The small study suggests that songs instil themselves deeply into the mind and may help reach people who have trouble remembering the past.
It's not clear whether the study results will lead to improved treatments for patients with brain damage. But they do offer new insight into how people process and remember music.
"This is the first study to show that music can bring to mind personal memories in people with severe brain injuries in the same way that it does in healthy people," said study lead author Amee Baird, a clinical neuropsychologist. "This means that music may be useful to use as a memory aid for people who have difficulty remembering personal memories from their past after brain injury."
Baird, who works at Hunter Brain Injury Service in Newcastle, Australia, said she was inspired to launch the study by a man who was severely injured in a motorcycle accident and couldn't remember much of his life. "I was interested to see if music could help him bring to mind some of his personal memories," she said.
The man became one of the five patients – four men, one woman – who took part in the study. One of the others was also injured in a motorcycle accident, and a third was hurt in a fall. The final two suffered damage from lack of oxygen to the brain due to cardiac arrest, in one case, and an attempted suicide in the other.
Two of the patients were in their mid-20s. The others were 34, 42 and 60. All had memory problems.
Baird played number one songs of the year for 1961 to 2010 as ranked by Billboard magazine in the United States. The patients were all from Australia, but the Australian pop charts are similar to those from the United States, she said.
Music a powerful stimulus
For most of the patients, three of the five, the songs did a better job of prompting memories about their lives than asking them questions about their pasts, Baird said. They also remembered events from their lives about as well as similar people who didn't have brain damage.
"All the patients enjoyed doing the study. They smiled, sang along and some even danced in their seats to the songs," she said. "On two occasions, participants became teary when hearing a song as it brought to mind a 'bittersweet' memory such as deceased parents. These reactions show that music is a powerful stimulus for eliciting emotions, both positive and negative, and I believe this is the reason that it is so efficient at activating memories."
For one 60-year-old man who was injured in a motorcycle accident, several songs evoked memories of his marriage of more than 40 years. "Bette Davis Eyes", by Kim Carnes, reminded him of buying the single for his wife. Meanwhile, Whitney Houston's "I Will Always Love You" reminded him of "loving my wife over the years, many happy memories", he told researchers.
Music richly encoded
Petr Janata, a professor of psychology at the Centre for Mind and Brain at the University of California, Davis, praised the study, saying it's "a really nice advance on what we know." He was especially intrigued by one of the patients who couldn't recall his past but could still sing along to some of the songs.
"It suggests that we encode music more richly," Janata said, "and this affords more possibilities for other memories to get tied in."
For her part, Baird said future research should examine how visual images (such as movies and television), smells and types of touch are tied to memories.
For now, Janata said, it's clear that music can help people with brain injuries such as stroke. "Any time that you can engage a brain and keep it active following injury, you are going to do good things for it. Music appears to be a great way to support that effort."
The study was recently published online in the journal Neuropsychological Rehabilitation.