Fisher's One and a Half Syndrome

Update item information
Identifier 166-20
Title Fisher's One and a Half Syndrome
Ocular Movements Unilateral Internuclear Ophthalmoplegia; Unilateral Horizontal Gaze Palsy; Upbeat Nystagmus on Upgaze; Convergence Normal
Creator Shirley H. Wray, M.D., Ph.D., FRCP, Professor of Neurology Harvard Medical School, Director, Unit for Neurovisual Disorders, Massachusetts General Hospital
Contributor Primary Shirley H. Wray, MD, PhD, FRCP, Professor of Neurology, Harvard Medical School; Director, Unit for Neurovisual Disorders, Massachusetts General Hospital
Subject Unilateral Internuclear Ophthalmoplegia; Unilateral Horizontal Gaze Palsy; Upbeat Nystagmus on Upgaze; Convergence Normal; Fisher's One-and-a-Half Syndrome; Multiple Sclerosis; Unilateral Internuclear Ophthalmoplegia; Unilateral Horizontal Gaze Palsy Demyelination; Gaze Evoked Upbeat Nystagmus; Abducting Nystagmus
Supplementary Materials PowerPoint Presentation: One-and-a-Half Syndrome: Shirley H. Wray, M.D., Ph.D., FRCP, Harvard Medical School
Presenting Symptom Dizziness Double vision
History This 28 year old woman had severe multiple sclerosis with a spastic paraparesis due to a lesion of the spinal cord. She was admitted to the Intensive Care Unit complaining of dizziness and double vision. Neuro-ophthalmologic examination: Visual acuity 20/30 OU Pupils, visual fields and fundi normal Ocular Motility: A left internuclear ophthalmoplegia on gaze right with adduction weakness OS Abducting nystagmus OD Left horizontal gaze palsy with gaze evoked nystagmus In primary gaze, esotropia OS Full vertical gaze Upbeat nystagmus on upgaze (ill sustained) Convergence normal Neuroimaging studies were not available at that time. Spinal tap: Cerebrospinal fluid showed a mildly elevated protein level, and increased number of white cells with elevated IgG and positive oligoclonal bands. Diagnosis: Multiple Sclerosis (MS)
Clinical This MS patient had Fisher's one-and-a-half Syndrome characterized by: • A left horizontal gaze palsy with gaze evoked nystagmus • A left internuclear ophthalmoplegia on gaze right with adduction weakness OS • Abducting nystagmus OD • Full vertical gaze • Upbeat nystagmus on upgaze (ill sustained) • Convergence normal The "One-and-a-Half" syndrome was first described by Fisher in 1967. The disorder is characterized by a lateral gaze palsy in one direction with an internuclear ophthalmoplegia (INO) in the other direction. In the complete form of the syndrome, the ipsilateral eye lies fixed at the midline for all lateral movements; the other eye can only abduct and exhibits horizontal jerk nystagmus in abduction. The syndrome is usually due to a unilateral lesion in the lower part of the dorsal pontine tegmentum, affecting the ipsilateral paramedian pontine reticular formation (PPRF), the abducens nucleus, and internuclear fibers of the ipsilateral medial longitudinal fasciculus (MLF). These internuclear fibers originate in the contralateral abducens nucleus and terminate in the ipsilateral medial rectus subnucleus of the third nerve nucleus. In 1983 Michael Wall, who was a Fellow of mine at that time, reviewed all the patients that I had seen with the one-and-a-half syndrome between 1968 and 1982. Films or video tapes of eye movements were available for review in 9 cases. In 12 of 20 patients, the lesion was on the right side. The patient's ranged in age from 16 to 78 years. Prior to our publication in Neurology there had been only 29 reported cases of the one-and-a-half syndrome in the literature: 6 proven and 6 probable infarctions, 8 hemorrhages (1 traumatic) 5 gliomas, 1 arteriovenous malformation, 1 metastatic melanoma and 2 patients with MS. We added a further 20 patients. (Table 1) Brainstem infarction was the most common cause in elderly adults (Patients 17 to 20 (Table 2)). Four patients were age 61 to 78 years mean, 70 years. Two of them had hypertension. Three patients presented with neurologic complaints and one with diplopia. MS was the most common cause in 14 young adults aged 18 to 52 years, (mean 32 years). Twelve had definite MS and 2 possible MS. (Table 1) In 4 patients the one-and-a-half syndrome represented the initial presentation of MS. Two of these patients complained first of diplopia and one of blurred vision. Only 7 of 14 MS patients had visual complaints as the major symptom. Nine had diplopia, 5 had blurred vision, 3 had oscillopsia, and 2 had difficulty looking to one side. (Table 2 and 3) Associated Ocular Motility signs: Gaze evoked upbeat nystagmus Skew deviation Horizontal ipsilateral gaze nystagmus Rotary component to horizontal ipsilateral gaze nystagmus Spontaneous nystagmus to the contralateral side Absent or impaired convergence Saccadic vertical pursuit Gaze evoked downbeat nystagmus Impaired upward gaze Exotropia Esotropia Orthotropic In 10 MS patients whose eye position was documented in straight ahead gaze, 4 had exotropia, 2 had an esotropia and 4 were orthotropic. (Table 4) Associated Neurological signs: The most common associated cranial nerve lesions were an ipsilateral trigeminal sensory loss and a peripheral-type facial palsy. Seven patients had impaired coordination of the limbs. Only one patient had no neurological abnormality other than the one-and-a-half syndrome. (Table 5) Ten of the fourteen MS patients had recovery of eye movements: Recovery was complete in eight patients between 4 and 16 weeks after onset, and partial recovery occurred in two other patients followed for 4 weeks and 9 weeks.
