Lithium-induced downbeat nystagmus.

Two patients who were treated with lithium for psychiatric illness developed primary position downbeat nystagmus. Previous reports have suggested that lithium causes this type of nystagmus, but other known causes were present in most cases. Several months after stopping the lithium, one patient had marked resolution, while the second patient had only minimal improvement. Valproate sodium proved to be useful in suppressing the nystagmus in the second patient. Lithium carbonate is a cause of primary position downbeat nystagmus. The nystagmus may be permanent or require several months of abstinence for improvement.

Sudden monocular visual loss in pseudotumor cerebri.

We describe a patient with papilledema due to benign intracranial hypertension who had sudden, painless monocular visual loss. Fear of further visual deterioration prompted vigorous therapeutic efforts to reduce intracranial pressure. Subsequent neuro-ophthalmologic evaluation disclosed that the visual loss was due to a subretinal neovascular membrane. Vision continued to improve after medical therapy was discontinued, and was accompanied by complete resolution of papilledema and headache. In any patient with minimal papilledema, sudden visual deterioration should initiate a search for other causes rather than zealous therapeutic efforts to reduce intracranial pressure.

See-saw nystagmus associated with Chiari malformation.

See-saw nystagmus has been seen with tumors of the parasellar region and diencephalon, brain-stem vascular lesions, syringobulbia, and after trauma. We report see-saw nystagmus in an adult with a Chiari malformation that was diagnosed by magnetic resonance imaging and confirmed intraoperatively. This patient's condition improved after surgical decompression. An association between see-saw nystagmus and Chiari malformation is potentially important because early diagnosis and decompression may improve neurologic function and prevent further deterioration.

Lateropulsion and upbeat nystagmus are manifestations of central vestibular dysfunction.

An elderly man presented with acute onset of gait instability, characterized by leaning to the left while walking, vertigo, diplopia, and transient facial numbness. The examination was remarkable for ocular lateropulsion and primary position upbeat nystagmus. Computed tomography of the brain revealed a right-hemispheric cerebellar infarction. This report illustrates that lateropulsion can occur in cerebellar lesions, but that it may be contralateral to the cerebellar hemisphere involved. Primary position upbeat nystagmus and lateropulsion may represent forms of central vestibular dysfunction due to interruption of vestibulo-ocular pathways.

Facial numbness and dysesthesia. New features of carotid artery dissection.

Facial numbness and dysesthesia have not been emphasized as presenting features in spontaneous internal carotid artery dissection. Progressive facial pain, accompanied by oculosympathetic paresis, altered taste, and facial numbness suggest the possibility of basal skull neoplasm. We describe a patient, with previously undiscovered fibromuscular dysplasia, who presented with severe neck and face pain, dysgeusia, oculosympathetic paresis, and markedly reduced facial sensation due to a spontaneous vascular dissection. Altered facial sensation should now be included in the symptomatology of internal carotid artery dissection.

Upbeat nystagmus and internuclear ophthalmoplegia with brainstem glioma.

We describe the unusual association of two ocular motor abnormalities: upbeat nystagmus and internuclear ophthalmoplegia in a young woman originally believed to have demyelinating disease. Quantitative eye movement recordings documented a unidirectional defect in upward visual pursuit with preservation of the vertical vestibulo-ocular reflexes. The ocular oscillation was characterized as a type of "pursuit defect" nystagmus. An enhancing lesion of the upper brainstem seen on computerized tomography was primarily localized to the midbrain on pneumoencephalography. Biosy of the lesion disclosed a malignant glial tumor. The patient's course initally progressed but became stable following radiotherapy and chemotherapy during the next eight months. We believe the association of upbeat nystagmus and internuclear ophthalmoglegia should prompt a detailed search for a structural lesion.

Exercise therapy for positional vertigo.

We present a common cause of vertigo, benign positional paroxysmal vertigo (BPPV), and its history, diagnosis, and therapy. BPPV is suggested by history, readily diagnosed by office examination, and cured by appropriate exercise therapy. Since the condition is so common and often unrecognized, physicians are encouraged to consider BPPV as a possible cause of treatable dizziness.

Palinopsia: cerebral localization with computed tomography.

We report three patients whose vivid visual experiences were initially attributed to psychiatric or metabolic derangements, in the absence of obvious neurologic findings. Each depicted repetitive visual images of previously viewed objects or scenes, not necessarily confined to the region of homonymous visual deficit. Each patient had a large occipital lobe lesion, well demonstrated by computed tomography. An important diagnostic clue was documentation that the portrayed images had actually been viewed recently and therefore represented visual transpositions in time or space.

