Dalfampridine, a potassium channel blocker prescribed for gait impairment was used in in a case series and the authors reported improvement in saccades and ocular motility in patients with INO secondary to demyelination in Multiple sclerosis.
Improved neuronal conduction along MLF has been discussed as a possible explanation for this effect seen [12]. The prognosis of most patients with an INO is good but the final outcome depends in part on treatment of the underlying etiology. Ischemic and demyelinating INO typically recover.
Create account Log in. Main page. Getting Started. Recent changes. View form. View source. Internuclear Ophthalmoplegia From EyeWiki. Jump to: navigation , search. Enroll in the Residents and Fellows contest. Enroll in the International Ophthalmologists contest. Residents and Fellows contest rules International Ophthalmologists contest rules. Original article contributed by :. All contributors:. Assigned editor:. Claudia Prospero Ponce, MD. Internuclear Ophthalmoplegia.
Nystagmus is thought to be the result of an adaptive response to weakness of the medial rectus muscle ipsilateral to the INO Hering law. The affected eye presents reduced saccadic velocity, predominantly in adduction. Oculocephalic reflexes were absent, which rules out the possibility of horizontal gaze pseudopalsy. Several INO plus syndromes have been described, including one-and-a-half syndrome lesion to the paramedian pontine reticular formation or the abducens nerve, associated with INO , wall-eyed bilateral INO bilateral damage to the MLF , eight-and-a-half syndrome one-and-a-half syndrome associated with seventh cranial nerve palsy , and half and half syndrome, which is extremely infrequent.
The most common aetiologies are inflammatory multiple sclerosis in young patients and vascular in older individuals. Half and half syndrome is a rare combination of neurological signs. To our knowledge, this is the second reported case of half and half syndrome of inflammatory origin and the third reported case of the syndrome with any aetiology.
This may partially be explained by underdiagnosis. As reported by Frohman et al. Neuro-ophthalmological examination should include systematic assessment of smooth pursuit movements, saccades, the vestibulo-ocular reflex, and vergence movements; this increases diagnostic sensitivity for milder cases. In conclusion, half and half syndrome should be included within the spectrum of INO and INO plus syndromes, which are frequent in multiple sclerosis, often presenting as the initial symptom; a high level of suspicion is therefore essential for early diagnosis.
ISSN: Previous article Next article. Issue 3. Pages April More article options. Letter to the Editor. Half and half syndrome as a presentation of multiple sclerosis. Download PDF. Corresponding author. This item has received. Under a Creative Commons license. Article information. Full Text. Dear Editor:. Figure 1. Frohman, S. Galetta, R. Fox, D. Solomon, D. Common manifestations Early symptoms include an erythema migrans rash, which may be followed weeks to months later by neurologic Diagnosis is suspected clinically and confirmed by imaging primarily Diagnosis is primarily clinical.
The disorder If a lesion in the MLF blocks signals from the horizontal gaze center to the 3rd cranial nerve, the eye on the affected side cannot adduct or adducts weakly past the midline. The affected eye adducts normally in convergence because convergence does not require signals from the horizontal gaze center.
This finding distinguishes internuclear ophthalmoplegia from 3rd cranial nerve palsy Third Cranial Oculomotor Nerve Disorders Third cranial nerve disorders can impair ocular motility, pupillary function, or both. Symptoms and signs include diplopia, ptosis, and paresis of eye adduction and of upward and downward gaze During horizontal gaze to the side opposite the affected eye, images are horizontally displaced, causing diplopia; nystagmus often occurs in the abducting eye.
Sometimes vertical bilateral nystagmus occurs during attempted upward gaze. This uncommon syndrome occurs if a lesion affects the horizontal gaze center and the MLF on the same side. The eye affected by the lesion cannot move horizontally to either side, but the eye on the side opposite the lesion can abduct; convergence is unaffected.
Causes of one-and-a-half syndrome include multiple sclerosis, infarction, hemorrhage, and tumor. With treatment eg, radiation therapy for a tumor, treatment of multiple sclerosis , improvement may occur but is often limited after infarction. Internuclear ophthalmoplegia results from a lesion in the medial longitudinal fasciculus, which coordinates abduction of one eye with adduction of the other. Common causes are multiple sclerosis in young people often bilateral and stroke in older people typically unilateral.
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