Neuroimaging No neuroimaging studies were available on this patient.
Anatomy The two constituents of the one-and-a-half syndrome (ipsilateral horizontal gaze palsy and INO) can be analyzed anatomically to provide the basis for topographic localization of the lesion at the bedside. Horizontal gaze palsy. There are four theoretical possibilities to account for the ipsilateral horizontal gaze palsy. It may be due to a single unilateral lesion affecting: 1. The ipsilateral paramedial pontine reticular formation (PPRF) only 2. The ipsilateral abducens nucleus alone 3. Both the ipsilateral paramedial pontine reticular formation (PPRF) and the abducens nucleus, or, when two lesions are involved 4. The motoneuron root fibers of the ipsilateral abducens nucleus to the lateral rectus and the contralateral medial longitudinal fasciculus (MLF). Paramedial pontine reticular formation. The medial portions of the nucleus reticularis magnocellularis (or nucleus centralis pontis oralis and caudalis) have been designated the "paramedian pontine reticular formation" (PPRF), rostral to the abducens nucleus. The region extends from the abducens nucleus in a rostral direction toward the brachium conjunctivum and trochlear nucleus. It has been defined functionally because there are no distinct histologic boundaries. But anatomically, Graybiel, Büttner-Ennever, and Grantyn et al all showed inputs from discrete areas. Two major oculomotor pathways originate from the PPRF. One pathway ascends rostrally, close to but outside of the MLF, to the rostral mesencephalon to coordinate horizontal and vertical gaze. The other pathway descends caudally and sends off a direct projection to the ipsilateral abducens nucleus. This excitatory pathway controls horizontal gaze to the ipsilateral side by stimulating motoneurons to the lateral rectus and internuclear abducens neurons, which project via the MLF to the medial rectus motoneurons of the contralateral oculomotor nucleus. Other major projections likely to be involved in gaze are projections from the PPRF to the nucleus prepositus hypoglossi and PPRF cerebellar pathways. No direct inhibitory pathway from the PPRF projects to the contralateral abducens nucleus. The inhibitory pathway from inhibitory burst neurons travels from the dorsomedial gigantocellular tegmental field just caudal to the abducens nucleus, crosses the brainstem and terminates in the contralateral abducens nucleus. The importance of this pathway has been demonstrated for saccades and quick phases of vestibular nystagmus, but it is still unclear whether an analogous pathway exists to control smooth pursuit movements. In any case, the PPRF generates all ipsilateral-directed saccades (including the quick phases of vestibular nystagmus). Abducens nucleus. The abducens nucleus contains typical motoneurons that give rise to root fibers that innervate the lateral rectus as well as internuclear neurons whose axons cross the midline and ascend via the contralateral MLF to the medial rectus subnucleus in the contralateral oculomotor (third nerve) nucleus. This projection is the main excitatory input to medial rectus motoneurons in lateral gaze. An old clinicopathologic case published by Bennett and Savill (1) described a unilateral gaze palsy with an associated "patch of softening" in the abducens nucleus without apparent involvement of neighboring structures. Clinical distinction PPRF: Abducens nucleus. At the bedside distinction can be made between the manifestations of gaze palsies in lesions of the PPRF in the upper pons from those of the PPRF in the lower pons at the level of the abducens nucleus. With PPRF lesions rostral to the abducens, there is ipsilateral paralysis of saccades and pursuit, but the eyes can be driven to the side of the gaze palsy with vestibular stimulation. At the level of the abducens nucleus, lesions of the PPRF are associated with ipsilateral gaze palsy and loss of reflex vestibular (and tonic neck) movements. This presumes that there is a critical synapse within the caudal PPRF for the vestibulo-ocular pathways or that, at the very least, the functional integrity of the PPRF at that level is necessary for vestibulo-ocular eye movements. An associated sign with abducens nuclear lesions, however is an ipsilateral "peripheral" facial palsy because the genu of the seventh nerve wraps around the abducens nucleus. The gustatory fibers are spared, because these fibers are carried in the intermediate branch of the facial nerve to the nucleus solitarius of the medulla. This sign was