Benign abducens nerve palsy of childhood

Benign acquired isolated abducens nerve palsy in infants and children is a rare condition and recurrence is even less common. The diagnosis is essentially one of exclusion. Six children (1 male, 5 females) are reported with benign isolated abducens nerve palsy, ranging in age from 8 months to 12 years (median: 5.5 years). The left side was affected in all patients. Recovery occurred within 18-55 days, but 3 patients developed recurrence with complete resolution of symptoms within 10-21 days.

Otologic neurotologic manifestations of HIV-related disease

Human immunodeficiency virus (HIV), the causative agent of acquired immunodeficiency syndrome (AIDS), has reached worldwide epidemic proportions and is increasing. Otologists, neurotologists, and audiologists practicing in metropolitan centers in North America can expect to encounter patients with HIV-related illnesses, including patients with AIDS-related complex (ARC) and AIDS. Five representative cases are presented: chronic otitis media, facial palsy, Gradenigo's syndrome with facial paralysis, otosyphilis, and Kaposi sarcoma of the mastoid. The common link in all cases was HIV infection. This presentation discusses the management of several HIV-infected patients with otologic and neurotologic findings. HIV infection has extended to all parts of North America. The worldwide incidence is increasing. As the epidemic continues to unfold, new challenges to both the diagnosis and treatment of otologic and neurotologic disease in HIV-positive patients will confront the audiologist and otolaryngologist. Recommendations for the safety of the examining audiologist and treating physician are given.

[Bilateral abducens nerve palsy followed by pseudoathetosis due to pontine hemorrhage--clinical and neuroradiological study]

Reported here are two cases with pontine hemorrhage presented with bilateral abducens nerve palsy and followed by pseudoathetosis, ataxia, and hemiparesis on the contralateral side of the lesion. The first case, a 57-year-old man, who suffered from bilateral abducens nerve palsy, deafness and hypoesthesia, ataxia, and hemiparesis of the right side of the body. MRI showed the confined lesion in the left side of tegmentum at the level of middle pons. When the abducens nerve palsy began to improve, pseudoathetosis of the right fingers appeared. About six months later, symptoms almost recovered, except for ataxia. The second case, a 48-year-old man who suffered from bilateral abducens nerve palsy, deafness of the left ear, and ataxia, hypoesthesia, and hemiparesis of the left side of the body was admitted. MRI disclosed a small lesion on the right side of the tegmentum at the level of middle pons. When the bilateral abducens nerve palsy was beginning to improve, pseudoathetosis of the left hand appeared. Three months later, pseudoathetosis of the left hand disappeared. Both patients presented here had a similar lesion in the tegmentum at the level of middle pons on the side contralateral to the side in which the pseudoathetosis was seen. Considering the clinical symptoms and radiological findings of these cases, it appears that a lesion which causes such rare neurological symptoms may involve the medial lemniscus, spinothalamic tract, lateral lemniscus, spinocerebellar fiber, and central tegmental tract at the tegmentum of the middle pons on the side contralateral to the cerebellar signs and pseudoathetosis.

Abducens palsy following shunting for hydrocephalus

Over a period of 12 years, 80 patients underwent ventricular shunting for normal pressure hydrocephalus. Three developed sixth cranial nerve palsy in the first two weeks after surgery. This uncommon complication is usually transitory following the same pattern of abducens palsy after lumbar puncture or spinal anesthesia. Traction on the nerve with local ischemia has been involved as the responsible mechanism in both instances.

Gradenigo syndrome: a case report

The case is presented of a 13-year-old boy with recurrent episodes of otitis media who developed Gradenigo syndrome. Mastoid and petrous bone involvement were demonstrated by CT. Symptoms resolved with antibiotic treatment.

African histoplasmosis (Duboisii) of the skull with neurological complication--a case report and review of literature

A case of African histoplasmosis of the skull associated with neurological deficit has been reported. There was complete recovery of neurological features after excision of the lesion followed by a course of co-trimoxazole. A review of the available literature indicates the rarity of this particular mode of presentation. The reversibility of the neurological complications makes it important that clinicians increase their awareness of this treatable condition.

