There have been various publications on the clinical validation and technology development of DeltaScan. Relevant references can be found on this page.
Relevant Publications for DeltaScan
Our suggested literature:
- In 2009, van Eijk, Slooter et al published that delirium is often under diagnosed, in particular hypoactive delirium. Van Eijk, M., Marum, R., Klijn, A., de Wit, N., Kesecioglu, J., Slooter, A.J. Comparison of delirium assessment tools in a mixed intensive care unit. Critical Care Medicine. 37(6):1881-1885, JUN 2009.
- In 2011, van Eijck, Slooter et al published an article on the performance of delirium screening tools currently used in routine daily practice. The results showed a poor sensitivity level of 47%. Sensitivity for the most prevalent type, hypoactive delirium was only 31%. This resulted in further studies aiming to develop an objective tool for the monitoring of delirium. Van Den Boogaard, M., van Eijk, M., Eikelenboom, P., van Matrum, R., Benner, P., & Honing, M. (2011). Routine use of the confusion assessment method for the intensive care unit. American Journal of Respiratory Critical Care Care Medicine, 184(3), 340-344.
- In 2015, Van Der Kooi, Slooter et al demonstrated the core principle for EEG-based Delirium Monitor technology.Van Der Kooi, A.W., I. J., Klijn, F.A., Koek, H.L., Meijer, R. C., Leijten, F. S., & Slooter, A. J. (2015). Delirium detection using EEG: what and how to measure. CHEST Journal, 147(1), 94-101.
- In 2017, Numan et al published a study highlighting the difficulty of delirium diagnosis. In 21% of cases the experts, using the Gold Standard for delirium diagnosis, disagreed. Only 32% of the actual delirium cases were reported in the nursing files, indicating under detection of delirium in clinical practice. There was a clear need for an easy-to-use, reliable method of detecting delirium in clinical practice. Bipolar EEG could therefore be a candidate for objective delirium detection. Numan, T., Boogaard, M. van den, Kamper, A.M., Rood, P. J., Peelen, L. M., & Slooter, A. J. (2017). Recognition of Delirium in Postoperative Elderly Patients: A Multicenter Study. Journal of the American Geriatrics Society.
- In 2019, Numan et al published findings to show that delirium can be detected in older postoperative patients using 1 minute single-channel EEG recordings analysed automatically. This method could enable objective detection of delirium, providing a continuous scale instead of a dichotomized outcome. Numan, T., Boogaard, M. van den, Kamper, A.M., Rood, P. J., Peelen, L. M., & Slooter, A. J. (2018). Delirium detection using relative delta power based on 1 minute single-channel EEG: a Multicenter Study. British Journal of Anaesthesia.
- In 2019, a study of Fleischman and colleagues showed that a combination of few EEG sensors can be used to accurately identify and diagnose patients with delirium even in a mixed cohort of several thousand patients. The diagnostic performance of quantitative EEG outpaced that of classic clinical delirium tests, despite the lack of a priori information about the patients’ condition. Fleischmann et al. – 2019 – Diagnostic Performance and Utility of Quantitative EEG Analyses in Delirium Confirmatory Results From a Large Retrospective Case-Control Study. Clinical EEG and Neuroscience, 50 (2), 111-120 .
- In 2019, Kimchi et al showed that clinical EEG slowing was related to delirium severity and predicted poor clinical outcomes such as longer hospitalisations, worse functional outcomes, and increased mortality. Kimchi E.Y., Neelagiri A., Whitt W., Rao A.S., Ryan, S.L., Gadbois, G., Groothuysen, D., Westover, M.B., (2019). Clinical EEG slowing correlates with delirium severity and predicts poor clinical outcomes. Neurology 93(12):e 1260-e1271
- In 2020, Tanabe et al published that delirium is related to frontal and occipital delayed EEG activity. Sean Tanabe1, Rosaleena Mohanty1,2, Heidi Lindroth1,3, Cameron Casey1, Tyler Ballweg1, Zahra Farahbakhsh1, Bryan Krause1, Vivek Prabhakaran2, Matthew I. Banks1 and Robert D. Sanders (link)
Breakthroughs in delirium research
The seriousness of delirium is progressively acknowledged. A dramatic increase in scientific publications reflects this; in 1995 only 10 delirium articles were published, in 2015 over 250.
The clear medical need for improved and early delirium detection, led us to develop DeltaScan.
The following publications gave us the drive to tackle delirium and develop DeltaScan:
In 2010, Heymann (Germany) showed that delayed treatment of delirium impairs patient outcomes. In 2011, Leslie and Inouye (USA) showed that delirium-attributed healthcare costs rank between the costs for diabetes and those of cardiovascular disease. In 2013, Pandharipande, Ely et al (USA) showed that a longer duration of a delirium episode worsens long-term cognitive impairment. Ely, and later Pisani, showed that delirium is independently associated with a 10% higher chance of mortality per day of delirium.
Slooter (NL) showed that delirium causes impaired outcomes in many cases, independent of the severity of the underlying condition. As the seriousness of the condition became more apparent, scientists worked in parallel on a means for early detection. Already in 2001, Marcantonio (USA) et al showed that intensive screening by geriatricians can result in a reduced burden of delirium. However, in 2011, Slooter (NL) et al showed poor sensitivity (47%) of currently used delirium screening tools in routine ICU care.
