Eyelid and eye movements following fourth to third nerve anastomosis.

A 34-year-old woman presented with brainstem compression from a large third nerve schwannoma although third nerve function was intact. At surgery, preservation of the proximal third nerve was not possible. Because of preexisting amblyopia of the contralateral eye, an attempt was made to surgically reinnervate the affected third nerve. The fourth nerve was divided at its entry into the tentorium and anastomosed to the distal stump of the third nerve. Partial recovery of third function occurred over several months and is still present 6 years later. Successful long-term reinnervation of the third nerve by direct anastomosis with the fourth nerve may be useful when third repair is not possible.

Visual field deficits following anterior temporal lobectomy: long-term follow-up and prognostic implications.

PURPOSE: The aim of this study was to assess the incidence of mild (90 degrees from vertical) visual field defects (VFDs) in patients after anterior temporal lobectomy (ATL), and their postoperative improvement over time. METHODS: The angles of postoperative VFDs of 75 patients who underwent ATL were recorded at various time points (1, 2, 6, 12, 18, 24, and 36+ months). RESULTS: Of all 23 patients who came in for their <1 month postoperative appointment, 65% of patients had surgically induced VFDs <90 degrees , whereas 35% had VFDs >90 degrees postoperatively. Patients in the latter group were reported for suspension of their driver's license. However, 38% experienced improvement of their VFD to <90 degrees such that their driver's license could be reinstated. Of patients with any VFD, 18-30% improved on average by a magnitude of 38 degrees within the first year postoperatively. DISCUSSION: Although 35% of the VFDs that occur following temporal lobe surgery are severe, approximately 38% of these patients (especially those with starting postoperative VFDs closer to the 90 degrees angle) experience some improvement shortly after surgery. This may increase their chances of having their driver's license reinstated.

Predicting conversion to MS--the role of a history suggestive of demyelination.

BACKGROUND: The ability to predict conversion to multiple sclerosis (MS) accurately when assessing a patient with a clinically isolated syndrome (CIS) is of paramount importance. Magnetic resonance imaging (MRI) is the best paraclinical tool currently available; however the significance of a history of an event suggestive of demyelination prior to CIS presentation has not been evaluated. METHODS: A retrospective chart review of all optic neuritis cases presenting as CIS to a single neuro-ophthalmologist in London, Ontario between 1990 to 1998 was performed. Data were collected regarding demographics, past medical history, history of present illness, and family history. Conversion to MS was determined by the McDonald criteria after ten years of follow-up. Bayesian statistics and logistic regression were used to determine the best predictors of conversion to MS from CIS. RESULTS: One hundred and sixteen optic neuritis subjects were included in the analysis. After ten years, 42.2% had converted to MS. The best predictor of future conversion remained at least one brain lesion, disseminated in space, on MRI (sensitivity 0.90, specificity 0.75). However, if the subject additionally had a history suggestive of a demyelinating event in the past that had not been confirmed clinically, the specificity increased to 0.96. These two traits taken together had an odds ratio of 27.8 for conversion to MS in the next ten years (p<0.001). CONCLUSIONS: A history of an event suggestive of demyelination prior to presenting with optic neuritis as CIS increases the ability of the clinician to predict conversion to MS in the next ten years.

Conservative management of pituitary macroadenoma contacting the optic apparatus.

OBJECTIVES: To describe the tumor characteristics and visual function in conservatively managed patients with non-functioning pituitary macroadenoma (NFMA) that contacted/compressed the visual pathway. DESIGN: Retrospective case-series. SETTING: Tertiary-care academic institution. PARTICIPANTS: Six patients with diagnosis of NFMA. MAIN OUTCOME: Visual function and radiological characteristics of the optic apparatus and pituitary tumor. RESULTS: All patients had radiological evidence of optic apparatus compression but only one had visual field defect at the initial presentation. While two of the six patients developed visual field changes during followup (41±34.8 months), the patient with visual field defect at the time of diagnosis improved to normal vision. CONCLUSIONS: Select NFMAs that contact the optic apparatus, without visual dysfunction, may be managed with close ophthalmological and radiographic monitoring, depending on tumor and imaging characteristics. This may be of particular relevance in patients considered to have a high peri-operative risk, such as advanced age or significant co-morbidities.

Direct carotid-cavernous fistula causing brainstem venous congestion.

A 39-year-old man who presented with unilateral proptosis and periocular pain rapidly developed reduced consciousness, facial numbness, dysarthria, and gait ataxia from a direct carotid-cavernous fistula (CCF) with drainage into posterior fossa veins. Brain MRI revealed abnormal signal throughout the brainstem, indicative of venous hypertension and edema. Closure of the fistula by detachable balloon eliminated the clinical and imaging abnormalities. This is the fifth reported case of brainstem complications of a direct CCF. It highlights potentially serious complications of this condition and their reversibility with prompt treatment.

Creutzfeldt-Jakob disease presenting with visual manifestations.

