scholarly journals Simultaneous activation of multiple vestibular pathways upon electrical stimulation of semicircular canal afferents

2020 ◽  
Vol 267 (S1) ◽  
pp. 273-284
Author(s):  
Anissa Boutabla ◽  
Samuel Cavuscens ◽  
Maurizio Ranieri ◽  
Céline Crétallaz ◽  
Herman Kingma ◽  
...  
Keyword(s):  
Phase 1 ◽  
Bilateral Vestibulopathy ◽  
Growth Functions ◽  
Simultaneous Activation ◽  
Promising Treatment ◽  
Stimulation Current ◽  
Electrical Stimuli ◽  
Amplitude Growth ◽  
Vestibular Pathways ◽  
Stimulation Of

Abstract Background and purpose Vestibular implants seem to be a promising treatment for patients suffering from severe bilateral vestibulopathy. To optimize outcomes, we need to investigate how, and to which extent, the different vestibular pathways are activated. Here we characterized the simultaneous responses to electrical stimuli of three different vestibular pathways. Methods Three vestibular implant recipients were included. First, activation thresholds and amplitude growth functions of electrically evoked vestibulo-ocular reflexes (eVOR), cervical myogenic potentials (ecVEMPs) and vestibular percepts (vestibulo-thalamo-cortical, VTC) were recorded upon stimulation with single, biphasic current pulses (200 µs/phase) delivered through five different vestibular electrodes. Latencies of eVOR and ecVEMPs were also characterized. Then we compared the amplitude growth functions of the three pathways using different stimulation profiles (1-pulse, 200 µs/phase; 1-pulse, 50 µs/phase; 4-pulses, 50 µs/phase, 1600 pulses-per-second) in one patient (two electrodes). Results The median latencies of the eVOR and ecVEMPs were 8 ms (8–9 ms) and 10.2 ms (9.6–11.8 ms), respectively. While the amplitude of eVOR and ecVEMP responses increased with increasing stimulation current, the VTC pathway showed a different, step-like behavior. In this study, the 200 µs/phase paradigm appeared to give the best balance to enhance responses at lower stimulation currents. Conclusions This study is a first attempt to evaluate the simultaneous activation of different vestibular pathways. However, this issue deserves further and more detailed investigation to determine the actual possibility of selective stimulation of a given pathway, as well as the functional impact of the contribution of each pathway to the overall rehabilitation process.

scholarly journals Effect of Chronological Age on Pulse Rate Discrimination in Adult Cochlear-Implant Users

2021 ◽  
Vol 25 ◽  
pp. 233121652110073
Author(s):  
Kelly C. Johnson ◽  
Zilong Xie ◽  
Maureen J. Shader ◽  
Paul G. Mayo ◽  
Matthew J. Goupell
Keyword(s):  
Pulse Rate ◽  
Compound Action Potential ◽  
Action Potential Amplitude ◽  
Growth Functions ◽  
Evoked Compound Action Potential ◽  
Rate Discrimination ◽  
Amplitude Growth ◽  
Temporal Pulse ◽  
Compound Action Potential Amplitude ◽  
Compound Action

Cochlear-implant (CI) users rely heavily on temporal envelope cues to understand speech. Temporal processing abilities may decline with advancing age in adult CI users. This study investigated the effect of age on the ability to discriminate changes in pulse rate. Twenty CI users aged 23 to 80 years participated in a rate discrimination task. They attempted to discriminate a 35% rate increase from baseline rates of 100, 200, 300, 400, or 500 pulses per second. The stimuli were electrical pulse trains delivered to a single electrode via direct stimulation to an apical (Electrode 20), a middle (Electrode 12), or a basal location (Electrode 4). Electrically evoked compound action potential amplitude growth functions were recorded at each of those electrodes as an estimate of peripheral neural survival. Results showed that temporal pulse rate discrimination performance declined with advancing age at higher stimulation rates (e.g., 500 pulses per second) when compared with lower rates. The age-related changes in temporal pulse rate discrimination at higher stimulation rates persisted after statistical analysis to account for the estimated peripheral contributions from electrically evoked compound action potential amplitude growth functions. These results indicate the potential contributions of central factors to the limitations in temporal pulse rate discrimination ability associated with aging in CI users.

