NEUROTECHNIX 2013 Abstracts


Full Papers
Paper Nr: 4
Title:

Robotic Grasp Initiation by Gaze Independent Brain-controlled Selection of Virtual Reality Objects

Authors:

Christoph Reichert, Matthias Kennel, Rudolf Kruse, Hans-Jochen Heinze, Ulrich Schmucker, Hermann Hinrichs and Jochem W. Rieger

Abstract: Assistive devices controlled by human brain activity could help severely paralyzed patients to perform everyday tasks such as reaching and grasping objects. However, the continuous control of anthropomorphic prostheses requires control of a large number of degrees of freedom which is challenging with the currently achievable information transfer rate of noninvasive Brain Computer Interfaces (BCI). In this work we present an autonomous grasping system that allows grasping of natural objects even with the very low information transfer rates obtained in noninvasive BCIs. The grasp of one out of several objects is initiated by decoded voluntary brain wave modulations. A universal online grasp planning algorithm was developed that grasps the object selected by the user in a virtual reality environment. Our results with subjects demonstrate that training effort required to control the system is very low (<10 min) and that the decoding accuracy increases over time. We also found that the system works most reliably when subjects freely select objects and receive virtual grasp feedback.

Paper Nr: 12
Title:

Striving for Better and Earlier Movement Prediction by Postprocessing of Classification Scores

Authors:

Sirko Straube, Anett Seeland and David Feess

Abstract: Brain-computer interfaces that enable movement prediction are useful for many application fields from telemanipulation to rehabilitation. Current systems still struggle with a level of unreliability that requires improvement. Here, we investigate several postprocessing methods that operate on the classification outcomes. In particular, the data was classified after preprocessing using a support vector machine (SVM). The output of the SVM, i.e. the raw score values, were postprocessed using previously obtained scores to account for trends in the classification result. The respective methods differ in the way the transformation is performed. The idea is to use trends, like the rise of the score values approaching an upcoming movement, to yield a better prediction in terms of detection accuracy and/or an earlier time point. We present results from different subjects where upcoming voluntary movements of the right arm were predicted using the lateralized readiness potential from the EEG. The results illustrate that better and earlier predictions are indeed possible with the suggested methods. However, the best postprocessing method was rather subject-specific. Depending on the requirements of the application at hand, postprocessing the classification scores as suggested here can be used to find the best compromise between prediction accuracy and time point.

Paper Nr: 16
Title:

A Low Cost Platform based on FES and Muscle Synergies for Postural Control Research and Rehabilitation

Authors:

D. Galeano , F. Brunetti, D. Torricelli, S. Piazza and J. L. Pons

Abstract: This paper presents a low cost system for the assessment, diagnosis and training of balance based on static posturography and functional electrical stimulation (FES). This system includes low cost technology as the Wii Fit Balance Board and the Kinect. The posturography is a complementary tool to clinical diagnosis, and allows to find sensory systems and inputs degraded by different pathologies. The presented system also allows to explore new rehabilitation techniques based on functional electrical stimulation. Precisely, this paper describes the implementation of a novel balance and posture control rehabilitation approach based on muscle synergies.

Short Papers
Paper Nr: 5
Title:

Does an Angry Salesman Scary the Students of University of Silesia? - Visual ERP Studies

Authors:

Karina Maciejewska and Zofia Drzazga

Abstract: Three visual ERP tasks with oddball paradigm (geometric figures, picture of a nice lady and an angry salesman, a sentence with non logic word) were performed by students of University of Silesia. Few ranges of band-pass filters and artifact correction were examined to evaluate the optimal parameters of data analysis. Shape, latency and amplitude of P300 in the task with a picture of angry salesman as well as in the sentence task did not differ from the simple task with geometric figures. These results indicate that emotional picture or a sentence with illogical word did not affect cognitive activity in studied group of students, probably because the task was not very complex.

Paper Nr: 7
Title:

Proposal of a P300-based BCI Speller using a Predictive Text System

Authors:

Ricardo Ron Angevin and Leandro da Silva-Sauer

Abstract: This paper presents a P300-based BCI speller system that uses a virtual 4 x 3 keyboard based on the T9 interface developed on mobile phones in order to increase the writing speed. To validate the effectiveness of the proposed BCI, we compared it with two adaptations of the classical Farwell and Donchin speller, which is based on a 6 x 6 symbol matrix. Three healthy subjects took part in the experiment. The preliminary results confirm the effectiveness of T9-based speller, since the time needed to spell words and complete sentences was considerably reduced.

