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To identify cutpoints for visual measures at baseline and 1 month predictive of abnormal 6-month vision that could be used as eligibility criteria in a clinical trial to test potential neuroprotection or myelin repair agents in patients with optic neuritis. To determine whether moderate-to-severe dysfunction in one or more visual measures at baseline or 1 month correlates with having major vision loss at 6 months.We used the Optic Neuritis Treatment Trial database to evaluate various cutpoints for baseline and 1-month vision levels that predicted abnormal 6-month vision. For selected cutpoints, we computed a 95% CI for positive predictive value and the required sample size if the cutpoint was to be used for clinical trial eligibility. We evaluated whether the degree of visual loss at baseline, 1 month, or change in visual function from baseline to 1 month correlated with 6-month visual acuity, contrast sensitivity, or threshold visual field.The best cutpoints for baseline and 1 month were visual acuityor= 20/50, contrast sensitivity1.0 log units, and visual field mean deviationor= -15 dB. The same levels of visual dysfunction at 1 month, but not at baseline, correlated with having 6-month moderate-to-severe loss for each of these measures (p = 0.01). A trial could require as few as 100 subjects for an outcome variable of one or more abnormal measures. Cutpoints at 1 month were highly predictive of abnormal 6-month vision, but the proportion of patients who would be eligible for a trial would be small.Provided data can be used either for the clinician to counsel patients on expected visual outcome or for designing studies to test therapies that might reduce the amount of permanent optic nerve damage due to optic neuritis in high-risk patients.

We reviewed retrospectively 114 prednisone dose reduction attempts in 63 myasthenic patients. Dose reduction was considered successful if a patient remained asymptomatic for more than 1 year on no prednisone or a stable low dose of prednisone. Successful dose reduction attempts were more common in patients taking azathioprine, but thymectomy did not influence taper outcome. Slower rate of dose reduction and higher ending dose of prednisone improved the chance of success.

We reviewed the efficacy of CSF diversion for pseudotumor cerebri (PTC) in patients from six different institutions. Thirty-seven patients underwent a total of 73 lumboperitoneal shunts and nine ventricular shunts. Only 14 patients remained “cured” after a single surgical procedure. The average time between shunt insertion and shunt replacement was 9 months, although 64% of shunts lasted less than 6 months. Shunt failure (55%) and low-pressure headaches (21%) were the most common causes for reoperation. The vision of most patients improved (13) or stabilized (13) postoperatively. However, three who had initially improved subsequently lost vision. Six had a postoperative decrease in vision. Two patients improved in one eye but worsened postoperatively in the other. Four lost vision despite apparently adequate shunt function. Shunt failure with relapse of PTC occurred as late as 7 years after insertion. CSF diversion procedures have a significant failure rate as well as a high frequency of side effects.

The extracranial carotid systems of 105 patients with retinal ischemia were examined using B-mode ultrasonography with integrated pulsed Doppler. Sixty-four patients had amaurosis fugax (AF), 17 central retinal artery occlusions (CRAO), and 21 branch retinal artery occlusions (BRAO). The prevalence of carotid stenosis (greater than or equal to 60%) ipsilateral to the symptomatic eye was low (16%). Eighty-six percent of AF patients had either no plaque causing less than a 60% stenosis. A significant proportion of subjects with normal duplex scans had alternative explanations for their retinal ischemia (eg, migraine, cardiac embolus). Patients with Hollenhorst plaques were more likely to have stenotic or ulcerated plaque (p = 0.04). The degree of carotid stenosis correlated significantly with the number of vascular risk factors identified in individual patients (p = 0.02). The presence of risk factors was more common in CRAO and BRAO patients compared with the AF group. Combined ultrasound-Doppler investigations of the carotid bifurcation are valuable noninvasive tools for the screening of patients with retinal ischemia.

we reviewed the records of 36 patients with myasthenia gravis who had CT of the anterior mediastinum before thymectomy in an effort to improve preoperative detection of thymoma. At surgery, 10 patients had thymomas, 21 had germinal center follicular hyperplasia, and 5 had histologically normal glands. CT performed on an EM1 5005 was abnormal in 23 of 36 patients; 10 had thymoma, 11 had hyperplasia, 1 had a normal gland, and 1 had a cyst. Tumors were detected by routine chest x-ray in 5 of 10 patients and by linear tomography in 7 of 8. All four patients with calcified masses on CT had thymomas (including the patient with normal linear tomograms). CT alone is too sensitive a screening test; 12 of 25 patients with hyperplasia or normal glands had abnormal scans. However, in combination with chest x-ray and linear tomography, we detected 10 of 10 patients with thymoma with reasonable certainty.

We studied two patients who could make saccades of normal velocity and amplitude only in association with a simultaneous blink. In one patient, the initiation of saccades was also facilitated by blinks. Both patients had signs of cerebellar or brainstem dysfunction, suggesting a posterior fossa localization for blink facilitation of saccadic velocity and amplitude.

We used 18-F-fluoro-2-deoxyglucose positron emission tomography (PET) and computed tomography (CT) to study eight patients with homonymous hemianopias or quadrantanopias due to ischemic lesions of the visual pathways. Four patients with ischemic damage to all or part of the occipital lobe had decreased glucose metabolism in the affected region. Three patients with ischemic damage limited to the optic radiations had decreased glucose metabolism in the portion of striate cortex appropriate for the visual field defect. Changes in glucose metabolism frequently occurred in the undamaged ipsilateral thalamus and visual association areas.

A 56-year-old man with chronic lymphocytic leukemia, progressive multifocal leukoencephalopathy, and a dense left homonymous hemianopia had 18F-fluorodeoxyglucose positron emission tomography. Cortical glucose metabolism was decreased in the right cerebral hemisphere and the left cerebellar hemisphere. To our knowledge, this is the first demonstration of cerebral and cerebellar hypometabolism due solely to white matter disease.

Central nervous system involvement in melioidosis is unusual. We describe a 34-year-old man who developed a Pseudomonas pseudomallei meningitis, manifested as bilateral third-nerve palsies, 13years after having been in southeast Asia. Diagnosis was established by a fourfold rise in the serum antibody titer for the bacterium. Recovery occurred after treatment with rifampin, isoniazid hydrochloride, ethambutol, and trimethoprim-sulfamethoxazole. Since a long latent period from exposure to overt infection is possible, additional cases of melioidosis in the United States can still be expected in veterans of the Vietnam War.

We studied 11 patients with the uncommon finding of traumatic chiasmal syndrome after closed head trauma. Visual field defects varied from complete monocular blindness and contralateral temporal hemianopia to subtle bitemporal arcuate scotomas. The degree of visual loss was not necessarily related to the severity of the craniocerebral trauma. Diabetes insipidus was present in half of these patients, but unlike the visual abnormalities, this complication was transient.

We compared intrathecal metrizamide-enhanced CT (metrizamide-CT) and magnetic resonance imaging (MRI) in the evaluation of 17 patients with clinical suspicion of lesions at the cervicomedullary junction. MRI was superior in imaging the position of the cerebellar tonsils and the size and extent of mass lesions. MRI and metrizamide-CT were equal in detecting syringomyelia. CT with and without IV contrast enhancement was necessary to detect calcium or defects in the blood-brain barrier within neoplasms.