Leber's congenital amaurosis. Relationship of structural CNS anomalies to psychomotor retardation.

Three patients (two of them siblings) had Leber's congenital amaurosis and cerebellar disease. Despite blindness and severe motor deficits, all three patients have achieved relatively normal intellectual and psychosocial milestones. Computed tomographic scans, performed in two patients, demonstrated hypoplasia of the cerebellar vermis in both. The presence of delayed speech and motor development as well as structural CNS abnormalities in children with Leber's congenital amaurosis does not necessarily imply that severe intellectual impairment will be present.

Optic neuropathy and paratrigeminal syndrome due to Aspergillus fumigatus.

Chronic Aspergillus meningitis and cerebral vasculitis occurred in a 67-year-old man. He experienced periorbital pain that increased in severity during a ten-month period. Although no focal neurologic deficits were initially present, oculosympathetic paresis, corneal hypesthesia, and optic neuropathy developed. This is the first report, to our knowledge, of paratrigeminal syndrome with optic neuropathy due to aspergillosis. The case was also unusual because it was chronic and there was no extracerebral infection or predisposing factors, such as underlying malignancy or collagen vascular disease.

Delayed visual loss due to trauma of the internal carotid artery.

The group of six patients in this study experienced delayed visual loss following head trauma. Visual loss occurred from 1 day to 13 years after the initial injury. All patients suffered indirect trauma to the internal carotid artery resulting in formation of either an aneurysm or pseudoaneurysm or a carotid-cavernous fistula. Review of the radiologic and clinical findings was performed in six patients. The diagnosis was established by computed tomography, magnetic resonance imaging, and angiography. All patients had follow-up clinical evaluation and imaging studies. Treatment by neurosurgical or interventional neuroradiologic procedures resulted in significant visual improvement in five patients. Different pathophysiologic mechanisms could be correlated with the delayed visual loss produced by the two types of lesions. The pathologic changes associated with the aneurysms/pseudoaneurysms included direct compression of optic nerves and/or chiasm and intracranial hematoma. A carotid-cavernous fistula caused delayed visual loss by either hematoma at the orbital apex or compression of the chiasm and/or optic nerves by saccular dilatation of the cavernous sinus. The delayed onset of decreased vision following head trauma should alert the physician to the possibility of a traumatic aneurysm/pseudoaneurysm or a carotid-cavernous fistula. Different neuro-ophthalmologic symptoms can usually be correlated with the pathologic changes demonstrated by neuroimaging procedures.

Human presaccadic spike potentials. Of central or peripheral origin?

Electroencephalographic (EEG) activity associated with voluntary and spontaneous saccades were analyzed in 12 normal subjects to determine the influence of volition upon the presaccadic spike potentials (SPs). In addition, two different electrode configurations, of a temporal and a parietal derivation, and two different filter bandwidths were simultaneously analyzed to clarify issues regarding the structure, function, and origin of SPs. An off-line averaging of the pre- and postsaccadic EEG epochs showed distinct spike potentials associated with spontaneous saccades in both the temporal and the parietal locations. Subsequent statistical analyses indicated that the amplitude of the SPs associated with spontaneous saccades was not significantly different from the respective amplitude of SPs preceding voluntary saccades. Independent effects of filter bandwidth and electrode derivation are suggestive of a complex late presaccadic EEG activity.

Regional optic nerve blood flow and its autoregulation.

An autoradiographic method (14C-iodoantipyrine autoradiography) was used to measure regional optic nerve blood flow (ONBF) under basal conditions in 11 adult female cats. Flow was measured in six regions of the optic nerve: (1) prelaminar, (2) laminar, (3) 1 mm post-laminar, (4) 4 mm post-laminar, (5) 6 mm post-laminar, and (6) intracranial optic nerve and chiasm. A gradient of flow rates was found with relatively high flow in the prelaminar, laminar, and 1-mm post-laminar optic nerve, and significantly lower flow in the 4- and 6-mm post-laminar nerve and in the intracranial optic nerve and chiasm. Blood flow in the 4- and 6-mm post-laminar nerve and in the intracranial nerve and chiasm was comparable to previously reported values for cerebral white matter in the cat. With alteration of mean arterial blood pressure (MABP), optic nerve blood flow demonstrated autoregulatory compensation in all areas.

Optic nerve blood flow and its regulation.