present in four of our MS patients (Table 2). An identical ipsilateral gaze palsy can be produced by damage to axons of abducens neurons as they course through the brainstem, namely, the ipsilateral sixth nerve fascicle and those axons which ascend the contralateral MLF. Separation of these two anatomic sites suggests two lesions. A lateral gaze palsy that always remains conjugate is consistent with one lesion of the abducens nucleus, whereas one that is not conjugate at any time would better fit two lesions. Two examples, in our patient group, were both patients with definite MS. Internuclear ophthalmoplegia Both human and experimental data have established the localization of the lesion that causes INO. A unilateral INO is due to the interruption of the ipsilateral MLF after it has crossed the midline caudally in the pons from its site of origin in the contralateral abducens nucleus. Clinically, the syndrome is characterized by: 1. Paresis or paralysis of adduction of the ipsilateral eye on attempted horizontal gaze to the contralateral side. 2. Horizontal jerk nystagmus in the contralateral abducting eye and 3. Typically convergence is intact if the lesion does not extend to the mesencephalon. Other associated findings are abnormalities in vertical smooth pursuit, OKN, the vertical VOR with normal vertical saccades if the INO is bilateral, gaze evoked vertical nystagmus on upward gaze more frequent than downgaze if the lesion is bilateral and skew deviation. The one-had-a-half syndrome is characterized by, on horizontal gaze: 1. An ipsilateral gaze paresis or palsy 2. An INO on contralateral gaze 3. At rest, an exotropia of the eye contralateral to the lesion in the acute phase, or no deviation at rest, or less commonly, an esotropia of the eye ipsilateral to the lesion resulting from paresis of the sixth nerve. Occasionally, ocular bobbing occurs, which may be periodic or limited to the ipsilateral eye. Anisocoria is also reported. Personal observation: All of our patients with the one-and-a-half syndrome showed a complete or partial ipsilateral horizontal gaze palsy and a clinical or subclinical INO on contralateral gaze. Slow and incomplete adduction of the ipsilateral eye was attributed to deficient medial rectus excitation and horizontal jerk nystagmus in the abducting eye was attributed to deficient tonic inhibition of the medial rectus. This interpretation is consistent with the results of oculographic studies. The association of exotropia in the one-and-a-half syndrome was observed by Fisher and later termed "paralytic pontine exotropia" by Sharpe et al. In this distinctive supranuclear syndrome, the deviated, exotropic eye shows abduction nystagmus during attempts to move it further laterally, and there is extreme slowness of adduction saccades when the eye is used to fixate to move it to the midline. Paralytic pontine exotropia is attributed to tonic contralateral ocular deviation of the eyes, which implies acute ipsilateral involvement of the PPRF. Failure of the ipsilateral eye to deviate medially is explained by the INO. Three autopsy cases of paralytic pontine exotropia confirm the lesion site. Esotropia of the ipsilateral eye may be due to a lesion of the fasciculus of the ipsilateral sixth nerve.
Pathology The anatomic localization of the lesion in the one-and-a-half syndrome has been confirmed at autopsy in seven patients. Six of them had a single unilateral lesion in the pontine tegmentum ipsilateral to the gaze palsy involving the PPRF and the ipsilateral MLF. The abducens nucleus was spared by discrete lesions and involved in extensive lesions resulting from infarction, hemorrhage or glioma. In Fisher's case, extensive pontine infarction involved both the PPRF and the abducens nucleus. Crevits et al correlated the gaze palsy with a single discrete infarct 3 by 2 mm in diameter in the ipsilateral PPRF and MLF. The lower fascicles of the ipsilateral sixth nerve passed through the necrotic area. This was probably the smallest lesion associated with the one-and-a-half syndrome. Newman et al reported a similar clinical case, but they found an ipsilateral PPRF lesion and "ischemic necrosis in the region of the abducens nucleus, although individual neurons could be identified". Partial damage to the contralateral PPRF was also found. In another pathologically confirmed case evaluated clinically by electro-oculography, a hypertensive hemorrhage in the rostral pontine tegmentum had spread into the right basis pontis to destroy the ipsilateral PPRF and abducens nucleus.
