Background: We performed an electrophysiological study in order to objectifys uppression in strabismus. The extent of cortical involvement in the process of interocular suppression was also explored. Possible differen...Background: We performed an electrophysiological study in order to objectifys uppression in strabismus. The extent of cortical involvement in the process of interocular suppression was also explored. Possible differences in the suppressive process of esotropic and exotropic strabismics were alsostudied. Methods: An electroencephalographic recor- der with eight leads was applied to the posterior one-third of the skull; three occipital, three parietal, and two temporal leads. We measured the activity of these visual cortical areas during stimulation of each eye under monocular as well as binocular viewing conditions with hemisinusoidal light pulses in a natur e-like complex visual background. Recordings were made from six primary esotropic strabismic subjects and four primary exotropic and one consecutive exotropic strabismic subject. Also, five normal controls were studied. Results: A characte ristic, triphasic response complex was found at approximately 80 ms following the start of each light pulse under monocular viewing conditions in the dominant and the nondominant eye. However, under dichoptic viewing conditions in the nondo minanteye of all esotropic cases as well as in the nondominant eye of three of five exotropic cases, this response complex was completely absent. They showed a pproximately 100%reduction of their cortical response activity. Conclusions: Th ese results show the vast extent of the cortex that is involved in the suppressi ve process, giving a good insight in the power of suppression.展开更多
文摘Background: We performed an electrophysiological study in order to objectifys uppression in strabismus. The extent of cortical involvement in the process of interocular suppression was also explored. Possible differences in the suppressive process of esotropic and exotropic strabismics were alsostudied. Methods: An electroencephalographic recor- der with eight leads was applied to the posterior one-third of the skull; three occipital, three parietal, and two temporal leads. We measured the activity of these visual cortical areas during stimulation of each eye under monocular as well as binocular viewing conditions with hemisinusoidal light pulses in a natur e-like complex visual background. Recordings were made from six primary esotropic strabismic subjects and four primary exotropic and one consecutive exotropic strabismic subject. Also, five normal controls were studied. Results: A characte ristic, triphasic response complex was found at approximately 80 ms following the start of each light pulse under monocular viewing conditions in the dominant and the nondominant eye. However, under dichoptic viewing conditions in the nondo minanteye of all esotropic cases as well as in the nondominant eye of three of five exotropic cases, this response complex was completely absent. They showed a pproximately 100%reduction of their cortical response activity. Conclusions: Th ese results show the vast extent of the cortex that is involved in the suppressi ve process, giving a good insight in the power of suppression.
