Getting around and communicating with the environment: visual cognition and language in Parkinson's disease.

Vision in PD. In PD an impairment of dopaminergic neurons of the preganglionic retina and a defect of the retinal nerve fibers (axons of the retinal ganglion cells) has been demonstrated and a correlation of loss of spatial contrast sensitivity, with the progression of motor impairment in PD has been described. These low level visual deficits contribute but do not directly explain behavioural visual deficits in PD involving spatial cognition, internal representation, space navigation and visual categorization. Language deficits in non-demented PD patients can include impairments in comprehension, verbal fluency, and naming. Comprehension deficits become evident when patients are required to process sentences with non-canonical, irregular grammatical structures. Semantic memory deficits may result in the impairments in category fluency and confrontational naming. Selective language deficits may be due to impaired dynamics of the "phonological loop" connecting the pre-frontal cortex and the basal ganglia. A more encompassing linguistic and functional model of PD specific language impairments would be useful for evaluating language deficits in the context of motor dysfunction.

Late cognitive and radiographic changes related to radiotherapy: initial prospective findings.

BACKGROUND: Assumptions about the damaging effects of radiotherapy (XRT) are based on studies in which total dose, dose fraction, treatment volume, degree of malignancy, chemotherapy, tumor recurrence, and neurologic comorbidity interact with XRT effects. This is a prospective, long-term study of XRT effects in adults, in which total dose and dose fraction were constrained and data related to tumor recurrence and neurologic comorbidity (e.g., hypertension) were excluded. METHODS: The effects of XRT on the cognitive and radiographic outcomes of 26 patients with low-grade, supratentorial, brain tumors yearly from baseline (6 weeks after surgery and immediately before XRT) and yearly to 6 years were examined. Radiographic findings were examined regionally. RESULTS: Selective cognitive declines (in visual memory) emerged only at 5 years, whereas ratings of clinical MRI (T2 images) showed mild accumulation of hyperintensities with post-treatment onset from 6 months to 3 years, with no further progression. White matter atrophy and total hyperintensities demonstrated this effect, with subcortical and deep white matter, corpus callosum, cerebellar structures, and pons accounting for these changes over time. About half of the patients demonstrated cognitive decline and treatment-related hyperintensities. CONCLUSIONS: There was no evidence of a general cognitive decline or progression of white matter changes after 3 years. Results argue for limited damage from XRT at this frequently used dose and volume in the absence of other clinical risk factors.

Genotypes of the circulating rotavirus strains in the seven prevaccine seasons from September 2000 to August 2007 in South Korea.

A Korean nationwide surveillance on circulating rotavirus strains was conducted from September 2000 to August 2007 aiming to obtain prevaccine data for predicting vaccine effectiveness. The predominant strains among the 2779 strains analyzed varied annually and only approximately 50% had either a G or a P antigen present in both RotaTeq (Merck & Co. Inc., Whitehouse Station, NJ, USA) and Rotarix (GlaxoSmithKline, Brentford, UK).

Molecular epidemiology and genetic diversity of human astrovirus in South Korea from 2002 to 2007.

The present study was conducted to survey the prevalence and genotypic distribution of human astrovirus (HAstV) circulating in South Korea. Of 160,027 patients with acute gastroenteritis, 2,057 (1.3%) were positive for HAstV antigen. We determined the genotypes of 187 HAstV strains collected from laboratories across the country. Genetic analysis revealed genotype 1 to be the most prevalent, accounting for 72.19% of the strains, followed by genotypes 8 (9.63%), 6 (6.95%), 4 (6.42%), 2 (3.21%) and 3 (1.60%). Our findings indicate that HAstV is less common but, even so, a potentially important viral agent of gastroenteritis in South Korea, with significant genetic diversity among circulating HAstV strains.