Who hasn't heard an old song and been transported back to the time when they first heard it? Music makes powerful memories, and a new study suggests that it can also help restore memories for people with brain injuries.

Whether it's the Beatles, the Black Eyed Peas or Beethoven, most people's lives are set to music, so it seems only natural that hearing that same music again could bring back certain memories. But nearly all previous studies of music's ability to evoke memories have been performed on healthy people or on those with Alzheimer's disease.

Memories that seem to be forgotten aren't really gone. All it may take is a gentle nudge — a sound, smell, or taste — to find them.

The small study looked at five people who had suffered a brain injury. They ranged in age from 25 to 60 and had varying degrees of memory impairment. Playing familiar songs did a better job calling up memories from their pasts than did asking questions.

Using 50 years' worth of Billboard's Number 1 songs of the year, researchers played portions of these songs for each person, from the top hit of the year they turned five all the way to the top hit of 2010. The songs were played in random order.

Researchers also played the same musical selections for five matched control subjects with no brain injury. Patients and controls were all asked to record how familiar they were with each song, whether they liked it, and what memories it evoked.

The songs were as likely to evoke memories in people with brain injuries as they were for the controls. All the participants enjoyed the music, whether it sparked memories or not.

On average, nearly half (42%) of the songs heard by the patients did evoke memories from their past. The most common types of memories were of people or of a life period. These memories tended to be both positive and vivid.

The study shows how music can bring to mind personal memories, even in people with severe brain injuries, making it useful as a memory aid, according to the study's lead author, Amee Baird, a clinical neuropsychologist and associate investigator at Macquarie University, New South Wales, Australia.

Just how well familiar music can jog memories that seem to be lost isn't clear yet. But it seems to be fertile ground for researchers to keep exploring.

Baird's study offers more hope that memories that seem to be forgotten aren't really gone. And that all it may take is a gentle nudge — a sound, smell, or taste — to find them.

The study appears in Neuropsychological Rehabilitation.