Midbrain paresis of horizontal gaze

Unilateral paramedian involvement of the midbrain tegmentum causes monocular paralysis of adduction in the ipsilateral eye, paresis of contralateral saccades in the opposite eye, and conjugate paresis of ipsilateral smooth pursuit. The adduction paralysis can be nuclear, or internuclear from a lesion in the medial longitudinal fasciculus. This distinctive midbrain syndrome of horizontal gaze paresis is exemplified by means of quantitative infrared oculographic, radiological, and neuropathological correlation in two patients with predominantly paramedian midbrain tumors involving the mesencephalic reticular formation and the oculomotor nucleus. Binocular paralysis of elevation provided evidence that one human oculomotor nucleus contains axons to both superior rectus muscles, as does the simian oculomotor nucleus. The midbrain tectum was spared. These pathophysiological correlations indicate that the mesencephalic reticular formation contains pathways that control contralateral saccades and ipsilateral smooth pursuit.     

Prenuclear paresis of homolateral inferior rectus and contralateral superior oblique eye muscles

In a case of left inferior rectus paresis, it is demonstrated that the lesion must be prenuclear. On downward gaze, the left eye, although it reached the required target with a rapid saccade, drifted back towards the midline immediately afterwards. During the drift, several corrective saccades appeared. A dissociated "gaze paretic" nystagmus resulted. Synchronously, the right eye showed an incyclorotary nystagmus. We suspect a lesion of "tonic" fibers supplying the nuclear region of the left inferior rectus and the right superior oblique muscle.     

A case presenting vertical one-and-a-half syndrome and seesaw nystagmus due to thalamomesencephalic infarction]

A 58-year-old woman presented, conjugate upgaze palsy and monocular paresis of downward gaze in the ipsilateral eye (vertical one-and-a-half syndrome; VOHS) as well as seesaw nystagmus (SSN). Vertical oculocephalic response and conjugate horizontal gaze were preserved. Magnetic resonance imaging revealed a right thalamo-mesencephalic infarction including the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) and the interstitial nucleus of Cajal. On the 22nd hospital day SSN was disappeared, and then on the 32nd day VOHS was improved. The lesions of VOHS may have affected the efferent tracts of riMLF and the descending fibres to the ipsilateral subnucleus of the inferior rectus and contralateral subnucleus of the superior oblique. Furthermore, it was assumed that SSN was caused simultaneously by a lesion in the interstitial nucleus of Cajal existing in the adjacent area of riMLF.     

A case of partial fascicular oculomotor paresis caused by midbrain infarction]

We report a 74-year-old man with an ischemic lesion in the ventral midbrain. He presented with contralateral ptosis and marked upward gaze paresis of the right eye. Neurological examination revealed partial oculomotor nerve palsy caused by impairment of the right levator palpebrae, superior rectus and inferior oblique muscles. This finding is highly suggestive of a possible lesion in the midbrain affecting the oculomotor fascicular fibers. Magnetic resonance images showed an ischemic lesion in the paramedian area of the right midbrain tegmentum. The coronal view of T 2-weighted imaging clearly demonstrated to be the site of lesions below the red nucleus. It seemed to be coincidental with the impaired site of involving the caudal part of oculomotor fascicular fibers emerging from the nucleus. This report is considered to be a typical case of partial fascicular oculomotor paresis based on impairment of the caudal part of oculomotor fascicles for the levator palpebrae, superior rectus, and inferior oblique muscles. This is a valuable case to be documented in which neurological site of lesions are consistent with those found in radiological study.     

Upgaze palsy and monocular paresis of downward gaze from ipsilateral thalamo-mesencephalic infarction: a vertical “one-and-a-half” syndrome

Summary A patient with an infarct limited to the paramedian thalamus and upper mesencephalon on the right side suffered a conjugate upgaze palsy associated with a monocular paresis of downward gaze in the ispsilateral eye (vertical one-and-a-half syndrome). This paresis involved tonic and phasic components. Vertical oculocephalic movements and conjugate horizontal gaze were normal. It is suggested that the unilateral lesion destroyed the fibres of the posterior commissure and the descending fibres to the ipsilateral subnucleus of the inferior rectus and contralateral subnucleus of the superior oblique just after they decussate, probably above the level of the third nerve nucleus. A complex disturbance of vertical gaze may be due to a unilateral thalamo-mesencephalic lesion.

