Delirium detection based on monitoring of blinks and eye movements.
OBJECTIVE
To investigate whether delirious patients differ from nondelirious patients with regard to blinks and eye movements to explore opportunities for delirium detection.


METHODS
Using a single-center, observational study in a tertiary hospital in the Netherlands, we studied 28 delirious elderly and 28 age- and gender-matched (group level) nondelirious elderly, postoperative cardiac surgery patients. Patients were evaluated for delirium by a geriatrician, psychiatrist, or neurologist using the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria. Blinks were automatically extracted from electro-oculograms and eye movements from electroencephalography recordings using independent component analysis. The number and duration of eye movements and blinks were compared between patients with and without delirium, based on the classification of the delirium experts described above.


RESULTS
During eyes-open registrations, delirious patients showed, compared with nondelirious patients, a significant decrease in the number of blinks per minute (median: 12 [interquartile range {IQR}: 5-18] versus 18 [IQR: 8-25], respectively; p = 0.02) and number of vertical eye movements per minute (median: 1 [IQR: 0-13] versus 15 [IQR: 2-54], respectively; p = 0.01) as well as an increase in the average duration of blinks (median: 0.5 [IQR: 0.36-0.95] seconds versus 0.34 [IQR: 0.23-0.53] seconds, respectively; p <0.01). During eyes-closed registrations, the average duration of horizontal eye movements was significantly increased in delirious patients compared with patients without delirium (median: 0.41 [IQR: 0.15-0.75] seconds versus 0.08 [IQR: 0.06-0.22] seconds, respectively; p <0.01).


CONCLUSIONS
Spontaneous eye movements and particularly blinks appear to be affected in delirious patients, which holds promise for delirium detection.
Department of Intensive Care Medicine, Brain Center Rudolf Magnus, University Medical Center Utrecht, the Netherlands. Electronic address: a.w.vanderkooi@umcutrecht.nl.
Arendina W
AW
van der Kooi
Department of Intensive Care Medicine, Brain Center Rudolf Magnus, University Medical Center Utrecht, the Netherlands.
Marjolijn L
ML
Rots
Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, the Netherlands.
Geertjan
G
Huiskamp
Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, the Netherlands.
Francina A M
FA
Klijn
Department of Geriatrics, University Medical Center Utrecht, the Netherlands.
Huiberdina L
HL
Koek
Department of Cardio-Thoracic Surgery, University Medical Center Utrecht, the Netherlands.
Jolanda
J
Kluin
Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, the Netherlands.
Frans S S
FS
Leijten
Department of Intensive Care Medicine, Brain Center Rudolf Magnus, University Medical Center Utrecht, the Netherlands.
Arjen J C
AJ
Slooter
D000368:Aged; D000369:Aged, 80 and over; D001767:Blinking / Q000502:physiology*; D003693:Delirium / Q000175:diagnosis* / Q000503:physiopathology; D004569:Electroencephalography; D004585:Electrooculography; D053483:Eye Movement Measurements; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male
Delirium; electro-oculogram; electroencephalogram; eye movements