Short-latency sinusoidal wavelets to bright flashed stimuli: Studies with corneal lens, nasopharyngeal, retrobulbar and scalp recordings

Lucia Sanarelli, P. M. Rossini, P. Rizzo, E. Stefano, G. Soldati, F. Pierelli, C. Morocutti

Research output: Contribution to journalArticlepeer-review

Abstract

Short-latency flash visual evoked potentials (VEPs) and electroretinograms (ERGs) were recorded in 30 healthy volunteers and 14 patients (7 with retrobulbar neuritis and 7 with retinitis pigmentosa). Simultaneous recordings were performed by corneal, scalp, nasopharyngeal and retrobulbar (5 patients) electrodes. In 18 out of 30 healthy controls a brief sequence of oscillating wavelets was recorded between 15 and 40 ms on the scalp sites behind the vertex. In retrobulbar neuritis (RBN) patients normal responses were recorded by lens, retrobulbar, nasopharyngeal and frontal scalp electrodes. On the contrary none of these patients displayed short-latency activity behind the Cz scalp position. In 5 out of the 7 patients with retinitis pigmentosa, corneal, nasopharyngeal and scalp electrodes failed to detect any reliable waveform time-locked to the flash onset. In the remaining 2, a small lens ERG was recorded, while all other electrodes recorded a sequence of low-volted wavelets initiating 30 ms after the stimulus onset. In these patients an occipital VEP reduced in amplitude and with prolonged latency was also recorded. It is concluded that in presence of a normal corneal ERG because of the presence of volume spread oscillating retinal activity, it is hard to define while part of the scalp recorded, short latency, oscillating potentials is generated in subcortical visual structures.

Original languageEnglish
Pages (from-to)306-311
Number of pages6
JournalEuropean Neurology
Volume29
Issue number6
DOIs
Publication statusPublished - 1989

Keywords

  • Electroretinogram
  • Retinitis pigmentosa
  • Retrobulbar neuritis
  • Short-latency oscillating wavelets
  • Visual evoked potentials

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology

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