Paper Nr: 8
Title:

Separation of Auditory Evoked Responses to the Right- and Left-Ear Inputs

Authors:

S. Kuriki, H. Kurumaya, K. Tanaka and Y. Uchikawa

Abstract: In the monitoring/examination of auditory neural functions in rehabilitation, it is desirable to observe the responses from the central auditory system separately to the right- and left-ear inputs during binaural stimulation of sounds. However, mixed responses in the right or left auditory cortices are difficult to discriminate. Here, we report a novel method to discriminate transient responses evoked by binaural sounds delivered simultaneously to the right and left ears. Simulations showed that transient phasic responses were much attenuated in amplitude after repeated averaging of the response-epochs using triggers that were asynchronous to the sound onsets, while original waveform of the response was reserved by synchronous averaging time-locked to the sounds. In the measurements of evoked magnetic fields, we obtained separated responses to a speech sound and a pure tone delivered to the right and left ears by using two sets of triggers that were time-locked to the right and left stimuli with random intervals but uncorrelated with each other.

Paper Nr: 10
Title:

Carrier Frequency Specificity of Short-sound Elicited Auditory Steady-State Response and Effect of Animation Presentation

Authors:

Keita Tanaka, Fumie Kudo, Shinya Kuriki and Yoshinori Uchikawa

Abstract: This study examined the frequency dependence of the Auditory Steady-State response (ASSR) that was evoked by short AM sounds of equal loudness. We also examined the effect of presentation of silent animation movie on ASSR to keep the wakefulness. The stimulus sounds consisted of short AM tones of 0.78 s length having different carrier frequencies of 240, 480, 960, 1920 and 3840 Hz. As a result, the amplitude of the measured ASSR of EEG was decreased above 1000 Hz. The amplitude did not depend on the presence of the animation.

Paper Nr: 11
Title:

Comparison of Parametric and Non-Parametric Spectral Estimation Methods for Automatic Tremor Detection against Clinical Evaluation

Authors:

O. Martinez-Manzanera, J. H. Elting, J. W. van der Hoeven and N. M. Maurits

Abstract: Psychogenic tremor (PT) is a condition where the person affected suffers from tremor with variable characteristics that can make it difficult to diagnose. To help in the diagnosis an automatic tremor detection method applied to long-term kinematic recordings is proposed. The recorded signal is divided in segments which are analyzed and classified automatically as “tremor” or “no tremor”. The classification is done according to the location of the dominant frequency of the power spectral density (PSD) of each segment. Different PSD estimation methods are explored to determine the optimum method for segments of short length. The performance of each method is compared against a clinical assessment of tremor.

Paper Nr: 13
Title:

Memory and Processing Efficient Formula for Moving Variance Calculation in EEG and EMG Signal Processing

Authors:

Mario Michael Krell, Marc Tabie, Hendrik Wöhrle and Elsa Andrea Kirchner

Abstract: Adaptation of human-machine interaction devices by means of physiological data requires online analysis. We introduce new update formulas for otherwise time-demanding calculations of window based current mean and variance of the signal. Those were required for efficient realtime time series data processing. We discuss the formulas with the help of synthetic data. They differ from existing incremental calculations due to a decremental component, because of samples leaving the window of observation. An example application for EMG-based movement onset prediction is presented.

Paper Nr: 15
Title:

A Dataflow-based Mobile Brain Reading System on Chip with Supervised Online Calibration - For Usage without Acquisition of Training Data

Authors:

Hendrik Woehrle, Johannes Teiwes, Mario Michael Krell, Elsa Andrea Kirchner and Frank Kirchner

Abstract: Brain activity is more and more used for innovative applications like Brain Computer Interfaces (BCIs). However, in order to be able to use the brain activity, the related psychophysiological data has to be processed and analyzed with sophisticated signal processing and machine learning methods. Usually these methods have to be calibrated with subject-specific data before they can be used. Since future systems that implement these methods need to be portable to be applied more flexible tight constraints regarding size, power consumption and computing time have to be met. Field Programmable Gate Arrays (FPGAs) are a promising solution, which are able to meet all the constraints at the same time. Here, we present an FPGA-based mobile system for signal processing and classification. In addition to other systems, it is able to be calibrated and adapt at runtime, which makes the acquisition of training data unnecessary.

