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Don’t Let the ICU Turn Emergencies into Memory Problems

patient, nurse, icu
A hospital's Intensive Care Unit (ICU) can bring on Alzheimer's-like symptoms in brain-healthy patients. See doctors discuss 4 ways to prevent this. (Video+Article)

Patients treated in intensive care units across the globe enter with no evidence of cognitive impairment, but oftentimes leave with deficits similar to those seen in patients with mild Alzheimer’s disease (AD). Researchers were surprised to further reveal that symptoms tend to persist for a year or more. (Article continued below video…)

These troubling statistics are according to a Vanderbilt study published in the world-renowned New England Journal of Medicine.

The study, led by members of Vanderbilt’s ICU Delirium and Cognitive Impairment Group, found that 74 percent of the 821 patients studied, all adults with respiratory failure, cardiogenic shock or septic shock, developed delirium while in the hospital, which the authors found is a predictor of a dementia-like brain disease even a year after discharge from the ICU.

Long-Term Cognitive Loss

Delirium, a form of acute brain dysfunction common during critical illness, has consistently been shown to be associated with higher mortality, but this large study of medical and surgical ICU patients demonstrates that it is associated with long-term cognitive impairment in ICU survivors as well.

At three months, 40 percent of patients in the study had global cognition scores similar to patients with moderate traumatic brain injury (TBI), and 26 percent scored similar to patients with Alzheimer’s disease (AD).

Deficits occurred in both older and younger patients, irrespective of whether they had coexisting illness, and persisted to 12 months, with 34 percent and 24 percent still having scores similar to TBI and AD patients, respectively.

“As medical care is improving, patients are surviving their critical illness more often, but if they are surviving their critical illness with disabling forms of cognitive impairment then that is something that we will have to be aware of because just surviving is no longer good enough,” said lead author Pratik Pandharipande, M.D., MSCI, professor of Anesthesiology and Critical Care.

“Regardless of why you come in to an ICU, you have to know that, on the back end of your critical care, you are very likely to be suffering cognitively in ways similar to a TBI patient or an AD patient, except that most of the medical profession doesn’t even know that this is happening and few around you suspect anything, leaving most to suffer in silence,” said senior author Wes Ely, M.D., professor of Medicine.

How To Prevent ICU-Related Memory Loss

There are many areas where doctors, caregivers and patients can help prevent these dementia-like symptoms. Some basic ones include:

  1. LESS SEDATION – Use less sedation and keep patients more awake for longer
  2. MORE ALERT – Keep patients alert and walking around in the ICU, even while still on a ventilator
  3. GET UP SOONER – Patients should be walking earlier
  4. COGNITIVE REHAB – “Brain exercises”, such as challenging games, help rebuild cognitive function and memory, especially once a patient is released from the hospital.

“Delirium in critically ill, hospitalized adults is a serious yet understudied issue,” said Molly Wagster, Ph.D., chief of the Behavioral & Systems Neuroscience Branch in the National Institute on Aging, part of the NIH. “These new findings provide important evidence of the extent of the problem, the imperative for greater recognition and the pressing need for solutions.”

Ely said at least some component of this brain injury may be preventable through efforts to shorten the duration of delirium in the ICU by using careful delirium monitoring and management techniques, including earlier attempts at weaning from sedatives and mobility protocols that can save lives and reduce disability.

“Even after the patient leaves the hospital, we think that cognitive rehabilitation might be helpful to somebody like this, and we have some early preliminary data supporting this,” he said.


Vanderbilt University Medical Center, via Newswise.


    1. P.P. Pandharipande, T.D. Girard, J.C. Jackson, A. Morandi, J.L. Thompson, B.T. Pun, N.E. Brummel, C.G. Hughes, E.E. Vasilevskis, A.K. Shintani, K.G. Moons, S.K. Geevarghese, A. Canonico, R.O. Hopkins, G.R. Bernard, R.S. Dittus, E.W. Ely.
      Long-Term Cognitive Impairment after Critical Illness.
      New England Journal of Medicine; 369 (14): 1306 DOI: 10.1056/NEJMoa1301372

More Information:

    • This project was supported by grants from the National Institutes of Health (AG027472, AG035117, AG034257, AG031322, AG040157, HL111111, and 2 T32 HL087738-06), and the Veterans Affairs Tennessee Valley Geriatric Research, Education and Clinical Center and the VA Clinical Science Research and Development Service.
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Gail G Preston
Gail G Preston
June 17, 2015 1:45 pm

Two years ago my 82 year old father had a tumble in the bedroom and hit his head on furniture. Needless to say he was admitted into the hospital and checked out to make sure he was okay. Never did we dream at that point, physically he would be confined to outpatient ICU until they can determine why he was disoriented. During the first weeks we were informed that anesthesia could also promote, create a situation called Natural Hydrocephalus Pressure. He was treated for this by inserting a shunt to drain the fluid from the brain to other places in his body. This did not cure his situation and yet we continue to wonder why once he had received NHP treatment that this did not at least alleviate the situation.

