The authors wanted to know whether chronic reductions in slow-wave sleep over time are linked with dementia risk in humans and vice versa — whether dementia-related processes in the brain may contribute to getting less of this type of sleep.

研究作者们想知道，慢波睡眠时间的长期减少长远来看是否会增加人们患痴呆症的风险，反之，大脑中与痴呆症相关的进行性退化是否会导致慢波睡眠时间减少。