Joint pain, physical function, and balance self-confidence in acromegaly versus nonfunctioning pituitary adenoma patients.

CONTEXT: Patients with acromegaly (PWA) experience balance issues, despite achieving biochemical remission, that may significantly impair their quality of life. OBJECTIVE: We sought to assess the prevalence of falls and balance self-confidence in PWA in comparison with a control group. Furthermore, we investigated the effect of joint pain and function as predictors for their balance self-confidence. DESIGN: Cross-sectional, case-controlled. SETTING: Tertiary care centers. PARTICIPANTS: In this case-control study, we surveyed PWA (n = 94) and nonfunctioning pituitary adenoma (PNA; n = 82) with similar age, sex, and body mass index from two Canadian centers. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Data were obtained on number of falls during the past 12 months, self-confidence to maintain balance, joint pain, joint surgery, pain medication usage, and upper and lower extremity musculoskeletal disability. RESULTS: While both PWA and PNA had a similarly high risk of falls, PWA had lower self-confidence to maintain balance (P < .01). Patients with acromegaly had higher joint pain scores and more functional impairment in upper extremity, hip, knee, and ankle joints (all P < .01). In both groups, age, sex, and ankle functional score were predictors of balance self-confidence. For PWA, hip functional score was also a predictor of balance self-confidence in contrast to knee and back pain scores being predictors for the PNA group. CONCLUSIONS: We confirmed an increased prevalence of falls in both groups with diminished balance confidence in PWA. This reduced balance self-confidence seems to be related to their increased hip functional impairment in comparison with PNA.

Intraosseous Cavernous Hemangioma of the Middle Turbinate: A Case Report.

BACKGROUND: We report a case of an intraosseous cavernous hemangioma originating from the middle turbinate that expanded into the anterior skull base, without traversing the cribriform plate. METHODS: The mass was found incidentally after a computed tomography head was ordered for unrelated reasons. On questioning, the patient denied any nasal symptoms. Magnetic resonance imaging showed an enhancing mass and the radiological imaging supported a broad differential. RESULTS: The lesion was removed by endoscopic image-guided surgery, and the pathology was that of a benign intraosseous cavernous hemangioma. There was no residual hemangioma on postoperative imaging and the nasal mucosa healed well. This is the first report of an intraosseous cavernous hemangioma of the middle turbinate showing superior expansion to the anterior skull base. CONCLUSION: This case demonstrates the extent to which cavernous hemangiomas may expand into surrounding tissues. While these lesions are uncommon, they can be considered as part of a broad differential diagnosis of sinonasal tumors.

Staged reflexive artificial intelligence driven testing algorithms for early diagnosis of pituitary disorders.

BACKGROUND: Sellar masses (SM) frequently present with insidious hormonal dysfunction. We previously showed that, by utilizing a combined reflex/reflecting approach involving a laboratory clinician (LC) on common endocrine test results requested by non-specialists, and subsequently adding further warranted tests, previously undiagnosed pituitary disorders can be identified. However, manually employing these strategies by an LC is not feasible for wider screening of pituitary disorders. OBJECTIVE: The aim of this study was to compare the accuracy and financial impact of an Artificial Intelligence (AI) based, fully computerized reflex protocol with manual reflex/reflective intervention protocol led by an LC. METHODS: We developed a proof-of-concept AI-based framework to fully computerize multi-stage reflex testing protocols for pituitary dysfunction using automated reasoning methods. We compared the efficacy of this AI-based protocol with a reflex/reflective protocol based on manually curated retrospective data in identifying pituitary dysfunction based on 12 months of laboratory testing. RESULTS: The AI-based reflex protocol, as compared with the manual protocol, would have identified laboratory tests for add-on that either directly matched or included all manual add-on tests in 92% of cases, and recommended a similar specialist referral in 90% of the cases. The AI-based protocol would have issued 2.8 times the total number of manual add-on laboratory tests at an 85% lower operation cost than the manual protocol when considering marginal test costs, technical staff and specialist salary. CONCLUSION/DISCUSSION: Our AI-based reflex protocol can successfully identify patients with pituitary dysfunction, with lower estimated laboratory cost. Future research will focus on enhancing the protocol's accuracy and incorporating the AI-based reflex protocol into institutional laboratory and hospital information systems for the detection of undiagnosed pituitary disorders.

