Category: neuroscience

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Unraveling the Interplay of Omicron, Reinfections, and Long Covid

Liz Szabo, Kaiser Health News

The latest covid-19 surge, caused by a shifting mix of quickly evolving omicron subvariants, appears to be waning, with cases and hospitalizations beginning to fall.

Like past covid waves, this one will leave a lingering imprint in the form of long covid, an ill-defined catchall term for a set of symptoms that can include debilitating fatigue, difficulty breathing, chest pain, and brain fog.

Although omicron infections are proving milder overall than those caused by last summer’s delta variant, omicron has also proved capable of triggering long-term symptoms and organ damage. But whether omicron causes long covid symptoms as often — and as severe — as previous variants is a matter of heated study.

Michael Osterholm, director of the University of Minnesota’s Center for Infectious Disease Research and Policy, is among the researchers who say the far greater number of omicron infections compared with earlier variants signals the need to prepare for a significant boost in people with long covid. The U.S. has recorded nearly 38 million covid infections so far this year, as omicron has blanketed the nation. That’s about 40% of all infections reported since the start of the pandemic, according to the Johns Hopkins University Coronavirus Research Center.

Long covid “is a parallel pandemic that most people aren’t even thinking about,” said Akiko Iwasaki, a professor of immunobiology at Yale University. “I suspect there will be millions of people who acquire long covid after omicron infection.”

Scientists have just begun to compare variants head to head, with varying results. While one recent study in The Lancet suggests that omicron is less likely to cause long covid, another found the same rate of neurological problems after omicron and delta infections.

Estimates of the proportion of patients affected by long covid also vary, from 4% to 5% in triple-vaccinated adults to as many as 50% among the unvaccinated, based on differences in the populations studied. One reason for that broad range is that long covid has been defined in widely varying ways in different studies, ranging from self-reported fogginess for a few months after infection to a dangerously impaired inability to regulate pulse and blood pressure that may last years.

Even at the low end of those estimates, the sheer number of omicron infections this year would swell long-covid caseloads. “That’s exactly what we did find in the UK,” said Claire Steves, a professor of aging and health at King’s College in London and author of the Lancet study, which found patients have been 24% to 50% less likely to develop long covid during the omicron wave than during the delta wave. “Even though the risk of long covid is lower, because so many people have caught omicron, the absolute numbers with long covid went up,” Steves said.

A recent study analyzing a patient database from the Veterans Health Administration found that reinfections dramatically increased the risk of serious health issues, even in people with mild symptoms. The study of more than 5.4 million VA patients, including more than 560,000 women, found that people reinfected with covid were twice as likely to die or have a heart attack as people infected only once. And they were far more likely to experience health problems of all kinds as of six months later, including trouble with their lungs, kidneys, and digestive system.

“We’re not saying a second infection is going to feel worse; we’re saying it adds to your risk,” said Dr. Ziyad Al-Aly, chief of research and education service at the Veterans Affairs St. Louis Health Care System.

Researchers say the study, published online but not yet peer-reviewed, should be interpreted with caution. Some noted that VA patients have unique characteristics, and tend to be older men with high rates of chronic conditions that increase the risks for long covid. They warned that the study’s findings cannot be extrapolated to the general population, which is younger and healthier overall.

“We need to validate these findings with other studies,” said Dr. Harlan Krumholz, director of the Yale New Haven Hospital Center for Outcomes Research and Evaluation. Still, he added, the VA study has some “disturbing implications.”

With an estimated 82% of Americans having been infected at least once with the coronavirus as of mid-July, most new cases now are reinfections, said Justin Lessler, a professor of epidemiology at the University of North Carolina Gillings School of Global Public Health.

Of course, people’s risk of reinfection depends not just on their immune system, but also on the precautions they’re taking, such as masking, getting booster shots, and avoiding crowds.

New Jersey salon owner Tee Hundley, 43, has had covid three times, twice before vaccines were widely available and again this summer, after she was fully vaccinated. She is still suffering the consequences.

