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Brain-imaging differences evident at 6 months in infants who develop autism

This is an image of white matter pathways extracted from diffusion tensor imaging data for infants at-risk for autism. Warmer colors represent higher fractional anisotropy. Credit: Image created by Jason Wolff, Ph.D.

A new study led by the University of North Carolina at Chapel Hill found significant differences in brain development starting at age 6 months in high-risk infants who later develop autism, compared to high-risk infants who did not develop autism.

"It's a promising finding," said Jason J. Wolff, PhD, lead author of the study and a postdoctoral fellow at UNC's Carolina Institute for Developmental Disabilities (CIDD). "At this point, it's a preliminary albeit great first step towards thinking about developing a biomarker for risk in advance of our current ability to diagnose autism."

The study also suggests, Wolff said, that autism does not appear suddenly in young children, but instead develops over time during infancy. This raises the possibility "that we may be able to interrupt that process with targeted intervention," he said.

Joseph Piven, MD, director of the CIDD, is senior author of the study.

The study was published online on Friday, Feb. 17 at AJP in Advance, a section of the website of the American Journal of Psychiatry. Its results are the latest from the ongoing Infant Brain Imaging Study (IBIS) Network, which is funded by the National Institutes of Health and headquartered at UNC. Piven received an NIH Autism Centers of Excellence (ACE) program network award for the IBIS Network in 2007. ACE networks consist of researchers at many facilities in locations throughout the country, all of whom work together on a single research question.

Participants in the study were 92 infants who all have older siblings with autism and thus are considered to be at high risk for autism themselves. All had diffusion tensor imaging – which is a type of magnetic resonance imaging (MRI) – at 6 months and behavioral assessments at 24 months. Most also had additional brain imaging scans at either or both 12 and 24 months.

At 24 months, 28 infants (30 percent) met criteria for autism spectrum disorders while 64 infants (70 percent) did not. The two groups differed in white matter fiber tract development – pathways that connect brain regions – as measured by fractional anisotropy (FA). FA measures white matter organization and development, based on the movement of water molecules through brain tissue.

This study examined 15 separate fiber tracts, and found significant differences in FA trajectories in 12 of the 15 tracts between infants who did develop autism versus infants who did not. Infants who later developed autism had elevated FA at six months but then experienced slower change over time. By 24 months of age, infants with autism had lower FA values than infants without autism.

"This evidence, which implicates multiple fiber pathways, suggests that autism is a whole-brain phenomenon not isolated to any particular brain region," Wolff said.

Provided by University of North Carolina School of Medicine

"Brain-imaging differences evident at 6 months in infants who develop autism." February 17th, 2012. http://medicalxpress.com/news/2012-02-differences-autism-brain-early-months.html

Posted by
Robert Karl Stonjek

Cranky today? Even mild dehydration can alter our moods

Most people only think about drinking water when they are thirsty; but by then it may already be too late.

Even mild dehydration can alter a person's mood, energy level, and ability to think clearly, according to two studies recently conducted at the University of Connecticut's Human Performance Laboratory.

The tests showed that it didn't matter if a person had just walked for 40 minutes on a treadmill or was sitting at rest – the adverse effects from mild dehydration were the same. Mild dehydration is defined as an approximately 1.5 percent loss in normal water volume in the body.

The test results affirm the importance of staying properly hydrated at all times and not just during exercise, extreme heat, or exertion, says Lawrence E. Armstrong, one of the studies' lead scientists and a professor of physiology in UConn's Department of Kinesiology in the Neag School of Education.

"Our thirst sensation doesn't really appear until we are 1 [percent] or 2 percent dehydrated. By then dehydration is already setting in and starting to impact how our mind and body perform," says Armstrong, an international expert on hydration who has conducted research in the field for more than 20 years. "Dehydration affects all people, and staying properly hydrated is just as important for those who work all day at a computer as it is for marathon runners, who can lose up to 8 percent of their body weight as water when they compete."

Separate groups of young women and men were tested. Twenty-five women took part in one study. Their average age was 23. The men's group consisted of 26 men with an average age of 20. All of the participants were healthy, active individuals, who were neither high-performance athletes nor sedentary – typically exercising for 30 to 60 minutes per day.

Each participant took part in three evaluations that were separated by 28 days. All of the participants walked on a treadmill to induce dehydration, and all of the subjects were hydrated the evening before the evaluations commenced. As part of the evaluation, the subjects were put through a battery of cognitive tests that measured vigilance, concentration, reaction time, learning, memory, and reasoning. The results were compared against a separate series of tests when the individuals were not dehydrated.

In the tests involving the young women, mild dehydration caused headaches, fatigue, and difficulty concentrating, according to one of the studies, which appears in the February issue of The Journal of Nutrition. The female subjects also perceived tasks as more difficult when slightly dehydrated, although there was no substantive reduction in their cognitive abilities.

