The participants, who had an average age of 50, were recruited from pain and chiropractic clinics in Ohio. They had been suffering from a range of painful conditions, including osteoarthritis, disc problems and rheumatoid arthritis, for an average of six and a half years.

Ninety percent said the pain affected more than one part of their bodies and 95 percent said it was continuous. Before the music study, participants reported that their usual pain averaged just under six on a zero to 10 pain scale and their worst pain exceeded nine out of 10.

"The people who took part in the music groups listened to music on a headset for an hour a day and everyone who took part, including the control group, kept a pain diary," Siedlecki explained. "Forty people were assigned to the two music groups and the other 20 formed the control group. The first group was invited to choose their own favorite music and this included everything from pop and rock to slow and melodious tunes and nature sounds traditionally used to promote sleep or relaxation."

Siedlecki said the second group chose from five relaxing tapes selected by the researchers. Those featured piano, jazz, orchestra, harp and synthesizer and had been used in previous pain studies by co-author Good.

At the end of the trial:

• The music groups reported that their pain had fallen by between 12 and 21 percent, when measured by two different pain measurement scales. The control group reported that pain increased by between one and two percent.
• People in the music groups reported 19 to 25 percent less depression than the control group.
• The music groups reported feeling nine to 18 percent less disabled than those who hadn't listened to music and said they had between five and eight percent more power over their pain than the control group.

"Our results show that listening to music had a statistically significant effect on the two experimental groups, reducing pain, depression and disability and increasing feelings of power," Siedlecki said. "There were some small differences between the two music groups, but they both showed consistent improvements in each category when compared to the control group. Non-malignant pain remains a major health problem and sufferers continue to report high levels of unrelieved pain despite using medication. So anything that can provide relief is welcomed."

Good says listening to music also plays a role in modern health care, helping patients to remain drug-free, if possible.

"Listening to music has already been shown to promote a number of positive benefits and this research adds to the growing body of evidence that it has an important role to play in health care today and beyond," Good said.

Previous research by Good and Hui-Ling Lai, published in the Journal of Advanced Nursing in 2005 and republished in the journal's 30th anniversary issue this year, showed that listening to 45 minutes of soft music before bedtime can improve sleep by more than a third.