Botulinum toxin type A (Botox) in the treatment of migraine and other headaches

Botulinum toxin type A (Botox) is increasingly used in the management of migraine and tension-type headaches. The results from small placebo-controlled trials and extensive open-label experience has suggested a significant role for this neurotoxin in the management of refractory headache. Several large placebo-controlled trials of episodic and chronic migraine are currently underway.

Attempted control of hyperglycemia during cardiopulmonary bypass fails to improve neurologic or neurobehavioral outcomes in patients without diabetes mellitus undergoing coronary artery bypass grafting

OBJECTIVE

Hyperglycemia worsens outcomes in critical illness. This randomized, double-blind, placebo-controlled clinical trial tested whether insulin treatment of hyperglycemia during cardiopulmonary bypass would reduce neurologic, neuro-ophthalmologic, and neurobehavioral outcomes after coronary artery bypass grafting.

METHODS

Three hundred eighty-one nondiabetic patients undergoing isolated coronary artery bypass grafting were given infusions of insulin or placebo when their blood glucose concentration exceeded 100 mg/dL during cardiopulmonary bypass. The primary outcome measure was the combined incidence of new neurologic, neuro-ophthalmologic, or neurobehavioral deficits or neurologic death observed at 4 to 8 days postoperatively. This same measure was assessed secondarily at 6 weeks and 6 months. Length of hospital stay was also compared as a secondary assessment.

RESULTS

The 2 groups were well matched at baseline. The insulin-treated group had significantly lower blood glucose concentrations during bypass. Sixty-six percent of subjects in the insulin-treated group and 67% of subjects in the control group demonstrated a new or worsening neurologic, neuro-ophthalmologic, or neurobehavioral deficit or neurologic death at the 4- to 8-day assessment. Outcomes were also similar in the 2 groups at 6 weeks (37% and 39% incidence, respectively) and 6 months (30% and 25%, respectively). Median lengths of stay were 7 and 6 days, respectively, in the treatment and control groups. None of these outcome differences was statistically significant.

CONCLUSION

Attempted control of hyperglycemia during cardiopulmonary bypass had no significant effect on the combined incidence of neurologic, neuro-ophthalmologic, or neurobehavioral deficits or neurologic death and failed to shorten the length of hospital stay. These results do not contradict those of other studies showing that aggressive control of hyperglycemia in the postoperative period will improve outcome.

Vestibular migraine

Vestibular symptoms such as vertigo and dizziness are quite common in migraine. There is no specific category in the new International Headache Society Classification for vestibular migraine. However, given the symptomatology often described, it would fit best under basilar-type migraine, even though by definition monosymptomatic attacks with rotational vertigo for a few seconds to minutes do not strictly fit the criteria. Vestibular migraine must be regarded as a migraine equivalent because it is a prominent symptom in many migraineurs.

Age and other risk factors for neuropsychologic decline in patients undergoing coronary artery bypass graft surgery

OBJECTIVE

To evaluate if increasing age is a major determinant of long-term neuropsychologic (NP) dysfunction in patients undergoing coronary artery bypass graft (CABG) surgery.

DESIGN

Prospective cohort study.

SETTING

A single university hospital.

PARTICIPANTS

Three hundred eighty-one patients undergoing elective CABG surgery.

INTERVENTIONS

Baseline preoperative and intraoperative characteristics were assessed for all patients. A comprehensive NP test battery was conducted preoperatively and at 1 month postoperatively.

MEASUREMENTS AND MAIN RESULTS

Of the initial 381 patients, 319 (84%) returned for the 1-month visit. The overall incidence of an NP deficit was 21.6%. There was no significant difference seen with increasing age, although a trend was observed with highest NP deficit rate in the older than 65 age group. Other preoperative risk factors, including gender, education level, and preexisting diseases, were nonsignificant. Intraoperative variables were evaluated and revealed no significant differences across the age groups.

CONCLUSIONS

This cohort study did not find an increased incidence of NP deficits in elderly patients after CABG surgery. It has addressed the limitations of other studies, however, with (1) a comprehensive NP test battery, (2) longer-term follow-up, and (3) adequate sample size.

