Flicker Electroretinograms: A Systems Analytic Approach

Odom, J. Vernon; Reits, D.; Burgers, N; Riemslag, Frans C. C.

doi:10.1097/00006324-199202000-00003

Cited by 44 publications

(37 citation statements)

References 28 publications

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“…In the previous study [8], we argued that these higher-order harmonics must originate from the cone pathway since cones are sensitive to high flicker frequencies while rods are not [31]. In this study, we found a high correlation between the amplitudes of the 15, 30, and 45 Hz components of the responses to stimuli of high flash strengths.…”

Section: Discussionsupporting

confidence: 58%

An extended 15 Hz ERG protocol (2): data of normal subjects and patients with achromatopsia, CSNB1, and CSNB2

et al. 2011

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The amplitude versus flash strength curve of 15 Hz electroretinograms (ERGs) shows two minima. The minima are caused by interactions between the primary and the secondary rod pathways (first minimum), and the secondary rod pathway and the cone-driven pathway (second minimum). Furthermore, cone pathway contributions cause higher-order harmonics to occur in the responses. We measured 15 Hz ERGs in 20 healthy subjects to determine normal ranges and in patients to verify our hypotheses on the contributions of the different pathways and to investigate the clinical application. We analyzed the amplitudes and phases of the 15, 30, and 45 Hz components in the ERGs. The overall shape of the 15 Hz amplitude curves was similar in all normal subjects and showed two minima. The 30 and 45 Hz amplitude curves increased for stimuli of high flash strengths indicating cone pathway contributions. The 15 Hz amplitude curve of the responses of an achromat was similar to that of the normal subjects for low flash strengths and showed a minimum, indicating normal primary and secondary rod pathway function. There was no second minimum, and there were no higher-order harmonics, consistent with absent cone pathway function. The 15 Hz ERGs in CSNB1 and CSNB2 patients were similar and of low amplitude for flash strengths just above where the first minimum normally occurs. We could determine that in the CSNB1 patients, the responses originate from the cone pathway, while in the CSNB2 patients, the responses originate from the secondary rod pathway.

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Section: Discussionsupporting

confidence: 58%

An extended 15 Hz ERG protocol (2): data of normal subjects and patients with achromatopsia, CSNB1, and CSNB2

et al. 2011

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“…This approach has been previously adopted in the study of both primate and nonprimate retina [9][10][11][12][13][14][15]. From these studies it has become apparent that ERG temporal response functions to luminance stimuli across different primate species share common features.…”

Section: Introductionmentioning

confidence: 99%

Temporal characteristics of L- and M-cone isolating steady-state electroretinograms

et al. 2014

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Cone isolating stimuli were used to assess the temporal frequency response characteristics of L- and M-cone electroretinograms (ERGs) in nine trichromatic and four dichromatic human observers. The stimuli comprised sinusoidal temporal modulations varying from 5 to 100 Hz. ERGs were recorded using corneal fiber electrodes and subjected to fast Fourier transform analysis. At low temporal frequencies (<10 Hz) the L- and M-cone ERGs had similar amplitude and exhibited minimal differences in apparent latency. At higher flicker rates (>20 Hz) L-cone ERGs had greater amplitudes and shorter apparent latencies than the M-cone responses. These differences between the L- and M-cone ERGs are consistent with their mediation by chromatic and luminance postreceptoral processing pathways at low and high temporal frequencies, respectively.

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“…However, in the square wave flicker, the second and thirdorder components (30 Hz and 45 Hz) are small, while they are large in the short flash flicker. It has been shown that rods can respond linearly to flicker frequencies of up to 30 Hz [8,26]. Odom et al [26] found that the sensitivity of rods declines exponentially with flicker frequency and that rods are 2 log units less sensitive to 30 Hz than to 15 Hz flicker.…”

Section: Introductionmentioning

confidence: 99%

“…However, higher harmonic components can occur when the rod pathways respond to the 15 Hz component in a nonlinear manner. The temporal flicker sensitivity of cones is described as a band-pass filter that is dependent on the average intensity of the stimulus [25][26][27]. Nevertheless, the sensitivity of cones to flicker frequencies of 15, 30 and 45 Hz is of the same order.…”

Section: Introductionmentioning

confidence: 99%

An extended 15 Hz ERG protocol (1): the contributions of primary and secondary rod pathways and the cone pathway

et al. 2011

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The minimum in the amplitude versus flash strength curve of dark-adapted 15 Hz electroretinograms (ERGs) has been attributed to interactions between the primary and secondary rod pathways. The 15 Hz ERGs can be used to examine the two rod pathways in patients. However, previous studies suggested that the cone-driven pathway also contributes to the 15 Hz ERGs for flash strengths just above that of the minimum. We investigated cone pathway contributions to improve upon the interpretation of (abnormal) 15 Hz ERGs measured in patients. We recorded 15 Hz ERGs in five healthy volunteers, using a range of flash strengths that we extended to high values. The stimuli were varied in both colour (blue, green, amber, and red) and flash duration (short flash and square wave) in order to stimulate rods and cones in various ways. The differences in the responses to the four colours could be fully explained by the spectral sensitivity of rods for flash strengths up to approximately 12.5 log quantaÁdeg -2 . At higher flash strengths, higher-order harmonics appeared in the responses which could be attributed to cones being more sensitive than rods to higher frequencies. Furthermore, the amplitude curves of the blue and green responses showed a second minimum suggesting rod to cone interactions. We present a descriptive model of the contributions of the rod and cone pathways. In clinical application, we would advise using the short flash flicker instead of the square wave flicker, as the responses are of larger amplitude, and cone pathway contributions can be recognized from large higher-order harmonics.

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Flicker Electroretinograms: A Systems Analytic Approach

Cited by 44 publications

References 28 publications

An extended 15 Hz ERG protocol (2): data of normal subjects and patients with achromatopsia, CSNB1, and CSNB2

An extended 15 Hz ERG protocol (2): data of normal subjects and patients with achromatopsia, CSNB1, and CSNB2

Temporal characteristics of L- and M-cone isolating steady-state electroretinograms

An extended 15 Hz ERG protocol (1): the contributions of primary and secondary rod pathways and the cone pathway

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