Friday, October 19, 2012

Childhood stimulation key to brain development, study finds

Alok Jha, science correspondent
The Guardian, Sunday 14 October 2012

Twenty-year research project shows that most critical aspect of cortex development in late teens was stimulation aged four

An early childhood surrounded by books and educational toys will leave positive fingerprints on a person's brain well into their late teens, a two-decade-long research study has shown.

Scientists found that the more mental stimulation a child gets around the age of four, the more developed the parts of their brains dedicated to language and cognition will be in the decades ahead.

It is known that childhood experience influences brain development but the only evidence scientists have had for this has usually come from extreme cases such as children who had been abused or suffered trauma. Martha Farah, director of the centre for neuroscience and society at the University of Pennsylvania, who led the latest study, wanted to find out how a normal range of experiences in childhood might influence the development of the brain.

Farah took data from surveys of home life and brain scans of 64 participants carried out over the course of 20 years. Her results, presented on Sunday at the annual meeting of the Society for Neuroscience in New Orleans, showed that cognitive stimulation from parents at the age of four was the key factor in predicting the development of several parts of the cortex – the layer of grey matter on the outside of the brain – 15 years later.

The participants had been tracked since they were four years old. Researchers had visited their homes and recorded a series of details about their lives to measure cognitive stimulation, details such as the number of children's books they had, whether they had toys that taught them about colours, numbers or letters, or whether they played with real or toy musical instruments.

The researchers also scored the participants on "parental nurturance" – how much warmth, support or care the child got from the parent. The researchers carried out the same surveys when the children were eight years old. When the participants were between 17 and 19, they had their brains scanned.

Farah's results showed that the development of the cortex in late teens was closely correlated with a child's cognitive stimulation at the age of four. All other factors including parental nurturance at all ages and cognitive stimulation at age eight – had no effect. Farah said her results were evidence for the existence of a sensitive period, early in a person's life, that determined the optimal development of the cortex. "It really does support the idea that those early years are especially influential."

As the brain matures during childhood and adolescence, brain cells in the cortex are pruned back and, as unnecessary cells are eliminated, the cortex gets thinner. Farah found that the more cognitive stimulation a participant had had at the age of four, the thinner, and therefore more developed, their cortex. "It almost looks like whatever the normal developmental process is, has either accelerated or gone further in the kids with the better cognitive stimulation," she said.

The most strongly affected region was the lateral left temporal cortex, which is on the surface of the brain, behind the ear. This region is involved in semantic memory, processing word meanings and general knowledge about the world.

Around the time the participants had their brains scanned in their late teens, they were also given language tests and, Farah said, the thinner their cortex, the better their language comprehension.

Andrea Danese, a clinical lecturer in child and adolescent psychiatry at the Institute of Psychiatry, King's College London, said the study suggested that the experience of a nurturing home environment could have an effect on brain development regardless of familial, perhaps genetic, predispositions to better brains. Danese added that this kind of research highlighted the "tremendous role" that parents and carers had to play in enabling children to develop their cognitive, social, and emotional skills by providing safe, predictable, stimulating, and responsive personal interactions with children.

"Parents may not be around when their teenage children are faced with important choices about choosing peers, experimenting with drugs, engaging in sexual relationships, or staying in education," said Danese. "Yet, parents can lay the foundations for their teenage children to take good decisions, for example by promoting their ability to retain and elaborate information, or to balance the desire for immediate reward with the one for greater, long-term goals since a young age."

Bruce Hood, an experimental psychologist who specialises in developmental cognitive neuroscience at the University of Bristol, said his advice to parents was just to "be kind to your children. Unless you raise them in a cardboard box without any stimulation or interaction, then they will probably be just fine."

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Tuesday, October 16, 2012

Autism Risk Linked To Space Between First And Second Pregnancy

Written by Christian Nordqvist

A second child is three times more likely to be diagnosed with autism if they are born within twelve months of their siblings, compared to those born three or more years apart, researchers from the Lazarsfeld Center for the Social Sciences at Columbia University, New York revealed in the journal Pediatrics. The investigators gathered information on 660,000 second children born in California between 1992 to 2002.

Sociologist Peter Bearman, and team set out to find out whether there might be a link between the length of time between the birth of one child and his/her brother or sister and autism risk. They found that in cases where pregnancies were less than 12 months apart, the risk of autism in the second-born child was three times as high, compared to pregnancies spaced at least three years apart.

They also found that pregnancy spaced between 1 to 2 years apart had double the risk of autism in the second child compared to those at least 3 years apart.

The researchers examined data from the California Department of Developmental Services to determine how many children had been diagnosed with autism.

Even when other factors that might influence autism risk were taken into account, such as the age of the mother or father, low birth weight, or being born preterm, "we see this really profound association". The authors added that they could not clearly determine what the causes might be.

Peter Bearman said:

"When you see something so robust and so stable, it provides an important clue as to what we should be looking at next."

They suggest that possibly a mother who soon becomes pregnant again may not have fully replenished crucial nutrients. Perhaps parents are better at identifying autism-like traits, such as delayed milestones, after their second child is born.

The authors explained that their study did not include autism in first-born children.

Previous studies had found a link between higher autism risk in a second child if the first child had an autism spectrum disorder, including Asperger's syndrome.

The authors concluded in the journal's abstract:

"These results suggest that children born after shorter intervals between pregnancies are at increased risk of developing autism; the highest risk was associated with pregnancies spaced <1 apart.="apart." br="br" year="year">

According to data from the CDC (Centers for Disease Control and Prevention), the incidence of autism in the USA has risen tenfold during the last four decades, to approximately 1 in every 110 children in 2006.

Although increased awareness and better diagnosing techniques account for some of the increase, Bearman believes that other factors have also had an impact.

A comprehensive study published in the BMJ (British Medical Journal) last week clearly showed that a 1998 report by Dr. Andrew Wakefield linking childhood vaccines to autism risk was "an elaborate fraud". BMJ editor in Chief, Dr. Fiona Godlee said "The MMR scare was based not on bad science but on a deliberate fraud.. (such) clear evidence of falsification of data should now close the door on this damaging vaccine scare." Link to article about the report

"Closely Spaced Pregnancies Are Associated With Increased Odds of Autism in California Sibling Births"
Keely Cheslack-Postava, PhD, MSPH, Kayuet Liu, DPhil, Peter S. Bearman, PhD
PEDIATRICS January 10, 2012 (doi:10.1542/peds.2010-2371)

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