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A letter to the editor is presented in response to the article related to electrophysiology assessment and neuroimaging in previous issue.

The article discusses the 'Act FAST' public education campaign launched in Great Britain in February 2009 with aim to reduce presentation time of patient with storke. Topics discussed include symptoms of sudden visual loss, occipital lobe and eye stoke, public awareness of visual manifestations of stroke and role of early diagnosis to minimize carotid endarterectomy. It also discusses the significance of improved opportunities for thrombolysis.

Background: The existence of transsynaptic retrograde degeneration (TRD) in the human visual system has been established, however the dependence of TRD on different factors such as lesion location, size and manner of lesion acquisition has yet to be quantified. Methods: We obtained T1-weighted structural and diffusion-weighted images for 26 patients with adultacquired or congenital hemianopia and 12 age-matched controls. The optic tract (OT) was defined and measured in the structural and diffusion-weighted images, and degeneration assessed by comparing the integrity of tracts in the lesioned and in the undamaged hemisphere. Results: OT degeneration was found in all patients with established lesions, regardless of lesion location. In patients with acquired lesions, the larger the initial lesion, the greater is the resulting TRD. However, this was not the case for congenital patients, who generally showed greater degeneration than would be predicted by lesion size. A better predictor of TRD was the size of the visual field deficit, which was correlated with degeneration across all patients. Interestingly, although diffusion-weighted imaging (DWI) is more frequently used to examine white matter tracts, in this study the T1- weighted scans gave a better indication of the extent of tract degeneration. Conclusions: We conclude that TRD of the OT occurs in acquired and congenital hemianopia, is correlated with visual field loss, and is most severe in congenital cases. Understanding the pattern of TRD may help to predict effects of any visual rehabilitation training. [ABSTRACT FROM AUTHOR]

Background Non-arteritic anterior ischaemic optic neuropathy (NA-AION) can cause disabling visual loss and traditionally, visual prognosis has been considered poor, although recent studies have demonstrated improvements in visual acuity in about 30% of patients over time. The aim of the study was to determine whether there was significant cortical reorganisation with functional MRI (fMRI) after acute NA-AION by comparing affected individuals with healthy controls. Methods 9 patients with NA-AION were studied acutely and then after 1, 2, 3 and 6 months. 23 healthy volunteers underwent scanning at least twice. At each time point, patients were assessed clinically and with fMRI. For the fMRI experiments, subjects underwent monocular visual stimulation (wearing goggles with flashing LED displays). Results When stimulating the affected eye, occipital activation was reduced in patients compared with controls. Also, within the NA-AION group, activation in the right Brodmann areas (BA) 44 and 45 was seen during the early phase of the condition. The same areas were activated within the NA-AION group several months later for fellow eye stimulation. When the NA-AION and healthy control groups were formally compared however, these areas (BA 44/45) were not significantly different. NA-AION subjects did show greater activation in visual related areas compared with controls when stimulating the fellow eye. Visual acuity was correlated with more occipital cortex activation when stimulating the affected eye. Conclusions There is cortical re-organisation of the fMRI response in extra-visual areas, seen when both affected and fellow eyes are stimulated after NA-AION. [ABSTRACT FROM AUTHOR]

Background: Despite corticosteroid treatment, patients with temporal arteritis may continue to lose vision. However, predictors of progressive visual loss are not known. Methods: We retrospectively reviewed 341 consecutive patients with suspected temporal arteritis who underwent temporal artery biopsy. 90 patients with biopsy proven temporal arteritis were included in our study. Results: Twenty-one patients (23%} experienced continuous visual symptoms despite steroid therapy and 14 among these suffered persistent visual deterioration. Based on univariate analysis, visual loss on presentation was associated with disc swelling and a history of hypertension. Risk factors for progressive visual loss included older age, elevated C reactive protein and disc swelling. Conclusion: Although corticosteroid therapy improves the visual prognosis in temporal arteritis, steroids may not stop the progression of visual loss. Our study reliably establishes the risk factors for visual loss in this serious condition. Whether addressing these risk factors early in their presentation can alter the visual outcome remains unknown. Individual risk anticipating treatment regimens and strategies might improve the visual prognosis in temporal arteritis in the future. [ABSTRACT FROM AUTHOR]