But do they work?

The journal Archives of Pediatrics and Adolescent Medicine just published a study conducted by a team of researchers at the University of California at Riverside. The study included 95 babies/toddlers between the ages of 12 and 25 months. These children were randomly assigned to a Baby Wordsworth DVD condition or to a no DVD group. Parents of the children in the DVD group were asked to use the Baby Wordworth DVD as they would use any other media at home. The no DVD group simply completed a series of laboratory tasks but were not provided with a dvd to watch at home.  The study lasted for 6 weeks. Before and after the 6 weeks, the children went through a battery of tests and the parents completed a series of scales designed to measure the baby’s language and cognitive skills.

The results:

1.      By the end of the 6 weeks,  there was no difference between those infants who were repeatedly exposed to the dvd and those who were not exposed to the dvd in regards to their general language and cognitive abilities.

The above finding is not really surprising as it would be unrealistic to expect that the dvd would have a major impact on the children’s cognitive or language function in just 6 weeks. So a better question would be: Does the dvd help children learn those 30 words?

2.      By the end of the 6 weeks, those infants who watched the dvd during this time were not more likely than those who didn’t watch the DVD to say the words, recognize the words, or identify the words using pictures of the objects.

The findings suggest that the educational DVD does not facilitate the learning of these words by infants when exposed to the dvd in a naturalistic setting for 6 weeks. So far, I had not been surprised by these results, but I was a bit surprised by the following:

3.      Those infants exposed to the dvd at an earlier age (closer to 12 months) had lower overall language scores at the end of the 6 weeks than those exposed to the dvd at a later age (closer to 24 months) or those not exposed at all.

This seems to suggest that early exposure to the dvd can actually negatively impact language development. Although a couple of previous studies have found similar effects, this study is critical because it helps us answer one key question: does early exposure to the dvd affect language development or do children with language delays simply tend to watch more tv/dvds? For example, it is possible that parents of children who have more language delays buy the educational DVDs in order to help their children. If this is the case, there would be an association between watching dvds and language delays, but it would not be the DVD that contributed to the language delay. But this study suggests that this may not be the case because the participants in this study were randomly assigned to the DVD or the no DVD group. That is, in this study, the use of the DVD is unlikely to be due to parental concerns about the children’s language development.

So what can explain the possible detrimental effects of watching these educational dvds at an early age? The authors mentioned a couple of possibilities. It is possible that having the dvd as a tool kept the parents from engaging verbally with the infants leading to a delay in language development. It is also possible that the dvd lacks one major component of the language learning process: The Authors explain:

Regarding word learning specifically, a large body of language acquisition research suggests infants are more likely to learn words for novel objects if a speaker is looking at an object rather than attending elsewhere or looking directly at the child.18 Thus, learning words from a television screen requires children to be paying attention to the screen and also to be aware of the relevant referent object to which the on-screen labeler is referring. In the case of the DVD used in this study, the onscreen character looked directly at the children and signed the name for the object while a voice-over spoke the label. This scenario is very different from the optimal word learning scenario for children younger than 2 years.

Regardless of the reason, the results of this and previous studies seem to suggest that exposing young infants to television, even when such media was specifically designed as an educational tool for babies, may be associated with a delay in language development.
The reference: Richert, R., Robb, M., Fender, J., & Wartella, E. (2010). Word Learning From Baby Videos Archives of Pediatrics and Adolescent Medicine DOI: 10.1001/archpediatrics.2010.24

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As you know, the brain has two lobes. The studies show that music engages both hemispheres of the brain — its creativity and emotion engage the right lobe, while rhythm and pitch engage the left. So people who receive musical exposure at a young age develop a bundle of nerves that connects those two halves*

*I should go on, but I must note that the only thing correct in the above quote is that music indeed engages both hemispheres of the brain.

Since then, the effect of Mozart on intelligence was discredited. In fact, a comprehensive meta-analysis (a statistical reviews of previous studies on the topic) concluded that listening to Mozart actually had no effect on intelligence.

Yet, something very positive came out of these studies. Soon after, a series of studies showed that Mozart improves performance in some people because of its calming effects. That is, listening to mozart reduces stress in many people, and for those who are anxious, such reduction in stress would lead to better performance (e.g., whether a test or a sporting event). Other studies also showed that playing Mozart to at risk infants (premature or those with severe medical complications) resulted in better medical outcomes, such as fewer hospitalization days and more rapid weight gain.  Yet, researchers have not been able to identify the actual mechanisms that explain why premature babies react this way to Mozart.