Isolated bilateral abducens nerve palsies caused by the rupture of a vertebral artery aneurysm

We report two cases with isolated bilateral abducens nerve palsies due to the rupture of a vertebral aneurysm. Surgery revealed that the aneurysm did not directly compress the abducens nerve. Within a year after the subarachnoid hemorrhage, the patients gained full recovery from the bilateral abducens nerve palsies. In view of the clinical and operative findings, it may be regarded as a compression and/or stretching of the bilateral abducens nerves by a thick clot in the prepontine cistern, and not as a manifestation of the raised intracranial pressure. The mechanisms of the isolated abducens nerve palsy are discussed.

Acquired oculomotor, trochlear, and abducent cranial nerve palsies in pediatric patients

Between January 1966 and December 1988, 160 pediatric patients (age range, 0 to 17 years) were seen at the Mayo Clinic with an acquired oculomotor (35 patients), trochlear (19 patients), abducent (88 patients), or multiple (18 patients) cranial nerve palsy. The clinical findings in the 160 pediatric patients were compared with the results obtained in other reviews of cranial nerve palsies in the pediatric age group and with the adult Mayo Clinic patients with acquired cranial nerve palsies. Trauma was the most common reason for an acquired cranial nerve palsy in our pediatric group. The percentage of patients with an acquired cranial nerve palsy resulting from trauma was significantly greater in the pediatric group (42.5%) than in adults (15.4%) (P < .01). The difference between the percentage of adults (15.2%) and pediatric patients (16.9%) with a cranial nerve palsy secondary to a neoplasm was not statistically significant (P = .28).

Schwannoma of the cavernous sinus. Case report and review of the literature

A patient operated on for a schwannoma entirely developed into the cavernous sinus is described. Abducens nerve is supposed to be the origin of the tumor, although it could not be identified during the operation. Schwannomas of the cavernous sinus are exceedingly rare lesions. Only four reports exist in the literature. In three cases the tumor arose from the abducens nerve, in one case probably from the trochlear nerve. Direct approach to the cavernous sinus has become possible in recent years, but preoperatively impaired cranial nerve function shows a slim chance of postoperative recovery.

Giant aneurysm at the junction of the left internal carotid and persistent primitive trigeminal arteries--case report

A 67-year-old female presented with an unruptured giant aneurysm at the junction of the left internal carotid artery (ICA) and the persistent primitive trigeminal artery (PTA), manifesting as progressive left abducens nerve paresis. The PTA was clipped by the left suboccipital approach. The aneurysm was then successfully thrombosed by ligation of the left ICA at the cervical portion following left superficial temporal artery-middle cerebral artery anastomosis. The left abducens nerve paresis improved postoperatively. Magnetic resonance imaging was of considerable value in the pre- and postoperative evaluation of the giant aneurysm.

Chronic idiopathic inflammation of the retropharyngeal space presenting with sequential abducens palsies

We describe a patient who presented with sequential, bilateral abducens palsies associated with a mass of the nasopharynx. Biopsy of the mass showed chronic non-specific inflammation and fibrosis. The diagnosis of idiopathic inflammatory pseudotumor was arrived at by exclusion of other known causes of inflammation of the retropharyngeal space. Magnetic resonance imaging suggested that injury to the sixth cranial nerves probably occurred as they traversed the dura and subarachnoid space overlying the clivus.

Sixth nerve palsy as the initial presenting sign of metastatic prostate cancer. A case report and review of the literature

Cranial nerve palsies secondary to metastatic prostate cancer are uncommon occurrences. Usually appearing late in the course of the disease, they are associated with a poor prognosis. We report a case of a 71-year-old man who initially complained of diplopia and was found to have a right sixth nerve palsy and hyperdeviation caused by a mass in the clivus. Biopsy of the mass and extensive systemic workup revealed metastatic adenocarcinoma of the prostate gland.

Neurinoma of the third, fourth, and sixth cranial nerves: a survey and report of a new fourth nerve case

A rare case of trochlear nerve neurinoma is described. Including this case, the number of reported intracranial tumors arising from the sheaths of the third, fourth, and sixth cranial nerves is 38. By site and relationship to the nerve segment, they fall into three groups: cisternal, cisternocavernous, and cavernous. In cisternal tumors of the third and sixth nerves, paresis of the nerve hosting the tumor is the unique nerve deficit; by contrast, in those of the fourth nerve, paresis of the trochlear nerve can be absent and that of the third nerve present. In the latter tumors, a peculiar ataxic hemiparesis syndrome is produced by midbrain compression. Cisternocavernous neurinomas often cause symptoms of intracranial hypertension, while cavernous neurinomas bring about two clinical features: paresis of one or more nerves of the cavernous sinus and a clinicoradiological orbital apex syndrome. At surgery, generally cisternal neurinomas are totally removed and the nerve source of the tumor identified; in cisternocavernous and cavernous neurinomas, total removal of tumor and identification of the parent nerve have been reported in only half of the cases. In the majority of parasellar neurinomas, clinical differences can be found between those arising from the nerves governing eye movement and those arising from the gasserian ganglion.

