21/198. Dorsal midbrain syndrome secondary to a pineocytoma.BACKGROUND: Dorsal midbrain syndrome is a triad of signs consisting of vertical gaze palsy, light-near dissociation of the pupils, and convergence retraction nystagmus. Associated findings may also be present. The most-common etiologies are pineal gland tumors and midbrain infarction. pineal gland tumors are rare tumors that show a predilection for males. The specific tumor reported herein, a pineocytoma, shows no gender predilection and is most common in mid- to late adulthood. CASE REPORT: A 38-year-old Native American man came to us with signs and symptoms consistent with dorsal midbrain syndrome. A neurological evaluation revealed the presence of a pineocytoma, which was later excised unsuccessfully. An explanation of the findings associated with dorsal midbrain syndrome is provided. CONCLUSION: patients who demonstrate signs consistent with dorsal midbrain syndrome should be referred for a neurological evaluation--including an MRI--to rule out any midbrain lesion.- - - - - - - - - - ranking = 1keywords = ms (Clic here for more details about this article) |
22/198. Acquired pendular nystagmus with voluntary inhibition.This report documents a case of voluntary inhibition of acquired pendular nystagmus after head trauma. A 30-year-old male developed oscillopsia and decreased visual acuity, as well as findings of acquired pendular nystagmus with voluntary inhibition after head trauma. The EOG finding was horizontal 18-20 Hz bilateral symmetrical pendular nystagmus in all directions of gaze at near and distant fixation. Nystagmus did not change with 14 Prism Diopter base-out prisms on both eyes, but it was possible to abolish it intentionally. baclofen and clonazepam had no effect in improving the patient's symptoms and EOG finding.- - - - - - - - - - ranking = 2keywords = ms (Clic here for more details about this article) |
23/198. Congenital mitochondrial cytopathy and chronic progressive external ophthalmoplegia.BACKGROUND: Chronic Progressive External ophthalmoplegia (CPEO) encompasses different conditions having in common a slowly progressive external and general ophthalmoplegia. The discovery of CPEO is suggestive of mitochondrial cytopathy, but this is not necessarily so. CASE REPORT: We report here a case, presenting at age 9 months, characterized by bilateral blepharoptosis and partial third nerve oculomotor deficiency, with no nystagmus. Mitochondrial cytopathy was suspected on cranial MRI and confirmed by muscle biopsy. Enzyme studies revealed a defect on the complex I respiratory chain. This case is unique in that the symptoms completely resolved under a Ketogen diet.- - - - - - - - - - ranking = 1keywords = ms (Clic here for more details about this article) |
24/198. A pilot study of gabapentin as treatment for acquired nystagmus.The effects of the anticonvulsant gabapentin were measured on vision and eve movements in three patients with acquired pendular nystagmus. In two patients, the nystagmus was associated with multiple sclerosis and, in the other, it followed brainstem stroke. A single oral 600 mg dose of gabapentin produced improvement of vision due to changes in ocular oscillations in all three patients. The effect was sustained after five weeks of treatment in two patients who elected to continue taking gabapentin 900-1500 mg/day. The results of this pilot study suggest that a controlled trial of gabapentin should be conducted to evaluate its role in the treatment of acquired forms of nystagmus.- - - - - - - - - - ranking = 3397.4747177396keywords = multiple sclerosis, sclerosis, ms (Clic here for more details about this article) |
25/198. Two types of foveation strategy in 'latent' nystagmus: fixation, visual acuity and stability.The authors studied the foveation dynamics of two individuals with latent/manifest latent nystagmus (LMLN) to test the hypothesis that oscillopsia suppression and good visual acuity require periods of accurate target foveation at low slip velocities. Congenital nystagmus (CN) waveforms contain post-saccadic foveation periods; the LMLN waveform does not and yet allows for both oscillopsia suppression and good acuity. During fixation with both eyes open, there were intervals when the eyes were still and correctly aligned; at other times, there was esotropia and nystagmus with slow-phase velocities less than /- 4 deg/sec and each fast phase pointed the fovea of the fixating eye at the target. However, cover of either eye produced LN and a different strategy was employed: the fast phases carried the fixating eye past the target and the fovea subsequently reacquired it during the slowest parts of the slow phases. The authors confirmed this in both subjects, whose high acuities were made possible by foveation occuring during the low-velocity portions of their slow phases. A nystagmus foveation function (NFF), originally developed for CN, was calculated for both LN and MLN intervals of fixation and it was found to track visual acuity less accurately for individuals with high acuity. Individuals with LMLN exhibit two different foveation strategies: during low-amplitude LMLN, the target is foveated immediately after the fast phases; and during high-amplitude LMLN, target foveation occurs towards the end of the slow phases. Therefore, the saccadic system can be used to create retinal error rather than eliminate it if this strategy is beneficial. Individuals with LMLN foveated targets with the same eye-position and -velocity accuracy as those with CN and the NFF provides a rough estimate of acuity in both. Current calibration methods for both infrared and search-coil techniques need to be altered for subjects with LMLN.- - - - - - - - - - ranking = 1keywords = ms (Clic here for more details about this article) |
