Spread of Excitation (SoE) — A Non-Invasive Assessment of Cochlear Implant Electrode Placement

Brain Computer Interface consists of hardware and software that convert brain signals into action. It changes the nerves, muscles, and movements they produce with electro-physiological signs. The BCI cannot read the brain and decipher the thought in general. The BCI can only identify and classify specific patterns of activity in ongoing brain signals associated with specific tasks or events. EEG is the most commonly used non-invasive BCI method as it can be obtained easily compared to other methods. In this study; It will be given how EEG signals are obtained from the scalp, with which waves these frequencies are named and in which brain states these waves occur. 10-20 electrode placement plan for EEG to be placed on the scalp will be shown.

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Hydraulic insertions of cochlear implant electrode arrays into the human cadaver cochlea: preliminary findings

European Archives of Oto-Rhino-Laryngology ◽

10.1007/s00405-021-06979-z ◽

2021 ◽

Author(s):

M. Geraldine ◽

Thomas Lenarz ◽

Thomas S. Rau

Keyword(s):

Cochlear Implant ◽

Outcome Measurement ◽

Round Window ◽

Handling Time ◽

Human Cadaver ◽

Hydraulic Actuator ◽

Electrode Arrays ◽

Non Invasive ◽

Insertion Tool ◽

Set Up

Abstract Objectives (1) To evaluate the feasibility of a non-invasive, novel, simple insertion tool to perform automated, slow insertions of cochlear implant electrode arrays (EA) into a human cadaver cochlea; (2) to estimate the handling time required by our tool. Methods Basic science study conducted in an experimental OR. Two previously anonymized human cadaver heads, three commercially available EAs, and our novel insertion tool were used for the experiments. Our tool operates as a hydraulic actuator that delivers an EA at continuous velocities slower than manually feasible. Intervention(s): the human cadaver heads were prepared with a round-window approach for CI surgery in a standard fashion. Twelve EA insertion trials using our tool involved: non-invasive fixation of the tool to the head; directing the tool to the round window and EA mounting onto the tool; automated EA insertion at approximately 0.1 mm/s driven by hydraulic actuation. Outcome measurement(s): handling time of the tool; post-insertion cone-beam CT scans to provide intracochlear evaluation of the EA insertions. Results Our insertion tool successfully inserted an EA into the human cadaver cochlea (n = 12) while being attached to the human cadaver head in a non-invasive fashion. Median time to set up the tool was 8.8 (7.2–9.4) min. Conclusion The first insertions into the human cochlea using our novel, simple insertion tool were successful without the need for invasive fixation. The tool requires < 10 min to set up, which is clinically acceptable. Future assessment of intracochlear trauma is needed to support its safety profile for clinical translation.

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Intraoperative transimpedance and spread of excitation profile correlations with a lateral-wall cochlear implant electrode array

Hearing Research ◽

10.1016/j.heares.2021.108235 ◽

2021 ◽

Vol 405 ◽

pp. 108235

Author(s):

Samuel Söderqvist ◽

Satu Lamminmäki ◽

Antti Aarnisalo ◽

Timo Hirvonen ◽

Saku T. Sinkkonen ◽

...

Keyword(s):

Cochlear Implant ◽

Electrode Array ◽

Lateral Wall ◽

Excitation Profile ◽

Spread Of Excitation

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Electro-haptic hearing: Speech-in-noise performance in cochlear implant users is enhanced by tactile stimulation of the wrists

10.31234/osf.io/j6bn4 ◽

2019 ◽

Author(s):

Mark D. Fletcher ◽

Amatullah Hadeedi ◽

Tobias Goehring ◽

Sean R Mills

Keyword(s):

Cochlear Implant ◽

Speech Intelligibility ◽

Tactile Stimulation ◽

Electrical Signal ◽

Noise Performance ◽

Speech In Noise ◽

Non Invasive ◽

Real World Application ◽

Before And After ◽

Stimulation Of

Cochlear implant (CI) users receive only limited sound information through their implant, which means that they struggle to understand speech in noisy environments. Recent work has suggested that combining the electrical signal from the CI with a haptic signal that provides crucial missing sound information (“electro-haptic stimulation”; EHS) could improve speech-in-noise performance. The aim of the current study was to test whether EHS could enhance speech-in-noise performance in CI users using: (1) a tactile signal derived using an algorithm that could be applied in real time, (2) a stimulation site appropriate for a real-world application, and (3) a tactile signal that could readily be produced by a compact, portable device. We measured speech intelligibility in multi-talker noise with and without vibro-tactile stimulation of the wrist in CI users, before and after a short training regime. No effect of EHS was found before training, but after training EHS was found to improve the number of words correctly identified by an average of 8.3 %-points, with some users improving by more than 20 %-points. Our approach could offer an inexpensive and non-invasive means of improving speech-in-noise performance in CI users.

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Accuracy of BIS monitoring using a novel interface device connecting conventional needle-electrodes and BIS sensors during frontal neurosurgical procedures

PLoS ONE ◽

10.1371/journal.pone.0258647 ◽

2021 ◽

Vol 16 (10) ◽

pp. e0258647

Author(s):

Hideki Harada ◽

Seiya Muta ◽

Tatsuyuki Kakuma ◽

Misa Ukeda ◽

So Ota ◽

...

Keyword(s):

Mixed Model ◽

Linear Mixed Model ◽

Clinical Performance ◽

Clinical Situation ◽

Electrode Placement ◽

Neurosurgical Procedures ◽

Non Invasive ◽

Invasive Method ◽

Data Points ◽

Interface Device

Background Bispectral index (BIS) monitoring is a widely used non-invasive method to monitor the depth of anesthesia. However, in the event of surgeries requiring a frontal approach, placement of the electrode may be impossible at the designated area to achieve a proper BIS measurement. Methods We developed an investigational interface device to connect needle-electrodes to BIS sensors. The safety and clinical performance were investigated in patients who underwent surgery. Direct BIS values from a disposable BIS electrode and indirect values via the interface device were simultaneously recorded from the same areas of electrode placement in a single patient. The agreement between the direct and indirect BIS values was statistically analyzed. Results The interface device with a silver electrode demonstrated sufficient electric conduction to transmit electroencephalogram signals. The overall BIS curves were similar to those of direct BIS monitoring. Direct and indirect BIS values from 18 patients were statistically analyzed using a linear mixed model and a significant concordance was confirmed (indirect BIS = 7.0405 + 0.8286 * direct BIS, p<0.0001). Most observed data (2582/2787 data points, 92.64%) had BIS unit differences of 10 or less. Conclusions The interface device provides an opportunity for intraoperative BIS monitoring of patients, whose clinical situation does not permit the placement of conventional adhesive sensors at the standard location.

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