In the last issue of the journal Pediatrics, there was a very small yet fascinating study on the effects of Mozart on premature babies. A team in Tel Avid was interested in examining whether changes in metabolic efficiency could explain the better outcomes observed among premature babies exposed to Mozart. In the study, the authors examined 20 preterm infants with a mean gestational age at birth of 29 weeks (range 26-35) and who were otherwise medically stable. At the time of the study, the infants were at a chronological gestational age of 30 to 37 weeks.  The methodology involved a “randomized cross-over design”. This means all babies where tested in both conditions during 2 consecutive days at the same time of the day. Some babies listened to Mozart during day 1 and underwent the no music condition during day 2, while other babies experienced the no music condition during day 1 and listened to Mozart during day 2.

The results:

The authors found that within 10 minutes of the start of the music the infants experienced an average of a 10-13% reduction in their “Resting Energy Expenditure” (REE). REE is often considered a measure of the amount of calories required to function during a specific time period during resting conditions. How could this contribute to our understanding of the Mozart effect on premature babies? If a baby reduces his/her REE, the baby then requires LESS calories to function. Imagine for a second that you require 2000 calories to function during the day. If you eat a 2,000 calorie diet, you would theoretically maintain your weight. Now imagine that you reduce your REE so now you only require 1,500 calories to function, yet you continue to eat the 2,000 calories (I think we call this aging!). What would happen? A similar process may be at play with these infants. It is possible that exposing the infants to Mozart reduces their REE and this results in a higher ratio of ‘consumed calories’ to ‘calories used’, and thus more rapid weight gain and better medical outcomes.

Although this is a very compelling study, the authors warned that more research is necessary with larger samples. Yet, these findings, combined to previous findings showing improved medical outcomes among at-risk infants exposed to music, makes you wonder whether neonatal intensive care units should consider music exposure as standard practice for at risk infants.

The Reference:

Lubetzky, R., Mimouni, F., Dollberg, S., Reifen, R., Ashbel, G., & Mandel, D. (2009). Effect of Music by Mozart on Energy Expenditure in Growing Preterm Infants PEDIATRICS, 125 (1) DOI: 10.1542/peds.2009-0990

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In the latest issue of the journal of the American Academy of Pediatrics there is a new epidemiological examination of the association between prematurity and autism that highlights the point I was making to my students. There are a number of studies that have found a link between prematurity and autism, in that premature babies are at greater risk for developing autism than full term babies. However, other studies have failed to replicate such findings. What could explain such discrepancy? One possibility is that it is not about being premature that increases the risk for autism, but instead such increased risk is due to complications and other factors associated with prematurity. If these variables have not been controlled similarly across studies then you will find studies providing conflicting results due to unknown, or uncontrolled, characteristics of the sample.

In the study published in Pediatrics, a Swedish team of researchers examined a population sample of 1,216 individuals with a autism spectrum diagnosis and over 6,000 non affected peers. These groups were similar in sex distribution, age, and most importantly: birth hospital. This is key, because it theoretically eliminates the possibility that any differences found between the groups are due to differences in the health services received during birth.  The authors first compared the risk for autism spectrum disorders associated with prematurity, and then examined whether specific neonatal complication factors could explain the observed risk.

Main finding:

1. Being born at or before 31 weeks of gestation doubled the risk for developing an autism disorder  when compared to full term infants.
2. Being born between 32 and 36 weeks of gestation increased the risk for an autism disorder by 55%.

However:

After adjusting (controlling) for neonatal complications and related factors, being born prematurely – even before 32 week gestation – DID NOT increase the risk of developing autism. That is, prematurity itself was not associated with autism once we take into account specific complications that are common among premature infants.

So what are the neonatal factors associated with autism risk?

While controlling for all neonatal and related factors:

1. Low weight for gestational age was a risk factor for autism. Specifically, being small for gestational age increased the risk for developing autism by 86%.
2. Having congenital malformations increased the risk by 106%
3. Having intra-cranial bleeding, edema, or seizures increased the risk by 206%
4. Having Hypoglycemia increased the risk for ASD by 120%

The following neonatal factors were NOT associated with an increased risk for autism: Jaundice, respiratory distress, infections, head and neck injuries during delivery, apgar score, being a twin, or being large for gestational age.

The results are consistent with other findings suggesting that “weight for gestational age” and related complications are more informative when estimating the probability of future neurodevelopmental disorders than simply being premature. This may also help explain why many premature babies don’t show any lasting effects, even when they are born severely premature (<32 weeks), while others have significant developmental complications  (autism, ADHD, learning disabilities) even when they are born only a few weeks premature.

Buchmayer, S., Johansson, S., Johansson, A., Hultman, C., Sparen, P., & Cnattingius, S. (2009). Can Association Between Preterm Birth and Autism be Explained by Maternal or Neonatal Morbidity? PEDIATRICS, 124 (5) DOI: 10.1542/peds.2008-3582

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Deficits in executive functioning has been examined as a possible source of impairment in premature children. However, executive functioning is a broad term that refers to a number of cognitive processes, such as working memory, cognitive control, planning and organizing, etc, and it is unknown which of these components of executive functioning is particularly affected in preterm children.

