Electrophysiological Examinations of the Visual System in the Acute Phase after Head Injury

Abstract

Assessment of the function of the visual system in the acute phase after head injury is often difficult, since consciousness may be affected. In this report, we wish to stress that combined electroretinography and the averaged visual evoked potential should be the examinations of choice because they do not depend on the patient’s cooperation or state of consciousness. The case histories of five patients are reported. Only by means of the electrophysiological methods was a diagnosis made possible, since clinical examinations failed to clarify the state of their visual systems.

Surgical decompression in traumatic optic neuropathy

“…Initial assessments of VA may be difficult with an uncooperative, inebriated or partially conscious patient. When possible, the use of visual evoked responses may help in the diagnosis of bilateral ocular deficit (Feinsod & Auerbach 1973), but this method was not used in this study.…”

Prognostic Value of Visual Evoked Potentials in Occipital Blindness following Basilar Artery Occlusion

“…However, unequal VEPS obtained by pairs of electrodes placed at equal distances from the median line above the two occipital cortices were found to point to lesions in one occipital lobe which result in a homonymous field defect [8,14,16,17,22], In experimental studies in monkeys following ablation of one occipital lobe [9,30], as well as in man after surgical removal of one occipital lobe [10], responses from the damaged area were absent or at best very small. In case of severe occipital lobe injury [12,19] or occipital blindness of vascular origin [17], preserved VEPs, even of abnormal shape and subnormal ampli tude, point to a favorable prognosis of progressive recovery of visual function.…”

“…They were also helpful to estimate the damage caused to the occipital lobe after head trauma [12,19]. However, only one case of occipital blindness of vascular origin was ex amined by means of the VEP [17] and displayed early abnormal and asymmetric responses.…”

Ultrastructural Findings and SOD Levels in Experimental Optic Nerve Injury: Effect of Thyroid-Releasing Hormone on the Degenerative and Regenerative Processes

“…actions, visual-evoked response (VER), ophthalmoscopic, neuroradiologic, and histochemical examinations are being used for the evaluation of optic nerve lesions [8,9,32], In contrary to the previous studies, recent experiments revealed that optic nerve fibers are to some extent capable of regeneration [18,26,28].…”

“…However, determining the site and the extent of the lesion may be quiet difficult in an unconscious patient [22,29,32]. The most affected site o f the nerve in cranial trauma is the intracanalicular segment [8,34], The nerve is less likely to be injured in the orbita because of some protective factors such as the surrounding orbital fat, …”