Functional paralysis of horizontal gaze.

A 52-year-old steelworker displayed a consistent defect in leftward voluntary gaze across the midline. Both fast (saccadic) and slow (pursuit) eye movements were affected. Neuro-ophthalmologic evaluation revealed no additional neurologic or ophthalmologic deficit. Pupilary miosis occurred during leftward gaze attempt, indicating that the gaze palsy was due to spasm of the near reflex. Special maneuvers during clinical eye movement testing disclosed full ability to make normal horizontal fast and slow eye movements despite the apparent defect in "voluntary" leftward gaze.

Macro square wave jerks.

Quantitative eye movement recordings in a patient with multiple sclerosis who had both macro square wave jerks and an internuclear ophthalmoparesis supported the concept of an internal brain-stem monitor that mediates corrective eye movements. A brain-stem model of this monitor illustrates the patient's motility disorder and the normal function of providing synergistic version and vergence corrections for dysmetric eye movements. Thus, the careful study of pathologic disturbances provides information relevant to the normal operation of the ocular motor system.

Intermittent downbeat nystagmus and oscillopsia reversed by suboccipital craniectomy.

We describe an unusual case of vertical oscillopsia and primary position downbeat nystagmus associated with an adult Arnold-Chiari malformation. A unique aspect of the ocular motor abnormality was the intermittent nature of the nystagmus, which displayed no relationship to head position, emotion, or the Valsalva maneuver. Conventional computed tomography with posterior fossa views was normal, but metrizamide cisternography demonstrated an extramedullary mass originally believed to be a meningioma. There was a dramatic diminution of the visual complaints and downbeat nystagmus after suboccipital craniectomy for an Arnold-Chiari malformation. Nystagmus characteristics were documented by serial quantitative eye movement recordings.

Intrachiasmal hemorrhage: a cause of delayed post-traumatic blindness.

A 49-year-old man presented with blurred vision 9 days following frontal head trauma. Visual loss progressed to bilateral blindness. Magnetic resonance imaging revealed hemorrhage and swelling within the optic nerves and chiasm. Indirect trauma to the anterior visual pathways may cause delayed blindness due to hemorrhage and edema within these structures.

A false-positive edrophonium test in a patient with a brainstem glioma.

We report a photographically documented false-positive edrophonium test in a patient with a histologically verified brainstem glioma. While a positive response to intravenous edrophonium should usually be regarded as confirmatory for myasthenia gravis, the possibility of a false-positive test must be considered in patients with atypical physical findings.

Monocular elevation paresis caused by an ipsilateral lesion.

A 52-year-old woman presented with a paresis of elevation of the right eye, equally severe in abduction and adduction (monocular elevation paresis). CT demonstrated a small, right-sided tumor of the mesodiencephalic junction. Monocular elevation paresis has been attributed to lesions of the contralateral pretectum, although proof has been lacking. Now, with documentation of an ipsilateral brainstem etiology, we can postulate a lesion affecting the upgaze efferents from the ipsilateral rostral interstitial nucleus of the medial longitudinal fasciculus.

Quality improvement in neurology residency programs. Report of the Quality Improvement Committee of the Association of University Professors of Neurology.

The neurology residency programs in the United States are facing a crisis of quality. The Association of University Professors of Neurology (AUPN) approved the Quality Improvement Committee to examine this situation and make recommendations, which have been accepted by the AUPN. The recommendations are (1) that the educational goals of neurology residency training be dissociated from patient-care needs in academic medical centers and (2) that minimum levels of quality be applied to residents in neurology residency programs and to these programs themselves. These minimum criteria should include minimum educational criteria for entry into the program, minimum criteria for advancement from one year to the next in the program, and minimum criteria for performance of the graduates of neurology residency programs for program accreditation. The implementation of these recommendations will require a shift of funding of the care of indigent patients from the graduate medical education budget to direct patient-care sources. These recommendations will significantly improve the quality of neurologists and neurologic care in the United States.

Variability and development of a normative data base for saccadic eye movements.

The duration, peak velocity, and acceleration of the saccadic eye movements of 13 normal subjects are plotted as functions of saccadic magnitude. The apparent peak velocity of a saccadic eye movement is sensitive to the algorithms used to calculate the velocity. The velocity channel filter should have zero phase shift and a cutoff frequency between 60 and 100 Hz in order to limit noise but pass all the signal information. Some subjects fatigue rapidly; their parameters fall outside the normal range of values.

Occipital lobe arteriovenous malformations. Clinical and radiologic features in 26 cases with comments on differentiation from migraine.

