Romulus Lontis

Movement Related Cortical Potentials and Sensory Motor Rhythms during Self Initiated and Cued Movements

In this study we have explored the two EEG phenomena that accompany movement preparation and execution: movement related cortical potentials (MRCP) and event-related desynchronization/synchronization (ERD/ERS). The experiments comprised the two conditions for motor task initiation, self paced and cued. The aim of the study was to explore how the introduction of the cue influences the morphological features of the MRCP and ERD/ERS curves. Preliminary results of the tests in 9 healthy subjects showed statistically significant differences in MRCP components for the two conditions and no significant differences in ERD/ERS morphology. Brain-Computer Interface algorithms for online control of assistive devices for restoration of movement may benefit from these results.

Learning to type with the tip of the tongue: a performance study for a tongue-computer interface

This study is motivated by the need to know the characteristics of the learning processes in tongue-computer interaction and to obtain a useful insight to a better design of the tongue-computer interface for computer text input. Tongue-typing can be a good alternative to hand input methods for physically disabled individuals or tasks where hand-typing is not possible. In order to evaluate the process of typing with the tip of the tongue, eight volunteers participated in tip-of-tongue selectivity training experiments using an inductive tongue-computer interface. Performance data based on typing speed and accuracy fits a general learning model based on the power law of practice, which can be used to estimate further improvements of tongue-typing performance. Simulated expert typing rates predict a tongue-typing performance 8 times slower than normal QWERTY keyboard, but duplicate the performance of other alternative input interfaces. Our results encourage the use of a tongue-computer interface over other methods for physically disabled individuals.

Detection of Movement Intention from Movement-Related Cortical Potentials with Different Paradigms

In this study, we compared the effects of two imagery paradigms typically used within the field of brain computer interfaces on the detection of movement intention from scalp electroencephalography (EEG). This issue is important in the rehabilitation area because of its direct relation with appropriately timed neurofeedback. Subjects were asked to imagine hand or foot movements using either a random or a non-random cue. Templates were constructed individually for each subject. Movement intent was detected according to the correlation between the movement related cortical potentials (MRCP) of single trials with the initial part of the template. The large Laplacian filter was used to increase the signal to noise ratio (SNR). For the random cue, the true positive rate (TPR) of detection of movement intention was 63.5±5.9% for foot movement and the corresponding detection latency was 202.8±129.5 ms before movement onset. For the non-random cue, foot movement intention was detected with TPR of 75.3±5.5% and latency of 291±169.3 ms. These results demonstrate that cue type, random or non-random, has a significant effect on the performance of MRCP-based movement intention detection algorithms.

Comparison of tongue interface with keyboard for control of an assistive robotic arm

This paper demonstrates how an assistive 6 DoF robotic arm with a gripper can be controlled manually using a tongue interface. The proposed method suggests that it possible for a user to manipulate the surroundings with his or her tongue using the inductive tongue control system as deployed in this study. The sensors of an inductive tongue-computer interface were mapped to the Cartesian control of an assistive robotic arm. The resulting control system was tested manually in order to compare manual control of the robot using a standard keyboard and using the tongue interface. Two healthy subjects controlled the robotic arm to precisely move a bottle of water from one location to another. The results shows that the tongue interface was able to fully control the robotic arm in a similar manner as the standard keyboard resulting in the same number of successful manipulations and an average increase in task duration of up to 30% as compared with the standard keyboard.

The changing brain: bidirectional learning between algorithm and user

In 2013–2014 we have advanced our MRCP-based BCI by demonstrating: (1) the ability to detect movement intent during dynamic tasks; (2) better detection accuracy than conventional approaches by implementing the locality preserving projection (LPP) approach; (3) the ability to use a single channel for accurate detection; and (4) enhanced neuroplasticity by driving a robotic device in an online mode. To realize our final goal of an at home system, we have characterized alterations during single session use in our extracted signal when the user is undergoing complex learning or experiencing significant attentional shifts—all seriously affecting the detection of user intent. Learning enhances the variability of MRCP at specific recording sites while attention shifts result in a more global increase in signal variability. With the results presented, we are working towards an adaptive brain–computer interface where bidirectional learning (either user or algorithm) is possible.

Controlling a Drone by the Tongue – A Pilot Study on Drone Based Facilitation of Social Activities and Sports for People with Complete Tetraplegia

Tetraplegia is a devastating condition, resulting in severe disability and isolation from social activities and entertainment. Drones may provide a severely paralyzed individual the possibility of participation in drone-sports and thereby in social interaction and further it may give a sense of freely moving. However, individuals with tetraplegia currently lack options for controlling a drone. Researchers at Aalborg University have developed a wireless intraoral tongue computer interface (ITCI) for disabled users. This study investigates the possibility of controlling a drone by the ITCI. One able-bodied experimental participant controlled the drone using a standard keyword, the ITCI while keeping it in the hand, and by mounting the ITCI inside the mouth and using the tongue. The performance of the ITCI was compared with respect to the keyboard. The mean distance from the target and the mean flight time were 36% and 16% greater when using the ITCI inside the mouth with respect to controlling by the keyboard.

Evaluation of the effect of sensory feedback on phantom limb pain in multi-center clinical trials

The EPIONE consortium aims to evaluate the effect of artificial sensory stimulation using an operant conditioning paradigm as a therapy for Phantom Limb Pain (PLP). A uniform therapy /assessment protocol was developed for a multi-center study to evaluate the effect of the therapy on their (1) Phantom Limb Pain, (2) psychological state and (3) sensory motor cortical map. Participating subjects complete several phases of assessment. Post hoc analyses will compare results from testing done before, during, and after therapy. Outcomes of the intervention aim to improve the current understanding of pain and the psychophysical effects of pain management, which will progress the pilot therapy program toward a fully developed PLP solution.

Gender effect on discrimination of location and frequency in surface electrical stimulation.

This work investigated the gender effect on discrimination of surface electrical stimulation applied on the human forearm. Three experiments were conducted to examine the abilty of discriminating stimulation frequency, location, or both parameters in 14 healthy subjects. The results indicated a statistically significant impact of gender on the discrimination performance in all the three experiments (p <; 0.01, p <; 0.01, and p <; 0.001, respectively). The female group performed noticeably better than the male group (i.e., mean difference 15.4%, 11.9%, and 16.7% in repective experiment). The findings may provide evidence of gender difference in perceiving and interpreting electrical stimulation. Considering the gender difference may improve the efficacy of electrically evoked sensory feedback in applications such as prosthetic use and pain relief.