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Robotic orthosis compared to virtual hand for Brain–Computer Interface feedback

Cantillo-Negrete Jessica, Carino-Escobar Ruben I., Carrillo-Mora Paul, Barraza-Madrigal José A., Arias-Carrión Oscar

Biocybernetics and Biomedical Engineering

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2019

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Vol. 39, no. 2

263--272

EN

Brain–Computer Interfaces (BCI) allow the control of external devices by decoding the users' intentions from their central nervous system. Feedback, one of the main elements of a closed- loop BCI, is used to enhance the user's performance. The present work aimed to compare the effect of two different feedback sources; congruent anatomical visual hand representation and passive hand movement on BCI performance and cortical activations. Electroencephalography of 12 healthy right-handed subjects was recorded to set a BCI activated by right-hand motor imagery. Afterward, the subjects were asked to control the system by imagining the movement. The system provided either visual feedback, shown on a computer screen or kinesthetic feedback, provided by a robotic hand orthosis. Differences in performance and cortical activations were assessed, using classification accuracy and event-related desynchronization/synchronization in μ and β bands, respectively. Performance was significantly better with kinesthetic feedback as it allowed for higher correct classification of motor imagery. Cortical activations in the ipsilateral central channel in μ were different between the two feedback modalities. Our results imply that healthy subjects can achieve a greater degree of control using a motor imagery-based BCI with kinesthetic feedback than with anatomically congruent visual feedback. Furthermore, cortical activation differences show that kinesthetic feedback seems to elicit higher recruitment of sensorimotor cortex brain cells, which probably reflects enhanced local information modulation related to fine motor processing. Therefore, kinesthetic feedback provided by a robotic orthosis could be a more suitable feedback strategy for BCI systems designed for neuromodulation and neurorehabilitation.

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Adaptation of the humanoid robot to speech disfluency therapy

Kwaśniewicz Ł., Kuniszyk-Jóźkowiak W., Wójcik G. M., Masiak J.

Bio-Algorithms and Med-Systems

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2016

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Vol. 12, no. 4

169--177

EN

The paper describes an application that allows to use a humanoid robot as a stutterer’s assistant and therapist. Auditory and visual feedback has been used in the therapy with a humanoid robot. For this purpose, the common method of “echo” was modified. The modification is that the speaker hears delayed speech sounds uttered by the robot. The sounds of speech coming from an external microphone are captured and delayed by a computer and then, using User Datagram Protocol (UDP), sent to the robot’s system and played in its speakers. This system allows the elimination of negative feedback and external sound field’s noise. The effect of this therapy is enhanced by the fact that, in addition to the effect, relating to the action of the delayed feedback, the speaker has company during the difficult process of speaking. Visual feedback has been realized as changes in the robot’s hand movements according to the shape of the speech signal envelope and possibility of controlling speech with a metronome effect.

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EtCO2 -Based Biofeedback Method of Breath Regulation Increases Speech Fluency of Stuttering People

Stankiewicz B., Zieliński K., Darowski M., Michnikowski M.

Archives of Acoustics

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2015

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Vol. 40, No. 4

469–-474

EN

Respiratory disturbances frequently accompany stuttering. Their influence on lung ventilation can be assessed by measurement of the end-tidal CO2 concentration (EtCO2). The effectiveness of the CO2-based visual feedback method of breath regulation (VF) designed for stuttering therapy was tested in this study. The aim of the study was to answer the question if the VF helps to reduce respiratory disturbances in stuttering and increase speech fluency. 20 stuttering volunteers aged 13–45 years took part in the 3-parts test consisting of: 1. speaking without any techniques improving speech fluency, 2. learning the VF method, 3. VF-assisted speaking. The CO2/time signal and an acoustic signal of an utterance were recorded during the test. Significant increase of FE – the factor of breath ergonomics during speaking (based on both signals), from 47% to 71% (P < 0.01), and significant decrease of %SS – the percent of syllables stuttered, from 14% to 10% (P < 0.01) were received for VF-assisted utterances compared to the utterances without VF assistance. The results indicate that the VF can help to eliminate respiratory disturbances in stuttering and increase speech fluency.

4

Visual feedback based on expired CO2 as a therapy method for respiratory disturbances in stuttering

Stankiewicz B., Adamczyk B., Zieliński K., Darowski M.

Archives of Acoustics

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2006

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Vol. 31, No. 4

439-444

EN

A new CO2-based visual feedback therapy method (VF) for respiratory disturbances in stuttering was preliminarily assessed. Sound and expired CO2 signals were registered in 12 stutterers and 12 fluent speakers while speaking without and with VF to control breathing as well as during rest respiration, before each utterance. In stutterers, the end-tidal CO2 (ETCO2), the area under CO2/a time curve (SCO2), and the average emission of CO2 (ECO2 = SCO2/tbreath_cycle) for the CO2 peaks connected with the phrases containing tonic errors (with reference to rest respiration) were higher than those connected with fluent phrases (p<0.000001). Thus, a tendency to hypoventilation caused by tonic errors was observed. The factors of breath ergonomics while speaking FE (based on both signals) of stutterers were lower than those in fluent speakers (p<0.001). Using VF by stutterers increased FE (p<0.005) and decreased stuttering intensity.