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Archive for July, 2017

More evidence that outdoor time may help prevent nearsightedness

Kids who spend more time outdoors and who play sports are less likely to be near-sighted, according to a recent study in a large, diverse group of urban 6-year-olds.

“Lifestyle in early youth is very much associated with onset of myopia,” says Dr. Caroline Klaver of Erasmus Medical Center in Rotterdam.

“Not being outside, and performing lots of near work will increase risk a lot.”

While factors like being highly educated and of non-European heritage have traditionally been linked to nearsightedness, the new study suggests that how young children spend their time is likely to be the underlying source of these differences, the study team writes in the British Journal of Ophthalmology.

The researchers looked at 5,711 children in Rotterdam who have been participating since birth, along with their mothers, in a long-term study. At age 6, prevalence of myopia was 2.4% (n=137). Myopic children spent more time indoors and less outdoors than non-myopic children (p<0.01), had lower vitamin D (p=0.01), had a higher body mass index and participated less in sports (p=0.03).

The researchers used statistical techniques to analyze a wide variety of factors, including social and economic aspects of the household, ethnicity, lifestyle, parents’ education levels, children’s’ activities and any links between these and the likelihood a child would be nearsighted.

The study team found that myopic children spent less time outdoors, had lower levels of vitamin D, had a higher body mass index and were less likely to play sports than children who weren’t nearsighted. While being of non-European descent, having a mother with a low education level and low family income were also associated with myopia, the researchers found that lifestyle factors explained most of these risks.

The study was limited by the low number of children with myopia and the lack of information about parents’ nearsightedness – “a well-known myopia risk factor,” the authors note.

“Differences in myopia prevalence between ethnic groups that have commonly been assumed to be down to genetics may in fact be due to differences in lifestyle between ethnic groups,” Dr. Jeremy Guggenheim, an optometry professor at Cardiff University in the UK, told Reuters Health in an email.

“The new study and other recent work suggests that this preventative effect of time outdoors is beneficial even at very young ages, e.g. 3 – 6 years-old,” said Guggenheim, who studies the causes of myopia and sometimes collaborates with Klaver’s team, but was not involved in the current study.

“Too much close work, such as reading and using hand-held devices, may also be a risk – although the jury is still out on this question,” he added.

To help prevent myopia, Klaver said, parents should have children play outside for 15 hours a week, and limit “near work” to no longer than 45 continuous minutes.

“It’s important to keep in mind that this type of study can never pin-point the precise causes of myopia in the way that is possible using purpose-designed clinical trials,” Guggenheim said. “Nevertheless, the risk factors that were identified in the new study fit neatly with what has been learned in recent years from such trials.”

“Basically this study adds very nicely to the evidence that we already see from many other studies and many other countries that there is definitely a connection between outdoor activity and myopia in children,” said Susan Vitale at the U.S. National Eye Institute.

“The main thing to remember is that if parents have any concerns about their child’s vision it’s very important that they get a dilated eye exam from a health care professional,” Vitale said. Regular eye care is the most important thing people can do to maintain their eye health, she added.

(Reuters Health)

Pictures: https://commons.wikimedia.org

SOURCE: Tideman JWL, Polling JR, Hofman A, Jaddoe VW, Mackenbach JP, Klaver CC. Environmental factors explain socioeconomic prevalence differences in myopia in 6-year-old children. Br J Ophthalmol. 2017 Jun 12. pii: bjophthalmol-2017-310292. doi: 10.1136/bjophthalmol-2017-310292.

Other studies have also looked at the relationship between time outdoor and myopia (and many more…):

• Wu PC, Huang HM, Yu HJ, Fang PC, Chen CT. Epidemiology of Myopia. Asia Pac J Ophthalmol (Phila). 2016 Nov/Dec;5(6):386-393.

• Deng L, Pang Y. The role of outdoor activity in myopia prevention. Eye Sci. 2015 Dec;30(4):137-9.

• Isaacs D, Wood N. Let’s not be short-sighted: Increased outdoor activity reduces myopia. J Paediatr Child Health. 2016 Oct;52(10):969. doi: 10.1111/jpc.13358.

• Suhr Thykjaer A, Lundberg K, Grauslund J. Physical activity in relation to development and progression of myopia – a systematic review. Acta Ophthalmol. 2016 Dec 14. doi: 10.1111/aos.13316.