Preclinical Evaluation of the Stealth Autoguide Robotic Guidance Device for Stereotactic Cranial Surgery: A Human Cadaveric Study.

INTRODUCTION: Stereotactic procedures are routinely performed for brain biopsies, deep brain stimulation, and placement of stereoelectroencephalography (SEEG) electrodes for epilepsy. The recently developed Stealth Autoguide (Medtronic, Minneapolis, MN, USA) device does not require patients to don a stereotactic frame. In this preclinical study, we sought to quantitatively compare the Stealth Autoguide robotic system to 2 devices commonly used in clinical practice: the Navigus biopsy system (Medtronic) and the Leksell stereotactic frame (Elekta Ltd., Stockholm, Sweden). METHODS: In the first experimental setup, we compared target accuracy of the Stealth Autoguide to the Navigus system by using phantom heads filled with gelatin to simulate the brain tissue. In the second experimental setup, we inserted SEEG electrodes to targets within cadaveric heads in a simulated operating room environment. RESULTS: Using a homogeneous gelatin-filled phantom 3D reconstruction of a human head, we found that using the Stealth Autoguide system, while maintaining accuracy, was faster to use than the Navigus system. In our simulated operating room environment using nonliving human cadaveric heads, we found the accuracy of the Stealth Autoguide robotic device to be comparable to that of the Leksell frame. DISCUSSION/CONCLUSION: These results compare the use of the Stealth Autoguide robotic guidance system with commonly used stereotactic devices, and this is the first study to compare its use and accuracy with the Leksell frame. These findings provide mounting evidence that Stealth Autoguide will have potential clinical uses in various stereotactic neurosurgical procedures.

Validation of 3D fluoroscopy for image-guidance registration in depth electrode implantation for medically refractory epilepsy.

BACKGROUND: Frame registration is a critical step to ensure accurate electrode placement in stereotactic procedures such as stereoelectroencephalography (SEEG) and is routinely done by merging a computed tomography (CT) scan with the preoperative magnetic resonance (MR) examination. Three-dimensional fluoroscopy (XT) has emerged as a method for intraoperative electrode verification following electrode implantation and more recently has been proposed as a registration method with several advantages. METHODS: We compared the accuracy of SEEG electrode placement by frame registration with CT and XT imaging by analyzing the Euclidean distance between planned and post-implantation trajectories of the SEEG electrodes to calculate the error in both the entry (EP) and target (TP) points. Other variables included radiation dose, efficiency, and complications. RESULTS: Twenty-seven patients (13 CT and 14 XT) underwent placement of SEEG electrodes (319 in total). The mean EP and TP errors for the CT group were 2.3 mm and 3.3 mm, respectively, and 1.9 mm and 2.9 mm for the XT group, with no statistical difference (p = 0.75 and p = 0.246). The time to first electrode placement was similar (XT, 82 ± 10 min; CT, 84 ± 22 min; p = 0.858) and the average radiation exposure with XT (234 ± 55 mGy*cm) was significantly lower than CT (1245 ± 123 mGy*cm) (p < 0.0001). Four complications were documented with equal incidence in both groups. CONCLUSIONS: The use of XT as a method for registration resulted in similar implantation accuracy compared with CT. Advantages of XT are the substantial reduction in radiation dose and the elimination of the need to transfer the patient out of the room which may have an impact on patient safety and OR efficiency.

In-Hospital Endocrinology Consultation After Transsphenoidal Surgery: Is It Always Necessary?

BACKGROUND: Patients with sellar masses undergoing transsphenoidal surgery (TSS) frequently develop endocrine dysfunction; therefore, in-hospital endocrinology consultation (IHEC) is recommended. However, we wondered whether routine endocrinology assessment of all TSS patients is always necessary. METHODS: We developed an IHEC Physician's Guide to identify patients who would require peri-operative IHEC. An analysis of all patients undergoing TSS for a sellar mass over a 4-year period was conducted to assess the predictive value of the IHEC Physician's Guide in identifying patients who required IHEC. RESULTS: A total of 116 patients underwent TSS; 24 required IHEC. As expected, the risk of endocrine complications requiring peri-operative endocrine management was significantly higher in the IHEC group versus no-IHEC group (96% vs. 1%; p < 0.001). The negative predictive value of the IHEC Physician's Guide in identifying patients who did not require IHEC was 0.99 (95% CI 0.9409-0.9997); Fisher's exact test, p < 0.001), meaning that the IHEC Physician's Guide successfully identified all but one patient who truly required IHEC. CONCLUSION: Results from our study show that most patients do not need IHEC after TSS and that those patients requiring IHEC can be reliably predicted at surgery by using a simple IHEC Physician's Guide.

