Pediatricians say that children under age 2 should not watch television. But age is not the only factor parents should be concerned about. A new study suggests that fast-paced programming can harm executive functioning, including memory and self-regulation, at least in the short term.
Researchers from the University of Virginia randomly assigned 60 4-year-olds to spend nine minutes drawing or watching either an educational cartoon or a fast-moving cartoon. The fast cartoons were characterized by near-constant motion and a scene change averaging every 11 seconds, three times as fast as in the educational cartoon. (Think “Mr. Rogers’ Neighborhood’’ vs. “SpongeBob SquarePants,’’ an accompanying commentary suggests.)
The children were then asked to complete several tasks meant to measure how well they could remember and follow directions and whether they could wait to eat when presented with a snack. Even when the researchers used statistical methods to try to account for differences in attention span and early development, children who watched the fast cartoons received lower scores.
The researchers attribute the change both to the pace of the cartoons and the fantastical content. Understanding unfamiliar events may deplete the brain’s resources, they said.
BOTTOM LINE: Four-year-olds who watch fast-paced cartoons experience a short-term drop in memory and control.
CAUTIONS: Most of the participants were white and from middle- or upper-middle-class families. The results may not apply to older children. The study did not look at how long the effects of the cartoons last.
WHERE TO FIND IT: Pediatrics, October 2011
Depression late in life could be sign of dementia
Studies looking at a link between depression that develops in older adults and dementia have produced varying results. But a recent study led by researchers at the University of Washington found that people who become depressed late in life have a greater likelihood of developing dementia.The study enrolled 3,410 people age 65 and older in the Seattle area, without dementia. Over an average of about 7 years of follow-up, about 19 percent developed dementia.
The study found no connection between early-life depression and the development of dementia. But those who experienced depression late in life were about 46 percent more likely to develop dementia than those with no history of depression.
The authors said their results point to the possibility that late-life depression may be more than a risk factor for dementia. It may be an early manifestation of the degenerative condition, they wrote.
BOTTOM LINE: Late-life depression may be an early sign of dementia.
CAUTIONS: Symptoms of depression were self-reported by participants. People with mild cognitive impairment or the most early signs of dementia may not have been identified in the study.
WHERE TO FIND IT: Archives of General Psychiatry, September 2011
CHELSEA CONABOY
Chelsea Conaboy can be reached at cconaboy@boston.com. Follow her on Twitter @cconaboy. 
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