Visual Dysfunction after Repetitive Mild Traumatic Brain Injury in a Mouse Model and Ramifications on Behavioral Metrics.

Mild traumatic brain injury (mTBI) is a major cause of morbidity and mortality with a poorly understood pathophysiology. Animal models have been increasingly utilized to better understand mTBI and recent research has identified visual deficits in these models that correspond to human literature. While visual impairment is being further characterized within TBI, the implications of impaired vision on behavioral tasks commonly utilized in animal models has not been well described thus far. Visual deficits may well confound behavioral tests that are believed to be isolated to cognitive functioning such as learning and memory. We utilized a mouse model of repetitive mTBI (rmTBI) to further characterize visual deficits using an optomotor task, electroretinogram, and visually evoked potential, and located likely areas of damage to the visual pathway. Mice were tested on multiple behavioral metrics, including a touchscreen conditional learning task to better identify the contribution of visual dysfunction to behavioral alterations. We found that rmTBI caused visual dysfunction resulting from damage distal to the retina that likely involves pathology within the optic nerve. Moreover, loss of vision led to poorer performance of rmTBI animals on classic behavioral tests such as the Morris water maze that would otherwise be attributed solely to learning and memory deficits. The touchscreen conditional learning task was able to differentiate rmTBI induced learning and memory dysfunction from visual impairment and is a valuable tool for elucidating subtle changes resulting from TBI.

Clinical observation on removal of small foreign bodies touching the optic nerve in the deep orbital region: a case series.

PURPOSE: Five patients presented to our institution with deep intraorbital foreign bodies adjacent to the optic nerve. We removed all foreign bodies by lateral orbitotomy to evaluate the treatment and the benefits of their extraction. METHODS: The clinical outcomes of the five patients were retrospectively analyzed. RESULTS: Radiology in all five patients revealed small foreign bodies touching the optic nerve in the deep orbital region. All patients also suffered from significant secondary psychological disturbances, these including anxiety and altered sleep patterns. They had become preoccupied with a strong desire to remove the intraorbital foreign bodies [IFB]. In this cohort, two had no light perception before surgery, another two had light perception, and one had hand motion perception as well as vitreous hemorrhage that had been plugged with silicone oil in other hospital. All foreign bodies were removed via lateral orbitotomy. Visual acuity improved after the operation in only three cases. However, the psychological well-being of all five patients improved. CONCLUSIONS: Consideration should be given to removal of intraorbital foreign bodies adjacent to the optic nerve, even where a significant degree of vision has already been lost. Furthermore some patients can achieved vision improvement and such surgery can frequently address the significant psychological disturbance that can be associated with such orbital foreign bodies.

Chronic mild stress eliminates the neuroprotective effect of Copaxone after CNS injury.

Copolymer (Cop)-1, also known as glatiramer acetate, is an active compound of Copaxone, a drug widely used by patients with multiple sclerosis (MS). Copaxone functions in MS through two mechanisms of action, namely immunomodulation and neuroprotection. Because the immune system is suppressed or altered in depressed individuals, and since depression is often associated with neurological conditions, we were interested in examining whether the neuroprotective effect of Copaxone persists under conditions of stress-induced depressive behavior. We exposed mice to unpredictable chronic mild stress for 4 weeks and then treated them with three doses of Copaxone at 3-day intervals, with the last dose given immediately before the mice underwent a crush injury to the optic nerve. Whereas nonstressed mice exhibited a strong neuroprotective response after Copaxone treatment, this effect was completely absent in mice that underwent chronic mild stress. Interestingly, when Copaxone was combined with Prozac, the neuroprotective effect of Copaxone was regained, suggesting that chronic mild stress interferes with the neuroprotective effect of Copaxone. These results may shed a light on mechanism of action of Copaxone and lead to new combined therapies for neurodegenerative and neuroinflammatory disorders.

Optic nerve massaging: an extremely rare cause of self-inflicted blindness.

PURPOSE: To report a patient whose self-inflicted blindness was not clinically apparent by history or external signs of trauma. DESIGN: Observational case report. METHODS: A 12-year-old girl with a history of social and behavioral problems was noted to have visual loss in her right eye. Examination revealed no light perception, optic nerve atrophy, partial upper lid ptosis, exotropia, and hypoesthesia of the cheek, all on her right side. RESULTS: After undergoing extensive examinations which were unrevealing for a diagnosis, the patient admitted to a recurrent maneuver, which she secretly used to relieve anxiety and stress. This maneuver consisted of inserting her index finger under the right supraorbital rim and forcibly subluxating her globe out of the orbital space. CONCLUSIONS: Self-inflicted visual loss can occur in nonpsychotic and nonviolent patients. Accurate diagnosis is important, as there is a risk of similar involvement to the fellow eye, and referral for psychiatric counseling is mandatory.