Complex sentence: Bispectral index (BIS) monitors are modern neurophysiologic monitoring devices that continually analyse patients' electroencephalograms during general anaesthesia to assess the level of anaesthesia.
Split into simpler sentences: Bispectral index (BIS) monitors are modern neurophysiologic monitoring devices. They continually analyse patients' electroencephalograms during general anaesthesia to assess the level of anaesthesia.