---

Zusammenfassung Wir beschreiben einen Patienten mit einem Infarkt rechts paramedian im Thalamus und oberen Mesencephalon mit Blicklähmung nach oben und einer Parese nach unten nur ipsilateral. Betroffen waren sowohl die tonischen wie die phasischen Bewegungskomponenten. Die vertikalen okulocephalen Reflexe und der konjugierte horizontale Blick waren normal. Wir vermuten, daß die einseitige Läsion Fasern der hinteren Kommissur und abwärts führende Fasern zum ipsilateralen Kern des Rectus inferior und zum gegenseitigen Kern des Obliquus superior zerstörte kaudal ihrer Kreuzung, wahrscheinlich rostral des Nucleus oculomotorius. Eine komplexe Störung der vertikalen Blickbewegung kann auf eine einseitige thalamo-mesencephale Läsion hinweisen.

     

Isolated acquired unilateral horizontal gaze paresis from a putative lesion of the abducens nucleus.

In three patients, acute horizontal gaze pareses developed that could not be overcome with the oculocephalic maneuver, indicating a putative lesion of the ipsilateral abducens nerve nucleus. None of the patients had a facial nerve paresis or evidence of a trigeminal sensory neuropathy. Although most lesions that affect the abducens nerve nucleus also damage the ipsilateral fasciculus of the facial nerve, small lesions in this region can produce an isolated horizontal gaze paresis.     

A case of left third nerve palsy and contralateral vertical gaze palsy with medial midbrain infarction]

An 81-year-old man developed oculomotor nerve palsy of the left eye and vertical gaze palsy of the right eye due to left medial midbrain infarction. His left eyelid was ptotic and the pupil was dilated. His right eye showed normal horizontal movement and Bell's phenomenon was preserved although the oculocephalic reflex was incomplete. There were no other abnormal neurological findings. The brain MRI revealed a high-intensity lesion in left medial midbrain on T2 weighted image. This lesion involved the oculomotor nerve nucleus, the interstitial nucleus of Cajal, and the rostral intersititial nucleus of the medial longitudinal fasciculus (riMLF). We thought that upward gaze palsy of the right eye was resulted from the infarction of the left riMLF or disruption of the axonal collateral of upward gaze fibers in the left oculomotor nucleus. Downward gaze palsy was resulted from the damage of the downward gaze fibers before their decussation, or the damage of the left interstitial nucleus of Cajal. This case provides evidence that unilateral lesion of the midbrain could cause contralateral vertical gaze palsy.     

Internuclear ophthalmoplegia,prenuclear paresis of contralateral superior rectus,and bilateral ptosis

Summary A patient with infarction of the paramedian part of the lower mid-brain on the right side is described, in whom internuclear ophthalmoplegia and bilateral ptosis were associated with limitation of elevation of the contralateral eye from paresis of the superior rectus. Supranuclear paresis was suggested by partial dissociation between phasic and tonic components of upward gaze. It is suggested that the right-sided lesion involved the rostral median longitudinal fasciculus before it reached the oculomotor nucleus, the central caudal nucleus medially situated in the lower end of the oculomotor nucleus, and the prenuclear fibres from the posterior commissure to the ipsilateral nucleus of the contralateral superior rectus. A supranuclear lesion may be suspected when there is a complex association of dysconjugate palsy of oculomotor muscles.

---

Zusammenfassung Es wurde eine Patientin mit Infarkt des paramedianen Teils des unteren Mittelhirns rechts untersucht. Es lag eine internukleäre Ophthalmoplegie und eine bilaterale Ptose mit Heberschwäche des kontralateralen Auges bei Parese des M. rectus superior vor. Wegen einer partiellen Dissoziation von phasischen und tonischen Komponenten der Heberfunktion vermuteten wir eine supranukleäre Parese. Die Läsion umfaßt wahrscheinlich rechts das rostrale mediale Längsbündel, den zentralen caudalen Teil des Nucleus oculomotorius und die prenucleären Fasern der Commisura posterior.

     

Paramedian thalamopeduncular infarction: clinical syndromes and magnetic resonance imaging.

