Validation of a delirium monitor in postoperative elderly patients

Delirium is an acute disturbance of consciousness and cognition that tends to
fluctuates over time. It is a common disorder in hospitalized patients,
especially in postoperative elderly, with a reported incidence between 4% and
65% after major surgery. Delirium is associated with higher mortality, longer
hospital stay, long-term cognitive impairment, and increased costs. Despite its
frequency and impact, recognition of delirium by physicians (30-50%) is poor.
Various delirium assessment tools have been developed for use by
non-psychiatric personnel such as the confusion assessment method (CAM) and
delirium observation scale (DOS). These scales are applicable in research
setting, however in clinical practice some delirious patients were still
missed. Therefore, an objective detection tool is needed to monitor delirium.
From previous literature we know that electroencephalography (EEG) can
distinguish patient with and without using certain EEG parameters. Besides, it
was shown that it is possible to use only four electrodes (reference electrode,
and three recording electrodes) of the EEG recordings to detect delirium. This
resulted in the development of a prototype of an EEG-based delirium monitor,
based on a standardized EEG recording with only 4 electrodes.

The research objective is to investigate the sensitivity, specificity, and
predictive values of the delirium monitor based on 4 standardized EEG
electrodes who record brain activity.

This study is an observational, mono-center study with repeated diagnostic
measurements which will be performed in the University Medical Center Utrecht
(main center), Radboud University Medical Center in Nijmegen, Isala Klinieken
in Zwolle and Charité Universitätmedizin in Berlin.

No risks are expected for recordings with the delirium monitor, because the
delirium monitor is based on a standardized EEG recording. EEG recordings are
performed without any risks.
The burden of the measurement is estimated as low. A maximum of 3 simple EEG
measurements with 4 electrodes of maximal 7 minutes will be performed.
Furthermore, a maximum of 3 evaluations of the DRS-R-98 and VAS score by the
delirium expert, will be conducted on 3 days. The electrodes will be fixed with
gel without any harm. Removal of the electrodes is also harmless and no hair is
needed to be shaved. The patient has to keep the eyes open for two minutes
followed by 5 minutes eyes closed during the registration with the EEG monitor.
The psychiatric evaluation will be recorded on video which will be evaluated by
a gold standard (neurologist, geriatrician, or psychiatrist).

From our previous study we know that a complete EEG recording in delirious
patients is feasible without any problems. The delirium monitor will only make
use of four electrodes instead of 25, and is designed to have optimal
usability. However, if a patient is objecting, for example verbally or by
pulling the electrodes, we will remove the electrodes immediately and suspend
the registration.