Intracranial optic nerve blood flow was measured by the radiolabeled microsphere technique in 30 adult sheep under light barbiturate anesthesia. Regional blood-flow rates were determined under basal conditions. The responses of regional blood flow to alterations in PaCO2 and to changes in arterial blood pressure were also measured. Under basal conditions blood flow was comparable to that found in other cerebral white matter (14 +/- 1 ml/100 gm/min). Responses to hypercarbia and hypocarbia were also similar to reported measurements for other cerebral white matter. With alteration of arterial blood pressure, intracranial optic nerve blood flow remained constant within the limits of cerebral autoregulation.

Ischemic optic neuropathy in migraine.

Two patients with histories of migraine had ischemic optic neuropathy develop during an episode of migraine. Clinical and radiologic studies excluded other causes of visual loss. Fluorescein angiography confirmed as ischemic process involving the optic dis. In both cases, visual loss was permanent. No further visual disturbance has occurred in either patient during a two-year period of follow-up while taking oral doses of propranolol hydrochloride.

Metastatic endophthalmitis due to Salmonella typhimurium.

A 48-year-old man with chronic lymphocytic leukemia had endophthalmitis as the first sign of generalized sepsis due to Salmonella typhimurium. The organism grew from the anterior chamber aspirate as well as from the blood cultures. The eye required enucleation, and pathologically identifiable organisms were present in the vitreous cavity. To our knowledge, a case of metastatic endophthalmitis due to S typhimurium has not been previously reported. Salmonella is an opportunistic organism and should be considered in cases of endophthalmitis occurring in an immunocompromised host.

Churg-Strauss syndrome (allergic granulomatous angiitis). Neuro-ophthalmologic manifestations.

Two patients with severe bronchial asthma, hypereosinophilia, and peripheral neuropathy were initially observed with neuro-ophthalmologic signs and symptoms that included amaurosis fugax, superior oblique palsy, ischemic optic neuropathy, and scattered areas of retinal infarction. Clinical investigation led to the diagnosis of Churg-Strauss syndrome (allergic granulomatous angiitis). As in other collagen vascular diseases, ocular signs or symptoms may occasionally be the most prominent manifestation of the disease. Recognition of this systemic disorder by the ophthalmologist may minimize systemic and ocular complications.

Bone formation in association with a limbal dermoid.

A healthy female infant was born with a unilateral limbal dermoid. When the lesion was surgically excised, a plaque of bone was found under the scleral portion of the lesion. The occurrence of bone in ocular dermoinds is extremely uncommon and, to our knowledge, has been reported only twice in dermoids that occur in epibulbar locations away from the limbus.

Congenital Horner's syndrome.

Patients with congenital Horner's syndrome (who seemed, on the basis of their clinical history and the distribution fo anhidrosis, to have a preganglionic lesion) had partial mydriatic failure with hydroxyamphetamine hydrobromide and a supersensitivity to phenylephrine hydrochloride. This apparent paradox can be readily explained by postulating an aorthograde transsynaptic dysgenesis of the postganglionic neuron, such as has been demonstrated in the sympathetic nervous system of newborn animals. The failure of hydroxyamphetamine to cause mydriasis indicates damage to the postganglionic sympathetic neuron, but in the neonate this damage may be secondary to a preganglionic lesion.

Acute syphilitic optic neuritis.

Two patients experienced acute unilateral visual loss as a manifestation of early infectious (secondary) neurosyphilis. In both cases, optic disc swelling was preceded by the development of a characteristic rash accompanied by mild signs of meningeal inflammation. Other signs of ocular inflammation, such as uveitis or retinal vasculitis, were absent. Optic neuritis may occur as a manifestation of the meningeal inflammation that can accompany secondary syphilis. In such patients, it is important to confirm involvement of the CNS and to institute appropriate antibiotic therapy.

Massively invasive diffuse choroidal melanoma.

A 74-year-old woman was found to have increasing proptosis in a blind, painful left eye with neovascular glaucoma. Uveal malignant melanoma with massive orbital involvement was diagnosed, and the patient underwent orbital exenteration, with preoperative and postoperative orbital irradiation. The tumor was a mixed-cell, diffuse uveal malignant melanoma with involvement of the optic nerve adjacent to the line of surgical transection and of the optic nerve sheath. Subsequently, the cerebrospinal fluid cytology disclosed cells consistent with malignant melanoma, despite the absence of neurologic signs or symptoms. Cerebrospinal fluid cytology is essential in such cases, and ultrasonography is of value.

