As we age, our brains become slower to process incoming information, especially in challenging environments, such as when we are trying to understand a conversation in a crowded restaurant or bar. This phenomenon, called neural slowing, is a natural part of getting older. Hearing aids can make sounds louder, but they cannot compensate for slower speed of neural processing.
But, before giving up on going out, you should know that there is good news: You can train your brain to hear better.
Dr. Samira Anderson, an assistant professor in BSOS’s Department of Hearing & Speech Sciences, recently published the results of her dissertation work, “Reversal of Age-Related Neural Timing Delays with Training,” in Proceedings of the National Academy of Sciences. The study, carried out at Northwestern University’s Auditory Neuroscience Laboratory, focused on the effects of auditory training on the brain’s ability to rapidly process sound. Essentially, auditory training involves teaching the brain to listen. For those with unimpeded hearing, this normally occurs early in life and is part of a young child’s rearing. Later in life, or for those who require additional support, auditory training is usually supervised by an audiologist or speech-language pathologist and involves exposure to stimuli and coaching to help individuals identify and distinguish sounds.
Dr. Anderson’s research included 67 adults between the ages of 55 and 70. They completed in-home computerized training for 40 hours over eight weeks. The training involved discriminating between consonant-vowel syllables that were initially spoken slowly with exaggerated enunciation. As they improved, the syllables were compressed in time and were more difficult to distinguish. In addition, participants received memory training that focused attention on the syllables as they were presented in words, sentences and stories. “For most of my participants, the training was quite a positive experience,” Anderson said. “Many of them reported that they enjoyed the challenge and that they noticed the benefits of hearing better in social activities. In fact, I had no difficulty recruiting participants because they encouraged their friends to come in for the study. I was impressed with their high motivation to do activities that might offset the effects of aging.”
After training, the study participants had better scores on tests of speech-in-noise perception, memory and speed of processing—demonstrating their improved ability to decipher speech in challenging environments. They also had faster neural timing in the auditory brainstem, indicating that their brain’s processing speed was partially restored to typical timing in young adults. Nina Kraus, director of the Auditory Neuroscience Laboratory at Northwestern University and Anderson’s research partner, commented on the training’s effectiveness.
“After training, the participants’ neural timing did not become equivalent to that of a young adult…but they were, however, able to successfully hear, remember, and understand sentences in noisy background listening conditions—conditions that prior to training, rendered understanding of what had been said impossible,” Kraus said. In fact, participants that repeated behavioral and electrophysiological tests post training understood about 20% more words and could process about 15% more cognitive items on a timed test, and showed a 50% increase in neural timing. Participants that received no training showed no improvements in any area of their hearing and processing capabilities.
Participants also noticed improvement in everyday settings. For example, one individual stated that she was able to make out words with less effort, and subsequently could turn down the volume on her television after training. These findings provide hope for individuals who struggle to hear in noisy environments. “For most of my participants, the training was quite a positive experience. Many of them reported that they enjoyed the challenge and that they noticed the benefits of hearing better in social activities. In fact, I had no difficulty recruiting participants because they encouraged their friends to come in for the study. I was impressed with their high motivation to do activities that might offset the effects of aging,” Anderson said.
Treating the brain in addition to the ears, in a more comprehensive approach to language training, is very likely to lead to better ability to socialize in crowded places.
Following the study’s publication, several prominent speech-language pathology researchers have weighed in on the importance and impact of the findings. “The behavioral measures give you perspective on whether a treatment could actually work in helping improve the communicative abilities of older adults, while biological or auditory electrophysiology measures give you an indication of the actual mechanistic pathways that the training may be affecting,” said Frank Lin, an otolaryngologist at Johns Hopkins University.
The findings are important, Lin adds, considering recent research that points to a link between hearing loss in the elderly and age-related dementia. “We currently think that peripheral, age-related hearing loss could contribute to cognitive decline and dementia through two mechanistic pathways—social isolation and cognitive load,” he said. “This study is tremendously important given the aging of the population and our need to identify novel and effective interventions to reduce age-related cognitive and functional declines in older adults.”