After her second infection, she returned to work as a cosmetologist at her Jersey City salon but struggled with illness and shortness of breath for the next eight months, often feeling like she was “breathing through a straw.”

She was exhausted, and sometimes slow to find her words. While waxing a client’s eyebrows, “I would literally forget which eyebrow I was waxing,” Hundley said. “My brain was so slow.”

When she got a breakthrough infection in July, her symptoms were short-lived and milder: cough, runny nose, and fatigue. But the tightness in her chest remains.

“I feel like that’s something that will always be left over,” said Hundley, who warns friends with covid not to overexert. “You may not feel terrible, but inside of your body there is a war going on.”

Although each omicron subvariant has different mutations, they’re similar enough that people infected with one, such as BA.2, have relatively good protection against newer versions of omicron, such as BA.5. People sickened by earlier variants are far more vulnerable to BA.5.

Several studies have found that vaccination reduces the risk of long covid. But the measure of that protection varies by study, from as little as a 15% reduction in risk to a more than 50% decrease. A study published in July found the risk of long covid dropped with each dose people received.

For now, the only surefire way to prevent long covid is to avoid getting sick. That’s no easy task as the virus mutates and Americans have largely stopped masking in public places. Current vaccines are great at preventing severe illness but do not prevent the virus from jumping from one person to the next. Scientists are working on next-generation vaccines — “variant-proof” shots that would work on any version of the virus, as well as nasal sprays that might actually prevent spread. If they succeed, that could dramatically curb new cases of long covid.

“We need vaccines that reduce transmission,” Al-Aly said. “We need them yesterday.”

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Beyond Burnout: Docs Decry ‘Moral Injury’ From Financial Pressures Of Health Care

Melissa Bailey, Kaiser Health News

Dr. Keith Corl was working in a Las Vegas emergency room when a patient arrived with chest pain. The patient, wearing his street clothes, had a two-minute exam in the triage area with a doctor, who ordered an X-ray and several other tests. But later, in the treatment area, when Corl met the man and lifted his shirt, it was clear the patient had shingles. Corl didn’t need any tests to diagnose the viral infection that causes a rash and searing pain.

All those tests? They turned out to be unnecessary and left the patient with over $1,000 in extra charges.

The excessive testing, Corl said, stemmed from a model of emergency care that forces doctors to practice “fast and loose medicine.” Patients get a battery of tests before a doctor even has time to hear their story or give them a proper exam.

“We’re just shotgunning,” Corl said.

The shingles case is one of hundreds of examples that have led to his exasperation and burnout with emergency medicine. What’s driving the burnout, he argued, is something deeper — a sense of “moral injury.”

Corl, a 42-year-old assistant professor of medicine at Brown University, is among a growing number of physicians, nurses, social workers and other clinicians who are using the phrase “moral injury” to describe their inner struggles at work.

The term comes from war: It was first used to explain why military veterans were not responding to standard treatment for post-traumatic stress disorder. Moral injury, as defined by researchers from veterans hospitals, refers to the emotional, physical and spiritual harm people feel after “perpetrating, failing to prevent, or bearing witness to acts that transgress deeply held moral beliefs and expectations.”

Drs. Wendy Dean and Simon Talbot, a psychiatrist and a surgeon, were the first to apply the term to health care. Both wrestled with symptoms of burnout themselves. They concluded that “moral injury” better described the root cause of their anguish: They knew how best to care for their patients but were blocked from doing so by systemic barriers related to the business side of health care.

That idea resonates with clinicians across the country: Since they penned an op-ed in Stat in 2018, Dean and Talbot have been flooded with emails, comments, calls and invitations to speak on the topic.

Burnout has long been identified as a major problem facing medicine: 4 in 10 physicians report feelings of burnout, according to a 2019 Medscape report. And the physician suicide rate is more than double that of the general population.

Dean said she and Talbot have given two dozen talks on moral injury. “The response from each place has been consistent and surprising: ‘This is the language we’ve been looking for for the last 20 years.’”

