A new laser interferometer for the stimulation of pattern-reversal visual evoked potentials

Kusel, R.; Wesemann, W.; Rassow, B.

doi:10.1088/0143-0815/6/3/004

Cited by 6 publications

(2 citation statements)

References 14 publications

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“…However, in the midfrequency range, the recordings were sufficiently short for clinical application (e.g., 91.5 seconds at 12 Hz). This is close to the resolution presented earlier 5,31…”

Section: Discussionsupporting

confidence: 91%

“…In contrast to applying m-sequences for multifocal steady-state stimulation, as was done previously,4 we here used a multifrequency method. It has been shown that fundamental and higher harmonic components in the frequency domain have extremely small bandwidths and can be very stable 5,6. As a consequence, if stimuli with only slight differences in temporal frequency are delivered simultaneously, the responses elicited by these stimuli can be separately analyzed in the frequency domain (i.e., after Fourier transform), provided that the time of a measurement is sufficiently long to resolve the temporal frequency differences.…”

Section: Introductionmentioning

confidence: 99%

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Steady-State Visually Evoked Potentials Elicited by Multifrequency Pattern-Reversal Stimulation

Hohberger

Kremers

Horn

2019

Trans. Vis. Sci. Tech.

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Purpose It has been shown that multifrequency stimulation with multifocal electroretinography can reduce recording time without a loss in signal-to-noise ratio. Here, we studied the applicability of multifrequency stimulations for steady-state visually evoked potential (VEP) recordings. Methods Multifrequency VEPs were recorded monocularly from 10 healthy subjects using pattern-reversal stimuli. The reversal frequency varied between 5 and 30 Hz. Pattern-reversal checkerboard stimuli were generated using four square arrays, each containing 100 light-emitting diodes (LEDs), positioned in four quadrants. Each array had a temporal frequency that differed slightly from the nominal frequency. The long duration of the data acquisition ensured that the slightly different stimulus frequencies in the four LED arrays can be resolved and that the responses to the stimulus in each array can be distinguished (e.g., with a frequency resolution: 0.011 Hz at 12 Hz). The best response from the four recording electrode configuration, defined as the recording with the maximal signal-to-noise ratio, was used for further analysis. Algorithmic latencies were calculated from the ratio of phase data and frequencies in a range of 4 and 20 Hz. Results Quadrant-VEPs with simultaneous pattern-reversal stimulation yielded a significant dependency on temporal frequency and stimulus location. The frequency range leading to the maximal response amplitude was between 10 and 12 Hz. Response phases decreased approximately linearly, with increasing temporal frequency suggesting a mean algorithmic latency between 112 and 126 ms. Conclusions Multifrequency stimulation using LED arrays is an efficient method for recording pattern-reversal VEPs while all stimuli are presented at the same time. Translational Relevance Simultaneously recorded VEPs as performed by the multi-frequency method can be used for objective measurements of visual field defects.

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“…However, in the midfrequency range, the recordings were sufficiently short for clinical application (e.g., 91.5 seconds at 12 Hz). This is close to the resolution presented earlier 5,31…”

Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Steady-State Visually Evoked Potentials Elicited by Multifrequency Pattern-Reversal Stimulation

Hohberger

Kremers

Horn

2019

Trans. Vis. Sci. Tech.

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Retinal visual acuity with pattern VEP normal subjects and reproducibility

Simon¹,

Rassow²

1986

Graefe's Arch Clin Exp Ophthalmol

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Retinal visual acuity was determined using an objective method by means of VEP. Sixty subjects with subjective visual acuity ranging from 20/25 to 20/12 were measured with a computer-controlled laser interferometer, using interference fringes modulated in counterphase as pattern-reversal stimulus. Steady-state VEPs taken at different spatial frequencies were evaluated by Fourier analysis and linear regression. Objective retinal acuity was calculated as the intersection between the linear regression line and the linear scaled spatial frequency axis. In 68% of all cases, the difference between objective and subjective visual acuity was less than +/- 5.1 cycles per degree (c/d) (+/- 15.4% referred to subjective acuity); in 86%, the difference was less than +/- 7.7 c/d (+/- 23.1%).

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Meigen¹,

Bach²

1999

Documenta Ophthalmologica

142

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Steady-state stimulation is a useful paradigm in many physiologic and clinical situations, for ERG, Pattern-ERG and VEP. One of the advantages is the easy evaluation of the response via Fourier analysis. However, the question whether a given response is statistically significant or not has received little attention so far, although it is especially relevant in high noise, low amplitude recordings, as often occur in pathologic conditions. A given response is statistically significant if it is unlikely that its value is due to noise fluctuations. Thus appropriate estimates of noise and response are required. We have analytically derived formulas for the statistical significance of a given signal-to-noise-ratio s, based on two different estimates of noise: (1) Noise estimate by a 'no stimulus' recording, or by a '+/-average'. The former needs an additional recording, the latter can simultaneously be calculated as the standard average. (2) Noise is estimated as the average of the two neighboring spectral lines (one below, and one above the response frequency). Analytical solutions were obtained for both noise estimates that can easily be evaluated in all appropriate recordings. Noise estimate (1) performs much poorer than noise estimate (2), as can be seen from the following landmark values: Typical significance levels of 5%, 1%, and 0.1% require s values of 4.36, 9.95, and 31.6 (1), and 2.82, 4.55, and 8.40 (2). The noise estimate based on the neighboring frequencies can be easily applied after recording, provided that the noise spectrum is reasonably smooth around the response and frequency-overspill was avoided. It allows a quantitative assessment of low responses in physiological threshold analyses and pathological conditions, e.g., 'submicrovolt flicker-ERG'.

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A new laser interferometer for the stimulation of pattern-reversal visual evoked potentials

Cited by 6 publications

References 14 publications

Steady-State Visually Evoked Potentials Elicited by Multifrequency Pattern-Reversal Stimulation

Steady-State Visually Evoked Potentials Elicited by Multifrequency Pattern-Reversal Stimulation

Retinal visual acuity with pattern VEP normal subjects and reproducibility

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