Secondary pituitary hormonal dysfunction patterns: tumor size and subtype matter.

PURPOSE: Patients with sellar masses (SM) frequently have secondary hormonal deficiency (SHD) at initial presentation. While larger SM are more likely to present with SHD, it is unclear whether SHD at presentation is influenced by the type of SM. METHODS: We conducted a retrospective analysis of patients with SM prospectively enrolled in our comprehensive provincial neuropituitary registry between November 2005 and December 2018. SM were subdivided based on size: < 1 cm, 1-1.9 cm, 2-2.9 cm, and > 3 cm. RESULTS: A total of 914 patients met the inclusion criteria, including: 346 nonfunctioning adenomas (NFA), 261 prolactinomas (PRLoma), 51 growth hormone adenomas, 36 adrenocorticotropic adenomas, 93 Rathke's cleft cysts, 70 craniopharyngiomas and 57 meningiomas. The overall rate of SHD at presentation was highest in PRLoma (62.8%) and craniopharyngiomas (64.3%) and lowest in meningiomas (14%). While larger SM were significantly more likely to have SHD, the rate of SHD within each group was significantly different despite similar size (p < 0.001). Of the two largest groups of SM (NFA and PRLoma), NFA had significantly higher odds ratio (3.34, CI 1.89-5.89) of having multiple SHDs when compare with PRLoma, even when corrected for age, gender and size of tumor (p < 0.001). CONCLUSION: Our study shows that the rate and distribution of SHD in SM vary dependent upon the size of the tumor and specific pathology; in particular, NFA are more likely to present with multiple SHDs. Our data will help clinicians in determining adequate hormonal testing strategy for different SM.

Polysialylated - neural cell adhesion molecule (PSA-NCAM) promotes recovery of vision after the critical period.

Vision loss has long since been considered irreversible after a critical period; however, there is potential to restore limited vision, even in adulthood. This phenomenon is particularly pronounced following complete loss of vision in the dominant eye. Adult neural cell adhesion molecule (NCAM) knockout mice have an age-related impairment of visual acuity. The underlying cause of early deterioration in visual function remains unknown. Polysialylated (PSA) NCAM is involved in different forms of neural plasticity in the adult brain, raising the possibility that NCAM plays a role in the plasticity of the visual cortex, and therefore, in visual ability. Here, we examined whether PSA-NCAM is required for visual cortical plasticity in adult C57Bl/6J mice following deafferentation and long-term monocular deprivation. Our results show that elevated PSA in the contralateral visual cortex of the reopened eye is accompanied by changes in other markers of neural plasticity: increased brain-derived neurotrophic factor (BDNF) levels and degradation of perineuronal nets (PNNs). The removal of PSA-NCAM in the visual cortex of these mice reduced BDNF expression, decreased PNN degradation, and resulted in impaired recovery of visual acuity after optic nerve transection and chronic monocular deprivation. Collectively, our results demonstrate that PSA-NCAM is necessary for the reactivation of visual cortical plasticity and recovery of visual function in adult mice. It also offers a potential molecular target for the therapeutic treatment of cortically based visual impairments.

Securing the position of the nasoseptal flap in endoscopic transsphenoidal surgery: No need for a Foley catheter (technical report).

BACKGROUND: The pedicled nasoseptal mucoperiosteal flap is currently widely used for the reconstruction of a skull base defect following transsphenoidal surgery. The flap is generally secured in position by a Foley catheter balloon. We describe an alternative technique using cylinders of Gelfoam™ (Pfizer Incorporated) to buttress the flap in place, obviating the need for a balloon catheter. MATERIAL AND METHODS: A review of our database identified patients who underwent endoscopic transsphenoidal surgery for a pituitary macroadenoma with nasoseptal flap, secured with small rolls of Gelfoam™ (Pfizer Incorporated) rather than a nasal Foley catheter. Minimum follow-up clinical and MRI assessments: 3 months. RESULTS: 73 patients (mean follow-up: 22 months) met the inclusion criteria: 56 non-functioning and 17 functioning pituitary adenomas. 36 patients had an intraoperative CSF leak: 30 high flow and 6 low flow leaks. The surgical repair in 35 patients included fat +/- fascia graft. One patient had a post-operative CSF leak repaired by subsequent surgery without the use of a Foley catheter. CONCLUSION: Securing the nasoseptal flap using rolls of Gelfoam™ (Pfizer Incorporated) as described can be achieved without the use of a nasal Foley catheter.