Dean said that response has come from clinicians across disciplines, who wrestle with what they consider barriers to quality care: insurance preauthorization, trouble making patient referrals, endless clicking on electronic health records.

Those barriers can be particularly intense in emergency medicine.

Corl said he has been especially frustrated by a model of emergency medicine called “provider-in-triage.” It aims to improve efficiency but, he said, prioritizes speed at the cost of quality care. In this system, a patient who shows up to an ER is seen by a doctor in a triage area for a rapid exam lasting less than two minutes. In theory, a doctor in triage can more quickly identify patients’ ailments and get a head start on solving them. The patient is usually wearing street clothes and sitting in a chair.

These brief encounters may be good for business: They reduce the “door to doc” time — how long it takes to see a doctor — that hospitals sometimes boast about on billboards and websites. They enable hospitals to charge a facility fee much earlier, the minute a patient sees a doctor. And they reduce the number of people who leave the ER without “being seen,” which is another quality measure.

But “the real priority is speed and money and not our patients’ care,” Corl said. “That makes it tough for doctors who know they could be doing better for their patients.”

Dean said people often frame burnout as a personal failing. Doctors get the message: “If you did more yoga, if you ate more salmon salad, if you went for a longer run, it would help.” But, she argued, burnout is a symptom of deeper systemic problems beyond clinicians’ control.

Emergency physician Dr. Angela Jarman sees similar challenges in California, including ER overcrowding and bureaucratic hurdles to discharging patients. As a result, she said, she must treat patients in the hallways, with noise, bright lights and a lack of privacy — a recipe for hospital-acquired delirium.

“Hallway medicine is such a [big] part of emergency medicine these days,” said Jarman, 35, an assistant professor of emergency medicine at UC-Davis. Patients are “literally stuck in the hallway. Everyone’s walking by. I know it must be embarrassing and dehumanizing.”

For example, when an older patient breaks an arm and cannot be released to their own care at home, they may stay in the ER for days as they await evaluation from a physical therapist and approval to transfer to rehab or a nursing home, she said. Meanwhile, the patient gets bumped into a bed in the hallway to make room for new patients who keep streaming in the door.

Being responsible for discharging patients who are stuck in the hallway is “so frustrating,” Jarman said. “That’s not what I’m good at. That’s not what I’m trained to do.”

Jarman said many emergency physicians she knows work part time to curtail burnout.

“I love emergency medicine, but a lot of what we do these days is not emergency medicine,” she said. “I definitely don’t think I’ll make it 30 years.”

Also at UC-Davis, Dr. Nick Sawyer, an assistant professor of emergency medicine, has been working with medical students to analyze systemic problems. Among those they’ve identified: patients stuck in the ER for up to 1,000 hours while awaiting transfer to a psychiatric facility; patients who are not initially suicidal, but become suicidal while awaiting mental health care; patients who rely on the ER for primary care.

Sawyer, 38, said he has suffered moral injury from treating patients like this one: A Latina had a large kidney stone and a “huge amount of pain” but could not get surgery because the stone was not infected and therefore her case wasn’t deemed an “emergency” by her insurance plan.

“The health system is not set up to help patients. It’s set up to make money,” he said.

The best way to approach this problem, he said, is to help future generations of doctors understand “how decisions made at the systems level impact how we care about patients” — so they can “stand up for what’s right.”

Whether these experiences amount to moral injury is open for discussion.

Cynda Rushton, a nurse and professor of clinical ethics at Johns Hopkins University, who has studied the related notion of “moral distress” for 25 years, said there isn’t a base of research, as there is for moral distress, to measure moral injury among clinicians.

But “what both of these terms signify,” Rushton said, “is a sense of suffering that clinicians are experiencing in their roles now, in ways that they haven’t in the past.”