Effects of low-frequency stimulation of the superior colliculus on spontaneous and visually guided saccades

1993 ◽  
Vol 69 (3) ◽  
pp. 953-964 ◽  
Author(s):  
P. W. Glimcher ◽  
D. L. Sparks
Keyword(s):  
Superior Colliculus ◽  
Time Course ◽  
Low Frequency ◽  
Arbitrary Point ◽  
Visually Guided ◽  
Spontaneous Movements ◽  
Low Frequency Stimulation ◽  
Frequency Stimulation ◽  
Stimulation Current ◽  
Stimulation Of

1. The first experiment of this study determined the effects of low-frequency stimulation of the monkey superior colliculus on spontaneous saccades in the dark. Stimulation trains, subthreshold for eliciting short-latency fixed-vector saccades, were highly effective at biasing the metrics (direction and amplitude) of spontaneous movements. During low-frequency stimulation, the distribution of saccade metrics was biased toward the direction and amplitude of movements induced by suprathreshold stimulation of the same collicular location. 2. Low-frequency stimulation biased the distribution of saccade metrics but did not initiate movements. The distribution of intervals between stimulation onset and the onset of the next saccade did not differ significantly from the distribution of intervals between an arbitrary point in time and the onset of the next saccade under unstimulated conditions. 3. Results of our second experiment indicate that low-frequency stimulation also influenced the metrics of visually guided saccades. The magnitude of the stimulation-induced bias increased as stimulation current or frequency was increased. 4. The time course of these effects was analyzed by terminating stimulation immediately before, during, or after visually guided saccades. Stimulation trains terminated at the onset of a movement were as effective as stimulation trains that continued throughout the movement. No effects were observed if stimulation ended 40–60 ms before the movement began. 5. These results show that low-frequency collicular stimulation can influence the direction and amplitude of spontaneous or visually guided saccades without initiating a movement. These data are compatible with the hypothesis that the collicular activity responsible for specifying the horizontal and vertical amplitude of a saccade differs from the type of collicular activity that initiates a saccade.

scholarly journals The Precision of eCAP Thresholds Derived From Amplitude Growth Functions

2018 ◽  
Vol 39 (4) ◽  
pp. 701-711 ◽  
Author(s):  
Jan Dirk Biesheuvel ◽  
Jeroen J. Briaire ◽  
Johan H. M. Frijns
Keyword(s):  
Growth Functions ◽  
Amplitude Growth

scholarly journals Chronic Electrical Stimulation of the Otolith Organ: Preliminary Results in Humans with Bilateral Vestibulopathy and Sensorineural Hearing Loss

2019 ◽  
Vol 25 (Suppl. 1-2) ◽  
pp. 79-90 ◽  
Author(s):  
Angel Ramos Macias ◽  
Angel Ramos de Miguel ◽  
Isaura Rodriguez Montesdeoca ◽  
Silvia Borkoski Barreiro ◽  
Juan Carlos Falcón González
Keyword(s):  
Electrical Stimulation ◽  
Vestibular Evoked Myogenic Potentials ◽  
Head Impulse Test ◽  
Clinical Test ◽  
Otolith Organ ◽  
Bilateral Vestibulopathy ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
Chronic Electrical Stimulation ◽  
Stimulation Of

