Unwrapping of transient responses from high rate overlapping pattern electroretinograms by deconvolution

Objective: Due to overlapping, temporal information is mostly lost in high rate steady-state pattern electroretinograms (PERG(SS)). This study develops a deconvolution method and a display/recording system to "unwrap'' PERG(SS) and obtain a transient, "per stimulus'' response (PERG(tr)) regardless of reversal rate. Methods: Processing and instrumentation, including high temporal resolution display and acquisition were developed for deconvolving PERGs acquired at high rates by slight jittering of reversal onsets at a given mean rate. Results: The system was successfully tested at eight rates from 2.2 to 78.1 rps. At medium rates (17.4-41.2 rps) recordings with conventional morphology (N35-P50-N95) but earlier peaks and higher amplitudes were extracted up to 40 rps. At higher rates, smaller triphasic responses were obtained, exhibiting similar peak latencies, but reversed polarity. Oscillating potentials (OPs) were also recorded at all rates after deconvolution. Conclusions: Transient PERGs and OPs can be extracted from quasi steady-state PERG recordings obtained at high rates with a deconvolution algorithm using high temporal resolution display and acquisition systems. Significance: The methodology to extract transient and oscillatory responses from steady-state PERGs could be useful in understanding high rate responses and diagnosis of various retinal diseases by revealing temporal information on waveform components which cannot be normally observed. (C) 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.