Complex sentence: As of 2003 only three controlled clinical trials had tested "older adults with memory problems", and these studies had promising results, in which a 2003 Cochrane review decided that the results were inconclusive.
Split into simpler sentences: As of 2003 only three controlled clinical trials had tested "older adults with memory problems", and these studies had promising results. However, a 2003 Cochrane review decided that the results were inconclusive.