The holiday party season is over. But for Maria Neimark Geffen, PhD, assistant professor of Otorhinolaryngology: Head and Neck Surgery at the Perelman School of Medicine, the party must go on.
The focus of Dr. Geffen’s research is on understanding how the brain processes sound information in the natural world. An example of how this research impacts everyone is a relatively common phenomenon known as the “cocktail party effect.”
“When we walk into a crowded room, such as a noisy cocktail party, and begin a conversation with another person, it takes our ears and brain time to process what the other person’s voice is saying against the background of the other voices," says Dr. Geffen. “It may seem simple enough, yet it is an astonishing feat of our auditory system that we are able to do it at all.”
The cocktail party effect poses a particular problem to people who are hard of hearing, even if they are wearing hearing aids. As soon as they walk into a crowded room, they have trouble picking up the voice of their conversation partner from the noisy background. So for anyone with a hearing deficit, attending a social gathering can be a stressful endeavor if they fear they won’t be able to understand and interact with their fellow partygoers.
In steps the importance of neuro-auditory research.
Dr. Geffen’s research gets at two questions - How does the brain process sounds, such as a person’s voice, and attribute it to a specific source? And, how does the brain discard unnecessary information about the background?
Dr. Geffen and Mark Aizenberg, PhD, a postdoctoral fellow at Penn, in the lab
In a natural environment, sounds have a very specific physical structure. Dr. Geffen had previously discovered that natural sounds are fractal in their nature, as the same pattern is repeated at many different scales. Her research shows that neurons in the brain are tuned to detect those patterns in the auditory system. To test new theories, Dr. Geffen and her colleagues in the Penn Medicine Hearing Sciences Center use a variety of techniques across disciplines, including statistical analysis of natural auditory scenes; recording and analysis of responses of multi-neuronal ensembles in the auditory cortex of animal models; animal model behavioral studies; and psychophysical experiments with human subjects.
It all sounds very technical, but Dr. Geffen’s research has direct implications for clinical care.
“It is important to identify how neuronal ensembles are functioning, because people who have hearing issues experience deficits in central auditory processing,” said Dr. Geffen. “Understanding how the normal brain processes information about complex sounds can help physicians to treat patients with peripheral hearing deficits and improve the design of cochlear implants.”
Dr. Geffen says her research may also help to develop new types of cortical implants – devices that are implanted directly into the brain and help our natural organs, eyes and ears, function better by transmitting sensory information directly into the part of the brain that processes those signals.