Spontaneous regression of optic gliomas: thirteen cases documented by serial neuroimaging.

OBJECTIVE: To demonstrate spontaneous regression of large, clinically symptomatic optic pathway gliomas in patients with and without neurofibromatosis type 1 (NF-1). METHODS: Patient cases were collected through surveys at 2 consecutive annual meetings of the North American Neuro-Ophthalmology Society (NANOS) and through requests on the NANOSNET Internet listserv. Serial documentation of tumor signal and size, using magnetic resonance imaging in 11 patients and computed tomography in 2 patients, was used to evaluate clinically symptomatic optic pathway gliomas. All tumors met radiologic criteria for the diagnosis of glioma and 4 patients had biopsy confirmation of their tumors. In 3 patients, some attempt at therapy had been made many years before regression occurred. In one of these, radiation treatment had been given 19 years before tumor regression, while in another, chemotherapy had been administered 5 years before signal changes in the tumor. In the third patient, minimal surgical debulking was performed 1 year before the tumor began to shrink. RESULTS: Spontaneous tumor shrinkage was noted in 12 patients. Eight patients did not have NF-1. In an additional patient without NF-1, a signal change within the tumor without associated shrinkage was detected. Tumor regression was associated with improvement in visual function in 10 of 13 patients, stability of function in 1, and deterioration in 2. CONCLUSIONS: Large, clinically symptomatic optic gliomas may undergo spontaneous regression. Regression was seen in patients with and without NF-1. Regression may manifest either as an overall shrinkage in tumor size, or as a signal change on magnetic resonance imaging. A variable degree of improvement in visual function may accompany regression. The possibility of spontaneous regression of an optic glioma should be considered in the planning of treatment of patients with these tumors.

Acute loss of vision during pregnancy due to a suprasellar mass.

A pregnant woman presented with headaches, bilateral decreased visual acuity, and a central scotoma with a superotemporal hemianopic defect in the right eye and a superotemporal hemianopic defect in the left eye, and bilateral temporal optic disk pallor. Neuroimaging revealed an intrasellar mass with suprasellar extension. Biopsy of the lesion revealed lymphocytic hypophysitis (LH). Treatment with steroids produced marked improvement in visual function. The clinical presentation of lymphocytic hypothysitis may mimic pituitary adenoma and the diagnosis should be suspected in any pregnant or postpartum patient with an intrasellar or suprasellar mass.

The human pre-saccadic spike potential: influences of a visual target, saccade direction, electrode laterality and instructions to perform saccades.

Three components of pre-saccadic evoked potentials have been identified in humans: a slow negative shift (SNS), a positive antecedent potential (AP) and a spike potential (SP). This study examined the influences of: instructions to the subject to make saccades; the presence of a visual target; and the direction of the saccades on the amplitude of the averaged SP, which was recorded from P3 and P4 (International 10/20 System) in 20 normal, right-handed subjects. Recordings were made for spontaneous saccades prior to receiving instructions in six subjects. Twenty subjects performed self-paced saccades in the presence of a 10 degrees visual target (two red LEDs) and while blindfolded in a dark room. The SP was either absent or grossly altered (broadened) for spontaneous saccades in an illuminated room; it was robust for self-paced saccades in light or darkness. Three-way analysis of variance revealed a highly significant cortical laterality (P3 vs P4) X saccade direction interaction (P less than 0.001), reflecting that for a given saccade direction, the SP was larger over the contralateral recording site for the self-paced light (SPL) paradigm (Newman-Keuls test). In the self-paced dark (SPD) paradigm, though, this was only true for saccades to the right. By contrast, scatter plots of the directional indices (D.I. = [(SP for contralateral) - (SP for ipsilateral)]/[(SP for contralateral) + (SP for ipsilateral saccades)] for left (P3) and right (P4) recording sites from individual subjects revealed a significant negative correlation for both SPL (r = 0.78) and SPD (r = 0.74) paradigms.(ABSTRACT TRUNCATED AT 250 WORDS)

Human spike potentials prior to saccades and optokinetic nystagmus fast phases: effects of instructions, eye movement direction and electrode laterality.

