• What is acute encephalopathy and what is delirium?

    Definition acute encephalopathy and delirium

    The term acute encephalopathy refers to a rapidly developing (usually within hours to a few days) pathobiological process (disease) in the brain. The diagnosis is made by means of Electroencephalography, EEG. (source:  1. Slooter et al., 2020, Intensive Care Med ; Hut et al., 2021 Psychiatry and Clinical Neurosciences).
    Acute encephalopathy often manifests itself as delirium. Delirium is diagnosed based on clinical features. Both diagnoses are characterized by an underlying cause (suffering). Research shows that only 12% to 35% of delirious patients are recognized with current screening tools (source: Marcantonio, 2017, NEJM). 

    We at Prolira believe that acute encephalopathy and delirium can be treated. And that objective detection and monitoring is essential to achieve this objective. Please read further to see why we believe this.

    The impact of acute encephalopathy and delirium

    20 million per year

    20 million patients/yr in the US and the EU, need brain state monitoring, because they are at risk of acute encephalopathy/delirium. Incidence in ICU is up to 80%, in cardiosurgery about 30% and geriatric trauma 35%.

    Doubling hospital stay

    The length of stay in hospital is considerably prolonged by delirium.

    More dementia

    People aged 85 or higher have an 8x higher chance to get dementia after delirium.

    More nursing home admissions

    37% of the patients with post-acute encephalopathy and delirium are admitted to nursing homes.

    High mortality risk

    Patients with acute encephalopathy and delirium have a 1.5 times higher mortality risk in 1st year after discharge.

    High healthcare costs

    The economic impact of delirium is similar to that of Type 2 diabetes.

    About 33% of hospitalized patients over the age of 70 will suffer from acute encephalopathy a/o delirium

    15-50% of
    postoperative patients over the age of 70 will suffer from acute encephalopathy a/o delirium

    19-82% of
    intensive care

    patients will
    suffer from acute encephalopathy a/o delirium

    Delirium has a major impact on the patient

    The St. Antonius hospital in the Netherlands has implemented DeltaScan in 3 of their departments (C2 Internal Medicine ward, 4C Geriatric Trauma ward and G3/H3 Cardio Thoracic Surgery ward).

    St. Antonius Hospital strives to continuously improve acute encephalopathy/ delirium care.

    Acute encephalopathy and delirium are a common complication of which the underlying cause needs to be urgently treated. Detecting the syndrome is not easy but is very relevant! The longer an acute encephalopathy and/or delirium episode lasts, the worse the (cognitive) consequences for the patient.

    St. Antonius Hospital is continuously working on improvement processes in its care and DeltaScan fits perfectly in this strategy!

    Different types of delirium

    Delirium can express itself in different types. Up to 75% of delirious patients have hypoactive or silent delirium. With the current screening instruments, this group is often missed. Only 12% to 35% of delirious patients are recognized (source: Marcantonio, 2017, N Engl J Med). Hypoactive (silent) delirium is more difficult to recognize than hyperactive delirium and can often be confused with dementia or depression. Because of this lack of recognition, hypoactive delirium has been associated with worse patient outcomes.

    Hyperactive type

    Patients with hyperactive delirium are restless, often agitated and exhibit physical hyperactivity.

    Mixed type

    Patients with this type are occasionally restless.

    Hypoactive type

    Patients with hypoactive delirium are calm and may appear sleepy. This type is often mixed up with depression or dementia.

    The longer delirium lasts, the higher the impact

    The complex and unclear clinical presence makes it difficult to recognise delirium. According to international guidelines and research, only 12% to 35% of delirium cases are currently recognised in clinical practice. This means that 65% to 88% of people with delirium do not receive the necessary treatment (Source: Marcantonio, 2017, NEJM).

    Delirium is recognised too little and too late

    Within clinical practice, there is a need for better recognition of acute encephalopathy and delirium. Using questionnaires, the majority of patients are missed and often only patients with hyperactive delirium are recognized.

    Current situation

    Complex and unclear

    • 33% of patients over 70 years of age have acute encephalopathy and or delirium.
    • 50% of this group has ae/delirium when admitted to the hospital and the rest will get acute encephalopathy and or delirium during their stay in hospital
    • Only 12% to 35% of delirium cases of acute encephalopathy/delirium patients are recognized.

    The protocol

    Subjective and inefficient

    • In most hospitals, it is up to the nurses to detect delirium.
    • Patients at risk of ae/delirium are screened using a standardized checklist.
    • Acute encephalopathy is by definition missed because EEG is the only method to detect.
    • Current delirium screening tools (targeting clinical characteristics) are subjective, ineffective and are often not used.

    Desired situation

    With DeltaScan

    • With DeltaScan, Prolira offers a solution to the problem listed here.
    • With DeltaScan, healthcare professionals can measure their patients’ brain activity to determine whether characteristics of acute encephalopathy and delirium are present (polymorphic delta waves).
    • This allows DeltaScan to be a valuable and objective screening tool, supporting the diagnosis of acute encephalopathy and/or delirium.


    We offer 3 free e-learning modules, each of about 10 minutes, that
    are informative and interactive, partly because they contain videos:Ā 

    1. for nurses: delirium and acute encephalopathy
    2. for doctors: delirium
    3. for healthcare professionals: Prolira-DeltaScan use

    or contact our Account Managers

    DeltaScanĀ® is an EU registered trademark (Certificate Nr 018280613) Version 2.0

    Postal Address (for every letter/parcel/package):
    Prolira BV, Kruytgebouw, UInc
    Winthontlaan 30C
    3526 KV Utrecht
    The Netherlands

    Visiting Address:
    Prolira BV, Kruytgebouw
    Padualaan 8
    3584 CH Utrecht


    +31 (0)85 060 1656