Dean grew interested in moral injury from personal experience: After a decade of treating patients as a psychiatrist, she stopped because of financial pressures. She said she wanted to treat her patients in longer visits, offering both psychotherapy and medication management, but that became more difficult. Insurers would rather pay her for only a 15-minute session to manage medications and let a lower-paid therapist handle the therapy.

Dean and Talbot created a nonprofit advocacy group called Moral Injury of Healthcare, which promotes public awareness and aims to bring clinicians together to discuss the topic.

Their work is attracting praise from a range of clinicians:

In Cumberland County, Pennsylvania, Mary Franco, who is now 65, retired early from her job as a nurse practitioner after a large corporation bought out the private practice she worked in. She said she saw “a dramatic shift” in the culture there, where “revenue became all-important.” The company cut in half the time for each patient’s annual exam, she said, down to 20 minutes. She spent much of that time clicking through electronic health records, she said, instead of looking the patient in the face. “I felt I short-shrifted them.”

In southern Maine, social worker Jamie Leavitt said moral injury led her to take a mental health break from work last year. She said she loves social work, but “I couldn’t offer the care I wanted to because of time restrictions.” One of her tasks was to connect patients with mental health services, but because of insurance restrictions and a lack of quality care providers, she said, “often my job was impossible to do.”

In Chambersburg, Pennsylvania, Dr. Tate Kauffman left primary care for urgent care because he found himself spending half of each visit doing administrative tasks unrelated to a patient’s ailment — and spending nights and weekends slogging through paperwork required by insurers.

“There was a grieving process, leaving primary care,” he said. “It’s not that I don’t like the job. I don’t like what the job has become today.”

Corl said he was so fed up with the provider-in-triage model of emergency medicine that he moved his ER clinical work to smaller, community hospitals that don’t use that method.

He said many people frame burnout as a character weakness, sending doctors messages like, “Gee, Keith, you’ve just got to try harder and soldier on.” But Corl said the term “moral injury” correctly identifies that the problem lies with the system.

“The system is flawed,” he said. “It’s grinding us. It’s grinding good docs and providers out of existence.”

Kaiser Health News is a nonprofit news service covering health issues. It is an editorially independent program of the Kaiser Family Foundation, which is not affiliated with Kaiser Permanente.

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The Necessity of Psychotherapy

Years ago I wrote an essay about the death of psychotherapy. While I did not state that psychotherapy is currently dead, I did state that much of it might die in the wake of advances in understanding the neurobiology of psychological disorders. It will take decades for these advances to occur (if they ever do) so this post will now serve to balance my post from years ago.

I’m going to start with a story about two people (these are based on real events but names, situations, and identifying details have been changed to protect confidentiality). Jim was convicted of a violent crime and spent a number of years in prison. He was required to attend treatment throughout his years in prison – anger management and other therapies. He had a history of alcohol and drug abuse. A while after he got out of prison, he started therapy again to help him through some difficulties, including his experiences with homelessness. Jim was a very pleasant person to interact with; he was well-read and insightful. He was trying to improve his life.

The second person was named Frank. He was also homeless but was staying with a friend. He had past drug and alcohol abuse but had been free from drugs for about a year. He was anxious, paranoid, and not the most pleasant person to interact with. He had never received treatment for depression, which he experienced chronically and severely. He exhibited little insight into his problems. He thought the negative events in his life were all someone or something else’s fault.

The first patient had learned a lot from his psychotherapy over the years. The second never had therapy. While they were very different people, they experienced similar challenges and psychological issues over the years. Without disregarding individual differences, the patient who had had years of therapy had a lot of insight and self-knowledge but the other patient had very little.

Jim had been a violent man but over the years and through therapy, he learned a great deal of self-control and restraint. Psychotropic medications could not have taught Jim this. For him, psychotherapy was highly successful. Without out it he might not have been the pleasant person that he was.