We prospectively examined 11 patients with magnetic resonance imaging-documented infarction in the paramedian thalamopeduncular region, which is supplied by the superior mesencephalic and posterior thalamosubthalamic arteries. Variations in the size and rostral-caudal extent of infarction correlated with the following three clinical patterns: (1) With unilateral paramedian mesencephalic infarction, an ipsilateral third nerve paresis was accompanied by mild contralateral hemiparesis or hemiataxia. Contralateral ptosis and impaired upgaze were observed in two patients; one of them showed additional damage to the posterior commissure. (2) With bilateral infarction in the thalamopeduncular junction, involving the mesencephalic reticular formation, supranuclear vertical gaze defects were accompanied by impaired consciousness or memory, and mild aphasia in some patients. Persistent amnesia was observed only when the dominant anterior nucleus or mamillothalamic tract was damaged. (3) With larger thalamopeduncular infarcts, partial or complete third nerve paresis was combined with supranuclear gaze disturbance and delayed contralateral tremor. An unusual gaze disorder, a variant of the vertical "one-and-a-half syndrome," occurred with a small strategically placed lesion at the thalamopeduncular junction, best explained by selective damage to supranuclear pathways or partial nuclear involvement. The primary cause of these infarctions was embolism to the basilar apex or local atheroma at the origin of the posterior cerebral artery.     

Claude's syndrome associated with supranuclear horizontal gaze palsy caused by dorsomedial midbrain infarction

Claude's syndrome caused by dorsal midbrain lesion is characterized by ipsilateral third nerve palsy and contralateral ataxia. To date, reports in the literature concerning Claude's syndrome associated with the midbrain paresis of horizontal gaze are rare. A 62-year-old man suddenly developed left third cranial nerve palsy, right lateral gaze palsy, and right ataxia. Intact Bell's phenomenon and preserved right horizontal oculocephalic reflex suggested the lateral gaze palsy in the right eye was supranuclear in nature. Magnetic resonance imaging (MRI) revealed an infarction in the left dorsomedial midbrain. Although the red nucleus has often been suggested as the lesion site responsible for Claude's syndrome, a lesion of the superior cerebellar peduncle just below and medial to the red nucleus could be responsible for this syndrome. This case demonstrates neurological heterogeneity of midbrain infarction.     

Horizontal gaze paresis in hemispheric stroke

Of 156 stroke patients prospectively and consecutively evaluated, one-third had a homonymous hemianopia. Of those 52 patients, 46% had a horizontal conjugate gaze paresis at the time of presentation. This gaze paresis was most commonly seen with large hemispheric stroke. The overall prognosis in patients with a gaze paresis was poor. The 30-day case fatality rate was 49% which was significantly higher than for stroke patients presenting with homonymous hemianopia without a gaze paresis.     

Internuclear ophthalmoplegia of abduction: clinical and electrophysiological data on the existence of an abduction paresis of prenuclear origin.

Three patients showed unilateral and five bilateral abduction paresis. Five had associated adduction nystagmus of the contralateral eye. Electrophysiological testing of masseter and blink reflexes indicated an ipsilateral rostral pontine or mesencephalic lesion, and excluded a lesion of the infranuclear portion of the abducens nerve. Abduction paresis was attributed to impaired inhibition of the tonic resting activity of the antagonistic medial rectus muscle. The prenuclear origin of the disorder is based on morphological and neurophysiological evidence of an ipsilateral inhibitory connection between the paramedian pontine reticular formation and the oculomotor nucleus running close to but separated from the medial longitudinal fasciculus.     

Downward gaze in monkeys: stimulation and lesion studies.

