of kids in residence, there may not be as much attention available. There could also be individual stressful events that even people with good resources can have in their environments — like a sick family member who’s taking up a lot of attention. What do researchers already know about early life stressors? Researchers know that early life stress can cause cognitive problems, such as with memory and attention. They’ve shown changes in brain regions involved in those functions. The new thing that’s suggested by our results is that these cognitive problems may be partly because the auditory information that’s sent to the cognitive regions is already compromised — poorly encoded by auditory brain circuits. With animal models, researchers can mimic the early life stressors that humans experience, but under controlled conditions. Separating pups from their mothers mimics neglectful environments. And unpredictable stressors are much more stressful than predictable stressors — which I confirmed with my experiments. I started by separating the pups from their mothers at the same time each day, which had a small effect. Then I decided ok, let’s mix it up and do it randomly. That changed everything. That made it a much more stressful experience, and the animals’ auditory perception became worse. How about with humans? When you’re researching stress in humans, it’s not as controlled as with animal models. So, it’s inevitably more challenging to figure out which elements of stress contribute to poor outcomes later. You have to use questionnaires to measure stress, and relate that to kids’ ability to process speech, including detecting sounds that change rapidly over time.
What’s your timeline for this project? First, my lab is using animal models to determine exactly what changes occur in the auditory parts of the brain during early life stress, and how they affect sound perception. Then we’re doing the same for the interaction of stress and hearing loss. Finally, we’re testing whether auditory training that involves exposure to specific sounds can improve animals’ sound perception. This will help us understand the best approach to help kids with ear infections in stressful environments. I’ve recently applied to the NIH to renew my current grant, which looks at an animal model of hearing loss, in order to study stress and hearing loss together. At the same time, we’re moving forward on the collaboration with Akron Children’s, with my colleague Julia Huyck, Ph.D. She is an assistant professor in speech pathology and audiology at Kent State University, who studies auditory development in kids and teenagers. Dr. Huyck is an expert on using behavior on listening tasks to evaluate hearing in kids. This project will determine how early hearing loss and early life stress interact.
What would be the best possible outcome of your research? We’re expecting to find that early hearing loss and stress together cause problems with speech perception that emerge later on — and to identify at what ages kids are most susceptible. Dr. Jeyakumar, Dr. Huyck and I hope that by identifying these problems, we can make clinicians more attentive to home environments and encourage early intervention. This would of course involve the insertion of tympanostomy tubes to alleviate the hearing loss. Additionally, clinical practices could become more aware of the home environments and help in alleviating some of that stress. They could also recommend auditory training for high-risk children. We’ll be looking into what types of auditory training regimens could help — for example, training that’s used for kids with sensory processing disorders. We’re hoping that the results from our study can inform clinical guidelines, so kids get appropriate early intervention that could make a big difference as they grow up.
HOW WILL THIS RESEARCH HELP CHILDREN? “If we could catch more of these children early without watching and waiting, with true evidence-based research showing there is a negative impact to watching and waiting, then we could change the lives of millions of kids,’’ says Dr. Jeyakumar. “We need that concrete research, because people tend to not believe that basic science research unless we can show it in humans. If we can translate that, the potential to have an impact would be huge.’’ “It would also give more support to our clinical guidelines that say, ‘Ok, if there’s fluid in the ear for this long, then do this.’ Then we can get age-specific guidelines for certain situations. For example, if there’s an older kid, we can watch and wait, but for a younger child at peak language development, we wouldn’t wait. But again, we need the evidence to support these things, because a lot of what’s out there now is very anecdotal.” – Anita Jeyakumar, M.D.
NORTHEAST OHIO MEDIC AL UNIVERSITY
11