Introduction: Bilateral vestibulopathy is an important cause of imbalance that is misdiagnosed. The clinical management of patients with bilateral vestibular loss remains difficult as there is no clear evidence for an effective treatment. In this paper, we try to analyze the effect of chronic electrical stimulation and adaptation to electrical stimulation of the vestibular system in humans when stimulating the otolith organ with a constant pulse train to mitigate imbalance due to bilateral vestibular dysfunction (BVD). Methods: We included 2 patients in our study with BVD according to Criteria Consensus of the Classification Committee of the Bárány Society. Both cases were implanted by using a full-band straight electrode to stimulate the otoliths organs and simultaneously for the cochlear stimulation we use a perimodiolar electrode. Results: In both cases Vestibular and clinical test (video head impulse test, videonistagmography cervical vestibular evoked myogenic potentials, cVEMP and oVEMP), subjective visual vertical test, computerized dynamic posturography, dynamic gait index, Time UP and Go test and dizziness handicap index) were performed. Posture and gait metrics reveal important improvement if compare with preoperartive situation. Oscillopsia, unsteadiness, independence and quality of life improved to almost normal situation. Discussion/Conclusion: Prosthetic implantation of the otolith organ in humans is technically feasible. Electrical stimulation might have potential effects on balance and this is stable after 1 year follow-up. This research provides new possibilities for the development of vestibular implants to improve gravito-inertial acceleration sensation, in this case by the otoliths stimulation.

Differential Patterns of Spinal Sympathetic Outflow Involving a 10-Hz Rhythm

1999 ◽  
Vol 82 (2) ◽  
pp. 841-854 ◽  
Author(s):  
Gerard L. Gebber ◽  
Sheng Zhong ◽  
Craig Lewis ◽  
Susan M. Barman
Keyword(s):  
Brain Stem ◽  
Phase Angle ◽  
Sympathetic Nerves ◽  
Phase Relations ◽  
Sympathetic Outflow ◽  
Free Running ◽  
The Difference ◽  
Electrical Stimuli ◽  
The Brain ◽  
Stimulation Of

Time and frequency domain analyses were used to examine the changes in the relationships between the discharges of the inferior cardiac (CN) and vertebral (VN) postganglionic sympathetic nerves produced by electrical activation of the midbrain periaqueductal gray (PAG) in urethan-anesthetized, baroreceptor-denervated cats. CN-VN coherence and phase angle in the 10-Hz band served as measures of the coupling of the central oscillators controlling these nerves. The 10-Hz rhythm in CN and VN discharges was entrained 1:1 to electrical stimuli applied to the PAG at frequencies between 7 and 12 Hz. CN 10-Hz discharges were increased, and VN 10-Hz discharges were decreased when the frequency of PAG stimulation was equal to or above that of the free-running rhythm. In contrast, stimulation of the same PAG sites at lower frequencies increased, albeit disproportionately, the 10-Hz discharges of both nerves. In either case, PAG stimulation significantly increased the phase angle between the two signals (VN 10-Hz activity lagged CN activity); coherence values relating their discharges were little affected. However, the increase in phase angle was significantly more pronounced when the 10-Hz discharges of the two nerves were reciprocally affected. Importantly, partialization of the phase spectrum using the PAG stimuli did not reverse the change in CN-VN phase angle. This observation suggests that the increase in the CN-VN phase angle reflected changes in the phase relations between coupled oscillators in the brain stem rather than the difference in conduction times to the two nerves from the site of PAG stimulation. In contrast to the effects elicited by PAG stimulation, stimulation of the medullary lateral tegmental field induced uniform increases in the 10-Hz discharges of the two nerves and no change in the CN-VN phase angle. Our results demonstrate that changes in the phase relations among coupled brain stem 10-Hz oscillators are accompanied by differential patterns of spinal sympathetic outflow. The reciprocal changes in CN and VN discharges produced by PAG stimulation are consistent with the pattern of spinal sympathetic outflow expected during the defense reaction.