In the tests involving the young men, mild dehydration caused some difficulty with mental tasks, particularly in the areas of vigilance and working memory, according to the results of the second UConn study. While the young men also experienced fatigue, tension, and anxiety when mildly dehydrated, adverse changes in mood and symptoms were "substantially greater in females than in males, both at rest and during exercise," according to the study. The men's study was published in the British Journal of Nutrition in November 2011.

"Even mild dehydration that can occur during the course of our ordinary daily activities can degrade how we are feeling – especially for women, who appear to be more susceptible to the adverse effects of low levels of dehydration than men," says Harris Lieberman, one of the studies' co-authors and a research psychologist with the Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine in Natick, Mass. "In both sexes these adverse mood changes may limit the motivation required to engage in even moderate aerobic exercise. Mild dehydration may also interfere with other daily activities, even when there is no physical demand component present."

Why women and men are so adversely affected by mild dehydration is unclear, and more research is necessary. But other research has shown that neurons in the brain detect dehydration and may signal other parts of the brain regulating mood when dehydration occurs. This process could be part of an ancient warning system protecting humans from more dire consequences, and alerting them to the need for water to survive.

In order to stay properly hydrated, experts like Armstrong recommend that individuals drink eight, 8-ounce glasses of water a day, which is approximately equivalent to about 2 liters of water. People can check their hydration status by monitoring the color of their urine. Urine should be a very pale yellow in individuals who are properly hydrated. Urine that is dark yellow or tan in color indicates greater dehydration. Proper hydration is particularly important for high-risk groups, such as the elderly, people with diabetes, and children.

Provided by University of Connecticut

"Cranky today? Even mild dehydration can alter our moods." February 17th, 2012. http://medicalxpress.com/news/2012-02-cranky-today-mild-dehydration-moods.html

Posted by
Robert Karl Stonjek

Maternal depression and bilingual households can impact infant language development

While babies are born ready to learn any of the world's languages, the crucial developmental period when they attune to their native languages can change due to environmental influences such as maternal depression or a bilingual upbringing, according to new University of British Columbia research.

The findings, presented today at the American Association for the Advancement of Science (AAAS) Annual Meeting in Vancouver, B.C., is among the first to explore the impacts of maternal mental health and antidepressant exposure on the mechanics of early language acquisition. The preliminary findings provide important new insights into early childhood development and mother's mental health and will inform new approaches to infant language acquisition, the researchers say.

Previous research by UBC Psychology Prof. Janet Werker has found that during the first months of life, babies rapidly attune to the language sounds they hear and the sights they see (movements in the face that accompany talking) of their native languages. After this foundational period of language recognition, babies begin focusing on acquiring their native tongues and effectively ignore other languages.

However, in findings from two studies, Werker reports that this key developmental period – which typically ends between the ages of eight and nine months – can change. In one study, Werker finds the period lasts longer for babies in bilingual households than in monolingual babies, particularly for the face recognition aspects of speech.

In another study, Werker and collaborators at the Child & Family Research Institute (CFRI) at BC Children's Hospital and Harvard University find that maternal depression and its treatment with common antidepressant medication – serotonin reuptake inhibitors, or SRIs – can also affect the timing of speech perception development in babies. The team's preliminary findings suggest that SRI treatment may accelerate babies' ability to attune to the sounds and sights of the native language, while maternal depression untreated by SRIs may prolong the period of tuning.

"At this point, we do not know if accelerating or delaying the achievement of these milestones of early infancy has any consequences on later language acquisition," says Werker, noting that she aims to address such questions in future studies. "However, these preliminary findings highlight the importance of environmental factors on infant development and put us in a better position to support not only optimal language development in children but also maternal well-being."

This study followed three groups of mothers – one being treated for depression with SRIs, one with depression not taking antidepressants and one with no symptoms of depression. By measuring changes in heart rate and eye movement to sounds and video images of native and non-native languages, the researchers calculated the language development of babies at three intervals, including six and 10 months of age. Researchers also studied how the heart rates of unborn babies responded to languages at the age of 36 weeks in the uterus.

"Poor mental health during pregnancy is a major public health issue for mothers and their families" says co-author Dr. Tim Oberlander, a professor of developmental pediatrics at UBC and CFRI. "Non-treatment is never an option. While some infants might be at risk, others may benefit from mother's treatment with an SRI during their pregnancy. We are just not sure at this stage why some but not all infants are affected in the same way. It is really important that pregnant women discuss all treatment options with their physicians or midwives."

Provided by University of British Columbia

"Maternal depression and bilingual households can impact infant language development." February 17th, 2012.http://medicalxpress.com/news/2012-02-maternal-depression-bilingual-households-impact.html

Posted by
Robert Karl Stonjek