The differentiation of migraine headache, preceded by visual aura, from cerebral arteriovenous malformation (AVM) is often regarded as difficult. A study of 26 patients with occipital lobe AVM revealed two distinct syndromes in 18 patients--occipital epilepsy and occipital apoplexy. Occipital epilepsy is characterized either by elementary visual phenomena, such as brief flashes of light, or by dimming of a homonymous field. Occipital apoplexy results from hemorrhage and hematoma formation within the occipital lobe and is characterized by sudden headache and homonymous visual field loss. We conclude that patients harboring occipital AVMs may, indeed, have visual phenomena and headache that should not be confused with migraine because either a history of generalized seizure or bruits on examination will probably be present.

Risk factors and solutions for the development of neurobehavioral changes after coronary artery bypass grafting.

BACKGROUND: As operative mortality for coronary artery bypass grafting has decreased, greater attention has focused on neurobehavioral complications of coronary artery bypass grafting and cardiopulmonary bypass. METHODS: To assess risk factors and to evaluate changes in surgical technique, between 1991 and 1994 we evaluated 395 patients undergoing coronary artery bypass grafting with an 11-part neurobehavioral battery administered preoperatively and at 1 and 6 weeks postoperatively. Patients were instrumented with 5-MHz focused continuous-wave carotid Doppler transducers intraoperatively to estimate cerebral microembolism as an instantaneous perturbation of the velocity signal. Microembolism data were quantitated and compared with surgical technical maneuvers during operation and with neurobehavioral deficit (> or = 20% decline from preoperative performance on two or more neurobehavioral tests) postoperatively. These data and patient demographics were statistically analyzed (chi2, t test) and the results at 2 years (1991 and 1992; group A) were used to influence surgical technique in 1993 and 1994 (group B). RESULTS: Significantly associated with new neurobehavioral deficits were increasing patient age (p < 0.05), more than 100 emboli per case (p < 0.04), and palpable aortic plaque (p < 0.02). Group B patients had a significant decline in the neurobehavioral event rate (group A, 69%, 140/203; versus group B, 60%, 115/192; p < 0.05) of postoperative neurobehavioral deficits at 1 week and at 1 month (group A, 29%, 52/180; versus group B, 18%, 35/198; p < 0.01). The stroke rate was less than 2% in both groups (p = not significant). Modifications of surgical technique used in group B patients included increased use of single cross-clamp technique, increased venting of the left ventricle, and application of transesophageal and epiaortic ultrasound scanning to locate and avoid trauma to aortic atherosclerotic plaques. CONCLUSIONS: Neurobehavioral changes after coronary artery bypass grafting are common and associated with cerebral microembolization. Surgical technical maneuvers designed to reduce emboli production may improve neurobehavioral outcome.

Acquired cyclic esotropia in an adult.

A 67-year-old women developed periodic alternate-day esotropia, documented with videotape, 16-mm film, and quantitative eye-movement recordings, after retinal detachment surgery. The eye movements suggested that central reprocessing and adaptation to a peripheral defect was in part responsible for this adult form of acquired cyclic esotropia.

Brain embolic phenomena associated with cardiopulmonary bypass.

Various biologic and non-biologic materials may be embolized to the brain after the use of cardiopulmonary bypass (CPB) pumps during open heart surgery but their relative frequency and importance are uncertain. Among the nonbiologic materials, Antifoam A, which contains organosilicates and silicon, continues to be employed as an additive to prevent frothing. Recent improvements in filtration and oxygenation techniques have clearly reduced the incidence of large emboli and complications like stroke but other neurologic sequelae following open heart surgery are common and in many cases poorly explained. A recently developed histochemical technique for the demonstration of the endothelial alkaline phosphatase (AP) was employed in a post-mortem study of brains from 8 patients and 6 dogs dying within a few days after open heart surgery employing cardiopulmonary bypass perfusion. Brains from 38 patients and 6 dogs who were not subjected to heart surgery were studied as controls with the same technique. The AP-stained slides are suitable for both light microscopic examination of the thick celloidin sections as well as a subsequent processing for high-resolution microradiography. Small capillary and arteriolar dilatations (SCADs) were seen in the test subjects/animals but not controls. SCADs were seen in all parts of the brain. Approximately 50% of the SCADs showed birefringence when examined with polarized light. SCADs are putative embolic phenomena and the exact nature and source of the embolic material is under investigation. A glycolipid component is indicated by preliminary studies. SCADs are difficult to find in routine paraffin sections and most if not all of the offending material seems to be dissolved during processing.(ABSTRACT TRUNCATED AT 250 WORDS)