Neurotransmitters predict reading ability

MadeleineWitt
Photo by Madeleine Witt .

New research may provide a way to predict reading disorders in children, simply by measuring the levels of certain chemicals in the brain.

A study conducted at the Yale and University of Connecticut-affiliated Haskins Laboratories discovered that higher levels of two neurotransmitters, glutamate and choline, were associated with lower reading proficiency in young children. Initial levels of glutamate continued to correlate with reading levels observed two years later. The finding is the first pediatric study to show that levels of chemicals in the brains of children that are beginning to learn to read can predict later reading outcomes, said Ken Pugh, president and director of research at Haskins Laboratories and study co-author.

“Good reading skills are very important for success in the modern world,” Pugh said. “We’re trying to solve the mystery of why reading can be so difficult for so many children who are otherwise of normal intelligence.”

The research team administered a series of behavioral tests to 75 children six to 10 years of age to measure their reading, language and cognition skills. Additionally, they conducted magnetic resonance spectroscopy (MRS) to measure the levels of a variety of chemicals in the brain. MRS is a relatively novel technique that provides researchers with a non-invasive way to identify neurotransmitter levels, said Nicole Landi, professor of psychology at the University of Connecticut and study co-author.

In the study, the researchers report a negative correlation between reading scores and concentrations of glutamate and choline. A follow-up behavioral assessment two years after the initial measurement showed that initial glutamate levels were still predictive of reading scores.

The results support previous studies on adults, which also identified elevated choline levels in individuals with reading disorders. Glutamate, a key neurotransmitter that has also been associated with disorders like ADHD, may contribute to impaired reading through excessive excitatory activity at high concentrations, Pugh said.

The researchers are cautiously optimistic about the implications these results may have for future treatments, as Pugh said they must replicate the findings before the results can be applied clinically. Even then, modulating neurotransmitter levels to improve reading would serve as only one component of a broader therapy program.

“You can’t remediate a reading problem with chemicals alone,” Pugh said. “However, it is conceivable going forward that pharmacological treatments helping the brain respond to learning opportunities will be developed.”

The study focused on a sample of children between the ages of six and 10 and is one of the first studies to study neurochemicals in humans at such a young age. Studying children is a particularly useful approach because it allows researchers to look at the brain before reading experiences have shaped the brain, said Albert Galaburda, professor of neuroscience and neurology at Harvard Medical School, who studies dyslexia.

Galaburda, who was not involved in the study, said future research should investigate whether neurotransmitters can predict reading ability in infants so that interventional treatment can begin as early as possible.

Despite the limitations of chemical-based treatment, Pugh said the study’s results provide deeper understanding of the underlying neurochemical mechanisms of reading disorders. Such knowledge can help educators facilitate reading in children who might otherwise struggle.

“My estimate would be that, in 10 years, the knowledge from neuroscience on how the brain learns will have a transformative impact on the classroom,” Pugh said.

The Haskins team will continue their research by attempting to understand reading disorders from other perspectives. Future research will involve looking into the genetic regulation of these neurotransmitters, as well as studies involving manipulation of neurotransmitters, Landi and Pugh said.

Guinevere Eden, a professor of pediatrics at Georgetown Medical Center, who was not involved in the study, praised the study for approaching the problem of reading ability from these multiple perspectives.

Haskins Laboratories has been in New Haven since 1970.

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