Size Distributions in Urban Aerosols

Lippmann, Morton

doi:10.1111/j.1749-6632.1980.tb19345.x

Cited by 7 publications

(5 citation statements)

References 14 publications

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“…Fiorentini et al (1981) used sinusoidal grating stimuli to produce PERGs reported its loss in a case of central retinal artery occlusion and a low amplitude in one patient with acute optic neuritis. Maffei (1982) observed Volume 10, No. 4 -November 1983 reduced PERGs in 10 patients with optic neuritis but did not present data.…”

Section: Discussionmentioning

confidence: 99%

The Pattern Electroretinogram in Optic Nerve Demyelination

Kirkham

Coupland

1983

Can. j. neurol. sci.

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The pattern electroretinogram (PERG) is probably generated by the ganglion cell layer of the retina whose axons constitute the conductive fibres of the optic nerves. A study was undertaken of the PERG in a group of patients with clinically definite multiple sclerosis who had suffered optic nerve demyelination to assess the value of recording the PERG as a method for electrophysiological determination of optic nerve dysfunction. Pattern visual evoked potentials (PVEP) were simultaneously recorded, each eye being stimulated separately, and four different check sizes were used. Although individual patients showed PERG abnormalities the results as a group showed no significant difference from the normal population so far as latency or amplitude of the PERG was concerned. Thus we conclude that the PERG, while an interesting measurement, does not satisfactorily reflect optic nerve dysfunction. Further, our results indicate that it is not such a useful measure as the pattern visual evoked response for detecting optic nerve disease. RESUME: L'electroretinogramme evoque par des patterns (PERG) semble avoir son origine au niveau des cellules de la couche ganglionnaire de la retine dont les axones constituent les fibres conductrices des nerfs optiques. Chez des malades souffrant de sclerose en plaques et d'atteinte optique demyelinisante, nous avons analyse les donnees de l'electroretinogramme evoque par des patterns pour en evaluer I'utilite dans la detection des lesions du nerf optique. Bien que des electroretinogrammes anormaux (PERG) aient ete obtenus chez plusieurs malades, les differences de lantence et d'amplitude ne se sont pas revelees significatives en comparaison de celles d'un groupe temoin normal. L'electroretinogramme evoque par des patterns (PERG) ne reflete done pas fidelement la presence de demyelinisation dans les nerfs optiques; en outre, il ne se revele pas aussi efficace que l'enregistrement des potentiels evoques visuels obtenus par renversement de pattern pour detecter une atteinte des nerfs optiques.

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Section: Discussionmentioning

confidence: 99%

The Pattern Electroretinogram in Optic Nerve Demyelination

Kirkham

Coupland

1983

Can. j. neurol. sci.

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“…The origin of the PERG is still obscure but is considered to be generated in a more proximal layer of the retina such as the ganglion ceU layer (Mallei and Fiorentini, 1981;Arden et al, 1982). Maffei in 1982 briefly reported that the PERGs were present in PRD where the FERGs were reduced or absent. His suggestions that the PERG originates in the ganglion cells were thus supported by chnical observaiton.…”

Section: Discussionmentioning

confidence: 99%

“…On the other hand, it is not yet known how the ERG to pattern stimuli (PERG) responds to PRD. Recently Maffei (1982) briefly reported that in PRD the PERG was present while the FERG was subnormal or absent. He suggested that the origin of both types of ERGs were different in such a way that the PERG was related to the ganglion cells and the FERG to more outwardly located retinal layers.…”

Section: Introductionmentioning

confidence: 99%

Pattern electroretinograms recorded with a skin electrode in pigmentary retinal degeneration

Murayama

1985

Doc Ophthalmol

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In 24 patients suffering from pigmentary retinal degeneration the electroretinograms to pattern stimulation (PERG) were recorded with a silver-cup electrode placed on the center of the lower eyelid skin referred to an electrode on the earlobe. The results were compared with the responses to flash stimulation (FERG) and pattern visual evoked cortical potentials. None of patients showed normal FERGs. Nineteen of 48 eyes showed subnormal FERGs. The PERG was recorded from those 19 eyes. In the remaining 29 eyes with flat FERG, 8 eyes showed clear PERGs. The peak latency of the first positive component of PERGs was found to be prolonged in these patients. PERGs seemed to be recordable in the patients whose visual acuity and central visual field were relatively well preserved.

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“…Clinical studies now commonly show reduced PERGs when FERGs remain normal [16][17][18][19] and parametric studies demonstrate pattern effects only seen in the inner retina, including spatial and temporal tuning [12][13][14][20][21][22][23][24][25]. These data are supported by those from physiological studies showing that, despite some species differences [26][27][28], the PERG is lost in mammals after optic nerve section [29][30][31][32][33][34] and that it has a distinctive depth profile that differs from the flash ERG [35,36] and focal ERG [35].…”

Section: Introductionmentioning

confidence: 99%

Fundamental differences between the nonlinearities of pattern and focal electroretinograms

Vaegan

Sutter

1990

Doc Ophthalmol

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We directly compared nonlinear kernels of normal human pattern electroretinograms (PERGs) and corresponding localized flash ERGs (FERGs). The FERG was triphasic and resembled an adaptive process because it decayed slowly without changing shape over several kernel orders and interpulse intervals. The PERG was biphasic in the slice nearest the diagonal of the second-order kernel, similar to the FERG in slices farther from this diagonal, and without power in higher-order kernels. The unique PERG features were short-term effects that immediately followed a contrast transition. The appearance-disappearance PERG had a triphasic first-order kernel and a biphasic second-order kernel. The latter was similar to, but half the size of, that for the contrast-reversal PERG. When the first off-diagonal slices of the two PERG second-order kernels were analyzed in detail, we found in both that the first positive peak was larger than the FERG at intermediate spatial frequencies. Both PERG peaks in the slice had a low contrast threshold and were linear with contrast. The three FERG peaks of the corresponding FERG slice had a higher threshold and were saturated with increasing contrast. These observations show that the PERG contains substantial pattern specific nonlinear components and cannot be dismissed as merely the nonlinear subcomponents of the corresponding FERG.

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Size Distributions in Urban Aerosols

Cited by 7 publications

References 14 publications

The Pattern Electroretinogram in Optic Nerve Demyelination

The Pattern Electroretinogram in Optic Nerve Demyelination

Pattern electroretinograms recorded with a skin electrode in pigmentary retinal degeneration

Fundamental differences between the nonlinearities of pattern and focal electroretinograms

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