BACKGROUND: Creutzfeldt-Jakob disease (CJD) is a rare and progressive degenerative disease of the central nervous system (CNS), characterized pathologically by spongiform changes in various CNS tissues. It most often presents with rapidly progressing dementia and cognitive decline, along with other neurologic findings that correspond to affected areas of the CNS. We present 5 sporadic cases of CJD presenting with visual manifestations, 2 of which were consistent with the Heidenhain variant, which predominantly affects the occipital lobe. METHODS: Each of the cases demonstrated electroencephalographic changes suggestive of CJD. The neuro-ophthalmic findings included both sensory and motor manifestations, including cortical blindness, hemianopsia, dysmetria, visual hallucinations, hypometric saccades, and diplopia. RESULTS: All patients died within 5 months after the onset of signs of the disease and pathologic specimens were obtained in 4 of the cases. INTERPRETATION: Although CJD is not a commonly seen condition, its possibility should be entertained in any patient presenting with typical neurologic deterioration and complaining of visual symptoms.

Quantitative evaluation of vision-related and health-related quality of life after endoscopic transsphenoidal surgery for pituitary adenoma.

OBJECTIVE Endoscopic resection of pituitary adenomas has been reported to improve vision function in up to 80%-90% of patients with visual impairment due to these adenomas. It is unclear how these reported rates translate into improvement in visual outcomes and general health as perceived by the patients. The authors evaluated self-assessed health-related quality of life (HR-QOL) and vision-related QOL (VR-QOL) in patients before and after endoscopic resection of pituitary adenomas. METHODS The authors prospectively collected data from 50 patients who underwent endoscopic resection of pituitary adenomas. This cohort included 32 patients (64%) with visual impairment preoperatively. Twenty-seven patients (54%) had pituitary dysfunction, including 17 (34%) with hormone-producing tumors. Patients completed the National Eye Institute Visual Functioning Questionnaire and the 36-Item Short Form Health Survey preoperatively and 6 weeks and 6 months after surgery. RESULTS Patients with preoperative visual impairment reported a significant impact of this condition on VR-QOL preoperatively, including general vision, near activities, and peripheral vision; they also noted vision-specific impacts on mental health, role difficulties, dependency, and driving. After endoscopic resection of adenomas, patients reported improvement across all these categories 6 weeks postoperatively, and this improvement was maintained by 6 months postoperatively. Patients with preoperative pituitary dysfunction, including hormone-producing tumors, perceived their general health and physical function as poorer, with some of these patients reporting improvement in perceived general health after the endoscopic surgery. All patients noted that their ability to work or perform activities of daily living was transiently reduced 6 weeks postoperatively, followed by significant improvement by 6 months after the surgery. CONCLUSIONS Both VR-QOL and patient's perceptions of their ability to do work and perform other daily activities as a result of their physical health significantly improved by 6 months after endoscopic resection of pituitary adenoma. The use of multidimensional QOL questionnaires provides a precise assessment of perceived outcomes after endoscopic surgery.

High resolution fMRI of ocular dominance columns within the visual cortex of human amblyopes.

Non-human primate models suggest that amblyopia has a neural basis in the form of a massive reduction in binocular neurons, and in some cases, a shift in ocular dominance of neural activity toward the unaffected eye. To date, the resolution of neuroimaging has been insufficient to investigate the neural basis of ocular dominance in human amblyopia. We used high spatial resolution (0.5 x 0.5 x 3 mm) functional magnetic resonance imaging (fMRI) to obtain maps of ocular dominance within the visual cortex of adult human amblyopes. fMRI maps of ocular dominance were similar in appearance to maps reported in the literature. For each of six adults with early-onset amblyopia, the number of map pixels corresponding to the unaffected eye was greater than the number corresponding to the amblyopic eye. This shift in ocular dominance was not seen for the two adults with later-onset amblyopia, suggesting that a shift in ocular dominance of neural activity occurs only if amblyopia onset is within the critical period of brain development. Our findings demonstrate how fMRI can non-invasively investigate the neural substrates underlying human amblyopia at the cortical column level.

Bilateral trochlear nerve palsy in a patient with neuromyelitis optica.

We present a unique case of isolated bilateral simultaneous cranial nerve (CN) IV palsy in a patient with neuromyelitis optica (NMO). Although some CN IV abnormalities have been described in multiple sclerosis (MS), no case of isolated bilateral simultaneous CN IV has been reported, to our knowledge, in either NMO or MS.

Visual outcomes for surgical treatment of large and giant carotid ophthalmic segment aneurysms: a case series utilizing retrograde suction decompression (the "Dallas technique").