Central pontine myelinolysis: delayed changes on neuroimaging

The authors report two cases, a 44-year-old woman and a 6-year-old girl who had mental status changes and hyponatremia. Serum sodium levels in both of these cases were corrected quickly with further decline in their mental status, and the patients became quadriparetic. Magnetic resonance imaging (MRI) studies performed then did not reveal any abnormalities, whereas a repeat imaging study performed 10-14 days after the shift in serum sodium revealed evidence for central pontine myelinolysis and extrapontine demyelination. The clinical manifestations and distribution of lesions seen on the imaging studies demonstrated that the above presentation of neurologic illness is the result of hyponatremia and its correction. The authors conclude that imaging studies performed early during the illness may be unremarkable, but still a diagnosis of central pontine myelinolysis should be suspected and, most importantly, a repeat imaging study might be required in 10-14 days to establish the diagnosis of central pontine myelinolysis.

A randomized, blinded trial of the antioxidant pegorgotein: no reduction in neuropsychological deficits, inotropic drug support, or myocardial ischemia after coronary artery bypass surgery

OBJECTIVE

To determine whether patients receiving pegorgotein preoperatively would be less likely than patients receiving placebo to demonstrate postoperative cerebral or myocardial dysfunction and thus would be less likely to (1) demonstrate a decline in neuropsychologic testing after cardiopulmonary bypass, (2) receive inotropic drug support, or (3) demonstrate electrocardiographic signs of ischemia or infarction.

DESIGN

Prospective, randomized, blinded clinical trial.

SETTING

University teaching hospital and clinics.

PARTICIPANTS

Sixty-seven patients with normal left ventricular function undergoing elective, primary coronary artery bypass surgery.

INTERVENTIONS

Six to 18 hours before aortic cross-clamping, patients received a single dose of placebo (n = 22); pegorgotein, 2,000 IU/kg intravenously (n = 23); or pegorgotein, 5,000 IU/kg intravenously (n = 22).

MEASUREMENTS AND MAIN RESULTS

Patients in the three groups were similar; the mean ages were 65, 66, and 67 years, and there were seven, eight, and seven women in the placebo; pegorgotein, 2,000 IU/kg; and pegorgotein, 5,000 IU/kg groups. Fifty-one of 67 patients demonstrated neuropsychologic deficit 5 to 7 days postoperatively (n = 17, 19, and 15 for placebo, 2,000 IU/kg, and 5,000 IU/kg; p = NS). Median duration of cardiopulmonary bypass was longer in patients with two or more deficits at 4 to 6 weeks than in those with fewer than two deficits (121 v. 98 minutes; p = 0.04). No patient demonstrated a perioperative stroke. Twenty-seven patients required inotropic drug support after cardiopulmonary bypass (n = 8, 11, and 8 for placebo, 2,000 IU/kg, and 5,000 IU/kg; p = NS). Inotropic drug support was associated with history of angina (p = 0.01) and increasing weight (p = 0.03). Nine patients demonstrated early postoperative ischemia or infarction (n = 1, 7, and 1 for placebo, 2,000 IU/kg, and 5,000 IU/kg; p = 0.07).

CONCLUSIONS

This study showed no positive influence of pegorgotein on the incidence of any of the findings and showed a trend toward an increased incidence of myocardial ischemia or infarction.

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.

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.

Middle cerebral artery velocity correlates with nitroglycerin-induced headache onset

