Whether it be music or just plain noise, it's undisputed that sound can have an affect on the human nervous system.

However, there is hardly any scientific evidence to show that sound can be beneficial for the human body. We are familiar with sound's positive affects by listening to music for relaxation.

"Ambient music with drifting rhythms, linear notes and gently flowing melodies is especially relaxing," says Hartmut Schroeder, head of the Institute for Trans-Cultural Health Studies at the European University Viadrina in Frankfurt-on-the-Oder in eastern Germany.

This is increasingly being put to use by hotels and spa owners.

"It's in places like that where what is known as wellness-music is being used in a very disorganised way. Individual rooms or entire buildings are flooded with non-descript background music," criticises Lutz Hertel, chairman of the German Wellness Association in Dusseldorf.

In contrast to such general use of calming, atmospheric music, sound therapy is tailored towards the individual.

"Music and sound therapy, however, are two different things," explains Karl Hoermann, a professor of music and dance studies at the University of Munster in northern Germany.

Music is composed of melodies and series of notes. Sound therapy on the other hand is limited purely to sound. It's about experiencing vibration and response.

The most widely used type of therapy is sound meditation. "As a user it's very hard for me to do anything wrong with this kind of therapy," says Schroeder.

In order to find out what you think is beneficial, Schroeder recommends beginning with a short session.

Sound massage is more targeted towards physical complaints such as muscle tension.

The best known form of this type of therapy is with sound bowls made from different metals. The bowls are placed on top of specific energy points or on tense regions of the clothed body.

The bowls are then struck with a mallet one after the other. Harps or didgeridoos are often used at the same time.

Proponents of this type of therapy say its affect is achieved in two ways: "On the one hand, getting a massage is pleasant. On the other, the acoustic noise then penetrates the body and spreads through the tissue where it causes vibrations," says Schroeder.

In this way self-healing energies are activated and a deep state of relaxation achieved which can even go as far as a trance.

Even more specific is sonopuncture, also known as phonophorese.

Similar to traditional acupuncture, individual points on the body's energy line system are stimulated.

But instead of needles, tuning forks are used. "There's not enough scientifically proven evidence to show the effects of this therapy," says Professor Hartmut Goebel, medical director of the Neurological Clinic at Kiel University.

But Goebel points out that unconventional therapies like sonopuncture can be used in addition to conventional medical treatment.

It can have a similar effect to behavioural training, which also uses relaxation techniques.

The important thing is that you seek advice from your doctor or alternative medicine practitioner.

But acoustic therapy can have some unwanted side effects. "Certain sounds can lead to an onset of symptoms in patients with difficult psychological problems," warns Goebel.

He also advises people who take drugs or psychotropic medicine not to try acoustic therapy.

Goebel also recommends stopping the treatment, if you feel uncomfortable or anxious.