Internuclear ophthalmoplegia

The Internuclear ophthalmoplegia ( INO ) is one of the pränukleären paralysis of eye movements, and therefore differs from a gaze palsy as a disturbance within the supranuclear centers. It occurs at a damage of the medial longitudinal fasciculus (MLF ) in the midbrain, the ( Abducens oculomotor nerve, trochlear nerve, ) coordinates different, the eye muscles controlling cranial nerve nuclei interaction. Since the medial longitudinal fasciculus is located near the midline, the INO often occurs on both sides. The INO affects mainly the internuclear neurons of the mutual Abduzenskerns which draw the core of the oculomotor nerve in the damaged medial longitudinal fasciculus on the same side ( ipsilateral ) to when looking to the healthy side, the adduction of the eye of on the side of the injury with the simultaneous abduction other ( contralateral ) eye coordination.

The correlated disorder is a partial view to complete inability to move the view to the opposite side the eye towards the nose ( Adduktionsschwäche ) on the side of the lesion. The other eye performs at the corresponding line of sight rapid pendulum motion, dissociated nystagmus called (see nystagmus). In the convergence reaction, the eye is paralyzed, however, to be able adduct. This is so because the coordination of the convergence reaction is not controlled by the medial longitudinal fasciculus. For a double- sided INO not only horizontal but also vertical motions are disturbed to a lesser extent ( shortened saccades ).

Cause of an isolated Internuclear ophthalmoplegia may be multiple sclerosis, as well as brain inflammation, tumors or small ( lacunar ) infarcts midbrain or cerebral hemorrhage.

The combination with a horizontal gaze palsy to the side of INO is called a half syndrome. It is a unilateral lesion in the region of the PPRF ( = horizontal gaze palsy ) and in the area of the ipsilateral medial longitudinal fasciculus ( = INO ). One eye is horizontally motionless (except for convergence, see above), the other eye can still be abducted.