Cavernous sinus involvement in human papillomavirus associated oropharyngeal squamous cell carcinoma: case report of an atypical site of distant metastasis.

BACKGROUND: HPV-associated OSCC (HPV-OSCC) has been determined to be a distinct disease entity from non-HPV associated OSCC. Patients affected by HPV-OSCC generally have a more favourable prognosis, with improved rates of locoregional control and survival compared with their non-HPV counterparts. Despite this, HPV-OSCC has a similar rate of distant metastases. Interestingly, recent evidence has emerged that demonstrates more frequent atypical metastasis patterns when compared to non-HPV associated disease. To the best of our knowledge, this report describes the first case of a confirmed HPV-OSCC with distant metastasis to the cavernous sinus. CASE PRESENTATION: A 62-year-old non-smoking male presented to the head and neck oncology clinic with a five-month history of enlarging right neck mass causing neck pain, dysphagia, and dysphonia. HPV-associated base of tongue squamous cell carcinoma (cT4aN2c) was diagnosed, and he was treated with primary chemoradiation. Shortly after treatment, he presented with progressive bilateral cranial nerve palsies including left cranial nerve III and right cranial nerve VI involvement. Imaging identified masses in the left cavernous sinus with extension of tumor into the sella and in the right cavernous sinus at the level of Dorello's canal. Endoscopic Image Guided Transsphenoidal biopsy of the left sellar mass confirmed distant metastases from the previously treated HPV-OSCC primary to the cavernous sinus. The patient was palliated with carboplatin and paclitaxel. CONCLUSION: The presented report is the first documented case of confirmed HPV-associated oropharyngeal squamous cell carcinoma metastasizing to the cavernous sinus, and the only HPV confirmed head and neck cancer case to present with metastasis to the cavernous sinus and limited extracranial disease. This case demonstrates the importance of recognizing presentations of atypical metastasis that are possible in HPV-associated oropharyngeal cancer. Given the rarity of metastasis to this region, vigilance in follow up is instrumental in early identification and treatment for these patients.

A comparative, population-based analysis of pituitary incidentalomas vs clinically manifesting sellar masses.

PURPOSE: Sellar masses may present either with clinical manifestations of mass effect/hormonal dysfunction (CMSM) or incidentally on imaging (pituitary incidentaloma (PI)). This novel population-based study compares these two entities. METHODS: Retrospective analysis of all patients within a provincial pituitary registry between January 2006 and June 2014. RESULTS: Nine hundred and three patients were included (681 CMSM, 222 PI). CMSM mainly presented with secondary hormone deficiencies (SHDs) or stalk compression (29.7%), whereas PIs were found in association with neurological complaints (34.2%) (P < 0.0001). PIs were more likely to be macroadenomas (70.7 vs 49.9%; P < 0.0001). The commonest pathologies among CMSM were prolactinomas (39.8%) and non-functioning adenomas (NFAs) (50%) in PI (P < 0.0001). SHDs were present in 41.3% CMSM and 31.1% PI patients (P < 0.0001) and visual field deficit in 24.2 and 29.3%, respectively (P = 0.16). CMSM were more likely to require surgery (62.9%) than PI (35.8%) (P < 0.0005). The commonest surgical indications were impaired vision and radiological evidence of optic nerve compression. Over a follow-up period of 5.7 years for CMSM and 5.0 years for PI, tumour growth/recurrence occurred in 7.8% of surgically treated CMSM and 2.6% without surgery and PI, 0 and 4.9%, respectively (P = 1.0). There were no significant differences in the risk of new-onset SHD in CMSM vs PI in those who underwent surgery (P = 0.7) and those who were followed without surgery (P = 0.58). CONCLUSIONS: This novel study compares the long-term trends of PI with CMSM, highlighting the need for comprehensive baseline and long-term radiological and hormonal evaluations in both entities.

Reflex and reflective testing strategies for early detection of pituitary dysfunction.