Paper Nr: 17
Title:

A Method to Detect Keystrokes using Accelerometry to Quantify Typing Rate and Monitor Neurodegenerative Progression

Authors:

Ana Londral, Mafalda Câmara, Hugo Gamboa, Mamede de Carvalho, Anabela Pinto and Luís Azevedo

Abstract: Progressive motor neurodegenerative diseases, as ALS, cause progressive loss of motor function in upper limbs. Motor involvement, also affecting speech at some stage of disease, cause increasing difficulties in accessing to computer devices (and internet tools) that allow communication with caregivers, and healthy professionals. Thus, monitoring progression is important to anticipate new assistive technologies (AT), e.g. computer interface. We present a novel methodology to monitor upper limb typing task functional effectiveness. In our approach, an accelerometer is placed on the index finger allows to measure the number of keystrokes per minute. We developed algorithm that was accurate when tested in three ALS patients and in three control subjects. This method to evaluate communication performance explores the quantification of movement as an early predictor of progression.

Paper Nr: 18
Title:

Simultaneous Optical Stimulation and Electrophysiological Recordings in Closed-loop Operation

Authors:

Thoa Nguyen, Ling Wang, Henrique Cabral, Georges Gielen, Francesco Battaglia and Carmen Bartic

Abstract: Closed-loop brain computer interfaces are rapidly progressing due to their application in fundamental neuroscience and prosthetics implemented. The integration of optical stimulation and electrophysiological recordings, on one hand, brings the advantage of cell-type selectivity. On the other hand, it provides an alternative solution to the stimulation-induced artifacts, a challenge in electrical stimulation. In this contribution, we describe a prototype allowing simultaneous optical stimulation and electrophysiological recordings in a closed-loop manner. The prototype is implemented with online spike detection and classification for selective cell-type stimulation.

Paper Nr: 20
Title:

Automated Algorithm for Synchronized Quantification of LFP Recordings and Individual Behavioural Parameters in an Animal Model for OCD

Authors:

T. Tambuyzer, H. Wu, K. Bauweleers, Kris van Kuyck, B. Nuttin and J.-m Aerts

Abstract: This work describes an algorithm which is developed for automated analyses of LFP recordings and behavioural parameters in freely moving rats. Here, we present the algorithm applied on a rat model for OCD (Schedule-induced polydipsia, SIP). The algorithm allows to extract detailed behavioural parameters based on images of a top view camera. Changes during the disease conditioning period can be tracked and correlated with synchronously measured changes in the LFP recordings. We believe that such automated algorithms can highly contribute to a deeper understanding of recorded local field potentials and their link with pathological behaviour of individual animals.

Paper Nr: 21
Title:

Molding Microchannel and Brain Implant Scaffolds from Microstructured Double Layer Photo Resin Master Casts - Concepts and Examples

Authors:

Rouhollah Habibey, Asiyeh Golabchi and Axel Blau

Abstract: Replica-casting finds wide application in soft lithography (Qin et al., 2010) and microfluidics (Bettinger et al., 2010). Most commonly, structures are molded with micro- to nano-patterned photoresists as master casts into polydimethylsiloxane (PDMS). PDMS features many favorable properties. It reproduces geometric details with nanometer fidelity, has low cytotoxicity, is transparent in the visible spectrum, biostable both in vitro and in vivo, can be plasma-bonded to itself, has low water permeability and is simple to handle and process. After curing, the PDMS can be easily peeled from the master and the latter usually be reused (Anderson et al., 2000) if patterns are not undercut (Yun et al., 2008). Here, we demonstrate a straightforward replica-molding process that can be exploited for the generation of perforated microchannel scaffolds for the in vitro use in axonal guidance and regeneration studies on microelectrode arrays (MEAs) or the production of tissue-conformal in vivo MEAs for neuroprosthetic applications, respectively.