Headache often accompanies treatment with nitroglycerin, but the cerebral hemodynamic effects and the exact mechanism of the headache are incompletely understood. Transcranial Doppler monitoring allows evaluation and monitoring of changes in blood flow velocity in the large intracranial arteries. The objective of this study was to assess middle cerebral artery (MCA) blood flow velocities with transcranial Doppler monitoring in subjects receiving continuous low-dose nitroglycerin intravenously or by patch, and correlate these with clinical headache. Twenty-eight normal adult men received nitroglycerin (0.12 micrograms/kg/min intravenously [n = 14] or 0.6 mg/min by transdermal patch [n = 14]), for up to 120 minutes, with monitoring of clinical headache status (standard 4-point scale), blood pressure, heart rate, end-expiratory PCO2 (CO2), and right MCA velocity. All subjects developed headache (mean time to onset, 34 min), reaching moderate or severe levels in 20. There were no differences in age, weight, mean blood pressure, mean heart rate, or resting end-tidal CO2 between those whose headache reached a moderate to severe level and those whose headache remained mild. MCA velocity decreased from baseline values at all levels of clinical headache (onset, -17%; moderate, -18%; severe, -16%; nitroglycerin stopped, -19%) (p, 0.0001 by t test for each stage of headache). MCA velocity remained decreased at the time of headache resolution (-14%; p < 0.001). Blood pressure, heart rate, and CO2 did not change significantly. There were no differences related to route of nitroglycerin dosing. These data show that continuous low doses of nitroglycerin by patch or intravenously produce headache in normal male subjects. MCA velocities were significantly decreased at headache onset and at all levels of headache severity. Changes in MCA velocity persisted beyond the clinical headache. These results suggest a direct MCA vasodilatory effect of nitroglycerin. This method may also be used to evaluate the intracranial hemodynamic effects of other vasoactive drugs, even in clinical settings.

Nimodipine neuroprotection in cardiac valve replacement: report of an early terminated trial

BACKGROUND

We conducted a double-blind, randomized clinical trial in patients undergoing cardiac valve replacement to determine whether nimodipine, a dihydropyridine calcium antagonist, reduced the risk of new neurological, neuro-ophthalmologic, or neuropsychological deficits-common complications associated with cardiac surgery-1 week after surgery.

METHODS AND RESULTS

Enrollment for a total of 400 patients started in May 1992 and was stopped in September 1994, with 150 patients randomized to the study. Nimodipine was given to the patients during the perioperative period. Patients underwent examinations before surgery and at approximately 1 week, 1 month, and 6 months after surgery. Major adverse events, including deaths and strokes, were monitored monthly. The trial was terminated early because of both an unexpected disparity in death rates between groups and a lack of evidence of a beneficial effect of nimodipine. New deficits were observed in 72% of the placebo group versus 77% of the nimodipine group (p=.55). In the 6-month follow-up period, 8 deaths (10.7%) occurred in the nimodipine group (n=75) compared with 1 death (1.3) in the placebo group (n=74) (p=.02). Major bleeding occurred in 10 patients in the nimodipine group versus 3 in the placebo group (13.3% versus 4.1%; P=.04). Six (46.2%) of the 13 patients with major bleeding died compared with 3 deaths (2.2%) among the 136 patients without major bleeding.

CONCLUSIONS

Our findings add to the growing evidence that calcium antagonists have a prohemorrhagic effect in some patients and suggest that nimodipine use should be restricted perioperatively in patients scheduled for cardiac valve replacement.

Ophthalmoplegic migraine

Ophthalmoplegic migraine is a rare condition usually beginning in infancy or childhood and characterized by paralysis of ocular cranial nerves in association with vascular headache. The diagnosis is one of exclusion. Most patients should have high resolution magnetic resonance imaging (MRI) or magnetic resonance angiography (MRA) to eliminate the possibility of aneurysm, tumor, or granulomatous inflammation.

Left dural to right cavernous sinus fistula. A case report

Direct carotid-cavernous sinus fistulas that present with signs and symptoms contralateral to the arterial supply of the fistulas are not uncommon. We present a thoroughly documented case of a dural-cavernous sinus fistula with symptoms exclusively contralateral to the arterial source, a rarer entity. The patient presented with a red, proptotic right eye and a history of transient horizontal diplopia and a "feeling of fullness" in that eye. Magnetic resonance imaging (MRI) of the brain and orbits performed at another hospital had shown no abnormalities. Carotid angiography performed on the right side was normal; carotid angiography performed on the left side showed a dural-cavernous sinus fistula, with shunting from branches of the left external carotid artery directly to the right cavernous sinus. Orbital duplex color-flow sonography showed reverse flow in a dilated right superior ophthalmic vein. This unusual manifestation of a dural-cavernous sinus fistula offers insight into the pathophysiology of arteriovenous fistulas involving the cavernous sinus, and is a reminder that bilateral injections are required when performing carotid angiography to characterize these disorders.

