Employees Who are Deaf or Hard of Hearing: Perceptions of Workplace Accommodations

The purpose of this paper is to measure the effectiveness of existing employment accommodations required by the Americans with Disabilities Act for employees who are Deaf or hard of hearing. Participants completed an online survey in which they identified with one of four levels of hearing loss and selected from descriptions of workplace accommodations. Each selection was ranked according to perceived importance and satisfaction. Accommodations that showed any significance of importance were endorsed by 18% or less of the respondents. The most important accommodations were computer assisted note-taking (18%) and flashing alarms (11%). Participants reported high satisfaction with most of the accommodations necessary to their job performance, but Deaf awareness training (36%) and coworker taking notes (29%) showed low satisfaction levels. As this study was limited, further research is necessary to draw significant conclusions that will lead to refining the ADA required workplace accommodations for Deaf or Hard of Hearing employees

Evoked Potentials Recorded From the Spinal Cord During Neurostimulation for Pain: A Computational Modeling Study

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153677/1/ner12965.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153677/2/ner12965_am.pd

Spinal neuromodulation using ultra low frequency waveform inhibits sensory signaling to the thalamus and preferentially reduces aberrant firing of thalamic neurons in a model of neuropathic pain

IntroductionMany forms of chronic pain remain refractory to existing pharmacotherapies and electrical neuromodulation. We have recently reported the clinical efficacy of a novel form of analgesic electrical neuromodulation that uses ultra low frequency (ULF™) biphasic current and studied its effects on sensory nerve fibers. Here, we show that in anesthetized rats, epidural ULF current reversibly inhibits activation of neurons in the thalamus receiving sensory spinothalamic input.MethodsIn naïve, neuropathic and sham-operated rats, recordings of ongoing and evoked activity were made from thalamic neurons, targeting the ventral posterolateral (VPL) nucleus.ResultsResponses to electrical stimulation of hind limb receptive fields were reduced in 25 of 32 (78%) neurons tested with lumbar epidural ULF neuromodulation. Cells preferentially responsive to low intensity stimulation were more likely to be found than cells responding to a range of stimulus intensities, or high intensity only; and low threshold responses were more likely to be inhibited by ULF than high threshold responses. On-going activity unrelated to hindlimb stimulation, observed in 17 of 39 neurons in naïve animals (44%), was reduced by lumbar epidural ULF current in only 3 of 14 (21%) neurons tested with ULF. By contrast, in rats with a well-characterized neuropathic injury, spinal nerve ligation (SNL), we found a much higher incidence of on-going activity in thalamic neurons: 53 of 55 neurons (96%) displayed firing unrelated to hindlimb stimulation. In this group, ULF current reduced thalamic neurone discharge rate in 19 of 29 (66%) neurons tested. In sham-operated animals, the incidence of such activity in thalamic neurons and the effect of ULF current were not significantly different from the naïve group.DiscussionWe conclude firstly that ULF current can acutely and reversibly interrupt signaling between sensory afferent fibers and relay neurons of the thalamus. Second, ongoing activity of thalamic neurons increases dramatically in the early stages following neuropathic injury. Third, this novel form of neuromodulation preferentially attenuates pathological thalamic activity in this neuropathic model compared to normal activity in naïve and sham-operated animals. This study, therefore, demonstrates that epidural ULF current can reduce nerve injury-related abnormal activity reaching the brain. These findings help advance understanding of possible mechanisms for the analgesic effects of ULF neuromodulation

Patient‐Specific Analysis of Neural Activation During Spinal Cord Stimulation for Pain

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156183/2/ner13037_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156183/1/ner13037.pd

Interpatient differences in neural recruitment patterns during pudendal nerve stimulation – a computational investigation

