Functional MRI for Acute Covert Consciousness: Emerging Data and Implementation Case Series.

Although research studies have begun to demonstrate relationships between disorders of consciousness and brain network biomarkers, there are limited data on the practical aspects of obtaining such network biomarkers to potentially guide care. As the state of knowledge continues to evolve, guidelines from professional societies such as the American and European Academies of Neurology and many experts have advocated that the risk-benefit ratio for the assessment of network biomarkers has begun to favor their application toward potentially detecting covert consciousness. Given the lack of detailed operationalization guidance and the context of the ethical implications, herein we offer a roadmap based on local institutional experience with the implementation of functional MRI in the neonatal, pediatric, and adult intensive care units of our local government-supported health system. We provide a case-based demonstrative approach intended to review the current literature and to assist with the initiation of such services at other facilities.

Soft Tissue Chondroma of the Eyelid.

A 54-year-old woman presented with a 2-year history of a slow-growing subcutaneous nodule of the medial right lower eyelid adjacent to the inferior canaliculus. The patient reported right-sided epiphora suggesting lacrimal outflow obstruction. The surgically excised nodule was consistent with a chondroma. A rare tumor, soft tissue chondroma, is most often seen in the extremities, but has also been observed in the head and neck region. To their knowledge, this is the first reported case of a soft tissue chondroma of the eyelid.

Neuromuscular ultrasound in patients with carpal tunnel syndrome and normal nerve conduction studies.

INTRODUCTION: Nerve conduction studies (NCS) are sensitive for carpal tunnel syndrome (CTS), but a small proportion of patients with clinical CTS have normal NCS. This retrospective study was designed to assess the neuromuscular ultrasound findings in a group of CTS patients. METHODS: The electronic medical record was reviewed by a neurologist to identify patients who had a diagnosis of CTS with normal NCS, including either mixed median-ulnar comparison or transcarpal sensory studies, and complete neuromuscular ultrasound evaluation for CTS. RESULTS: Fourteen individuals (22 wrists) met all criteria. A total of 92.3% had median nerve cross-sectional area enlargement at the wrist (mean 16.3 mm2 ), 100% had increased wrist-to-forearm median nerve area ratio (mean 2.4), 82.4% had decreased median nerve echogenicity, 75.0% had decreased median nerve mobility, and 7.1% had increased median nerve vascularity. CONCLUSION: A large proportion of patients with clinical CTS but normal NCS have abnormal neuromuscular ultrasound findings. Muscle Nerve 55: 913-915, 2017.

Dopamine deficiency contributes to early visual dysfunction in a rodent model of type 1 diabetes.

Dopamine (DA) functions as an essential neuromodulator in the brain and retina such that disruptions in the dopaminergic system are associated with common neurologic disorders such as Parkinson's disease. Although a reduction in DA content has been observed in diabetes, its effects in the development of diabetes-induced neuropathy remains unknown. Because the retina is rich in DA and has a well known diabetes-induced pathology (diabetic retinopathy or DR), this study was designed to examine the role of retinal DA deficiency in early visual defects in DR. Using rodent models of type 1 diabetes mellitus, we investigated whether diabetes caused a reduction in retinal DA content in both rats and mice and determined whether restoring DA levels or activating specific DA receptor pathways could improve visual function (evaluated with optokinetic tracking response) of diabetic mice, potentially via improvement of retinal function (assessed with electroretinography). We found that diabetes significantly reduced DA levels by 4 weeks in rats and by 5 weeks in mice, coincident with the initial detection of visual deficits. Treatment with l-DOPA, a DA precursor, improved overall retinal and visual functions in diabetic mice and acute treatment with DA D1 or D4 receptor agonists improved spatial frequency threshold or contrast sensitivity, respectively. Together, our results indicate that retinal DA deficiency is an underlying mechanism for early, diabetes-induced visual dysfunction and suggest that therapies targeting the retinal dopaminergic system may be beneficial in early-stage DR.

ANCA-associated vasculitis presenting with isolated neurological manifestations in a patient with cocaine abuse: a case report and literature review.

