The diagnostic value of multichannel VEPs for children without nystagmus.

Abstract

Purpose: This study explored the clinical value of routine multichannel pattern reversal visual evoked potential (prVEP) recordings in children without nystagmus.

Methods: A single centre, retrospective case note review was carried out of children without nystagmus who had multichannel prVEP recordings from midline, O1 and O2 electrodes referred to Fz to an ISCEV large check (50' check width), reversing 3/s in a full 30° field and right and left 0-15° half fields, during 2020. Full-field (FF) prVEPs were classified as abnormal if midline P100 amplitude and peak time fell outside reference limits. Trans-occipital distribution asymmetry was defined as differences ≥ 20% amplitude between FF-prVEP the O₁ and O₂ at the peak time of the midline P100. Half field (HF) prVEPs acted as the gold standard discriminator of abnormality. The trans-occipital distribution and amplitude of the HF-prVEP ipsilateral positive peak (iP100) were compared for each eye.

Results: FF-prVEP and HF-prVEP data from 63 children were classified. Group 1, 7/63 (11%), had abnormal midline FF-prVEP evidence of visual pathway dysfunction, whilst Group 2, 56/63 (89%), had normal midline FF-prVEPs. Group 2 was subdivided further according to the trans-occipital distribution of FF-prVEPs followed by HF-prVEPs. Group2A, 14/56 (25%), had symmetrical FF-prVEP distribution and normal HF-prVEPs. Group2B, 31/56 (55.4%), had asymmetrical FF-prVEP distribution, but lateralised HF-prVEPs that explained the FF-prVEP asymmetric distribution. Group2C, 11/56 (19.6%), had HF-prVEP evidence of pathway dysfunction with symmetric (n = 2) or asymmetric (n = 9) FF-prVEP distributions. Common referral reasons in all groups were reduced vision, glioma, craniopharyngioma, epilepsy presurgical evaluation, craniosynostosis, papilloedema/disc drusen, with various other specific conditions.

Conclusions: Multichannel prVEPs add value to investigations of reduced or unexplained vision in children without nystagmus. Visual pathway abnormalities would not have been identified without a multichannel FF- or HF-prVEP in 11/56 (19.6%) of children in this study who had normal midline FF-prVEPs.