Exogenous orienting of attention depends upon the ability to execute eye movements.
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Shifts of attention can be made overtly by moving the eyes or covertly with attention being allocated to a region of space that does not correspond to the current direction of gaze. However, the precise relationship between eye movements and the covert orienting of attention remains controversial. The influential premotor theory proposes that the covert orienting of attention is produced by the programming of (unexecuted) eye movements and thus predicts a strong relationship between the ability to execute eye movements and the operation of spatial attention. Here, we demonstrate for the first time that impaired spatial attention is observed in an individual (AI) who is neurologically healthy but who cannot execute eye movements as a result of a congenital impairment in the elasticity of her eye muscles. This finding provides direct support for the role of the eye-movement system in the covert orienting of attention and suggests that whereas intact cortical structures may be necessary for normal attentional reflexes, they are not sufficient. The ability to move our eyes is essential for the development of normal patterns of spatial attention. (+info)
Long term visual and neurological prognosis in patients with treated and untreated cavernous sinus aneurysms.
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OBJECTIVE: To determine the long term visual and neurological outcome of patients diagnosed with cavernous sinus aneurysms (CCAs). METHODS: Prospective follow up for at least five years or until death of 31 retrospectively recruited patients (27 women, 4 men) with treated and untreated CCAs. RESULTS: There were 40 aneurysms in all. Mean age at diagnosis was 60.4 years (range 25 to 86; median 64). The most common symptoms were diplopia (61%), headache (53%), and facial or orbital pain (32%). Fifteen patients (48%) were diagnosed after they developed cranial nerve pareses, four (13%) after they developed carotid-cavernous sinus fistulas (CCFs), and 12 (39%) by neuroimaging studies done for unrelated symptoms. Twenty one patients (68%) had treatment to exclude the aneurysm from circulation, 10 shortly after diagnosis and 11 after worsening symptoms. Immediate complications of treatment occurred in six patients and included neurological impairment, acute ophthalmoparesis, and visual loss. Ten patients (32%) were observed without intervention. Over a mean (SD) follow up period of 11.8 (7.7) years, eight had improvement in symptoms, five remained stable, and eight deteriorated. Among the 10 patients followed without intervention, none improved spontaneously, three remained stable, and seven worsened. CONCLUSIONS: Most treated patients in this series improved or remained stable after treatment, but none improved without treatment. The long term prognosis for treated cases is relatively good, with most complications occurring immediately after the procedure. Endovascular surgery has decreased the morbidity and mortality of treatment so should be considered for any patient with a CCA. (+info)
Identification of KIF21A mutations as a rare cause of congenital fibrosis of the extraocular muscles type 3 (CFEOM3).
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PURPOSE: Three congenital fibrosis of the extraocular muscles phenotypes (CFEOM1-3) have been identified. Each represents a specific form of paralytic strabismus characterized by congenital restrictive ophthalmoplegia, often with accompanying ptosis. It has been demonstrated that CFEOM1 results from mutations in KIF21A and CFEOM2 from mutations in PHOX2A. This study was conducted to determine the incidence of KIF21A and PHOX2A mutations among individuals with the third CFEOM phenotype, CFEOM3. METHODS: All pedigrees and sporadic individuals with CFEOM3 in the authors' database were identified, whether the pedigrees were linked or consistent with linkage to the FEOM1, FEOM2, and/or FEOM3 loci was determined, and the appropriate pedigrees and the sporadic individuals were screened for mutations in KIF21A and PHOX2A. RESULTS: Twelve CFEOM3 pedigrees and 10 CFEOM3 sporadic individuals were identified in the database. The structures of eight of the pedigrees permitted the generation of meaningful linkage data. KIF21A was screened in 17 probands, and mutations were identified in two CFEOM3 pedigrees. One pedigree harbored a novel mutation (2841G-->A, M947I) and one harbored the most common and recurrent of the CFEOM1 mutations identified previously (2860C-->T, R954W). None of CFEOM3 pedigrees or sporadic individuals harbored mutations in PHOX2A. CONCLUSIONS: The results demonstrate that KIF21A mutations are a rare cause of CFEOM3 and that KIF21A mutations can be nonpenetrant. Although KIF21A is the first gene to be associated with CFEOM3, the results imply that mutations in the unidentified FEOM3 gene are the more common cause of this phenotype. (+info)
Anticholinesterase therapy for patients with ophthalmoplegia following snake bites: report of two cases.
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Although ophthalmoplegia following snake bites is not indicative of a serious neurotoxic complication, symptoms of diplopia, dizziness and ocular discomfort can be emotionally devastating for patients. The authors experienced two cases of ophthalmoplegia following snake bites in Korea. The patients complained of diplopia that had developed several hours after the snake bites. The diplopia did not improve with antivenom treatment, but resolved completely after several injections of neostigmine. (+info)
Vergence-mediated changes in Listing's plane do not occur in an eye with superior oblique palsy.
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PURPOSE: As a normal subject looks from far to near, Listing's plane rotates temporally in each eye. Since Listing's plane relates to the control of torsional eye position, mostly by the oblique eye muscles, the current study was conducted to test the hypothesis that a patient with isolated superior oblique palsy would have a problem controlling Listing's plane. METHOD: Using the three-dimensional scleral search coil technique, binocular Listing's plane was measured in four patients with congenital and in four patients with acquired unilateral superior oblique palsy during far- (94 cm) and near- (15 cm) viewing. The results were compared to previously published Listing's plane data collected under exactly the same conditions from 10 normal subjects. RESULTS: In patients with unilateral superior oblique palsy, either congenital or acquired, Listing's plane in the normal eye rotated temporally on near-viewing, as in normal subjects, while in the paretic eye it failed to do so. In patients with acquired superior oblique palsy, Listing's plane was already rotated temporally during far-viewing and failed to rotate any farther on near-viewing, whereas in patients with congenital superior oblique palsy Listing's plane in the paretic eye was oriented normally during far-viewing and failed to rotate any farther on near-viewing. CONCLUSIONS: These results suggest that the superior oblique muscle, at least in part, is responsible for the temporal rotation of Listing's plane that occurs in normal subjects on convergence. (+info)
Internuclear ophthalmoplegia of abduction: clinical and electrophysiological data on the existence of an abduction paresis of prenuclear origin.
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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. (+info)
Total external ophthalmoplegia induced by phenytoin: a case report and review of literature.
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A 28-year-old male developed total external ophthalmoplegia following oral administration of phenytoin. The case is reported and its significance is discussed. (+info)
Blindness and total ophthalmoplegia after aesthetic polymethylmethacrylate injection: case report.
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Microspheres of polymethyl-methacrylate (PMMA) are exciting new soft-tissue fillers that are becoming increasing popular for facial rejuvenation. Some reports of side effects of this procedure are basically in respect to dermal reaction, with late-onset granulomatous lesion with giant cells and vacuoles. We report blindness and total ophthalmoplegia after PMMA injection into glabellar area in a healthy woman and review the literature. (+info)