Ten monkeys were stimulated unilaterally and bilaterally through bipolar electrodes placed stereotactically on each side of the midline under light barbiturate anaesthesia. Bilateral simultaneous stimulation elicited straight downward binocular movements from a core of tissue about 40 mm3 on each side which included the fields of Forel, zona incerta, subthalamic nucleus, oral pole of the red nucleus, fasciculus retroflexus and 'area tegmentalis'. Unilateral stimulation of the same points yielded downward eye movements in only 25 per cent of the instances. Upward deviation of the globes could be elicited by bilateral stimulation of tissue located more caudal, ventral and medial than that from which downward movements were obtained. Bilateral electrolytic lesions within the region outlined above caused significant defects in downward gaze both in saccadic and slow pursuit binocular movements. Passive bending of the head backwards, however, resulted in downward deviation of the globes (oculocephalic reflex). Optokinetic nystagmus and after-nystagmus downward were abolished. Oblique (45 degrees) optokinetic stimulation elicited a perverted response in the horizontal plane. Vestibulo-ocular reflexes elicited by bilateral warm irrigation of both ear canals with the monkey in the erect position, or by turning the animal while lying on one side, caused a strong tonic deviation upward with absence of nystagmus downward. Some of these monkeys showed additional alterations in upward gaze but they were less severe in intensity and duration than those of downward gaze. All eye deviations in the horizontal plane were consistently normal. Recovery occurred in all types of vertical binocular movements except in the rapid motions (saccades and quick phases of nystagmus) below the horizontal meridian. A unilateral lesion had no effect. The minimal damage producing downward gaze defects was about 1.7 mm in diameter, cetred in the prerubral fields, rostral and medial to the red nuclei with minimal involvement of the oral pole of these structures. The nuclei of Cajal, Darkschewitsch and interstitialis of the posterior commissure, as well as the fasciculus retroflexus and the posterior commissure, were spared by this lesion. The so-called rostral interstitial nucleus of the medial longitudinal fasciculus and the nucleus campi Foreli appear to be destroyed. These structures are known to receive an input from the paramedian pontine reticular formation and project on to the oculomotor nerve nucleus. These results demonstrate that the prerubral fields contain structures which are critical for rapid eye movements downward, and therefore an isolated downward gaze palsy is a strong indicator of a bilateral lesion of this zone. The findings in the few reported cases with this sign and available pathological analysis suggest that our conclusions from the experimental monkey apply to man as well. The concept of bilateral innervation for vertical eye movements is amply confirmed for the downward vectors...     

Monocular elevation paresis caused by an ipsilateral lesion

A 52-year-old woman presented with a paresis of elevation of the right eye, equally severe in abduction and adduction (monocular elevation paresis). CT demonstrated a small, right-sided tumor of the mesodiencephalic junction. Monocular elevation paresis has been attributed to lesions of the contralateral pretectum, although proof has been lacking. Now, with documentation of an ipsilateral brainstem etiology, we can postulate a lesion affecting the upgaze efferents from the ipsilateral rostral interstitial nucleus of the medial longitudinal fasciculus.     

Unusual MR findings of Wernicke encephalopathy with cortical involvement]

We report a 48-year-old chronic alcoholic man, who developed consciousness disturbance, oculomotor paresis, and flaccid tetraplegia. His dietary habit was very poor since one month prior to the present admission and he was drinking alcoholic beverage. On admission on April 19, 1999, he showed disturbance of consciousness, tetraparesis without sensory disturbance, gaze paresis, and vertical nystagmus on downward gaze. His blood thiamine level was 12 ng/ml (normal range: 23.8-45.9). MRI demonstrated symmetric hyperintense lesions in the motor and premotor cortices bilaterally, in addition to other changes indicating Wernicke's encephalopathy. His motor weakness and oculomotor disturbance improved after treatment with intravenous thiamine. His cortical MRI also normalized. We believe that his cortical abnormality was responsible for his motor paresis and this is an unusual and unique finding for Wernicke's encephalopathy.     

Unilateral midbrain infarction causing upward and downward gaze palsy.

We report on a 47-year-old-woman who developed sudden complete loss of vertical saccades, smooth pursuit, and vestibular eye movements bilaterally. MRI revealed a unilateral midbrain infarct involving the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) and the interstitial nucleus of Cajal (INC) and spared the posterior commissure (PC). The lesion is presumed to have interrupted the pathways involved in vertical gaze just before they decussate, inducing an anatomically unilateral but functionally bilateral lesion. Previous reports of bidirectional vertical gaze palsy have shown lesions involving the PC or both riMLFs. This case is the first to show that a unilateral lesion of the riMLF and the INC that spares the PC may cause complete bidirectional vertical gaze palsy.     

Divergence paresis: a nonlocalizing cause of diplopia.

