Untreated poor vision may be a contributing factor to late-life dementia and Alzheimer’s disease, a study in the February 11 online American Journal of Epidemiology found. Using data from the Health and Retirement Study and Medicare files from 1992 to 2005, researchers tracked the visual health of 625 elderly subjects with normal cognition for an average span of 8.5 years. Subjects with very good or excellent vision at baseline had a 63% reduced risk of dementia. Those with poorer vision who did not seek ophthalmologic treatment had a 9.5-fold increased risk of developing Alzheimer’s disease and a fivefold greater risk of cognitive impairment without dementia. Poorer vision without a previous eye procedure increased the risk of Alzheimer’s disease fivefold. In study subjects ages 90 years or older, 77.9% who maintained normal cognition had at least one previous eye procedure, compared with 51% of those who developed Alzheimer’s disease.

Behavioral signs of autism are not present from birth to age 6 months, but emerge with significantly declining trajectories over time, according to a study in the March issue of the Journal of the American Academy of Child and Adolescent Psychiatry. In a prospective longitudinal study, researchers compared 25 infants, who were later diagnosed with an autism spectrum disorder (ASD), with 25 gender-matched, low-risk control children, later determined to have typical development. Subjects were evaluated via videos taken at 6, 12, 18, 24, and 36 months. Researchers rated children based on frequency of gaze to faces, social smiles, and directed vocalizations. Both groups were similar at 6 months of age, but those with ASD declined significantly by 12 months of age. “Although repeated evaluation documented loss of skills in most infants with ASD, most parents did not report a regression in their child’s development,” the study authors wrote. “More children may present with a regressive course than previously thought, but parent report methods do not capture this phenomenon well.”

Treating children who have intractable epilepsy with a ketogenic diet appears to have no long-term adverse effects, researchers reported in the February 1 online Epilepsia. The investigators recruited questionnaires and laboratory reports from patients who were treated with the diet at Johns Hopkins Hospital between November 1993 and December 2008. Of the 101 responders (median age, 13), 96% would recommend the diet to others; however, just slightly more than half would have started the diet before trying anticonvulsants. The respondents’ mean total cholesterol was normal at 158 mg/dL, although most lipid levels were abnormal during the diet.

Elderly individuals who experience spontaneous alterations in cognition, attention, and arousal are 4.6 times more likely to have dementia, according to research published in the January 19 Neurology. In a study of 511 subjects (mean age, 78.1) at the Washington University Alzheimer Disease Research Center, investigators assessed patients for dementia using the Clinical Dementia Rating (CDR) and a neuropsychologic test battery. Participants also filled out the Mayo Fluctuations Questionnaire to assess cognitive changes and the Mayo Sleep Questionnaire to determine daytime alertness levels. Those presenting with disorganized, illogical thinking were 7.8 times more likely to have a CDR rating greater than 0. The incidence of a CDR rating of 0.5 was 13.4 times greater in patients with fluctuations than in those without, and a CDR 1 rating was associated with a 34-fold increase in patients with fluctuations.

An increase in brain magnesium enhances both short-term synaptic facilitation and longer-term potentiation and improves learning and memory functions, according to data published in the January 28 Neuron. In a study of young and old rats, researchers found that increasing brain magnesium using magnesium-L-threonate (MgT), a novel magnesium compound, enhanced learning ability, working memory, and short- and long-term memory in rats. “MgT treated rats had higher density of synaptophysin-/synaptobrevin-positive puncta in DG and CA1 subregions of the hypocampus that were correlated with memory improvement,” the authors wrote. “Functionally, magnesium increased the number of functional presynaptic release sites, while it reduced their release probability.” In addition, the researchers noted that when combined with upregulation of NR2B-containing NMDA receptors, MgT further enhanced synaptic plasticity.

A defect in the peroxisome proliferator-activated receptor-gamma (PPAR-gamma) signaling in Cftr-deficient mice can be corrected with rosiglitazone, which helped reduce the severity of the cystic fibrosis phenotype, investigators reported in the February 14 online Nature Medicine. Cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane conductance regulator. Treatment with the synthetic PPAR-gamma ligand rosiglitazone partially normalized the altered gene expression patterned, reducing disease severity. Although the drug had no effect on chloride secretion in the colon, it increased expression of the genes encoding carbonic anhydrases 4 and 2, increased bicarbonate secretion, and reduced mucus retention.

—Rebecca K. Abma

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