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)

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.

Amaurosis fugax due to pituitary tumor

Amaurosis fugax in a younger person in whom premature atherosclerotic disease and cardiac emboli have been eliminated is usually benign. We describe a 25-year-old man with recurrent painless left monocular visual loss lasting from 5 to 45 minutes. Initial physical examination, carotid ultrasound, and electrocardiogram were normal. Goldmann visual field testing demonstrated a small, left paracentral defect. Neuroimaging studies were initially declined for economic reasons, but later a magnetic resonance image disclosed a large pituitary tumor displacing the left optic nerve and chiasm. The tumor was removed via a transphenoidal approach, and the episodic visual symptoms disappeared. We stress that amaurosis fugax in young patients is not necessarily benign. A specific etiology should be diligently sought, particularly when ocular signs are present.

Cerebral vasculitis associated with cocaine abuse

BACKGROUND

Earlier reports of cocaine-associated cerebral vasculitis have been based primarily on angiographic findings without pathological verification.

CASE DESCRIPTION

We present a case of acute encephalopathy following intravenous and intranasal administration of cocaine. Brain biopsy revealed vascular changes involving primarily small arteries. Findings included lymphocytic infiltration, endothelial thickening, and deposition of proteinaceous amorphous material within and around vessel walls.

CONCLUSIONS

These abnormalities are consistent with pathological features of arteritis previously reported in association with amphetamine and multiple-drug abuse. Vasospasm-induced changes are an alternative explanation for the vascular picture seen in this case. The patient made modest improvement with high-dose intravenous steroids.

Periodic alternating oscillopsia: a symptom of alternating nystagmus abolished by baclofen

We describe an unusual patient with periodic alternating oscillopsia caused by periodic alternating nystagmus. A dramatic cessation of her symptomatology and disappearance of periodic alternating nystagmus was achieved with baclofen and has been maintained for a period of over nine months. The importance of proper diagnosis and therapy of patients with oscillopsia is described.

Cerebrovascular reactivity in migraineurs as measured by transcranial Doppler

Transcranial Doppler ultrasound is a relatively new diagnostic modality which allows the noninvasive assessment of intracranial circulation. A total of 10 migraine patients were studied and compared to healthy controls without headaches. Migraineurs during the headache-free interval demonstrated excessive cerebrovascular reactivity to CO2, evidenced by an increase in middle cerebral artery blood flow velocity of 47% +/- 15% compared to 28% +/- 14% in controls (p = 0.026). Differences between the two study groups revealed no significant decrease in middle cerebral artery blood flow velocity with hypocapnia. However, the differences between middle cerebral artery blood flow velocity during hyperventilation and CO2 inhalation were significantly different (p = 0.004) comparing migraineurs and controls. Instability of the baseline blood flow velocities was also noted in migraineurs during the interictal period. Characteristics which may allow differentiation of migraineurs from other headache populations could possibly be obtained from transcranial Doppler ultrasound flow studies.

Implications of the angiographic string sign in carotid atherosclerosis

We identified 60 patients (42 men and 18 women with an average age of 62.6 years) with angiographically documented carotid stenoses of greater than or equal to 95%; a string sign was demonstrated in 28. Twenty of the 60 patients (33%) were asymptomatic on presentation, 26 (43%) had hemispheric transient ischemic attacks, 21 (35%) had amaurosis fugax, and nine (15%) had previous ipsilateral infarctions. Demographics, mode of presentation, and prevalence of atherosclerotic risk factors were not significantly different between patients with and without a string sign. Doppler frequencies recorded in patients with a string sign were less than 6 or greater than 16 KHz. Real-time ultrasonography imaged a patent lumen in all but three cases with a string sign. Surgery was performed in 26 patients with a string sign and in 21 patients without a string sign. The rate of major perioperative complications was not influenced by the presence of a string sign, contralateral extracranial stenosis, or ipsilateral siphon stenosis. Average lumen size of the endarterectomy specimens was 0.94 mm in those with and 1.7 mm in those without a string sign. We conclude that combined noninvasive testing has a sensitivity of 83% for demonstrating a residual lumen in patients with greater than or equal to 95% carotid stenosis and that the angiographic string sign does not affect the mode of presentation or surgical outcome of these patients.