Management of VIth nerve palsy--avoiding unnecessary surgery

Unresolved VIth nerve palsy that is not adequately controlled by an abnormal head posture or prisms can be very suitably treated by surgery. It is however essential to differentiate partially recovered palsies, which are amenable to horizontal rectus surgery, from unrecovered palsies, which must be treated initially by a vertical muscle transposition procedure. Botulinum toxin is a valuable tool in making this distinction. It also facilitates full tendon transposition in unrecovered palsies, which appears to produce the best functional outcome of all the transposition procedures, with a reduction in the need for further surgery. A study of the surgical management of 12 patients with partially recovered VIth nerve palsy and 59 patients with unrecovered palsy provides clear guidelines on how to attain a successful functional outcome with the minimum amount of surgery.

Facial nerve involvement in pseudotumor cerebri

A woman with history of bifrontal headache, vomiting and loss of vision was diagnosed as a case of pseudotumor cerebri based on clinical and MRI findings. Bilateral abducens and facial nerve palsies were detected. Pseudotumor cerebri in this patient was not associated with any other illness or related to drug therapy. Treatment was given to lower the raised intracranial pressure to which the patient responded.

[Sphenoid sinus aspergillosis presenting abducens nerve palsy and visual field impairment; a case report]

A case of sphenoid sinus aspergillosis presenting abducens nerve palsy and visual field impairment is reported. A 73-year-old woman visited our hospital with the complaint of head heaviness on the 27th of March, 1989. Although results of neurological examinations were normal, craniogram revealed the destruction of the clivus, and CT scan and MRI showed a mass lesion, which was thought to be a mucocele in the sphenoid sinus. On the 1st of September, she developed right abducens nerve palsy and visual field impairment. MRI performed on the same day showed an enlargement of the mass lesion in the sphenoid sinus. In order to decompress the involved cranial nerves, her sphenoid sinus was explored on the 22nd of September. The sphenoid sinus was filled with purulent fluid and yellowish mass. Histopathological examination revealed colonies of aspergillus fumigatus. Fluconazole, a new antifungal drug, was given for 34 days postoperatively. The right abducens nerve palsy and the visual field impairment gradually improved along with a reduction of the mass lesion in her sphenoid sinus. Sphenoid sinus aspergillosis is a rare disease. Its diagnosis is difficult. However, MRI can show a specific low signal intensity in T2-weighted image. Also in our case, MRI on the first admission showed a definite low signal intensity in some parts of the lesion, which exhibited a high intensity later on during the second administration, probably due to a qualitative change. To our knowledge, only 33 such cases have been previously reported. Intracranial involvement occasionally occurs in this disease. In its early stage, cranial nerve palsies are caused by nerve compression or invasion by this disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Combined third and sixth nerve paresis following optic nerve sheath fenestration

The authors report a case of transient third and sixth nerve paresis as a complication of optic nerve sheath fenestration in a patient with pseudotumor cerebri. The motility and pupillary abnormalities that are commonly associated with this procedure are reviewed briefly.

[Unusual pathological ocular movement caused by dysfunction of the saccade generation mechanism]

We describe a patient with abnormal ocular movement, probably due to dysfunction of saccade generation mechanism in the lower pons involving the omnipause neuron and a feed-back circuit. A 26-year-old man had fever, mild headache and sore throat for a few days and also noted unstable gait and diplopia. These symptoms subsided, but he noticed oscillopsia about 2 months later. On admission in our hospital, the neurological examination revealed no abnormalities except for abnormal eye movements, which were induced by voluntary or involuntary ocular movement and lasted for a few minutes. The abnormal ocular movement was irregular in direction, amplitude and rhythmicity, and the voluntary and involuntary ocular movements could not be elicited during the period of this abnormal ocular movement. The abnormal ocular movement completely disappeared for about 1 hour by intravenous injection of TRH. At this time bilateral mild abducens palsy was demonstrated by EOG examination. The abnormal ocular movement in this patient, which has nerve been reported in the literature, was considered to be due to a disinhibition of excitatory burst neuron (EBN) caused by the dysfunction of omnipause neuron, and possibly due to a delay of feed-back information of saccade to the EBN.

