Effects of Task Complexity on Motor Imagery-Based Brain-Computer Interface.

The performance of electroencephalogram (EEG)-based brain-computer interfaces (BCIs) still needs improvements for real world applications. An improvement on BCIs could be achieved by enhancing brain signals from the source via subject intention-based modulation. In this work, we aim to investigate the effects of task complexity on performance of motor imagery (MI) based BCIs. In specific, we studied the effects of motor imagery of a complex task versus a simple task on discriminability of brain activation patterns using EEG. The results show an increase of up to 7.25% in BCI classification accuracy for motor imagery of the complex task in comparison to the simple task. Furthermore, spectral power analysis in low frequency bands, alpha and beta, shows a significant decrease in power value for the complex task. However, high frequency gamma band analysis unveils a significant increase for the complex task. These findings may lead to designing better BCIs with high performance.

Human-to-human closed-loop control based on brain-to-brain interface and muscle-to-muscle interface.

Novel communication techniques have always been fascinating for humankind. This pilot study presents an approach to human interaction by combining direct brain-to-brain interface (BBI) and muscle-to-muscle interface (MMI) in a closed-loop pattern. In this system, artificial paths (data flows) functionally connect natural paths (nerves). The intention from one subject (sender) is recognized using electroencephalography (EEG) based brain-computer interface (BCI), which is sent out to trigger transcranial magnetic stimulation (TMS) on the other subject (receiver) and induce hand motion; meanwhile TMS results in a significant change on the motor evoked potentials (MEP) recorded by electromyography (EMG) of the receiver's arm, which triggers functional electrical stimulation (FES) applied to the sender's arm and generates hand motion. Human-controlled loop and automatic control loop experiments were performed with 6 pairs of healthy subjects to evaluate the performance of the introduced mechanism. The results indicated that response accuracy during human-controlled experiments was 85% which demonstrates the feasibility of the proposed method. During the automatic control test, two subjects could accomplish repetitive and reciprocal hand motion control up to 85 times consecutively.

In vitro aerodynamic characterization of the dose emitted during nebulization of tobramycin high strength solution by novel and jet nebulizer delivery systems.

BACKGROUND: Chronic infections with Pseudomonas aeruginosa are a leading cause of morbidity in patients with cystic fibrosis (CF). The aim of tobramycin inhalation therapy in CF patients with chronic pulmonary infection is to deliver high amounts of drug directly to the site of infection. TOBI(®) is a tobramycin nebulizer solution (300 mg/5 ml) approved by FDA for maintenance therapy for patient with CF. The 20% tobramycin sulfate solution was reported as the optimal and maximal concentration. METHODS: Nebulization of high strength tobramycin solution (20% tobramycin sulfate) (HSTS) has been assessed in this study by using different selected high performance nebulizer delivery systems: two different designs of jet nebulizers, and three new nebulizers based on vibrating mesh technology. The aerosol particle size distribution and output characteristics were measured for in vitro performance assessment of the nebulizer systems. The methodology was adapted from the current European standard, EN 13544-1:2001E. RESULTS: The particle size distribution characteristic measurements showed that all tested nebulizers may be suitable for inhalation of HSTS. The mean (SD) of highest percentage of fine particles (<5 µm) was 77.64 (2.3) % for Sidestream(®), at flow rate 16 L/min. The highest respirable inhaled mass was for Pari LC Plus(®) combined with PariBoyN(®) compressor, with mean (SD) 90.85 (8.6) mg. The mean (SD) of highest drug wastage percentage was 63.9 (3.9) % for Sidestream(®) jet nebulizer combined with compressed air cylinder at flow rate 16 L/min, while the lowest was 2.3 (0.26) % for NE-U22 Omron(®) (high frequency). CONCLUSIONS: The HSTS can be nebulized by all tested nebulisers but the high frequency NE-U22 Omron(®) and Aeroneb Go(®) are more efficient. When the HSTS compared to TOBI(®), the respirable inhaled dose was increased to more than 73%.

A novel virtual motor rehabilitation system for Guillain-Barré syndrome. Two single case studies.

INTRODUCTION: This article is part of the Focus Theme of Methods of Information in Medicine on "New Methodologies for Patients Rehabilitation". OBJECTIVES: For Guillain-Barré patients, motor rehabilitation programs are helpful at the onset to prevent the complications of paralysis and in cases of persistent motor impairment. Traditional motor rehabilitation programs may be tedious and monotonous, resulting in low adherence to the treatments. A Virtual Motor Rehabilitation system has been tested in Guillain-Barré patients to increase patient adherence and to improve clinical results. METHODS: Two people with Guillain-Barré performed 20 rehabilitation sessions. We tested a novel system based on Motor Virtual Rehabilitation in three periods of time (baseline evaluation, final evaluation, and follow-up. In the training program, the participants carried out a specific treatment using the Active Balance Rehabilitation system (ABAR). The system is composed of customizable virtual games to perform static and dynamic balance rehabilitation. RESULTS: Significant improvements in clinical results were obtained by both participants, with significant results in the static balance clinical test of the Anterior Reach test in the standing position and unipedal stance time. Other significant results were found in dynamic balance clinical tests in the Berg Balance Scale test and the 30-second Sit-to-Stand test. With regard to acceptance of the system, both patients enjoyed the experience, and both patients thought that this system was helpful for their rehabilitation. CONCLUSIONS: The results show that Virtual Motor Rehabilitation for Guillain-Barré patients provides clinical improvements in an entertaining way.

Development and validation of HPLC method for the determination of tobramycin in urine samples post-inhalation using pre-column derivatisation with fluorescein isothiocyanate.

A reversed-phase liquid chromatography method involving pre-column derivatisation with fluorescein isothiocyanate (FITC, isomer I) for determination of tobramycin in urine samples after inhalation has been developed. FITC reacts with the primary amino groups of tobramycin and other aminoglycosides under mild conditions to form a highly fluorescent and stable derivative. The chromatographic separation was carried out on a Phenomenex Luna C(18) column at ambient temperature using a constant flow rate of 1 ml/min and mobile phase of acetonitrile-methanol-glacial acetic acid-water (420:60:5:515, v/v/v/v). The tobramycin-FITC derivative was monitored by fluorescent detection at an excitation wavelength 490 nm and emission wavelength 518 nm. The linearity of response for tobramycin was demonstrated at 11 different concentrations of tobramycin extracted from spiked urine, ranging from 0.25 to 20 microg/ml. Tobramycin and neomycin were extracted from spiked urine by a solid phase extraction clean-up procedure on a carboxypropyl-bonded phase (CBA) weak cation-exchange cartridge, and the relative recovery was >99% (n=5). The limit of detection (LOD) and limit of quantitation (LOQ) in urine were 70 and 250 ng/ml, respectively. The method had an accuracy of <0.2%, and intra-day and inter-day precision (in term of %coefficient of variation) were <4.89% and 8.25%, respectively. This assay was used for urinary pharmacokinetic studies to identify the relative lung deposition of tobramycin post-inhalation of tobramycin inhaled solution 300 mg/5 ml (TOBI) by different nebuliser systems.