V. On the phenomena accompanying stimulation of the gland-cells in the tentacles of drosera dichotoma

1886 ◽  
Vol 39 (239-241) ◽  
pp. 229-234 ◽  
Keyword(s):  
Chromic Acid ◽  
Picric Acid ◽  
Frog Muscle ◽  
Osmic Acid ◽  
Gland Cells ◽  
Electrical Stimuli ◽  
Stimulation Of

Method of Research .—Pieces of unstimulated leaves, and of leaves stimulated for periods varying from 5 minutes to 72 hours, were examined fresh, or after treatment with alcohol, picric acid, chromic acid, or osmic acid. The most satisfactory results were obtained from specimens treated for 12 hours with 1 and 2 per cent, chromic acid; such strengths dissolving the tannin precipitate first formed, and fixing the structures most successfully. The leaves were fed principally upon small flies or pieces of frog muscle, since these were found to succeed best. Heat stimuli, electrical stimuli, and stimulus produced by contact or cutting were also employed.

scholarly journals Vestibular implantation and longitudinal electrical stimulation of the semicircular canal afferents in human subjects

2015 ◽  
Vol 113 (10) ◽  
pp. 3866-3892 ◽  
Author(s):  
James O. Phillips ◽  
Leo Ling ◽  
Kaibao Nie ◽  
Elyse Jameyson ◽  
Christopher M. Phillips ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Human Subjects ◽  
Vestibular Function ◽  
Slow Phase ◽  
Vestibular Loss ◽  
Stimulation Current ◽  
Eye Velocity ◽  
Over Time ◽  
Stimulation Of

Animal experiments and limited data in humans suggest that electrical stimulation of the vestibular end organs could be used to treat loss of vestibular function. In this paper we demonstrate that canal-specific two-dimensionally (2D) measured eye velocities are elicited from intermittent brief 2 s biphasic pulse electrical stimulation in four human subjects implanted with a vestibular prosthesis. The 2D measured direction of the slow phase eye movements changed with the canal stimulated. Increasing pulse current over a 0–400 μA range typically produced a monotonic increase in slow phase eye velocity. The responses decremented or in some cases fluctuated over time in most implanted canals but could be partially restored by changing the return path of the stimulation current. Implantation of the device in Meniere's patients produced hearing and vestibular loss in the implanted ear. Electrical stimulation was well tolerated, producing no sensation of pain, nausea, or auditory percept with stimulation that elicited robust eye movements. There were changes in slow phase eye velocity with current and over time, and changes in electrically evoked compound action potentials produced by stimulation and recorded with the implanted device. Perceived rotation in subjects was consistent with the slow phase eye movements in direction and scaled with stimulation current in magnitude. These results suggest that electrical stimulation of the vestibular end organ in human subjects provided controlled vestibular inputs over time, but in Meniere's patients this apparently came at the cost of hearing and vestibular function in the implanted ear.

Hepatic glucose balance in response to direct stimulation of sympathetic nerves in the intact liver of cats

1978 ◽  
Vol 56 (6) ◽  
pp. 1022-1028 ◽  
Author(s):  
W. Wayne Lautt ◽  
Chong Wong
Keyword(s):  
Sympathetic Nerves ◽  
Direct Stimulation ◽  
Blood Flows ◽  
Parasympathetic Nerves ◽  
Hepatic Glucose ◽  
Simultaneous Activation ◽  
Glucose Output ◽  
Hepatic Nerves ◽  
Mixed Nerve ◽  
Stimulation Of

Changes in hepatic glucose balance in response to direct stimulation of the hepatic nerves were measured in cats. Simultaneous measurements were made of glucose concentrations entering and leaving the intact liver; this, combined with measured blood flows, allows calculation of hepatic glucose balance. Stimulation of the hepatic sympathetic nerves (8 Hz, 15 V, 1 ms) produced a rapid increase in hepatic glucose output that was statistically significant after 1 min and reached a peak 3–5 min after onset of stimulation, after which time the output declined somewhat. The half time for deactivation of the response was 1.8–2 min. Variability in the responses was largely accounted for by the variable control base lines measured immediately prior to stimulation. Those animals showing the highest basal output showed the least increase in output in response to the nerves. The response to stimulation of the mixed nerve trunk in the presence and absence of atropine (1 mg/kg, intraportal) was similar. Simultaneous activation of hepatic sympathetic and parasympathetic nerves therefore produces a purely sympathetic type of effect on net glucose balance across the liver. It was also shown that changes in net splanchnic output or simply in arterial – hepatic venous glucose differences are an adequate reflection of liver glucose balance under the currently tested responses.

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