role in the left parietal cortex for planning, executing, and suppressing praxis movements. The ERP and ERD show different patterns of activation and may reflect distinct neural movement-related activities., Significance: The data can guide further studies to determine the neurophysiological changes occurring in apraxia patients and help explain the unique error profiles seen in patients with left parietal damage.

Interventional paired associative stimulation (PAS) can induce plasticity in the cortex, and this plasticity was previously shown to be disordered in the primary motor cortex in focal hand dystonia (FHD). This study aimed to test whether associative plasticity is abnormal in the primary somatosensory cortex (S1) in FHD and whether PAS modulates excitatory or inhibitory interneurons within the cortex. Ten FHD patients and 10 healthy volunteers were studied. We investigated the changes in single- and double-pulse somatosensory-evoked potentials before and after PAS, which consisted of peripheral electrical nerve stimulation and subsequent transcranial magnetic stimulation over S1. Four sessions of somatosensory-evoked potentials recordings were performed: before PAS, and immediately, 15 and 30 min after PAS. We compared the time course of the somatosensory-evoked potentials between the FHD and healthy groups. In the single-pulse condition, the P27 amplitudes were significantly higher in FHD immediately after PAS than before PAS, while no changes were observed in healthy subjects. In the double-pulse condition, significant differences in the suppression ratio of P27 were found immediately after and 15 min after PAS, while there were no significant differences in healthy subjects. The P27 suppression tended to normalize toward the level of the healthy volunteer group. In FHD, PAS transiently induced an abnormal increase in excitability in S1. In addition, intracortical inhibition in S1 was found to increase as well. This abnormal plasticity of the intracortical neurons in S1 may contribute to the pathophysiology of dystonia.

Somesthetic temporal discrimination (STD) is impaired in focal hand dystonia (FHD). We explored the electrophysiological correlate of the STD deficit to assess whether this is due to dysfunction of temporal inhibition in the somatosensory inhibitory pathway or due to dysfunction in structures responsible for nonmodality-specific timing integration. Eleven FHD patients and 11 healthy volunteers were studied. STD threshold was investigated as the time interval required for perceiving a pair of stimuli as two separate stimuli in time. We also examined the somatosensory-evoked potential (SEP) in a paired-pulse paradigm. We compared STD threshold and recovery function of SEP between the groups. STD thresholds were significantly greater in FHD than in healthy volunteers. The amount of P27 suppression in the 5 ms-ISI condition was significantly less in FHD. It was also found that the STD threshold and P27 suppression were significantly correlated: the greater the STD threshold, the less the P27 suppression. Significantly less suppression of P27 with a lack of significant change in N20 indicates that the impairment of somatosensory information processing in the time domain is due to dysfunction within the primary somatosensory cortex, suggesting that that the STD deficit in FHD is more attributable to dysfunction in the somatosensory pathway., ((c) 2007 Movement Disorder Society.)

We sought to determine whether coherent networks which circumvent lesioned cortex are seen in patients with ideomotor apraxia (IMA) while performing tool-use pantomimes. Five normal subjects and five patients with IMA (three patients with corticobasal degeneration and two with left hemisphere stroke) underwent 64-channel EEG recording while performing three tool-use pantomimes with their left hand in a self-paced manner. Beta band (20-22 Hz) coherence indicates that normal subjects have a dominant left hemisphere network responsible for praxis preparation, which was absent in patients. Corticobasal degeneration patients showed significant coherence increase between left parietal-right premotor areas. Left hemisphere stroke patients showed significant coherence increases in a right parietofrontal network. The right hemisphere appears to store useable praxis representations in IMA patients with left hemisphere damage.

Unlabelled: To explore the reliability of a high performance brain-computer interface (BCI) using non-invasive EEG signals associated with human natural motor behavior does not require extensive training. We propose a new BCI method, where users perform either sustaining or stopping a motor task with time locking to a predefined time window. Nine healthy volunteers, one stroke survivor with right-sided hemiparesis and one patient with amyotrophic lateral sclerosis (ALS) participated in this study. Subjects did not receive BCI training before participating in this study. We investigated tasks of both physical movement and motor imagery. The surface Laplacian derivation was used for enhancing EEG spatial resolution. A model-free threshold setting method was used for the classification of motor intentions. The performance of the proposed BCI was validated by an online sequential binary-cursor-control game for two-dimensional cursor movement. Event-related desynchronization and synchronization were observed when subjects sustained or stopped either motor execution or motor imagery. Feature analysis showed that EEG beta band activity over sensorimotor area provided the largest discrimination. With simple model-free classification of beta band EEG activity from a single electrode (with surface Laplacian derivation), the online classifications of the EEG activity with motor execution/motor imagery were: >90%/ approximately 80% for six healthy volunteers, >80%/ approximately 80% for the stroke patient and approximately 90%/ approximately 80% for the ALS patient. The EEG activities of the other three healthy volunteers were not classifiable. The sensorimotor beta rhythm of EEG associated with human natural motor behavior can be used for a reliable and high performance BCI for both healthy subjects and patients with neurological disorders., Significance: The proposed new non-invasive BCI method highlights a practical BCI for clinical applications, where the user does not require extensive training.

