ABSTRACT
AIM: The authors described and tested a simple bedside procedure to detect non-organic visual-field loss. METHODS: Prospective comparative observational case series of 16 patients with non-organic visual-field loss and 15 patients with organic visual-field loss were examined. Saccade patterns provoked by a stimulus outside the claimed visual field were assessed by a masked observer. RESULTS: Whereas, in organic visual-field defects, eye movements as noted by the observer were in small and erratic searching patterns towards the visual-field defect in all patients (15/15), most patients with non-organic visual-field loss (14/16) were able to jump directly to the presented red cap in one directional large saccade, although the stimulus was outside their stated visual field. The sensitivity of the saccade test in detection of non-organic visual-field loss by a masked observer was 87% (95% CI 60% to 97%) and the specificity was 100% (95% CI 75% to 100%). The positive predictive value for non-organic visual-field loss of the saccade test was 100%, and the negative predictive value was 90%. CONCLUSIONS: The saccade test is a quick and reproducible examination to use and is largely independent of the patient's willingness for cooperation. The authors believe that the test will be of value to clinicians on bedside evaluation when non-organic visual-field loss is suspected.
Subject(s)
Saccades/physiology , Vision Disorders/diagnosis , Visual Fields/physiology , Adult , Female , Humans , Male , Patient Compliance , Photic Stimulation/methods , Predictive Value of Tests , Prospective Studies , Task Performance and Analysis , Vision Disorders/etiology , Visual Field Tests/methodsABSTRACT
BACKGROUND: Arnold-Chiari Syndrome I is a malformation of the cervicomedullary junction, manifesting usually with downbeat nystagmus, palsy of the caudal cerebral nerves, headache, and vertigo. PATIENTS AND METHODS: We present three patients with unusual symptomatology. RESULTS: A two-year-old child with isolated non-ocular torticollis, a 52-year-old male patient, and a 42-year-old female patient, both with gaze-evoked nystagmus, underwent a cerebral MRI examination. The findings of the first two patients were typical for an Arnold-Chiari syndrome. The malformation in the third patient was found only by reviewing the initial MRI. CONCLUSIONS: Arnold-Chiari malformation may manifest atypically. An important step in the work-up of these patients is to ask the neuroradiologist to include the cervicomedullary junction in his evaluation.
Subject(s)
Arnold-Chiari Malformation/diagnosis , Magnetic Resonance Imaging , Adult , Arnold-Chiari Malformation/surgery , Brain Stem/pathology , Cerebellum/pathology , Cervical Vertebrae/pathology , Child, Preschool , Cranial Nerve Diseases/etiology , Diagnosis, Differential , Female , Follow-Up Studies , Humans , Male , Middle Aged , Prognosis , Spinal Canal/pathology , Torticollis/etiologyABSTRACT
PURPOSE: To investigate contractions evoked by the thromboxane A2 analog U 46619 and by the inhibitor of nitric oxide formation NG-nitro-L-arginine methyl ester (L-NAME) in isolated porcine ciliary arteries and vortex veins. MATERIAL AND METHODS: In a myograph system (for isometric forces measurement), vessels were exposed (at different levels of wall tension) to 100 mM potassium chloride (KCl). At their optimal tension, vessels were exposed (in a cumulative manner) to increasing concentrations of U 46619 (0.1 nM-1 microM) in the absence or in the presence of L-NAME (0.1 mM). Contractions were expressed in mN or in percent of a 100 mM KCl-induced contraction. RESULTS: Optimal tension was higher in arteries (7 mN) than in veins (3 mN). Maximal contractions induced by KCl were stronger in arteries (24.4 +/- 3.6 mN; n = 8) than in veins (1.8 +/- 0.2 mN; n = 8). In contrast, maximal contractions evoked by U 46619 were proportionally higher (p < 0.001) in veins (178.3 +/- 8.9%; n = 8) than in arteries (108.4 +/- 2.6%; n = 5) and were not significantly affected by L-NAME. Sensitivity to U 46619 was not significantly different between arteries (pD50 = 7.7 +/- 0.1) and veins (pD50 = 7.9 +/- 0.1). In quiescent vessels, L-NAME evoked contractions that were higher (p < 0.001) in veins (43 +/- 7.9%; n = 13) than in arteries (7.5 +/- 1.7%; n = 10). CONCLUSIONS: When compared with KCl-induced contractions, contractions evoked by U 46619 or L-NAME are proportionally higher in porcine vortex veins than in ciliary arteries.