Intracavernous epidermoid tumor presenting with abducens nerve paresis--case report

An unusual case of a pediatric epidermoid tumor entirely located in the cavernous sinus is reported. A 6-year-old boy presented with left abducens nerve paresis which developed over 2 months. Neuroimaging demonstrated a lesion in the left cavernous sinus. Part of the tumor capsule and the pearly contents were removed by the left pterional approach through Dolenc's anterolateral triangle. No bleeding from the cavernous sinus occurred. The tumor was histologically identified as an epidermoid tumor. Postoperatively, the abducens nerve paresis improved. The presence of dural reflection in the lateral wall of the cavernous sinus and displacement of the intracavernous internal carotid artery are useful indicators for intracavernous lesions.

Clinical evidence for the onset of the sensitive period in infancy

Seven neonates had a IIIrd or VIth nerve palsy or afferent visual pathway pathology at birth. These abnormalities resolved within 6 weeks and the children have developed normal visual acuity, motor fusion, and stereopsis. We conclude that there is a latent period of 6 weeks before the onset of the sensitive period.

Causes and prognosis in 4,278 cases of paralysis of the oculomotor, trochlear, and abducens cranial nerves

We collected data from a large series of patients with ocular palsies and compared them with data in previous series from the Mayo Clinic. The largest group of patients among 4,278 cases was that in which the cause was undetermined for a long period of follow-up. The abducens nerve was most commonly affected. The probability of establishing a diagnosis was higher in patients younger than 50 years and among those with associated neurologic findings or multiple ocular palsies. The prognosis for recovery was best in the vascular group but was better than 50% for all groups except those with tumors. Investigation may be tailored to each patient according to clinical findings and probabilities of finding a cause, and judicious clinical judgement should be exercised.

[Isolated abducens nerve palsy caused by pontine infarction]

An 82-year-old hypertensive man suddenly developed diplopia during right lateral gaze. Neurological examination revealed right isolated abducens nerve palsy without any other findings. By cranial CT scan, a low density area over the posterior limb of right internal capsule and tortuosity of basilar artery were noted. 3 months later, his symptom disappeared and then he was well in next 2 years til he felt diplopia during left lateral gaze. On this time he showed left isolated abducens nerve palsy. Though cranial CT scan failed to find out new abnormality, T2-weighted cranial MRI disclosed high intensity spot over left pontine base located between medial lemniscus and pyramidal tract, which was supposed to coincide to fascicle of left abducens nerve Three months later, he recovered in the same manner as 2 years before. Hemilateral isolated abducens nerve palsy may be caused by many origins, but pontine infarct was not detected so much in pre-MRI era. Being the long-term prognosis of the lacunar infarction not satisfactory, it is important for the cases of isolated abducens palsy to ascertain whether there is pontine small infarction or not. So in these cases, precise examination including MRI should be needed.

Intracranial chordoma in a neonate

We report the first case of a congenital intracranial chordoma. Hydrocephalus, sixth and seventh cranial nerve palsy, and torticollis were observed shortly after birth. The tumour was delineated by sonography, CT scans and MRI and the diagnosis confirmed after subtotal resection at the end of the newborn period.

[Invasive aspergillosis of the sphenoid sinus and paralysis of the 6th nerve]

A case of aspergillosis of the sphenoid sinus manifested as an isolated sixth nerve palsy occurred in a 74-year old diabetic woman who had no complaints of headache or symptoms suggestive of sinusitis. A CT scan demonstrated a large mass occupying the sphenoid and ethmoid sinuses extending posteriorly to the clivus. There was a calcific density within the opacified sinus and bony erosion of the sphenoid walls and the sella turcica. The patient underwent a sublabial transseptal sphenoidotomy with removal of necrotic material and debridement of the surrounding tissue. Histologic examination revealed granulation tissue with chronic inflammatory cells and abundant dichotomously branching hyphae. Postoperatively the patient was given amphotericin B and 5-fluorocytosine. Three months later the sixth nerve palsy had completely cleared and the patient had no other complaint. Sphenoid sinus aspergillosis is a rare disease and may have variable clinical manifestations according to involvement of different structures located closely to the sinus. Our patient developed an isolated sixth nerve palsy which was at onset considered to be caused by diabetes. Computerized tomography scans disclosed abnormalities strongly indicative of invasive aspergillosis. It illustrates the need of appropriate work-up in cases of an isolated sixth nerve palsy even in patients with diabetes or other risk factors.

