People who suffer from Parkinson's disease can sing better, research suggests.
A pilot study showed that singing therapy led to fewer involuntary movements, improvement of the position and less stress.
Researchers warned that the early findings should be treated with caution, but said that the benefits for patients were similar to those for medication.
Dr. Elizabeth Stegemoller, from Iowa State University in the US, said: "We see the improvement every week when they leave the vocal group, it is almost as if they have a little fun in their step.
Some of the symptoms that improve, such as fingering and walking, do not always respond directly to medication, but with singing they improve
Dr. Elizabeth Stegemoller, Iowa State University
"We know that they feel better and that their mood is high.
"Some of the symptoms that improve, such as fingering and walking, do not always respond directly to medication, but with singing they improve."
Parkinson's disease causes progressive loss of motor control, leading to uncontrollable shaking, stiffness, slow movements and difficulty walking.
Thinking and behavioral problems can also occur.
About 145,000 people in the UK are diagnosed with Parkinson every year.
The disease is linked to insufficient levels of the chemical dopamine in the brain, but its causes are still poorly understood. Genetic and environmental factors both play a role.
Dr. Stegemoller's team studied 17 Parkinson's patients who participated in a therapeutic singing group.
Measurements were taken of the heart rate, blood pressure and levels of cortisol stress hormone of the participants.
All three measurements were reduced by singing, but not by an amount that achieved statistical significance.
The researchers look at the possible effects of singing on inflammation, neuroplasticity – the brain's ability to rewire itself to compensate for injury or disease – and blood levels of the binding hormone oxytocin.
Dr. Elizabeth Shirtcliff, also from the state of Iowa, said: "Part of the reason why cortisol goes down might be because the singing participants feel positive and less stressed by singing together with others in the group, which suggests that we looking at the binder hormone oxytocin.
"We also look at heart rate and heart rate variation, which can tell us how calm and physiologically relaxed the individual is after singing."
Earlier work by the same team showed that singing can improve respiratory control and the ability to reduce Parkinson's patients.
The research was presented at the Society for Neuroscience 2018 meeting in San Diego.