From BBC News
http://news.bbc.co.uk/2/hi/health/6960612.stm
New research demonstrates physical causes for phenomena usually ascribed to otherworldly influences. Berg certainly believed and taught that out-of-body and near-death experiences were spiritual in nature, not neurological as this research demonstrates.
Although there are other phenomena that don't yet have a scientific explanation, I think there is always a scientific explanation for all phenomena. It sometimes just takes time for those explanations to be found.