Bladder dysfunction impairs the quality of life for millions of individuals around the world. Common causes of bladder dysfunction include aging, trauma, and neurological disorders. Due to inadequacies in conventional treatments, neuromodulation therapies to address bladder dysfunction, such as sacral nerve stimulation, have emerged. However, patient needs still remain unmet. Pudendal nerve stimulation (PNS) has recently gained clinical interest as a promising treatment for bladder dysfunction. While PNS has been extensively investigated in preclinical settings, there is a gap in our understanding of the mechanisms of action and efficacy of PNS as limited studies of PNS have been performed on human subjects. We developed patient-specific computational models for 10 participants receiving PNS as part of their clinical care to improve our understanding of this therapy. Our modeling approach consisted of segmentation of pre- and post-operative magnetic resonance and computed tomography images to create a volume conductor model of each participant’s pelvic anatomy and implanted stimulator. We used the finite element method to approximate the electric fields generated by PNS for each participant. We then simulated each participant’s neural recruitment during PNS by coupling the electric field solutions to multicompartment axon models placed within the pudendal nerve. We used this modeling approach to simulate the neural recruitment order for each participant over a select range of stimulation parameters. Our simulations demonstrated neural recruitment profiles in agreement with the experimental stimulation thresholds measured in each participant. Our results suggest that stimulation waveform parameters, contact selection, and electrode array placement all have a significant impact on the efficacy of PNS. PNS is an emerging neuromodulation therapy which may help address bladder dysfunction that is refractory to conventional treatments. In this study, we used computational models to account for patient-specific anatomy and electrode array placement to simulate the effects of PNS. Our model results were in line with experimental measurements and underscore the importance of electrode placement relative to the roots, trunk, and branches of the pudendal nerve. Future models could be enhanced by considering histological studies that describe the somatotopic organization of the pudendal nerve. Including such data could provide further insight into the therapeutic mechanisms of PNS and optimize its use in clinical applications

PEDOT:PSS interfaces support the development of neuronal synaptic networks with reduced neuroglia response in vitro

The design of electrodes based on conductive polymers in brain-machine interface technology offers the opportunity to exploit variably manufactured materials to reduce gliosis, indeed the most common brain response to chronically implanted neural electrodes. In fact, the use of conductive polymers, finely tailored in their physical-chemical properties, might result in electrodes with improved adaptability to the brain tissue and increased charge-transfer efficiency. Here we interfaced poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) doped with different amounts of ethylene glycol (EG) with rat hippocampal primary cultures grown for 3 weeks on these synthetic substrates. We used immunofluorescence and scanning electron microscopy combined to single cell electrophysiology to assess the biocompatibility of PEDOT:PSS in terms of neuronal growth and synapse formation. We investigated neuronal morphology, density and electrical activity. We reported the novel observation that opposite to neurons, glial cell density was progressively reduced, hinting at the ability of this material to down regulate glial reaction. Thus PEDOT:PSS is an attractive candidate for the design of new implantable electrodes, controlling the extent of glial reactivity without affecting neuronal viability and function

Intradural Spinal Cord Stimulation: Performance Modeling of a New Modality

Introduction: Intradural spinal cord stimulation (SCS) may offer significant therapeutic benefits for those with intractable axial and extremity pain, visceral pain, spasticity, autonomic dysfunction and related disorders. A novel intradural electrical stimulation device, limited by the boundaries of the thecal sac, CSF and spinal cord was developed to test this hypothesis. In order to optimize device function, we have explored finite element modeling (FEM).Methods: COMSOL®Multiphysics Electrical Currents was used to solve for fields and currents over a geometric model of a spinal cord segment. Cathodic and anodic currents are applied to the center and tips of the T-cross component of the electrode array to shape the stimulation field and constrain charge-balanced cathodic pulses to the target area.Results: Currents from the electrode sites can move the effective stimulation zone horizontally across the cord by a linear step method, which can be diversified considerably to gain greater depth of penetration relative to standard epidural SCS. It is also possible to prevent spread of the target area with no off-target action potential.Conclusion: Finite element modeling of a T-shaped intradural spinal cord stimulator predicts significant gains in field depth and current shaping that are beyond the reach of epidural stimulators. Future studies with in vivo models will investigate how this approach should first be tested in humans

Evolving applications, technological challenges and future opportunities in neuromodulation: Proceedings of the fifth annual deep brain stimulation think tank

The annual Deep Brain Stimulation (DBS) Think Tank provides a focal opportunity for a multidisciplinary ensemble of experts in the field of neuromodulation to discuss advancements and forthcoming opportunities and challenges in the field. The proceedings of the fifth Think Tank summarize progress in neuromodulation neurotechnology and techniques for the treatment of a range of neuropsychiatric conditions including Parkinson's disease, dystonia, essential tremor, Tourette syndrome, obsessive compulsive disorder, epilepsy and cognitive, and motor disorders. Each section of this overview of the meeting provides insight to the critical elements of discussion, current challenges, and identified future directions of scientific and technological development and application. The report addresses key issues in developing, and emphasizes major innovations that have occurred during the past year. Specifically, this year's meeting focused on technical developments in DBS, design considerations for DBS electrodes, improved sensors, neuronal signal processing, advancements in development and uses of responsive DBS (closed-loop systems), updates on National Institutes of Health and DARPA DBS programs of the BRAIN initiative, and neuroethical and policy issues arising in and from DBS research and applications in practice