Etiology Review (16)
Disease/Diagnosis Multiple Sclerosis
References 1. Bennett H, Savill TH. A case of permanent conjugate deviation of the eyes and head, the result of a lesion limited to the sixth nucleus, with remarks on associated lateral movements of the eyeballs, and rotation of the head and neck. Brain 1889;12:102-116. 2. Bogousslavsky J, Miklossy J, Regli F, Deruaz JP, Despland PA. One-and-a-half syndrome in ischemic locked-in state. J Neurol Neurosurg Psychiatry 1984;47:927-935. 3. Carter JE, Rauch RA. One-and-a-half syndrome type II. arch Neurol 1994;51:87-80. 4. Crevits L, de Reuck J, vander Eecken H: Paralytic pontine exotropia in subarachnoid hemorrhage: a clinocopathological correlation. Clin Neurol Neurosurg 1975:78:269-276. 5. Fisher CM. Some neuro-ophthalmological observations. J Neurol Neurosurg Psychiatry 1967;30:383-392. 6. Fisher CM. Neuroanatomic evidence to explain why bilateral internuclear ophthalmoplegia may result from occlusion of a unilateral pontine branch artery. J Neuroophthalmol 2004;24:39-41. 7. Jackel RA, Gittinger JW Jr, Smith TW, Passarelli CB. Metastatic adenocarcinoma presenting as a one-and-a-half syndrome. J Clin Neuroopthalmol 1986; 6:116-119. 8. Kataoka S, Hori A, Shirakawa T, Hirose G. Paramedian pontine infarction. Neurological/topographical correlation. Stroke 1997;28:809-815. 9. Minagar A, Schatz NJ, Glaser JS. Case report: one-and-a-half syndrome and tuberculosis of the pons in a paient with AIDS. AIDS Patient Care STDS 2000;14:461-464. 10. Newman NM, Day SH, Aguilar MJ. Paralytic pontine exotropia a case report with clinicopathologic confirmation. Augenbewegungastörungen Neurophysiologie und Klinik, München JF Bergman Verlag, 1978. 11. Newton HB, Miner ME. "One-and-a-half syndrome after resection of a midline cerebellar astrocytoma: case report and discussion of the literature. Neurosurgery 1991;29:768-772. 12. Oommen KJ, Smith MS, Labadie EL. Pontine hemorrhage causing Fisher one-and-a-half syndrome with facial paralysis. J Clin Neuroophthalmol 1982;2:129-132. 13. Raps EC, Galetta SL, King JT Jr, Yachnis AT, Flamm ES. Isolated one-and-a-half syndrome with pontine cavernous angioma; successful surgical removal. J Clin Neuroophthalmol 1990;10:287-290. 14. Sharpe JA, Rosenberg MA, Hoyt WF, Daroff RB. Paralytic pontine exotropia. A sign of acute unilateral pontine gaze palsy and internculear ophthalmoplegia. Neurology 1974;24:1076-1081. 15. Smith MS, Buchsbaum HW, Masland WS. One-and-a-half syndrome. Occurrence after trauma with computerized tomographic correlation. Arch Neurol 1980;37:251. 16. Wall M, Wray SH. The one-and-a-half syndrome: a unilateral lesion of the pontine tegmentum. A study of 20 cases and review of the literature. Neurology 1983, 33:971-980. 17. Yigit A, Bingöl A, Mutluer N, Tascilar N. The one-and-a-half syndrome in systemic lupus erythematosis. J Neuroophthalmol 1996;16:274-276.
Relation is Part of 164-2, 166-14, 937-8, 941-4, 941-6
Contributor Secondary Ray Balhorn, Video Compressionist
Reviewer David Zee, M.D., Johns Hopkins Hospital, 2006
Publisher Spencer S. Eccles Health Sciences Library, University of Utah
Date 1972
Type Image/MovingImage
Format video/mp4
Source 16 mm film
Rights Management Copyright 2002. For further information regarding the rights to this collection, please visit:
Holding Institution Spencer S. Eccles Health Sciences Library, University of Utah, 10 N 1900 E, SLC, UT 84112-5890
Collection Neuro-ophthalmology Virtual Education Library: NOVEL
Language eng
ARK ark:/87278/s6ck1b26
Setname ehsl_novel_shw
Date Created 2008-04-16
Date Modified 2021-05-06
ID 188620
Reference URL
Back to Search Results