An enhancement of spatial-temporal reasoning performance after listening to Mozart's music for 10 minutes has been reported by several, but not all, researchers. Even in the studies with positive results the enhancement is small and lasts about 12 minutes. The effect varies between individuals and depends upon the spatial tasks chosen; general intelligence is not affected. Rather more impressively, there is a beneficial effect on some patients with epilepsy. The results are not specific to Mozart's compositions but the exact musical criteria required have not been completely defined.