Excitation‐inhibition Anomalies of the Extra‐ocular Muscles; Electromyographic Observations

Abstract

The electromyography (EMG) of a normal extraocular muscle in characterized by moderate electrical activity with the eye in the primary position, progressively increasing electrical activity in the direction of its field of action and progressively decreasing activity, sometimes up to complete electrical silence, with the eye moving in the antagonistic direction. (Bjork, 1954). EMG evidence of a n interplay of excitation (increase of activity) and inhibition (decrease of activity) between agonistic and antagonistic extmocular muscles is in accordance with the basic law of ocular motility, that excitation of one group om muscles is closely associated with inhibition of the contralateral group.As some disorders of the ocular motility may be related to a disturbance of this delicate reciprocal mechanism, we carried out EMG studies in such cases for further clarification. The results, which are presented here, will be discussed in the light of their clinical significance. Method and TechniqueThe EMG examination was carried out on a two-channel apparatus provided with mnemoscopic unit, filming camera and loud speaker, linked to a digital