Objective: To explore effective combinations of computational methods for the prediction of movement intention preceding the production of self-paced right and left hand movements from single trial scalp electroencephalogram (EEG)., Methods: Twelve naïve subjects performed self-paced movements consisting of three key strokes with either hand. EEG was recorded from 128 channels. The exploration was performed offline on single trial EEG data. We proposed that a successful computational procedure for classification would consist of spatial filtering, temporal filtering, feature selection, and pattern classification. A systematic investigation was performed with combinations of spatial filtering using principal component analysis (PCA), independent component analysis (ICA), common spatial patterns analysis (CSP), and surface Laplacian derivation (SLD); temporal filtering using power spectral density estimation (PSD) and discrete wavelet transform (DWT); pattern classification using linear Mahalanobis distance classifier (LMD), quadratic Mahalanobis distance classifier (QMD), Bayesian classifier (BSC), multi-layer perceptron neural network (MLP), probabilistic neural network (PNN), and support vector machine (SVM). A robust multivariate feature selection strategy using a genetic algorithm was employed., Results: The combinations of spatial filtering using ICA and SLD, temporal filtering using PSD and DWT, and classification methods using LMD, QMD, BSC and SVM provided higher performance than those of other combinations. Utilizing one of the better combinations of ICA, PSD and SVM, the discrimination accuracy was as high as 75%. Further feature analysis showed that beta band EEG activity of the channels over right sensorimotor cortex was most appropriate for discrimination of right and left hand movement intention., Conclusions: Effective combinations of computational methods provide possible classification of human movement intention from single trial EEG. Such a method could be the basis for a potential brain-computer interface based on human natural movement, which might reduce the requirement of long-term training., Significance: Effective combinations of computational methods can classify human movement intention from single trial EEG with reasonable accuracy.

Objective: To study spatiotemporal patterns of event-related desynchronization (ERD) preceding voluntary sequential finger movements performed with dominant right hand and nondominant left hand., Methods: Nine subjects performed self-paced movements consisting of three key strokes with either hand. Subjects randomized the laterality and timing of movements. Electroencephalogram (EEG) was recorded from 122 channels. Reference-free EEG power measurements in the beta band were calculated off-line., Results: During motor preparation (-2 to -0.5s with respect to movement onset), contralateral preponderance of event-related desynchronization (ERD) (lateralized power) was only observed during right hand finger movements, whereas ERD during left hand finger movements was bilateral., Conclusions: For right-handers, activation on the left hemisphere during left hand movements is greater than that on the right hemisphere during right hand movements., Significance: We provide further evidence for motor dominance of the left hemisphere in early period of motor preparation for complex sequential finger movements.

Objective: The main obstacle in interpreting EEG/MEG data in terms of brain connectivity is the fact that because of volume conduction, the activity of a single brain source can be observed in many channels. Here, we present an approach which is insensitive to false connectivity arising from volume conduction., Methods: We show that the (complex) coherency of non-interacting sources is necessarily real and, hence, the imaginary part of coherency provides an excellent candidate to study brain interactions. Although the usual magnitude and phase of coherency contain the same information as the real and imaginary parts, we argue that the Cartesian representation is far superior for studying brain interactions. The method is demonstrated for EEG measurements of voluntary finger movement., Results: We found: (a) from 5 s before to movement onset a relatively weak interaction around 20 Hz between left and right motor areas where the contralateral side leads the ipsilateral side; and (b) approximately 2-4 s after movement, a stronger interaction also at 20 Hz in the opposite direction., Conclusions: It is possible to reliably detect brain interaction during movement from EEG data., Significance: The method allows unambiguous detection of brain interaction from rhythmic EEG/MEG data.