OBJECT: The authors report their results in a series of large or giant carotid ophthalmic segment aneurysms clipped using retrograde suction decompression. METHODS: A retrospective review of clinical data and treatment summaries was performed for 18 patients with large or giant carotid artery ophthalmic segment aneurysms managed operatively via retrograde suction decompression. Visual outcomes, Glasgow Outcome Scale (GOS) scores, and operative complications were determined. Postoperative angiography was assessed. RESULTS: During a 17-year period, 18 patients underwent surgery performed using retrograde suction decompression. The mean aneurysm size was 26 mm. Three patients presented with subarachnoid hemorrhage. Fourteen of 18 patients presented with visual symptoms. Eleven (79%) of these 14 patients experienced visual improvement and the remaining 3 (21%) experienced worsened vision after surgery. Of 3 patients without visual symptoms and a complete visual examination before and after surgery, 1 had visual worsening postoperatively. One aneurysm required trapping and bypass, and all others could be clipped. Postoperative angiography demonstrated complete occlusion in 9 of 17 clipped aneurysms and neck remnants in the other 8 clipped aneurysms. One (5.5%) of 18 patients experienced a stroke. Eighteen patients had a GOS score of 5 (good outcome), and 1 patient had a GOS score of 4 (moderately disabled). There were no deaths. There was no morbidity related to the second incision or decompression procedure. Prolonged improvement did occur, and even in some cases of visual worsening in 1 eye, the overall vision did improve enough to allow driving. CONCLUSIONS: Retrograde suction decompression greatly facilitates surgical clipping for large and giant aneurysms of the ophthalmic segment. Visual preservation and improvement occur in the majority of these cases and is an important outcome measure. Developing endovascular technology must show equivalence or superiority to surgery for this specific outcome.

Transcortical venous approach for direct embolization of a cavernous sinus dural arteriovenous fistula: technical case report.

BACKGROUND AND IMPORTANCE: Dural arteriovenous fistulas (dAVFs) represent 10% to 15% of all intracranial arteriovenous malformations. Most often, embolization is accomplished with transfemoral catheter techniques. We present a case in which embolization of a cavernous sinus dAVF was made possible through transcranial cannulation of a cortical draining vein. CLINICAL PRESENTATION: An 82-year-old woman presented with diplopia, left sixth cranial nerve palsy, intraocular hypertension, and bilateral chemosis. Angiography revealed a complex cavernous dAVF with cortical venous reflux, supplied by both external carotid arteries and the left meningohypophyseal trunk. Percutaneous transvenous access failed, and only partial occlusion was achieved by transarterial embolization. A frontotemporal craniotomy was performed to access the superficial middle cerebral vein in the left sylvian fissure. Under fluoroscopic guidance, a microcatheter was advanced through this vein to the floor of the middle cranial fossa and into the dAVF, permitting coil occlusion. CONCLUSION: This transcranial vein technique may be a useful adjunct in dAVF therapy when percutaneous transarterial or transvenous approaches fail or are not possible.

Retinotopic organization of the visual cortex before and after decompression of the optic chiasm in a patient with pituitary macroadenoma.

Compression induced by a pituitary tumor on the optic chiasm can generate visual field deficits, yet it is unknown how this compression affects the retinotopic organization of the visual cortex. It is also not known how the effect of the tumor on the retinotopic organization of the visual cortex changes after decompression. The authors used functional MRI (fMRI) to map the retinotopic organization of the visual cortex in a 68-year-old right-handed woman before and 3 months after surgery for a recurrent pituitary macroadenoma. The authors demonstrated that longitudinal changes in visual field perimetry, as assessed by the automated Humphrey visual field test, correlated with longitudinal changes in fMRI activation in a retinotopic manner. In other words, after decompression of the optic chiasm, fMRI charted the recruitment of the visual cortex in a way that matched gains in visual field perimetry. On the basis of this case, the authors propose that fMRI can chart neural plasticity of the visual cortex on an individual basis and that it can also serve as a complementary tool in decision making with respect to management of patients with chiasmal compression.

Grasping the non-conscious: preserved grip scaling to unseen objects for immediate but not delayed grasping following a unilateral lesion to primary visual cortex.

Patients with damage to primary visual cortex can sometimes direct actions towards 'unseen' targets located in areas of the visual field that are deemed 'blind' on the basis of static perimetry tests. Here, we show that a patient with a complete right homonymous hemianopia after a V1 lesion remains sensitive to the width of objects presented in her blind field but only when reaching out to grasp them in 'real-time'. A subsequent fMRI experiment revealed spared extra-geniculostriate pathways, which may mediate her preserved abilities. Taken together, the results support the view that visually guided movements can be mediated by pathways that do not support visual consciousness.

Selective, non-lateralized impairment of motor imagery following right parietal damage.

Using variants of a visually guided pointing task, in which subjects make pointing movements towards targets of varying sizes, we explored motor imagery in a patient with visual neglect. When this patient actually pointed towards targets of different sizes he showed the normal correlation between movement duration (MD) and target size, such that MD increased as target size decreased. In contrast, his imagined movements did not show the same speed-accuracy trade-off observed for actual movements. This was true regardless of the hand used or the initial direction of movement (left versus right). The patient performed normally on several tasks of visual imagery, including size estimation, perceptual discrimination and localization of cities on an imagined map. This patient's performance suggests that the networks in the right parietal lobe play an important role in the generation of internal models of motor movements regardless of the hand used to perform the task.