OBJECTIVE: The clinical presentation of pituitary dysfunction is typically variable and may often be insidious, resulting in delayed diagnosis by up to decades. The complexity of presentation and difficulty in pattern recognition of first line hormone tests result in challenges in early diagnosis of this condition. The aim of this study was to determine the impact of reflective testing and interpretive commenting on the early detection and management of such cases from primary care. METHODS: Prospective audit over 12 months in which first line pituitary target organ hormones were identified via a reflex algorithm in the laboratory information system. Selected tests were reviewed by a laboratory clinician and decision made on reflective testing and interpretive commenting based on available clinical information and previous result trends. Patients who had a laboratory intervention were followed up to determine the clinical outcome. RESULTS: Out of 1099 patients identified, additional testing was made for 214. Interpretative comments were subsequently added to reports of 196 patients, 48 (25%) of whom were referred to endocrinology and 35 (73%) of these were directly related to the laboratory intervention. Eleven other patients had outcomes related to the intervention. Pituitary related conditions (insufficiency and/or adenoma) were found in 29 patients, 24 of which were identified as a result of laboratory intervention. CONCLUSIONS: This study highlights the clinical value of laboratory intervention in aiding early detection of pituitary dysfunction and may avoid the disease burden of delayed management.

Unusual AIP mutation and phenocopy in the family of a young patient with acromegalic gigantism.

Early-onset acromegaly causing gigantism is often associated with aryl-hydrocarbon-interacting receptor protein (AIP) mutation, especially if there is a positive family history. A15y male presented with tiredness and visual problems. He was 201 cm tall with a span of 217 cm. He had typical facial features of acromegaly, elevated IGF-1, secondary hypogonadism and a large macroadenoma. His paternal aunt had a history of acromegaly presenting at the age of 35 years. Following transsphenoidal surgery, his IGF-1 normalized and clinical symptoms improved. He was found to have a novel AIP mutation destroying the stop codon c.991T>C; p.*331R. Unexpectedly, his father and paternal aunt were negative for this mutation while his mother and older sister were unaffected carriers, suggesting that his aunt represents a phenocopy. LEARNING POINTS: Typical presentation for a patient with AIP mutation with excess growth and eunuchoid proportions.Unusual, previously not described AIP variant with loss of the stop codon.Phenocopy may occur in families with a disease-causing germline mutation.

Virtual Reality Surgical Simulation: Implications for Resection of Intracranial Gliomas.

Surgical simulation has the potential to play important roles in surgical training and preoperative planning. The advent of virtual reality (VR) with tactile haptic feedback has revolutionized surgical simulation, creating a novel environment for residents to learn manual skills without compromising patient safety. This concept is particularly relevant in neurosurgical training where the acquired skill set demands performance of technically challenging tasks under pressure and where the consequences of error are significant. The evolution of VR simulation is discussed here within the context of neurosurgical training and its implications for resection of intracranial gliomas. VR holds the promise of providing a useful educational tool for neurosurgical residents to hone their surgical skills and for neurosurgeons to rehearse specific segments of the surgery prior to the actual operation. Also discussed are several important issues related to simulation and simulation-based training that will need to be addressed before widespread adoption of VR simulation as a useful technology.

Radiological Growth Patterns of Prolactinomas and Nonfunctioning Adenomas.

OBJECTIVES: To compare growth patterns of nonfunctioning and prolactin-producing pituitary macroadenomas, and to find whether their specific growth patterns are associated with clinically significant effects on vision. MATERIALS AND METHODS: From our comprehensive provincial neuropituitary registry, we retrospectively identified 35 randomly selected patients each with nonfunctioning adenomas and prolactinomas >10 mm in any dimension. MRI scans were analyzed to determine the superior and inferior growth, volume, and maximum craniocaudal height of the adenomas. Patients underwent visual field testing at diagnosis. Continuous variables were compared using Student's t test, the Mann-Whitney U test, and ANOVA. Categorical variables were compared using the chi-square test. RESULTS: The mean height of prolactinomas (23.2±11.3 mm) was similar to nonfunctioning adenomas (22.3±9.3 mm, p=0.8), and so were mean tumor volumes (prolactinoma=5.9±8 ml vs. nonfunctioning adenoma=4.8±5 ml, p=0.47). However, the mean suprasellar growth for prolactinomas was 2.9±5.3 mm and 7.3±4.7 mm for nonfunctioning adenomas (p<0.001), and the mean infrasellar growth was 10.2±8.0 and 5.0±6.6 mm, respectively (p=0.04). The inferior growth pattern of prolactinomas was associated with a significantly lower likelihood of having visual field abnormalities (11.4 vs. 57.1%, p<0.001). CONCLUSIONS: Prolactinomas have predominantly inferior growth compared to nonfunctioning adenomas and are less likely to cause vision changes.

