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Velikay-Parel, M; Ivastinovic, D; Georgi, T; Richard, G; Hornig, R.
A test method for quantification of stimulus-induced depression effects on perceptual threshold in epiretinal prosthesis.
Acta Ophthalmol. 2013; 91(8):e595-e602 [OPEN ACCESS]
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Autor/innen der Med Uni Graz:
Georgi Thomas Patrick
Ivastinovic Domagoj
Velikay-Parel Michaela
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Abstract:
As part of a clinical trial, an investigational epiretinal implant (IMI Intelligent Medical Implant) was implanted in a retinitis pigmentosa patient. The prosthesis was wirelessly controlled by a visual interface containing a microcamera, providing wireless data and energy transmission. Forty-nine (49) electrodes were used for pattern recognition. This study examined the changes of perceptual thresholds over time and its relation to long-term stimulation. The goal of the study was to introduce stimulus-related depression of perceptual threshold (StirDepth) measurements as a method to gain further insight into the safety profile of electrical stimulation. The perceptual threshold was defined as the level of stimulation intensity at which a phosphene perception with a probability of 50% was detected using the Best-PEST method. StirDepth was measured by comparing the threshold changes immediately before and after a stimulation session of using three active electrodes and one passive electrode, which served as control. The initial threshold of the day remained stable over the observed period. In StirDepth measurement all thresholds raised significantly after the stimulation sessions. The threshold increase of the active electrodes never exceeded that of the inactive control electrode. StirDepth measurement is feasible in epiretinal implants. The prolonged stimulation raised no safety concerns in the patient. The threshold increase of both the active electrodes and the control electrode leads one to hypothesise that cognitive or neurophysiological effects are the cause rather than the desensitizing of the retinal network or incipient retinal damage. © 2013 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.
Find related publications in this database (using NLM MeSH Indexing)
Aged -
Electric Stimulation -
Electrodes, Implanted -
Epiretinal Membrane - physiopathology
Female -
Humans -
Pattern Recognition, Visual - physiology
Retinal Neurons - physiology
Retinitis Pigmentosa - physiopathology
Sensory Thresholds - physiology
Visual Prosthesis -

Find related publications in this database (Keywords)
epiretinal implant
perceptual threshold
retinitis pigmentosa
stimulus-induced neuronal depression
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