Paper Nr: 22
Title:

Command-line Electrophysiology - A Closed-loop Approach to Single Cell Characterisation

Authors:

João Couto, Daniele Linaro and  Michele  Giugliano

Abstract: Cellular electrophysiology is the gold standard in the study of the functional properties of synapses, neurons, and microcircuits, both in vitro and in vivo. Conventional experimental paradigms, however, only marginally approximate physiologically relevant stimulus-response conditions. In fact, they are typically open-loop, as the response of the system under analysis, be it a single neuron or a small ensemble of cells, has a very limited influence on the stimulation that is applied. A general experimental framework that enables the researcher to design closed-loop experiments where the stimulation that is applied to the neuron (or network of neurons) depends on dynamical quantities related to its state is lacking. We address this by presenting a highly customisable electrophysiology data acquisition and stimulation toolbox, which allows the experimenter to perform standard voltage and current clamp protocols but also novel closed-loop paradigms, such as clamping the firing frequency or temporal firing dynamics of a (group of) neuron(s). We include also features to to deliver stimulation waveforms at specific phases of firing or of local field potentials, and to easily perform conductance-clamp, artificial ion channel injections, and hybrid experiments. As an illustrative example we use whole-cell patch clamp recordings from L5 pyramidal neurons in acute brain slices to characterise its input-output (firing frequency vs current) relation and suggest a novel closed-loop approach to this common protocol using a PID controller. By enabling closed loop experiments at several degrees of abstraction (from ion channel simulation to clamping network properties) and allowing to interface with general-purpose scripting languages, this software has the potential to boost electrophysiological research to another level of automation and protocol complexity with minimal effort by the neuroscientist.

Paper Nr: 24
Title:

Neuromuscular Electrical Stimulation and Biofeedback Therapy to Improve Endometrial Growth in Patients with Thin Endometrium - A Randomized Controlled Study

Authors:

Madafeitom Meheza Abide Bodombossou Djobo, Xiaoli Chen, Zhuangyu He, Xiaomiao Zhao, Shaoqing Chen, Qingxue Zhang and Dongzi Yang

Abstract: Objective: to evaluate the efficacy of noninvasive Neuromuscular electrical stimulation (NMES) in the management of thin endometrium patients. Design: A randomized control study Patients: 115 patients with thin endometrium (≤7mm) and history of infertility Interventions: NMES group received NMES 3 to 4 times during one menstruation cycle from day 9-10 and in comparison, a similar group of subjects received the aspirin treatment protocol. Outcomes: Pre and post-treatment endometrium thickness, endometrial volume and Power Doppler Angiography (PDA) related parameters measured by three-dimensional ultrasound. Results: the endometrium was thicker in the NMES group compared with that in aspirin group [8.00 versus 7.72; P=0.028]. 32/55(58%) developed endometrial thickness equal to or more than 8 mm after NMES therapy in the NMES group and 16/48(33%) in aspirin group. The endometrial and sub-endometrial volumes at final point also differ significantly between groups [2.58 versus 2.28; P=0.008 and 1.40 versus 1.21; P=0.001 for endometrial volume and sub-endometrial volume respectively. The two groups did not differ significantly regarding endometrial vascularization index (VI) and vascularization flow index (VFI) at final point. But in another hand, endometrial flow index (FI), sub-endometrial vascularization index (sub-VI), sub-endometrial flow index (sub-FI) and sub-endometrial vascularization flow index (sub-VFI) differed statistically between groups (P=0.032, P=0.022, P=0.006 and P=0.018 respectively). Conclusion: NMES group showed better endometrial thickness, volume and vascularization than aspirin group. NMES may have a proliferative effect on endometrium and improve its vascularization.

Paper Nr: 25
Title:

Comparison of Neural Networks for Prediction of Sleep Apnea

Authors:

Yashar Maali and Adel Al-Jumaily

Abstract: Sleep apnea (SA) is the most important and common component of sleep disorders which has several short term and long term side effects on health. There are several studies on automated SA detection but not too much works have been done on SA prediction. This paper discusses the application of artificial neural net-works (ANNs) to predict sleep apnea. Three types of neural networks were investigated: Elman, cascade-forward and feed-forward back propagation. We assessed the performance of the models using the Receiver Operating Characteristic (ROC) curve, particularly the area under the ROC curves (AUC), and statistically compare the cross validated estimate of the AUC of different models. Based on the obtained results, generally cascade-forward model results are better with average of AUC around 80%.