Music therapy might also improve emotional well-being among those with dementia, researchers found. But they didn't find any benefits when it came to cognition and behavioral issues such as agitation or aggression, according to the report in the Cochrane Library journal.

Although the benefits of music therapy weren't large, "small effects are valuable, too, because even a small improvement or maintaining a certain level while otherwise a decline is expected is very important for people with dementia and those caring for them," said study leader Jenny van der Steen, a researcher with the department of public health and primary care at Leiden University Medical Center.

For the analysis, van der Steen and colleagues pooled data from 21 smaller randomized trials involving a total of 1097 patients. Patients in the trials received either music based therapies that involved at least five sessions, or usual care or some other activity with or without music.

Participants in the studies had dementia of varying degrees of severity and the majority were residents in institutions. Seven of the studies provided individual music therapy, while the others delivered the intervention in a group setting.

The new findings could have a significant impact on dementia patients, said Dr. Alexander Pantelyat, an assistant professor of neurology at the Johns Hopkins University School of Medicine and co-director of the Johns Hopkins Center for Music and Medicine.

"The alternative to these behavioral interventions is drugs with black box warning labels saying that they increase the risk of death," Pantelyat said. "The fact that they could be moderately confident that music-based treatments could improve symptoms of depression and overall behavioral problems would make this actionable from my standpoint even though the number of studies was low."

It's not surprising that music therapy could help those with dementia, Pantelyat said. "It's known that areas that process music in the brain overlap with the emotional areas and those that process language," he added. "If a song from somebody's youth is played it's possible it will bring back memories associated with the first time they heard it. And that speaks to the need for a tailored approach. Not a 'one song fits all' approach."