• Guo Y, Liu LJ, Tang P, Lv YY, Feng Y, Xu L, Jonas JB. Outdoor activity and myopia progression in 4-year follow-up of Chinese primary school children: The Beijing Children Eye Study. PLoS One. 2017 Apr 27;12(4):e0175921. doi: 10.1371/journal.pone.0175921. eCollection 2017.

 

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Does handwriting matter?

Not very much, according to many educators. The Common Core standards, which have been adopted in most states, call for teaching legible writing, but only in kindergarten and first grade. After that, the emphasis quickly shifts to proficiency on the keyboard.

But neuroscientists say it is far too soon to declare handwriting a relic of the past. New evidence suggests that the links between handwriting and broader educational development run deep.

Children not only learn to read more quickly when they first learn to write by hand, but they also remain better able to generate ideas and retain information. In other words, it’s not just what we write that matters — but how.

“When we write, a unique neural circuit is automatically activated,” said Stanislas Dehaene, from the Collège de France in Paris. “There is a core recognition of the gesture in the written word, a sort of recognition by mental simulation in your brain.

“And it seems that this circuit is contributing in unique ways we didn’t realize,” he continued. “Learning is made easier.”

A 2012 study led by Karin James, from Indiana University, lent support to that view. Children who had not yet learned to read and write were presented with a letter or a shape on an index card and asked to reproduce it in one of three ways: trace the image on a page with a dotted outline, draw it on a blank white sheet, or type it on a computer. They were then placed in a brain scanner and shown the image again.

The researchers found that the initial duplication process mattered a great deal. When children had drawn a letter freehand, they exhibited increased activity in three areas of the brain that are activated in adults when they read and write: the left fusiform gyrus, the inferior frontal gyrus and the posterior parietal cortex.

By contrast, children who typed or traced the letter or shape showed no such effect. The activation was significantly weaker.

Dr. James attributes the differences to the messiness inherent in free-form handwriting: not only must we first plan and execute the action in a way that is not required when we have a traceable outline, but we are also likely to produce a result that is highly variable.

In another study, Dr. James is comparing children who physically form letters with those who only watch others doing it. Her observations suggest that it is only the actual effort that engages the brain’s motor pathways and delivers the learning benefits of handwriting.

The effect goes well beyond letter recognition. In a study that followed children in grades two through five, Virginia Berninger, a psychologist at the University of Washington, demonstrated that printing, cursive writing, and typing on a keyboard are all associated with distinct and separate brain patterns — and each results in a distinct end product. When the children composed text by hand, they not only consistently produced more words more quickly than they did on a keyboard, but expressed more ideas. And brain imaging in the oldest subjects suggested that the connection between writing and idea generation went even further. When these children were asked to come up with ideas for a composition, the ones with better handwriting exhibited greater neural activation in areas associated with working memory — and increased overall activation in the reading and writing networks.

Samples of handwriting by young children. Dr. James found that when children drew a letter freehand, they exhibited increased activity in three significant areas of the brain, which didn’t happen when they traced or typed the letter. Credit Karin James

It now appears that there may even be a difference between printing and cursive writing — a distinction of particular importance as the teaching of cursive disappears in curriculum after curriculum. In dysgraphia, a condition where the ability to write is impaired, usually after brain injury, the deficit can take on a curious form: In some people, cursive writing remains relatively unimpaired, while in others, printing does.

Dr. Berninger goes so far as to suggest that cursive writing may train self-control ability in a way that other modes of writing do not, and some researchers argue that it may even be a path to treating dyslexia. A 2012 review suggests that cursive may be particularly effective for individuals with developmental dysgraphia — motor-control difficulties in forming letters — and that it may aid in preventing the reversal and inversion of letters.

Two psychologists, Pam A. Mueller of Princeton and Daniel M. Oppenheimer of the University of California, Los Angeles, have reported that in both laboratory settings and real-world classrooms, students learn better when they take notes by hand than when they type on a keyboard. Contrary to earlier studies attributing the difference to the distracting effects of computers, the new research suggests that writing by hand allows the student to process a lecture’s contents and reframe it — a process of reflection and manipulation that can lead to better understanding and memory encoding.

Reflection: Instead of giving a computer for continuous use to children with academic difficulties, such as dysgraphia, the child may have to be trained to write as well as he can (while using his computer) instead of giving up! Motor training can only help the child to write better. But as today, things that do not require any effort seem to take precedence. So, it is up to you, parents, to lead this battle!

From:
Karin H. James KH, Engelhardt L. The effects of handwriting experience on functional brain development in pre-literate children. Trends in Neuroscience and Education. Volume 1, Issue 1, December 2012, Pages 32–42