SUPRANUCLEAR LATERAL GAZE PALSY OF PONTINE ORIGIN - REPORT OF 2 CLINICOPATHOLOGICAL CASES WITH ELECTRO-OCULOGRAPHIC AND ELECTRO-MYOGRAPHIC DATA

  • 1 January 1979
    • journal article
    • research article
    • Vol. 135  (11) , 741-762
Abstract
Electro-oculographic, electromyographic (EMG) and pathological findings in 2 cases of supranuclear lateral gaze palsy of pontine origin determined the clinical and physiopathologic features of the pontine reticular formation (PRF) syndrome, and an hypothesis about the terminal portion of the occipito-pontine tract (OPT) involved in horizontal pursuit eye movements was formulated. The unilateral PRF syndrome is characterized by abnormal eye movements in the direction of the lesion. In the ipsilateral hemifield of movement there is paralysis of all movements from midline to extreme ipsilateral side, except oculo-cephalic reflex which remains intact (dissociated palsy); in the contralateral hemifield all saccades from extreme contralateral side to midline are suppressed, and this constitutes a specific abnormality of the PRF syndrome: quick phase of optokinetic and vestibular nystagmus are absent, while voluntary gaze is preserved but remarkably slow. This last fact is apparently due to simple disfacilitation arising from undamaged PRF. EMG findings suggest that the division between excitatory and inhibitory fibers of descending supranuclear oculomotor tracts ending in the abducens nuclei probably occurs in the lower pons. Anatomopathologic findings in the 2 cases show that the OPT runs in front of the medial longitudinal fasciculus or in the lateral tegmentum and that it decussates, at least once, below the upper pons.

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