Permanent cerebral blindness after cardiac catheterization

Cerebral blindness is usually a transient event that can complicate cardiac catheterization. The neurologic deficit clears in 1-3 days. We present a patient who developed permanent cerebral blindness after undergoing transfemoral cardiac catheterization. Bilateral hemorrhagic occipitotemporal infarcts were demonstrated on magnetic resonance imaging (MRI). The patient also demonstrated denial of blindness and had transient memory disturbances due to occipitotemporal lobe infarct. The probable source of the emboli was cardiac.

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.

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.

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.

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.

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.

Unilateral blepharoptosis with synkinetic movements of the eyelids on horizontal gaze

A 17-year-old woman with a left congenital ptosis and an alternating esotropia is presented. During horizontal gaze to the right and left, the eyelid of the abducting eye elevated and the eyelid of the adducting eye lowered. There were no synkinetic eyelid movements with contraction of the pterygoid, sternocleidomastoid, or facial muscles. Synkinetic eyelid movements due to aberrant regeneration were unlikely due to absence of previous third nerve palsy. A supranuclear innervational abnormality is proposed to explain the clinical findings.

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.

Optic neuritis due to acquired toxoplasmosis

A pediatric patient with well documented acquired toxoplasmic optic neuritis is presented. Use of immunoglobulin M immunofluorescent antibody studies allow easier identification of recently acquired toxoplasmosis. Toxoplasmic optic neuritis and retinitis should be considered along with toxoplasmic meningitis or encephalitis as complications of acquired toxoplasmosis. Therapy is available which may decrease the duration of visual symptomatology and reduce residual visual impairment.

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.

The effects of age on normal saccadic characteristics and their variability

Age effects on human saccadic eye movements were tested with infrared reflectance oculography in 34 subjects. In contrast to a prior report, only a slight non-significant change was observed in saccadic velocity and duration. An increase in saccadic latency comparable to that found in several previous reports was observed, however. All parameters showed considerable intersubject variability for both age groups. Decreased velocities or increased durations outside of these normal, broad ranges should be regarded as pathological for all subjects; they are not physiological effects of the aging process.

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.

An overview of ocular motor neurophysiology

A review of current concepts in ocular motor neurophysiology is presented. Four separate subsystems of eye movements are recognized: saccadic, smooth pursuit, vergence, and vestibular. Each subsystem is characterized by different physiologic characteristics and different anatomic substrates which may be selectively affected in different pathologic states. A further eye movement response, optokinetic nystagmus, is complex and may be considered a separate system. To regard the horizontal optokinetic response as merely a combination of pursuit and saccades is an oversimplification but one which may be useful in clinical localization.

Carotid-cavernous sinus fistula after external ethmoid-sphenoid surgery. Clinical course and management

The occurrence of a carotid-cavernous sinus fistula following transethmoidal-sphenoid sinus surgery is unusual. The etiology of this complication is related to the variations in anatomic position of the carotid artery and in the thickness of bone overlying the artery in the lateral sinus wall. In the case reported herein, the clinical course was complicated by the development of cranial nerve palsies and ocular ischemia. The patient's symptoms worsened following an attempted to close the fistula with a microcatheter balloon and isobutyl-cyanoacrylate embolization. Dramatic improvement in the patient's condition was obtained by subsequent occlusion of the carotid artery on the side of the fistula with a microcatheter balloon.

Abnormalities of gaze in cerebrovascular disease

Disorders of ocular motility may occur after injury at several levels of the neuraxis. Unilateral supranuclear disorders of gaze tend to be transient; bilateral disorders more enduring. Nuclear disorders of gaze also tend to be enduring and are frequently present in association with long tract signs and cranial nerve palsies on opposite sides of the body. Nystagmus is a reliable sign of posterior fossa or peripheral eight nerve pathology. Familiarity with these concepts may help the clinician answer questions regarding localization and prognosis.