26/198. Perverted head-shaking nystagmus: a possible mechanism.The authors describe a patient with acute MS who developed vertigo (tumbling) and downbeat nystagmus upon horizontal head oscillation (perverted head-shaking nystagmus). The only abnormality on brain MRI was a hyperintense signal in the caudal medulla that contains the nucleus Roller and nucleus intercalatus. These nuclei project to structures involved in the velocity storage system for horizontal vestibulocular reflex (VOR) and vertical VOR, and also to the vestibular cerebellum. The authors offer possible mechanisms for perverted nystagmus in this patient.- - - - - - - - - - ranking = 1keywords = ms (Clic here for more details about this article) |
27/198. Positional down beating nystagmus in 50 patients: cerebellar disorders and possible anterior semicircular canalithiasis.OBJECTIVES: To clarify the clinical significance of positional down beat nystagmus (pDBN). methods: A discussion of the neuro-otological findings in 50 consecutive patients with pDBN. RESULTS: In 38 patients there was evidence of CNS disease (central group) but in 12 there was not (idiopathic group). In the CNS group, presenting symptoms were gait, speech, and autonomic dysfunction whereas in the idiopathic group patients mostly reported positional vertigo. The main neurological and oculomotor signs in the CNS group were explained by cerebellar dysfunction, including 13 patients with multiple system atrophy. In patients with multiple system atrophy with a prominent extrapyramidal component, the presence of pDBN was helpful in the differential diagnosis of atypical parkinsonism. No patient with pDBN had the arnold-chiari malformation, a common cause of constant down beat nystagmus (DBN). In the idiopathic group, the pDBN had characteristics which suggested a peripheral labyrinthine disorder: vertigo, adaptation, and habituation. In six patients an additional torsional component was found (concurrently with the pDBN in three). Features unusual for peripheral disorder were: bilateral positive Dix-Hallpike manoeuvre in nine of 12 patients and selective provocation by the straight head-hanging manoeuvre in two. CONCLUSION: It is argued that some patients with idiopathic pDBN have benign paroxysmal positional vertigo (BPPV) with lithiasis of the anterior canal. The torsional component may be weak, because of the predominantly sagittal orientation of the anterior canal, and may not be readily seen clinically. Nystagmus provocation by bilateral Dix-Hallpike and straight head-hanging may be explained by the vertical upwards orientation of the ampullary segment of the anterior canal in the normal upright head position. Such orientation makes right-left specificity with the Dix-Hallpike manoeuvre less important than for posterior canal BPPV. This orientation requires a further downwards movement of the head, often achieved with the straight head-hanging position, to provoke migration of the canaliths. The straight head-hanging manoeuvre should be carried out in all patients with a history of positional vertigo and a negative Dix-Hallpike manoeuvre.- - - - - - - - - - ranking = 1keywords = ms (Clic here for more details about this article) |
28/198. Otorhinolaryngologic manifestations in Chiari malformation.The Chiari malformation causes herniation of the cerebellar amygdalae through the foramen magnum, resulting in the descent of the brain stem and/or traction on the lower cranial pairs. It is important for otolaryngologists to recognize Chiari malformations as part of the differential diagnosis of balance disorders, because patients may initially exhibit symptoms related to the vestibular system, including ataxia, nystagmus, or vertigo. We report 2 cases.- - - - - - - - - - ranking = 1keywords = ms (Clic here for more details about this article) |
29/198. Positional vertigo.Different forms of positional nystagmus, particularly the continuous (type I) variety, were found in 86 consecutive patients admitted to general and neurological hospitals. This series is compared with 365 patients with paroxysmal (type II) and 23 patients with type III positional nystagmus. In this series of 32 of the patients with continuous type I positional nystagmus (including 15 patients with head injury) and 18 of the patients with paroxysmal type II nystagmus were found to have central lesions.- - - - - - - - - - ranking = 1keywords = ms (Clic here for more details about this article) |
30/198. Ahhh, that's a strange eye movement.A 57-year-old woman presents with sudden onset of horizontal diplopia following surgical repair of a ruptured posterior fossa aneurysm. Neuro-ophthalmic examination revealed a left gaze palsy, right abducens palsy, bilateral facial nerve palsy, reverse ocular bobbing and oculopalatal myoclonus. These findings can be localized to the anterior pons caused by damage to the midline perforator vessels resulting in anterior pontine pathology. A video demonstration of the oculopalatal myoclonus and other types of vertical nystagmus is provided. The etiology and characteristics of these forms of nystagmus is discussed.- - - - - - - - - - ranking = 1keywords = ms (Clic here for more details about this article) |
| <- Previous || Next -> |