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

Toft-Nielsen, Jonathon; Bohórquez, Jorge; Özdamar, Özcan

doi:10.1016/j.clinph.2014.02.002

Cited by 11 publications

(26 citation statements)

References 35 publications

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“…The resulting quasi-steady-state PERG waveform can be mathematically deconvolved to extract conventional transient PERGs thus allowing measurement of the N35, P50, and N95 components; this may provide further information on retinal sources of the response. 18,39 …”

Section: Discussionmentioning

confidence: 99%

Next Generation PERG Method: Expanding the Response Dynamic Range and Capturing Response Adaptation

Monsalve

Triolo

Toft-Nielsen

et al. 2017

Trans. Vis. Sci. Tech.

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PurposeTo compare a new method for steady-state pattern electroretinogram (PERGx) with a validated method (PERGLA) in normal controls and in patients with optic neuropathy.MethodsPERGx and PERGLA were recorded in a mixed population (n = 33, 66 eyes) of younger controls (C1; n = 10, age 38 ± 8.3 years), older controls (C2; n = 11, 57.9 ± 8.09 years), patients with early manifest glaucoma (G; n = 7, 65.7 ±11.6 years), and patients with nonarteritic ischemic optic neuropathy (N; n = 5, mean age 59.4 ± 8.6 years). The PERGx stimulus was a black-white horizontal grating generated on a 14 × 14 cm LED display (1.6 cycles/deg, 15.63 reversals/s, 98% contrast, 800 cd/m2 mean luminance, 25° field). PERGx signal and noise were averaged over 1024 epochs (∼2 minutes) and Fourier analyzed to retrieve amplitude and phase. Partial averages (16 successive samples of 64 epochs each) were also analyzed to quantify progressive changes over recording time (adaptation).ResultsPERGLA and PERGx amplitudes and latencies were correlated (Amplitude R2 = 0.59, Latency R2 = 0.39, both P < 0.0001) and were similarly altered in disease. Compared to PERGLA, however, PERGx had shorter (16 ms) latency, higher (1.39×) amplitude, lower (0.37×) noise, and higher (4.2×) signal-to-noise ratio. PERGx displayed marked amplitude adaptation in C1 and C2 groups and no significant adaptation in G and N groups.ConclusionsThe PERGx high signal-to-noise ratio may allow meaningful recording in advanced stages of optic nerve disorders. In addition, it quantifies response adaptation, which may be selectively altered in glaucoma and optic neuropathy.Translational RelevanceA new PERG method with increased dynamic range allows recording of retinal ganglion cell function in advanced stages of optic nerve disorders. It also quantifies the response decline during the test, an autoregulatory adaptation to metabolic challenge that decreases with age and presence of disease.

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Section: Discussionmentioning

confidence: 99%

Next Generation PERG Method: Expanding the Response Dynamic Range and Capturing Response Adaptation

Monsalve

Triolo

Toft-Nielsen

et al. 2017

Trans. Vis. Sci. Tech.

Self Cite

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“…In addition to initial applications in ABR and/or MLR, the CLAD method was recently successfully used in other modalities. For example, CLAD sequences have been used to derive transient patterns in electroretinogram data at a rate from a large range, in which both C dec and sequence spectra were given [25,32]. More recently, a combination of Electrocochleography/ABR data were acquired at rapid rates using six CLAD sequences with appropriate C dec values [20].…”

Section: Discussionmentioning

confidence: 99%

“…The CLAD method can be applied to other transient responses than AEPs, for example, in extracting transient patterns in electroretinogram data [25], or in simultaneously recorded ABR and electrocochleography data [20]. Most applications of CLAD in AEPs are in the study of ABR and MLR recordings.…”

Section: Methodsmentioning

confidence: 99%

New metric for optimizing Continuous Loop Averaging Deconvolution (CLAD) sequences under the 1/f noise model

et al. 2017

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Continuous loop averaging deconvolution (CLAD) is one of the proven methods for recovering transient auditory evoked potentials (AEPs) in rapid stimulation paradigms, which requires an elaborated stimulus sequence design to attenuate impacts from noise in data. The present study aimed to develop a new metric in gauging a CLAD sequence in terms of noise gain factor (NGF), which has been proposed previously but with less effectiveness in the presence of pink (1/f) noise. We derived the new metric by explicitly introducing the 1/f model into the proposed time-continuous sequence. We selected several representative CLAD sequences to test their noise property on typical EEG recordings, as well as on five real CLAD electroencephalogram (EEG) recordings to retrieve the middle latency responses. We also demonstrated the merit of the new metric in generating and quantifying optimized sequences using a classic genetic algorithm. The new metric shows evident improvements in measuring actual noise gains at different frequencies, and better performance than the original NGF in various aspects. The new metric is a generalized NGF measurement that can better quantify the performance of a CLAD sequence, and provide a more efficient mean of generating CLAD sequences via the incorporation with optimization algorithms. The present study can facilitate the specific application of CLAD paradigm with desired sequences in the clinic.

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“…Such extraction of the PERG tr from the PERG SS response has been accomplished by jittering the pattern reversal rate to produce quasi SS (QSS) PERG (qPERG SS ) recordings and processing them with a recently developed deconvolution algorithm. 21 The Continuous Loop Averaging Deconvolution (CLAD) method, originally developed to extract auditory evoked potentials from SS responses at high rates, 22,23 exploits jittering to overcome the mathematical impossibility of deconvolving SS responses obtained with isochronic stimuli. By using jittered stimulus sequences, average responses to individual stimuli are extracted using mathematically constructed matrix equations in the time domain 22 or simpler equations for faster on-line operations in the frequency domain.…”

mentioning

confidence: 99%

“…[23][24][25] Using CLAD methodology, extraction of the PERG tr from PERG SS has been demonstrated up to approximately 80 reversals per second using low jitter sequences. 21 This study aims to investigate the relationship between the PERGs generated under tr and SS conditions by conducting a more detailed analysis of the superposition theory of PERG SS generation. Our previous study, 21 developed the methodology to extract tr, ''per-stimulus'' responses independent of reversal rate.…”

mentioning

confidence: 99%

Relationship Between Transient and Steady-State Pattern Electroretinograms: Theoretical and Experimental Assessment

Özdamar¹,

Toft-Nielsen²,

Bohórquez³

et al. 2014

Investigative Ophthalmology & Visual Science

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

Cited by 11 publications

References 35 publications

Next Generation PERG Method: Expanding the Response Dynamic Range and Capturing Response Adaptation

Next Generation PERG Method: Expanding the Response Dynamic Range and Capturing Response Adaptation

New metric for optimizing Continuous Loop Averaging Deconvolution (CLAD) sequences under the 1/f noise model

Relationship Between Transient and Steady-State Pattern Electroretinograms: Theoretical and Experimental Assessment

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