Case Report: Visual Snow Syndrome after Repetitive Mild Traumatic Brain Injury.

SIGNIFICANCE: Visual snow syndrome is a recently recognized condition with its own diagnostic criteria, evolving pathophysiologic research, and potential treatment options. PURPOSE: This report documents a rare but likely underdiagnosed condition called visual snow syndrome. A review of the current literature on pathophysiology and treatments is discussed. CASE REPORT: A 40-year-old Whiteman started experiencing symptoms of constant pulsating pixels throughout his entire visual field approximately 3 weeks after a series of mild concussions. In addition, he experienced a persistence of images and photosensitivity. The patient had normal eye examination results, visual fields, and retinal imaging result. Brain MRI, magnetic resonance angiography, electroencephalography, and cerebrospinal fluid analysis were unremarkable. A positron emission tomography scan demonstrated hypometabolism in the posterior parietal lobes and left posterior cingulate gyrus. Pharmacological treatment with antiepileptic and migraine medications was unsuccessful. Tinted lenses were essentially ineffective with a 10% reduction in symptoms reported with the use of a custom blue-tinted lens.Vision rehabilitation aids with optical character recognition were used for prolonged reading needs. CONCLUSIONS: Although rare, visual snow syndrome should be considered in all patients reporting continuous pixelations in their vision for more than 3 months, especially when accompanied by at least two of the following: photosensitivity, palinopsia, enhanced entopic phenomena, or nyctalopia. The pathophysiology is still unclear at this point, with evidence suggesting a link to the secondary visual cortex, specifically the lingual gyrus. More studies are needed to determine the exact cause, especially studies that separate visual snow syndrome patients with and without comorbid migraine. Because the pathophysiology is unclear, the treatment course is also unclear. Anecdotal evidence may suggest that tinted lenses may be of some value.

Effects of obesity on body temperature in otherwise-healthy females when controlling hydration and heat production during exercise in the heat.

BACKGROUND: Previous studies investigating body temperature responses in obese individuals during exercise in the heat fail to control metabolic heat production or hydration status during exercise. PURPOSE: To determine if there are differences in body temperature responses between obese and non-obese females when controlling metabolic heat production during exercise. METHODS: Twenty healthy females, ten obese (43.5 ± 4.5 % fat, 77.5 ± 14.4 kg) and ten non-obese (26.3 ± 6.2 % fat, 53.7 ± 6.4 kg), cycled for 60 min in a warm environment (40 °C, 30 % humidity) at a work load that elicited either 300 W of metabolic heat production (fixed heat production; FHP) or 175 W/m(2) of skin surface area (body surface area, BSA). Before and during exercise, rectal temperature (T re), mean skin temperature (T sk), oxygen uptake (VO2), and sweat rate were measured. Fluid was provided throughout exercise so that euhydration was maintained throughout. RESULTS: In the FHP trial, when absolute heat production was similar between obese (287 ± 15 W) and non-obese (295 ± 18 W) individuals (P > 0.05), there were no differences at the end of exercise in T re (38.26 ± 0.40 vs. 38.30 ± 0.30 °C, respectively) or T sk (36.94 ± 1.65 vs. 35.85 ± 0.67 °C) (all P > 0.05). In the BSA trials, relative heat production was similar between obese and non-obese individuals (168 ± 8 vs. 176 ± 5 W/m(2), respectively; P > 0.05). Similar to the FHP trials, there were no differences between obese and non-obese T re (38.45 ± 0.33 vs. 38.08 ± 0.29 °C, respectively) or T sk (36.82 ± 1.04 vs. 36.11 ± 0.64 °C) at the end of exercise (all P > 0.05). CONCLUSIONS: When obese and non-obese females exercised at a fixed metabolic heat production and euhydration was maintained, there were no differences in body temperature between groups.