Stimulus waveform design for decreasing charge and increasing stimulation selectivity in retinal prostheses. Issue 3 (23rd June 2020)

• Record Type: Journal Article
• Authors: Kosta, Pragya; Loizos, Kyle; Lazzi, Gianluca
• Is Part Of: Healthcare technology letters. Volume 7:Issue 3(2020)
• Page Start: 66
• Page End: 71
• Publication Date: 2020-06-23
• Subjects: prosthetics -- biological tissues -- neurophysiology -- cellular biophysics -- eye -- bioelectric potentials -- diseases; tissue damage -- proximal ganglion cells -- degenerated retina -- electrical stimulation -- multiscale computational model -- temporal spiking patterns -- retinal prosthetic devices -- ganglion cell activity -- oscillatory behaviour -- cone bipolar cells -- photoreceptors -- presynaptic input -- photoreceptor layer -- Retinitis pigmentosa -- retinal degenerative diseases -- retinal prostheses; Biomedical engineering -- Periodicals; Medical technology -- Periodicals; 610.28
• DOI: 10.1049/htl.2019.0115
• Languages: English
• ISSNs: 2053-3713

Abstract

Abstract : Retinal degenerative diseases, such as retinitis pigmentosa, begin with damage to the photoreceptor layer of the retina. In the absence of presynaptic input from photoreceptors, networks of electrically coupled AII amacrine and cone bipolar cells have been observed to exhibit oscillatory behaviour and result in spontaneous firing of ganglion cells. This ganglion cell activity could interfere with external stimuli provided by retinal prosthetic devices and potentially degrade their performance. In this work, the authors computationally investigate stimulus waveform designs, which can improve the performance of retinal prostheses by suppressing undesired spontaneous firing of ganglion cells and generating precise temporal spiking patterns. They utilise a multi‐scale computational model for electrical stimulation of degenerated retina based on the admittance method and NEURON simulation environments. They present a class of asymmetric biphasic pulses that can generate precise ganglion cell firing patterns with up to 55% lower current requirements compared to traditional symmetric biphasic pulses. This lower current results in activation of only proximal ganglion cells, provides more focused stimulation and lowers the risk of tissue damage.