Developmental dyslexia in Chinese and English populations: dissociating the effect of dyslexia from language differences

Previous neuroimaging studies have suggested that developmental dyslexia has a different neural basis in Chinese and English populations because of known differences in the processing demands of the Chinese and English writing systems. Here, using functional magnetic resonance imaging, we provide the first direct statistically based investigation into how the effect of dyslexia on brain activation is influenced by the Chinese and English writing systems. Brain activation for semantic decisions on written words was compared in English dyslexics, Chinese dyslexics, English normal readers and Chinese normal readers, while controlling for all other experimental parameters. By investigating the effects of dyslexia and language in one study, we show common activation in Chinese and English dyslexics despite different activation in Chinese versus English normal readers. The effect of dyslexia in both languages was observed as less than normal activation in the left angular gyrus and in left middle frontal, posterior temporal and occipitotemporal regions. Differences in Chinese and English normal reading were observed as increased activation for Chinese relative to English in the left inferior frontal sulcus; and increased activation for English relative to Chinese in the left posterior superior temporal sulcus. These cultural differences were not observed in dyslexics who activated both left inferior frontal sulcus and left posterior superior temporal sulcus, consistent with the use of culturally independent strategies when reading is less efficient. By dissociating the effect of dyslexia from differences in Chinese and English normal reading, our results reconcile brain activation results with a substantial body of behavioural studies showing commonalities in the cognitive manifestation of dyslexia in Chinese and English populations. They also demonstrate the influence of cognitive ability and learning environment on a common neural system for reading

Epidemiology and natural history of intestinal metaplasia of the gastroesophageal junction and Barrett's esophagus: a population-based study

Objectives: Population-based data on the epidemiology and outcomes of subjects with intestinal metaplasia of the gastroesophageal junction (IMGEJ) and Barrett's esophagus (BE) are limited. The objectives of this study were to (i) estimate the incidence of IMGEJ and BE diagnosed from clinically indicated endoscopy in Olmsted County, MN, over three decades (1976–2006) and prevalence as of 1 January 2007, (ii) compare baseline characteristics of subjects with IMGEJ and BE, and (iii) study the natural history and survival of both cohorts. Methods: This was a population-based cohort study. The study setting was Olmsted County, MN. Patients with BE (columnar segment >1cm with intestinal metaplasia) and IMGEJ (intestinal metaplasia in biopsies from the gastroesophageal junction) from 1976 to 2006 in Olmsted County, MN, were identified using Rochester Epidemiology Project resources. Demographic and clinical data were abstracted from medical records and pathology confirmed by gastrointestinal pathologists. The association of baseline characteristics with overall and progression-free survival was assessed using proportional hazards regression models. Outcome measures were baseline characteristics and overall survival of subjects with IMGEJ compared to those with BE. Results: In all, 487 patients (401 with BE and 86 with IMGEJ) were identified and followed for a median interval of 7 (BE subjects) to 8 (IMGEJ subjects) years. Subjects with BE were older, heavier, reported reflux symptoms more often, and had higher prevalence of advanced neoplasia than those with IMGEJ. No patient with IMGEJ progressed to esophageal adenocarcinoma (EAC) in contrast to BE subjects who had a cumulative risk of progression of 7% at 10 years and increased risk of death from EAC (standardized mortality ratio 9.62). The overall survival of subjects with BE and IMGEJ did not differ from that expected in similar age- and sex-distributed white Minnesota populations. Conclusions: Subjects with IMGEJ appear to have distinct clinical characteristics and substantially lower cancer progression risk compared to those with BE