Presaccadic potentials in humans consist of 3 components, a slow negative shift, a positive antecedent potential and a spike potential (SP). This study demonstrated the presence of the SP before another class of rapid eye movements, fast phases of optokinetic nystagmus (OKN), in 11 right-handed, normal human subjects and compared the amplitude of the averaged SP for OKN fast phases, recorded at P3 and P4 (International 10/20 System), with the SP amplitude for 10 degrees self-paced saccades between two red light-emitting diodes. In particular, the effects of electrode laterality, rapid eye movement direction and two sets of instructions during the OKN task were assessed. Subjects were told to either 'look at the screen' (OKN1 paradigm) or to 'try to slow or stop the motion of the pattern' (OKN2 paradigm) during presentation of optokinetic stimulation. As in the case of saccades, the OKN fast phase velocity spike was used to trigger the signal averager (Nicolet (CA-1000]. There were two significant differences in SP amplitude prior to saccades and OKN fast phases. First, 3-way analysis of variance (ANOVA) and Newman-Keuls comparisons revealed that the SP was attenuated significantly for OKN for either eye movement direction over either left or right recording sites (F = 16.045, P less than 0.001). This effect was not related to amplitude differences in eye movements in the different tasks, although a contribution of variance in the OKN fast phase amplitudes cannot be excluded.(ABSTRACT TRUNCATED AT 250 WORDS)

Directional tuning of the human presaccadic spike potential.

This study examined the behavior of the presaccadic spike potential (SP) in 20 normal, right-handed subjects for self-paced 10 degree saccades along vertical, horizontal and oblique meridians. The SP was recorded differentially between posterior parietal sites and a linked ear reference. The SP amplitude showed clear directional tuning properties with the maximum response prior to saccades directed in an oblique, downward and contralateral direction. The minimum response was obtained for upward saccades. The data were fitted to a model consisting of 3 components: (1) a constant component reflecting saccadic amplitude; (2) a component with narrow directional tuning that is modeled from properties of frontal eye field neurons in monkeys; and (3) a component with broad directional tuning that is designed to reflect directional tuning properties of potentials originating from horizontal and vertical saccade generators, motoneurons and extraocular muscles. The narrowly tuned mechanism is sufficient to encode the direction of saccades. One surprising finding, though, was that the broadly tuned mechanism was necessary and sufficient to account for differences in SP amplitude as a function of electrode laterality. Application of this model approach to published data for periorbital SP, recorded between periorbital and parietal sites (G. W. Thickbroom and F. L. Mastaglia, Electroencephalogr. Clin. Neurophysiol., 64 (1986) 211-214), suggested that this potential represents a broadly tuned mechanism with directional tuning opposite the parietal SP. These data indicate that the periorbital and parietal SPs represent activation of different networks of central generators.

Pupil cycle time in optic nerve compression.

We measured pupil cycle time before and after treatment in 11 patients with compressive optic nerve disease. Nine patients had chiasmal tumors and two had optic neuropathy of Grave's disease. Pupil cycle time before treatment was abnormal in at least one eye of all patients and in each case, pupil cycle time improved or worsened in accordance with the response to treatment of the patient's visual acuity and visual fields. This suggests that the pupil cycle time may be used as a simple objective office test for following up patients with impaired optic nerve conduction as the result of optic nerve compression. This information is similar to that gained from visual evoked response and may be used together with other objective clinical data such as disk pallor, nerve fiber loss, and relative afferent pupillary defect.

MR imaging of primary trochlear nerve neoplasms.

We present the clinical, anatomic, and MR imaging findings in six patients with seven primary trochlear nerve neoplasms, as well as the MR and clinical criteria that serve to establish the diagnosis of these rare cranial nerve neoplasms. Three patients had a history of neurofibromatosis and five patients had clinical evidence of a trochlear nerve palsy. Six of seven neoplasms produced localized, fusiform enlargement of the proximal cisternal segments of the trochlear nerves. The lesions that were visible on noncontrast MR scans (T1-, T2-, and proton density-weighted) had signal intensities that were virtually identical to normal brain parenchyma. All lesions showed intense, homogeneous enhancement on contrast-enhanced scans. Contrast-enhanced imaging was necessary for the detection of five of seven lesions and greatly increased the value of the MR study in all six patients.