According to the first publication in 1993 by Rauscher et al. [Nature 
1993;365:611], the Mozart effect implies the enhancement of reasoning skills 
solving spatial problems in normal subjects after listening to Mozart's piano 
sonata K 448. A further evaluation of this effect has raised the question 
whether there is a link between music-generated emotions and a higher level of 
cognitive abilities by mere listening. Positron emission tomography and 
functional magnetic resonance imaging have revealed that listening to 
pleasurable music activates cortical and subcortical cerebral areas where 
emotions are processed. These neurobiological effects of music suggest that 
auditory stimulation evokes emotions linked to heightened arousal and result in 
temporarily enhanced performance in many cognitive domains. Music therapy 
applies this arousal in a clinical setting as it may offer benefits to patients 
by diverting their attention from unpleasant experiences and future 
interventions. It has been applied in the context of various important clinical 
conditions such as cardiovascular disorders, cancer pain, epilepsy, depression 
and dementia. Furthermore, music may modulate the immune response, among other 
things, evidenced by increasing the activity of natural killer cells, 
lymphocytes and interferon-γ, which is an interesting feature as many diseases 
are related to a misbalanced immune system. Many of these clinical studies, 
however, suffer from methodological inadequacies. Nevertheless, at present, 
there is moderate but not altogether convincing evidence that listening to known 
and liked music helps to decrease the burden of a disease and enhances the 
immune system by modifying stress.