Polysialylated Neural Cell Adhesion Molecule Protects Against Light-Induced Retinal Degeneration.

PURPOSE: We previously demonstrated that neural cell adhesion molecule (NCAM) plays an important role in supporting the survival of injured retinal ganglion cells. In the current study, we used light-induced retinal degeneration (LIRD) as a model to investigate whether NCAM plays a functional role in neuroprotection and whether NCAM influences p75NTR signaling in modulating retinal cell survival. METHODS: Retinas from wild-type (WT) and NCAM deficient (-/-) mice were tested by electroretinogram before and after LIRD, and changes in the protein expressions of NCAM, polysialic acid (PSA)-NCAM, p75NTR, and active caspase 3 were measured by immunoblot from 0 to 4 days after light induction. The effects of NCAM and PSA-NCAM on p75NTR were examined by intraocular injections of the p75NTR function-blocking antibody and/or the removal of PSA with endoneuraminidase-N prior to LIRD. RESULTS: In WT mice, low levels of active caspase 3 activation were detected on the first day, followed by increases up to 4 days after LIRD. Conversely, in NCAM-/- mice, higher cleaved caspase 3 levels along with rapid reductions in electroretinogram amplitudes were found earlier at day 1, followed by reduced levels by day 4. The removal of PSA prior to LIRD induced earlier onset of retinal cell death, an effect delayed by the coadministration of endoneuraminidase-N and the p75NTR function-blocking antibody antiserum. CONCLUSIONS: These results indicate that NCAM protects WT retinas from LIRD; furthermore, the protective effect of NCAM is, at least in part, attributed to its effects on p75NTR.

Simulation-based training for burr hole surgery instrument recognition.

BACKGROUND: The use of simulation training in postgraduate medical education is an area of rapidly growing popularity and research. This study was designed to assess the impact of simulation training for instrument knowledge and recognition among neurosurgery residents. METHODS: This was a randomized control trial of first year residents from neurosurgery residency training programs across Canada. Eighteen neurosurgery trainees were recruited to test two simulation-based applications: PeriopSim™ Instrument Trainer and PeriopSim™ for Burr Hole Surgery. The intervention was game-based simulation training for learning neurosurgical instruments and applying this knowledge to identify correct instruments during a simulated burr hole surgery procedure. RESULTS: Participants showed significant overall improvement in total score (p < 0.0005), number of errors (p = 0.019) and time saved (p < 0.0005), over three testing sessions when using the PeriopSim™ Instrument Trainer. Participants demonstrated further performance-trained improvements when using PeriopSim™ Burr Hole Surgery. CONCLUSIONS: Training in the recognition and utilization of simulated surgical instruments by neurosurgery residents improved significantly with repetition when using PeriopSim™ Instrument Trainer and PeriopSim™ for Burr Hole Surgery.

Effect of NCAM on aged-related deterioration in vision.

The neural cell adhesion molecule (NCAM) is involved in developmental processes and age-associated cognitive decline; however, little is known concerning the effects of NCAM in the visual system during aging. Using anatomical, electrophysiological, and behavioral assays, we analyzed age-related changes in visual function of NCAM deficient (-/-) and wild-type mice. Anatomical analyses indicated that aging NCAM -/- mice had fewer retinal ganglion cells, thinner retinas, and fewer photoreceptor cell layers than age-matched controls. Electroretinogram testing of retinal function in young adult NCAM -/- mice showed a 2-fold increase in a- and b-wave amplitude compared with wild-type mice, but the retinal activity dropped dramatically to control levels when the animals reached 10 months. In behavioral tasks, NCAM -/- mice had no visual pattern discrimination ability and showed premature loss of vision as they aged. Together, these findings demonstrate that NCAM plays significant roles in the adult visual system in establishing normal retinal anatomy, physiology and function, and in maintaining vision during aging.