OBJECTIVES: To determine the causes, clinical characteristics, and localizing value of divergence paresis, which is characterized by acquired and uncrossed diplopia when viewing distant targets, fusion when viewing near targets, and no limitation of ocular ductions. Controversy persists regarding the diseases underlying divergence paresis and the existence of a divergence "center." MATERIALS AND METHODS: The charts of 15 patients with divergence paresis examined between 1983 and 1998 were reviewed. All patients underwent neuroimaging and detailed ocular motility testing, with measurement of esotropia in prism diopters in 14 patients. RESULTS: Divergence paresis in 15 patients was idiopathic in three patients, was associated with central nervous system microangiopathy or infarct in seven patients, and clivus lymphoma, chronic lymphocytic leukemia with sinusitis, Wernicke ophthalmoplegia, Parkinson disease, myasthenia gravis, cryptic cerebellar vascular malformation, and childhood esotropia in one patient each (two patients had two diagnoses). The mean maximum esotropia was 10.4 prism diopters, and there was no significant correlation (Fisher exact test) between the magnitude of esotropia and vasculopathic etiology or posterior fossa lesion site. Although six patients had posterior fossa disease, neuroimaging showed no common circumscribed lesion site or evidence of increased intracranial pressure. CONCLUSIONS: Divergence paresis is an uncommon cause of acquired diplopia. Divergence paresis is associated with diverse central nervous system diseases and can be mimicked by myasthenia. The absence of a single consistent lesion in our study, which is the largest reported series, suggests that divergence paresis is a nonlocalizing cause of horizontal diplopia and that multiple or diffusely distributed neural structures may govern divergence. Alternatively, elusive divergence "centers" may not exist, and divergence paresis may arise from impaired inhibition or from defective passive antagonism of orbital structures to convergence.     

Vocal cord paresis in acute ischemic stroke

We prospectively determined the frequency of vocal cord paresis (VCP) among first-ever acute ischemic stroke patients. Vocal cords were examined endoscopically within 48 h of stroke onset, at 1 week and 1 month. Of the 54 study patients, 64.8% had lacunar (group 1), 22.2% cortical/large subcortical (group 2), 9.3% lateral medulla (group 3) and 3.7% other brainstem (group 4) infarcts. VCP was found in 11 (20.4%): 11.4% of group 1, 16.4% of group 2, 100% of group 3 and 0% of group 4. VCP was contralateral to the brain lesion in groups 1 and 2, and ipsilateral in 80% of group 3. VCP was strongly correlated with dysphonia (p < 0.0001) and resolved in 2/11 patients after 1 week and in 5/11 after 1 month. Our finding of VCP among acute ischemic stroke patients questions the belief that the nucleus ambiguous is invariably bilaterally innervated by supranuclear centers.     

Supranuclear vertical gaze palsy: bilateral thalamo-mesencephalic lesions demonstrated by MRI

The exact location for the major control center of the vertical gaze, which is referred to as rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF), has been documental in a few autopsy studies. However, CT in some of the case reports of vertical gaze palsy have not clearly delineated this nucleus and its nearby complex anatomical structures. Discrete small, bilateral, symmetric infarcts in the thalamo-mesencephalic junction were demonstrated by MRI in a 59-year-old female patient who had sustained vertical gaze palsy over a period of nine years. Neurological examination revealed severe supranuclear combined downward and upward vertical gaze palsy, incomplete convergence, and slight limitation in adduction of the right eye. There was neither ptosis, pupillary disturbance, nor any further abnormalities of horizontal eye movements. The vertical vestibulo-ocular reflex was maintained, being similar to the other reported cases of vertical gaze palsy. MRI has advantages over CT in demonstrating lesions in the thalamo-mesencephalic junction in the cases of vertical gaze palsy, because clearer sagittal images can be obtained.     

Selective impairment of downward gaze; report of two cases of midbrain and bilateral paramedian thalamic infarction

Selective paralysis of downward gaze, first described by André-Thomas et al. in 1933, is rare to be observed and not many cases have been so far reported in the literature. Two additional cases of selective impairment of downward gaze have been reported. X-ray CT scan revealed the infarcted areas in the midbrain tegmentum and bilateral paramedian thalami in both cases. Angiographic studies have revealed that the arteries occluded might be the paramedian thalamic arteries and their mesencephalic branches. According to the reported clinico-pathological studies and, in addition, to the results of the physiological studies in animal models, the responsible site of lesion for downward gaze failure is thought to be the rostral interstitial nucleus of MLF (riMLF). In one of the cases (28 year-old female, case 1), while vertical slow pursuit eye movements and upward saccade were normal in speed and range, maximum speed of eyes in voluntary downward saccade was markedly reduced and the eyes moved down slowly as if moving in oil (slow eye movement, viscosité). Passively extending the patient's head while she tried to fix her eyes on an unmoving object (doll's eye phenomenon), the speed of her eyes in downward saccade did not increase. In the other case (45 year-old male, case 2), the patient's voluntary and reflex downward eye movements were completely impaired and he could not look down nor follow the object below extending the horizontal meridian level. With regard to the unique features of abnormal eye movements observed in our cases, the possibility of coexistence of saccadic and slow pursuit eye movement systems in the vertical plane was discussed.