Modern management of sixth nerve palsy

Between November 1982 and September 1991, 179 patients with unilateral or bilateral sixth nerve palsy were treated in the Botulinum Toxin Strabismus Clinic at Moorfields Eye Hospital. Indications for treatment included prophylaxis (as part of a prospective treatment trial), maintenance therapy, diagnosis and adjunct to surgical therapy. A management plan for established sixth nerve palsy based on the rational use of toxin and surgery is suggested.

Ruptured anterior communicating artery aneurysm causing bilateral abducens nerve paralyses--case report

A rare case of bilateral abducens nerve paralyses after rupture of an anterior communicating artery (AcoA) aneurysm occurred in a 56-year-old female after sudden onset of severe headache. Bilateral abducens nerve paralyses were present without additional neuro-ophthalmological signs. Computed tomography revealed subarachnoid hemorrhage (SAH). Angiography showed an AcoA aneurysm (15 mm in diameter, directed antero-inferiorly) that was successfully clipped. Postoperatively, the bilateral abducens nerve paralyses gradually recovered and disappeared 3 months after onset. Bilateral abducens nerve paralyses may occur after SAH due to ruptured AcoA aneurysm, and neurosurgeons should be alert to this possibility.

Acute isolated sphenoid sinusitis: a disease with complications

A case of acute isolated sphenoid sinusitis is described in a twelve year old boy who presented with ophthalmic complications. The literature is reviewed to emphasize the potential dangers of this condition.

Treatment of unilateral acute sixth-nerve palsy with botulinum toxin

We studied 29 consecutive patients with acute unilateral sixth-nerve palsy, who received botulinum toxin injection to the antagonist medial rectus muscle. The average interval between onset of palsy and treatment was 40 days and the mean follow-up from the last injection was 14 months. Before treatment, esotropia in the primary position ranged from 12 to 45 prism diopters and limitation to abduction in the affected eye ranged from -2 (approximately 15 degrees lateral to midline) to -6 (15 degrees nasal to midline). After treatment, 22 of 29 patients (76%) had complete recovery of motility as determined by version testing. Of the seven patients with a residual abduction deficit, two had fusion in the primary position, three had fusion with prismatic correction, and two patients required subsequent surgery. Botulinum toxin injection seems to be an effective treatment option in cases of acute unilateral sixth-nerve palsy.

Syndrome of inappropriate antidiuretic hormone secretion in a patient with intrasellar neurofibroma of the sixth nerve

The syndrome of inappropriate antidiuretic hormone (SIADH) secretion has been described in a wide range of neurological and other disorders. We wish to add an extremely rare case of a solitary, large, invasive neurofibroma of the sixth cranial nerve extensively destroying the sella turcica in the skull base and causing inappropriate secretion of antidiuretic hormone in a 44-year-old black man in the absence of neurofibromatosis.

[Abducens paresis, a rare complication to spinal analgesia]

A case of paresis of the abducens nerve following spinal analgesia is described. Cranial nerve paresis is a rare complication of spinal analgesia although described for all cranial nerves except nos. 1, 9 and 10. It is very useful to know that cranial nerve paresis after spinal analgesia often occurs after a delay of several days, and that treatment is unnecessary because symptoms nearly always disappear spontaneously in about 2-4 months.

Moebius syndrome with central hypoventilation and brainstem calcification: a case report

Moebius syndrome (MS) is described in an infant with central hypoventilation and brainstem calcification. The patient had limb defects and bilateral paralysis of the 6th, 7th, 9th, 10th, and 12th cranial nerves. Mechanical ventilation was continued from birth because of shallow spontaneous respiration. Computed tomography revealed brainstem atrophy and four small calcifications restricted to the dorsal portion of the pons and medulla. Prenatal brainstem injury such as ischaemia may have caused MS and central hypoventilation.

Spinocerebellar degeneration with slow eye movements and abducens nerve palsy

A 51-year-old woman with spinocerebellar degeneration manifested an unusual disorder of eye movements. She presented with bilateral abducens palsy and slow eye movements in the horizontal plane. Slow eye movements typically are seen with supranuclear lesions, whereas abducens palsies are of nuclear or infranuclear origin. This unique combination of eye movement disorders is discussed, as well as other features of ophthalmoplegias associated with spinocerebellar degeneration.

