August 18, 2011

The Recurrence Risk for Autism Between Siblings

Andrew Adesman, MD

About one in 110 US children has been diagnosed with an autism spectrum disorder (ASD), and children who have an older sibling diagnosed with ASD are more likely to receive that diagnosis, according to a study just published online by the journal Pediatrics.

Using data from 12 different sites internationally, this large, well-designed study of families with an older child with an autism spectrum disorder employed a systematic and rigorous approach to evaluating the recurrence risk for an autism spectrum disorder in subsequent children when evaluated at age 3.

This study found a higher than expected recurrence rate for an ASD. Whereas prior research has suggested that the recurrence rate for another child with an autism spectrum disorder ranges from 3 percent to 10 percent, this study suggests the overall recurrence rate is 18.7 percent. Recurrence risks were found to be especially high for boys and in families with more than one affected child. In this study, there was almost a three-fold greater risk for an ASD in later male children compared to female children (26.2 percent vs. 9.1 percent, respectively). In families with two or more older children, there was a much higher risk of recurrence if two older children had an ASD compared to households with only one affected older child (32.2 percent vs. 20.1 percent).

To the extent that recurrence risks were found to be higher than previously reported, these new findings must be rather sobering and disconcerting for parents who have one or more children with an ASD and who are considering having another child. Full Post - to Detail View

July 29, 2011

Innovative Study Looks at How the Brain Communicates with Itself

Ashesh Mehta, MD

In today’s world, networks operate in diverse situations, from communication networks that permit a cell phone conversation to social networks that link friends on Facebook. These networks have properties (e.g., each computer in your home with a wireless network) and hubs, where multiple separate sub-networks come together (e.g., a person who bridges multiple social networks). 

It is increasingly being recognized that these properties operate in our brain too – in both normal functioning and as a mechanism for disorders of the nervous system, like the spread of seizures across the brain. Functional magnetic resonance imaging (fMRI) is a non-invasive method that can be used to measure the tiny metabolic changes that take place in an active part of the brain. To date, fMRI has been typically used to study what parts of the brain become active when subjects respond to stimuli (e.g., being shown pictures) or perform tasks (e.g., rotating objects in their mind’s eye). Recently, there has been interest in looking at how the brain works at rest, by measuring the fMRI signals in different brain regions and seeing how they activate and deactivate together. By measuring the relationship of activity between different brain areas, it is possible to describe an individual’s brain network, including sub-networks where brain areas with higher correlation are more closely connected (much like friends in a social network). While this has been studied extensively with fMRI, results have been difficult to interpret, because of the unclear relationship between fMRI signals and brain electrical activity. 
 
Validation of this fMRI methodology has recently taken a major step forward, with the findings published in a recent issue of Full Post - to Detail View

July 18, 2011

Taking Antidepressants During Pregnancy May Cause Autism

Natalie Meirowitz, MD

A study recently performed by researchers at Stanford University found that environmental factors could be a possible cause of autism. The study, which was published recently in Archives of General Psychiatry, defined “environmental” factors as anything unrelated to genetic code. These factors could include advanced maternal or paternal age, assisted reproductive technology, artificial insemination and giving birth to multiples.

Another environmental factor that could cause an even greater risk of autism is the intake of antidepressants during pregnancy. The risk was three times higher if mothers took medication during early pregnancy, compared to children without the developmental disorder.

But even though taking antidepressants during pregnancy could harm the baby, going off the antidepressants could harm the baby as well as the mother in many ways. It may not be the best choice for mothers to go off their medication when pregnant. If they do, they may self-medicate in other ways such as using drugs and alcohol, failing to eat right and failing to keep their prenatal appointments.

The decision to stop medications must be carefully considered between the patient, her psychiatrist, obstetrician and significant other. Full Post - to Detail View