June 24, 2015 4:06 pm

Gail, I've done a lot of reading about Normal Pressure Hydrocephalus (NPH) and I've never seen any reference that claims anesthesia could cause it. NPH is a clinical symptom triad (gait apraxia, incontinence, and dementia) associated with the imbalance in CSF production and reabsorption. For example, communicating hydrocephalus is caused by overproduction of CSF (rarely), defective absorption of CSF (most often), or venous drainage insufficiency (occasionally). Noncommunicating hydrocephalus occurs when CSF flow is obstructed within the ventricular system or in its outlets to the arachnoid space. The most common form is obstructive, caused by intraventricular or extraventricular mass-occupying lesions that disrupt the ventricular anatomy.

NPH often occurs after head trauma, infections, and bleeding within the brain. I'd suspect your father's (if that is indeed what he had — it can be tricky to diagnose) developed from hitting his head on the furniture.

Some NPH patients respond well to the surgery … many do not. Many factors might affect the outcome, e.g., what is causing the imbalance in CSF production/reabsorption, what parts of the brain/vascular system are involved, where the shunt was placed, and what sorts of damage had been done to the brain by the NPH prior to the surgery.

June 24, 2015 4:30 pm

The original news release from Vanderbilt has been modified, and in such a way as to be misleading.

The study had nothing to do with surgery, and it did NOT conclude that hospital sedation causes memory loss.

The study involved patients with respiratory failure, cardiogenic shock or septic shock who were admitted to an ICU unit. Patients who had recently had surgery that might have affected the results (cardiac surgery during the previous three months) were EXCLUDED from the study.

The study concluded that the development of DELIRIUM is a strong risk factor associated with long-term cognitive impairment.

The full paper, which can be found at: says, "After adjustment for delirium, we did NOT find any consistent associations between the use of sedative or analgesic medications and long-term cognitive impairment."

The full press release can be found here:

Note that there are many other factors associated with hospitalization that can cause delirium, such as dehydration, infections (including urinary tract infections often caused by catheterization), and fever.

Reply to  Lizzie
February 11, 2018 10:58 pm

Lizzie, I appreciate the distinctions that you are making and clarifying the actual study and its findings. There is other research, however, related to the existence of post-surgical cognitive decline. It too has been made harder to study by lack of agreed definitions. It is clear that older adults are at particular risk. Here is a paper that has some great tables clarifying risk for developing delirium or worsening pre-existing dementia. It is useful info for patients and families to have prior to making decisions about having surgery.

Reply to  Lizzie
February 12, 2018 2:30 pm

Lizzie, you are absolutely right. Thank you for helping make the study results clear, no misunderstanding was intended and the corrections have been made. All the best.

January 24, 2016 3:54 pm

patient suffered heart failure, in hospital showed signs of dementia. Delirium
heavy sedation took two weeks to clear those medications and find the right medication for him. Has total dementia now and is a dementia unit.

Marvin Berman PhD
Marvin Berman PhD
July 19, 2020 2:06 pm

We provide both brainwave biofeedback and home-based infrared phototherapy for all patients to remediate the effects of surgery related sedation. I would think this type of precautionary measures would be helpful to people post-ICU treatment.

July 21, 2020 8:45 am

This comment has been removed by the author.

July 21, 2020 8:49 am

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B. Berger

This site was inspired by my Mom’s autoimmune dementia.

It is a place where we separate out the wheat from the chaffe, the important articles & videos from each week’s river of news. With a new post on Alzheimer’s or dementia appearing on the internet every 7 minutes, the site’s focus on the best information has been a help to many over the past 15 years. Thanks to our many subscribers for your supportive feedback.

The site is dedicated to all those preserving the dignity of the community of people living with dementia.

Peter Berger, Editor

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This site was inspired by my Mom’s autoimmune dementia.

It is a place where we separate out the wheat from the chaffe, the important articles & videos from each week’s river of news. With a new post on Alzheimer’s or dementia appearing on the internet every 7 minutes, the site’s focus on the best information has been a help to many over the past 15 years. Thanks to our many subscribers for your supportive feedback.

The site is dedicated to all those preserving the dignity of the community of people living with dementia.

Peter Berger, Editor

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