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of rare conditions predominantly affecting small vessels of skin, musculoskeletal, pulmonary, renal, and rarely central and peripheral nervous systems. Isolated neurological manifestations of AAV are uncommon and challenging to diagnose. Cocaine has been reported as a potential trigger for the development of AAV. There are only a few case reports of isolated neurological involvement in cocaine-induced AAV with poorly characterized histopathological features. We present a unique case of AAV with isolated neurological manifestations presenting with multiple cranial neuropathies, leptomeningeal enhancement on imaging and histopathologic evidence of small-vessel vasculitis in the leptomeninges and brain and extensive dural fibrosis in a patient with cocaine abuse. The patient's progressive neurological deficits were controlled after starting immunosuppression with rituximab and prednisone. We also reviewed the literature to provide the diagnostic overview of AAV and evaluate intervention options. To our knowledge, this is the first case of AAV with isolated neurological manifestations and histopathologic evidence of small-vessel vasculitis in a patient with cocaine abuse. Patients with multiple cranial neuropathies and meningeal involvement should be screened for AAV, especially if they have a history of cocaine abuse.

Retinal dopamine mediates multiple dimensions of light-adapted vision.

Dopamine is a key neuromodulator in the retina and brain that supports motor, cognitive, and visual function. Here, we developed a mouse model on a C57 background in which expression of the rate-limiting enzyme for dopamine synthesis, tyrosine hydroxylase, is specifically disrupted in the retina. This model enabled assessment of the overall role of retinal dopamine in vision using electrophysiological (electroretinogram), psychophysical (optokinetic tracking), and pharmacological techniques. Significant disruptions were observed in high-resolution, light-adapted vision caused by specific deficits in light responses, contrast sensitivity, acuity, and circadian rhythms in this retinal dopamine-depleted mouse model. These global effects of retinal dopamine on vision are driven by the differential actions of dopamine D1 and D4 receptors on specific retinal functions and appear to be due to the ongoing bioavailability of dopamine rather than developmental effects. Together, our data indicate that dopamine is necessary for the circadian nature of light-adapted vision as well as optimal contrast detection and acuity.

Bilateral exudative retinal detachments due to thrombotic microangiopathy associated with intravenous abuse of Opana ER.

PURPOSE: To report the only known case, to our knowledge, of bilateral exudative retinal detachments in the setting of thrombotic microangiopathy associated with intravenous abuse of extended-release oxymorphone (Opana ER). OBSERVATIONS: A 35-year-old male presented with headaches and acute, painless vision loss in the context of daily IV abuse of crushed oral Opana ER. The patient was found to have microangiopathic hemolytic anemia (MAHA), acute kidney injury in conjunction with hypertensive crisis and bilateral exudative retinal detachments. CONCLUSIONS AND IMPORTANCE: Bilateral exudative retinal detachments are rare ophthalmic complications that have been reported with thrombotic thrombocytopenic purpura (TTP). Non-TTP thrombotic microangiopathy, initially described as a "TTP-like illness" consisting of MAHA and thrombocytopenia, has been associated with the IV abuse of Opana ER. We report a case of bilateral exudative retinal detachments due to thrombotic microangiopathy in the setting of IV abuse of Opana ER.

Visually-driven ocular growth in mice requires functional rod photoreceptors.

PURPOSE: Proper refractive eye growth depends on several features of the visual image and requisite retinal pathways. In this study, we determined the contribution of rod pathways to normal refractive development and form deprivation (FD) myopia by testing Gnat1(-/-) mice, which lack functional rods due to a mutation in rod transducin-α. METHODS: Refractive development was measured in Gnat1(-/-) (n = 30-36) and wild-type (WT) mice (n = 5-9) from 4 to 12 weeks of age. FD was induced monocularly from 4 weeks of age using head-mounted diffuser goggles (Gnat1(-/-), n = 9-10; WT, n = 7-8). Refractive state and ocular biometry were obtained weekly using a photorefractor, 1310 nm optical coherence tomography, and partial coherence interferometry. We measured retinal dopamine and its metabolite, DOPAC, using HPLC. RESULTS: During normal development, the refractions of WT mice started at 5.36 ± 0.68 diopters (D) and became more hyperopic before plateauing at 7.78 ± 0.64 D. In contrast, refractions in Gnat1(-/-) mice were stable at 7.39 ± 1.22 D across all ages. Three weeks of FD induced a 2.54 ± 0.77 D myopic shift in WT mice, while Gnat1(-/-) mice did not respond to FD at any age. Axial lengths of Gnat1(-/-) and WT mice increased with age, but differences between genotypes or with goggling did not reach statistical significance and fell within the precision of the instruments. The DOPAC levels were significantly lower in Gnat1(-/-) mice from 2 to 12 weeks of age with DOPAC/dopamine ratio peaking earlier in Gnat1(-/-) compared to WT mice. No differences in dopamine were seen in response to FD or between genotypes. CONCLUSIONS: Functional rod photoreceptors are critical to normal refractive development and the response to FD in mice. Dopamine levels may not directly modulate the refractive state of the mouse eye, but tonic levels of dopamine during development may determine susceptibility to myopia.