The Journal of Abnormal Child Psychology recently published a comprehensive study of executive functioning among children born very preterm (less than 30 weeks gestation). The study included 50 premature children (27 boys, 23 girls) born at a mean gestational age of 28 weeks (range 25 to 30). The study also included 50 comparison children born at a mean gestational age of 37.7 weeks.  All children were about 6 years of age at the time of the study. Both groups completed a comprehensive battery of executive functioning tests (the Go/NoGo test, the Shape School task, the day-night stroop task. a verbal fluency task, Digit span, and the Object Classification Task for children). The children also completed a full IQ test (the WPPSI-R)

The Results:

Before controlling for processing speed and IQ, the premature children had significantly lower performance on tasks examining: accuracy and efficiency of cognitive switching, accuracy and efficiency of inhibitory control, verbal fluency, working memory, and concept categorization.

After controlling for processing speed and IQ separately, most of the previously observed differences remained, indicating that these deficits are not due to speed of processing or overall IQ. The only exception was efficiency in cognitive shifting, which was not different between these kids after controlling for processing speed.

The data suggest that impairments in executive functioning may be one of the underlying mechanism that contribute to the type of challenges that these children experience throughout childhood. However, the authors also raised one very interesting point. It is possible that these results do not reflect a stable pattern of deficits, but instead reflect a developmental lag. That is, these very preterm babies may just be delayed in the development of executive functioning skills and may not show the same patterns of deficits later in life.

The Reference: Aarnoudse-Moens, C., Smidts, D., Oosterlaan, J., Duivenvoorden, H., & Weisglas-Kuperus, N. (2009). Executive Function in Very Preterm Children at Early School Age Journal of Abnormal Child Psychology DOI: 10.1007/s10802-009-9327-z

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Most of the original research reports on infant movements have been focused on motor problems. It makes sense that motor movements would reflect the development of motor regions of the brain. However, some researchers have suggested that infant movements also reflect the integrity of regions of the brain near the motor cortex that are in charge of cognitive and emotional control. Thus, it is sensible to predict that anomalies in infant motor movements may also predict cognitive and social functioning later in life.

In an upcoming issue of the Journal of Child Psychology and Psychiatry, Dr. Phillipa R. Butcher and a team from the University of Groningen report findings from a large longitudinal study of preterm infants. The authors used video tapes made at 11 to 16 weeks post-term in 65 infants born at or before 33 weeks of gestation. These infants were the followed for many years and completed a battery of neurocognitive tests when they were 7 to 11 years of age.

The authors were primarily interested in three types of movements:

1. Fidgeting Movements: These are small, circular movements of varying speed that appear around 6 weeks post-term.

2. Concurrent Movements. At this age, normative concurrent movements included kicking, manipulating clothing, and playing with fingers.

3. Concurrent Postural Patterns. These include for example the ability to hold the head in the midline and manipulating fingers so that the fingers are independent of one another (as opposed to always having the fists closed or open).

The results:

1. While controlling for maternal IQ and attention problems, an index of motor quality score was a significant predictor of total IQ, Verbal IQ, and Performance IQ when the child was between 7 and 11 years of age.
2. This association was driven exclusively by the presence and absence of normal and atypical postural patterns. That is, fidgeting movements and concurrent movements did not predict IQ, but it was postural patterns that was the strong predictor of IQ.
3. There was no association between infant movements and behavior or emotional problems during middle childhood (internalizing and externalizing behavior problems).

The graphic below present a very clear picture of the findings. Note for example that the proportion on children with IQ in the 100 to 115 rage increased linearly as a function of the presence of normal postural patterns during infancy. Among those with less than 2 patterns, none of the children scored in the 100 to 114 rage, while among those with more than 2 postural patterns more than 50% of the children scored in that 100-114 range.

IQ scores as a function of infant postural patterns

The authors then commented on one additional important finding. The association between postural patterns and IQ was not explained by the presence of neurological problems. That is, even among the kids without clear neurological problems (such as Cerebral Palsy), infant movements still predicted IQ scores. These findings have important implications of preventive interventions. For example, the careful examination of infant motor patterns may help us determine which children may be at higher risk for cognitive deficits and could benefit from  intensive early intervention programs.
The Reference: Butcher, P., van Braeckel, K., Bouma, A., Einspieler, C., Stremmelaar, E., & Bos, A. (2009). The quality of preterm infants’ spontaneous movements: an early indicator of intelligence and behaviour at school age Journal of Child Psychology and Psychiatry DOI: 10.1111/j.1469-7610.2009.02066.x

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