Antibiotic responsive exophthalmos and lateral rectus paralysis

Sinusitis is an unusual cause of exophthalmos in adults since the advent of antibiotics. Many periorbital complications of sinusitis have been described; however exophthalmos associated with apparent sixth cranial nerve palsy in the absence of ipsilateral sphenoidal sinusitis is a rare and, to our knowledge, unreported complication of sinusitis. We report such a case that was treated with oral antibiotics. We believe that sinusitis must always be considered in adults as a treatable cause of exophthalmos and various orbital complications from isolated lateral rectus paralysis to acute-onset, acquired Brown's syndrome.

Isolated and combined pareses of cranial nerves III, IV and VI. A retrospective study of 412 patients

We evaluated the hospital records of 412 patients with isolated or combined ocular nerve palsies in a retrospective study. Palsies of the oculomotor nerve (n = 172) and of the abducens nerve (n = 165) were more frequent than those of the trochlear nerve (n = 25). Combined ocular nerve palsies (n = 50) were generally combinations of the 3rd and 6th cranial nerves (n = 21) or pareses of all three ocular nerves (n = 17). 165 ocular nerve palsies were due to vascular causes: in 135 of these cases diabetes mellitus and hypertension were present. The oculomotor nerve was most frequently affected; in 63% there was no involvement of the pupil. In inflammatory disease and brain tumor the abducens nerve was most frequently affected, with aneurysm of the oculomotor nerve. The origin of ophthalmoplegia was unclear in 73 patients. Ocular nerve paralysis was most common with tumors, aneurysm, and vascular processes and in 206 cases was only partial. Pain was associated with tumor, trauma and aneurysm. In trochlear nerve palsies concomitant pain was much less frequent than in palsies of the other two ocular nerves. The clinical course was followed for 3 weeks in 352 patients; in 191 patients there was a complete regression of the pareses and in 59 only a partial recovery. The most favorable prognosis was with inflammatory and vascular lesions; in the latter the outcome was improved by the administration of non-steroidal anti-inflammatory drugs.

Invasive squamous cell carcinoma in a patient with epidermodysplasia verruciformis

A patient with epidermodysplasia verruciformis died of intracranial invasion by squamous cell carcinoma (SCC). A biopsy of clinically normal skin had revealed perineural invasion by malignant keratinocytes. Because SCCs arising in patients with epidermodysplasia verruciformis may be biologically aggressive, it is best to excise them with careful control of the surgical tissue margins.

Early botulinum toxin treatment of acute sixth nerve palsy

Eight patients with total sixth nerve palsy were treated with botulinum toxin injection to the antagonist non-paretic medical rectus, within eight weeks of the onset of the palsy. Within a few days seven of the eight gained fusion without the necessity of a marked head turn, and none complained of confusing reversal of diplopia. The same seven recovered full function. The mean follow-up period after the last injection was 20 months. Seven palsies were the result of head trauma and one was due to cerebro-vascular disease. This preliminary report suggests that early botulinum toxin injection of patients with recent onset sixth nerve palsy is beneficial. Although all of the patients may possibly have recovered full lateral rectus function without treatment, the aetiologies of their palsies were of the type that frequently do no resolve. A randomised double-blind study is necessary more precisely to determine the effectiveness of this form of therapy.

Electrooculography and discriminant analysis in Duane's syndrome and sixth-cranial-nerve palsy

Eye-movement recordings may be helpful in the differentiation of Duane's syndrome from sixth-cranial-nerve palsy. Voluntary horizontal saccades were recorded and quantitated by electrooculography in 18 patients with unilateral type I Duane's syndrome and in 25 patients with sixth-nerve palsy. When ranges of abduction were matched, the peak velocities of abducting saccades in affected eyes were decreased equally in both groups. However, the peak velocities of adducting saccades in sound eyes were slowed in patients with Duane's syndrome. Because the standard deviations in saccadic velocities are large, computer-based, stepwise discriminant analyses were performed to identify the variables that proved to be useful in differentiating the two disorders. By entering these variables into the discriminant functions that were created, we could distinguish Duane's syndrome from sixth-nerve palsy in a statistically significant manner.