A recent article by Marcantonio, USA, in 2017, not only stated that up to 75% of patients have hypoactive/silent delirium, but also mentioned underdetection of delirium. Only 12% to 35% of the delirium is recognized. These are mainly patients with hyperactive delirium . Inouye et al. (US) described in 2014 that delirium can not only lead to higher mortality rates, but also increasing the chance of admission to a nursing home, partly due to the loss of ADL functionalities .
In 2010, Martin et al (US) in their study pointed to a relationship between delirium and (post-operative) sepsis, stating that delirium is an independent predictor of sepsis . Van den Boogaard et al. (NL) have shown that cognitive problems after hospitalisation are significantly higher in patients who have had delirium, compared to patients without delirium . Mulkey et al. (US) recently published the value of using EEG in the detection of delirium, stating that EEG, based on the latest techniques, can detect delirium earlier and more frequently.
 Heymann et al, 2010, J Int Med Res
 Leslie and Inouye, 2011, JAGS
 Pandharipande, et al., 2013, NEJM
 Ely et al, 2004, JAMA
 Pisani et al, 2009, AJRCCM
 Slooter, 2013,Nat Rev Neurol
 Marcantonio et al., 2001, JAGS
 Slooter et al., 2011, AJRCCM
 Marcantonio, 2017, NEJM
 Inouye et al., 2014, Lancet
 Martin et al., 2010, Crit Care
 Van Den Boogaard, 2012, Crit Care Med
 Mulkey et al., 2019, Dimens Crit Care Nurs
Research at UMC Utrecht leading up to DeltaScan:
- In 2017, Numan published her PhD thesis, titled “EEG in delirium”
Numan, T. (2017) “EEG in delirium” (Doctoral dissertation, Utrecht University).
- In 2014, van der Kooi published her PhD thesis which focuses on characterizing the neurophysiology of delirium and to assess whether alternations in the neurophysiology of delirium could provide opportunities for delirium detection.
van der Kooi, A. W. (2014) “Neurophysiology of delirium” (Doctoral dissertation, Utrecht University).
EEG without delirium
EEG with delirium
International delirium guidelines are unanimous
They all describe a need for improved and early delirium detection
European Society of Anaesthesiology evidence-based and consensus-based Guideline on Postoperative Delirium, 2017
“Given the enormous burden exerted by POD on patients, their families, healthcare organizations and public resources, anesthesiologists operating in Europe should engage to make efforts in designing integrated actions aimed to reduce the incidence and duration of POD.”
“Early diagnosis of POD is critical to trigger focused and effective treatment.”
“On the postoperative ward, POD should be monitored at least once per shift due to the fluctuating course of POD.”
“Delirium is reported to remain undiagnosed in more than half of cases.”
“Delays to initiation of treatment have been found to result in prolongation of delirium, which is associated with worse cognitive and functional recovery, and higher inpatient morbidity a mortality.”
Australia: Delirium clinical care standard, 2016
” Compared with patients of the same age without delirium, patients with delirium have an increased risk of death, increased length of stay, increased risk of falls, a greater chance of being discharged to a higher dependency of care and a greater chance of developing dementia.” Despite being a common condition, delirium is poorly recognized, and cases are often missed”. Prompt diagnosis & timely treatment of underlying causes are important for reducing the severity and duration of delirium and risk of complications from it.”
UK: National Institute for Health and Care Excellence, Delirium: prevention, diagnosis and management guideline, 2019
“It (delirium, red.) is a serious condition that is associated with poor outcomes. However, it can be prevented and treated if dealt with urgently”
The Netherlands: the Dutch Health Inspectorate annual report “Quality Indicators – Basic Hospital Set”, 2016
“Despite the negative prognostic implications of going through a delirium, in most hospitals little attention is paid to the occurrence of delirium …
Research shows that delirium is not recognized in two-thirds of the patients.” (page 79)
USA: Society of Critical Care Medicine Clinical Practice Guidelines for the Prevention and Management of Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU, 2018
“Early detection (of delirium, red.) may lead to prompt identification and correction (when possible) of etiology, assurance of patients experiencing distressing symptoms, treatment (pharmacologic or nonpharmacologic), and treatment effectiveness assessments.”
USA: American Geriatric Society Guideline on Postoperative Delirium, 2014
“Delays to initiation of treatment have been found to result in prolongation of delirium, which is associated with worse cognitive and functional recovery, and higher inpatient morbidity and mortality.”
Germany: S3-Leitlinie zu Analgesie, Sedierung und Delirmanagement in der Intensivmedizin, 2015
“The systemic monitoring of pain, sedation and delirium, targeted protocols for the management of sedation, analgesia and delirium are associated with lower incidence of nosocomial infections, a reduction in the duration of ventilation and length of ICU stay (LOS), lower mortality and lower resource consumption.”
“Delirium monitoring should be performed regularly (8-hourly) and be documented.”
USA, Joint Commission International, Safe surgery guide
Postoperative delirium can have negative effects, such as delaying postoperative movement, prolonging treatment, extending length of stay, and preventing early rehabilitation. There are several diagnostic tools available to help providers assess patients effectively and consistently. Organizations should consider using such a tool.” (page 153)
If detected in time, delirium can be treated
There are clear guidelines on how to treat the condition, see for example the guidelines:
- Postoperative delirium of the American Geriatric Society (USA, 2014)
- Pain-Agitation-Delirium guidelines of the Society of Critical Care Medicine (USA, 2013).
- Delirium: prevention, diagnosis and management of the National Institute for Health and Care Excellence NICE (UK, 2014).