Pediatric Visual Electrophysiology

Kriss, A.; Thompson, Dorothy

doi:10.1007/0-387-27933-4_1

Cited by 2 publications

(4 citation statements)

References 172 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In our previous study we showed that visual electrophysiological screening of infants with congenital nystagmus can establish or exclude retinal and postretinal pathway dysfunction [30]. Children with maldeveloped optic chiasm in this and other studies were electrophysiologically assessed due to their congenital nystagmus [4,6,8,9,31] or were suspected of having albinism [2]. Therefore, from previous studies and ours, we may assume that already in early infancy the distinctive VEP will help in the diagnosis of achiasmia.…”

Section: Discussionmentioning

confidence: 79%

VEP asymmetry with ophthalmological and MRI findings in two achiasmatic children

et al. 2007

View full text Add to dashboard Cite

Achiasmia is a rarely diagnosed visual pathway maldevelopment where all or the majority of nasal retinal fibres fail to decussate at the optic chiasm. It has been identified by neuroimaging and also by visual evoked potential (VEP) asymmetry. VEP asymmetry has not been defined consistently in previous studies. The aim was to study VEP asymmetry to flash stimulation in two children with maldevelopment of the optic chiasm in comparison to control children. Both children had congenital nystagmus, optic nerve hypoplasia with a bilateral small double ring, bitemporal visual field defect and normal colour vision. In child 1 visual acuity in both eyes was 0.1, in child 2 it was 0.2. MRI showed reduced chiasmal size in child 1, while in child 2 it was combined with other midline abnormalities. VEP to monocular flash stimulation showed in both children distinctive occipital distribution, which was not observed in control children. The N2 wave was distributed asymmetrically over the ipsilateral hemisphere to the stimulated eye, while the P2 wave was distributed over both hemispheres. The P2 wave was however better defined over the ipsilateral hemisphere. Flash VEP occipital distribution remained similar in child 1, who was followed from 10 months to 9 years. These cases of achiasmia demonstrate a distinctive VEP asymmetry in the distribution of the flash VEP N2 wave, as well as the expected structural defect determined by neuroimaging.

show abstract

Section: Discussionmentioning

confidence: 79%

VEP asymmetry with ophthalmological and MRI findings in two achiasmatic children

et al. 2007

View full text Add to dashboard Cite

show abstract

“…Therefore, the lack of uniformity in VEP asymmetries shown previously has also been found in the present study. In the majority of previous studies, ipsilateral asymmetry was observed with flash and pattern onset stimulation [3][4][5][6][7], while crossed asymmetry and crossed contralateral positivity have also been associated with achiasmia [8][9][10][11][12]36]. In the present study, the ipsilateral asymmetry defines the absent optic-nervefibre decussation at the chiasm for both of the eyes.…”

Section: Ocular Findings and Mri Characteristicsmentioning

confidence: 44%

“…Colour vision was tested with Ishihara plates, while visual field testing was performed with Goldmann perimetry and static perimetry (Octopus perimeter, G2 top programme). Table 1 gives the ophthalmological findings of the children with achiasmia (children 1-4) and with ocular albinism (children [5][6][7][8][9][10][11][12][13][14][15][16][17][18]. All of these children had infantile nystagmus, normal near vision and normal colour vision (analphabetic or Ishihara colour plates).…”

Section: Ophthalmological Examinationmentioning

confidence: 99%

“…In achiasmia, a number of VEP asymmetries have been described, with all of them defining absence of or reduced optic-nerve-fibre decussation at the chiasm. From each eye, the optic nerve fibres that mainly or solely project into the ipsilateral hemisphere produce VEP distributions that have been defined as: ipsilateral asymmetry [3][4][5][6][7], crossed asymmetry [8][9][10][11] and crossed contralateral positivity [12]. In all forms of albinism, VEP asymmetries have been described as contralateral asymmetry [13,14] and albino crossed asymmetry [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

VEP characteristics in children with achiasmia, in comparison to albino and healthy children

et al. 2012

View full text Add to dashboard Cite

Achiasmia is a rare disorder of visual pathway maldevelopment that can show diverse clinical and magnetic resonance imaging spectra. The aim of this study was to define the characteristics of visual evoked potentials (VEPs) that differentiate abnormal optic-nerve-fibre decussation in children with achiasmia versus children with albinism and healthy children. In four children with achiasmia, the following VEP characteristics were studied and compared to children with ocular albinism and with healthy control children: (a) flash and pattern onset VEP interhemispheric asymmetry; (b) flash N2, P2 and onset C1 amplitudes and latencies; (c) interocular polarity differences in interhemisphere potentials; and (d) chiasm coefficients (CCs). In the children with achiasmia, VEPs were related to an absence of or reduced optic-nerve-fibre decussation at the chiasm and showed: ipsilateral asymmetry, significantly higher VEP amplitudes over the ipsilateral hemisphere (p < 0.05), interocular inverse polarity and negative CC. Other VEP features (uncrossed asymmetry and positive CC) were also seen if additional visual pathway maldevelopment (such as severe optic nerve hypoplasia and/or absence of the optic tractus on one side) were associated with achiasmia. In the children with albinism, the VEPs were related to excess optic-nerve-fibre decussation at the chiasm and showed: contralateral asymmetry, significantly higher VEP amplitudes over the contralateral hemisphere (p < 0.001), interocular inverse polarity and negative CC. In achiasmia and albinism, the VEPs to flash stimulation were more robust and more clearly distinguished between the conditions compared with the VEPs to pattern onset stimulation. VEPs in achiasmia are associated with absent or reduced optic-nerve-fibre decussation, where ipsilateral interhemispheric asymmetry is associated with interocular inverse polarity and a negative CC.

show abstract

Pediatric Visual Electrophysiology

Cited by 2 publications

References 172 publications

VEP asymmetry with ophthalmological and MRI findings in two achiasmatic children

VEP asymmetry with ophthalmological and MRI findings in two achiasmatic children

VEP characteristics in children with achiasmia, in comparison to albino and healthy children

Contact Info

Product

Resources

About