Therapy teaches you skills; it gives you tools to deal with maladaptive thoughts and behaviors. It allows you opportunity to sort through your experiences and thoughts in a safe place. It allows to to talk to someone else without being judged. Therapy is thus treatment and education. It can have as strong or stronger effects on mood and behavior as medications and the benefits can last longer. Understanding biology is necessary to understand behavior but it is not sufficient to explain all behavior, at least not with our current knowledge. Will we ever had sufficiently advanced knowledge of neuroscience and biology to no longer need psychotherapy? I don’t know but if we do, it won’t happen for many years.

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One in five older adults experience brain network weakening following knee replacement surgery

Gainesville, FL – A new University of Florida study finds that 23 percent of adults age 60 and older who underwent a total knee replacement experienced a decline in activity in at least one region of the brain responsible for specific cognitive functions. Fifteen percent of patients declined across all brain networks the team evaluated.

“In essence, normally synchronized parts of the brain appeared more out of sync after surgery,” said Jared Tanner, Ph.D., the study’s co-lead author and a research assistant professor in the department of clinical and health psychology in the UF College of Public Health and Health Professions, part of UF Health.

Patients who were cognitively weaker before surgery – with worse working memory, slowed mental processing and evidence of brain atrophy as seen in imaging scans – demonstrated the biggest network declines after surgery.

Researchers say they do not yet know if or how patients perceive these network declines. They may contribute to brain “fuzziness” some patients experience right after surgery.

The study, which was published today online ahead of print in the Journal of Alzheimer’s Disease, was conducted to help scientists understand the causes of postsurgical cognitive impairment, which causes memory and thinking problems in about 15 to 30 percent of older adult patients, Tanner said. In most cases, these thinking and memory problems will resolve within six months to a year after surgery.

“Our study builds on 50 years of research into how the aging brain responds to anesthesia and surgery,” Tanner said. “We know older age and cognitive impairment before surgery are risk factors, but the specific causes are not known.”

For the UF study, the team conducted cognitive and brain imaging tests before and after surgery on 48 patients ages 60 and older undergoing a knee replacement. Results were compared with age-matched adults who have knee osteoarthritis, but did not have surgery.

The researchers used resting state functional MRI to look at patterns of blood flow in the brain while patients were lying still. Imaging data helped researchers understand how blood flow changes affected connections across brain networks that are responsible for functions such as memories of oneself and others, determining what outside stimuli deserve further attention, and working memory.

Participants who did not have surgery did not demonstrate any changes across the two brain scans, but 23 percent of participants who had knee replacement surgery showed large declines in connectivity in at least one brain network when tested 48 hours after surgery.

“It was surprising to observe such significant effects of orthopedic surgery on the human brain,” said Haiqing Huang, Ph.D., the study’s other lead author, a data manager at the University of Pittsburgh’s Brain Aging & Cognitive Health Lab and a graduate of the biomedical engineering program at the UF Herbert Wertheim College of Engineering.

The investigators say more research is needed to learn if the brain network changes persist.

“Our goals include investigating if patients who have this brain change after surgery continue to show this change later in their recovery, say at three months or one year after the surgery,” said Catherine Price, Ph.D., the study’s senior author and a UF associate professor of clinical and health psychology and anesthesiology.

People with concerns about their attention or memory should discuss them with their surgical team, Tanner said. At UF Health, neuropsychologists and anesthesiologists have established what is believed to be the first clinical service to identify older adults who may be at risk of developing cognitive problems after surgery so that health care providers can intervene to lessen the impact.

“We strongly believe clinicians need to consider preoperative memory and attention abilities in their patients,” said Price, also the co-director of the Perioperative Cognitive and Anesthesia Network, or PeCAN, service. “Across the nation, however, cognition is not routinely assessed prior to surgery.”

There are also actions patients can take on their own, based on previous studies of healthy aging.

“The brain is resilient and there are things we can do to help protect our brains before and after surgery,” Tanner said. “Exercise, following a Mediterranean-style diet (primarily vegetables, fruits and whole grains), remaining mentally and socially active and otherwise striving to stay as healthy as possible – all might help patients’ brains cope with surgery better,” Tanner said.

—

Mingzhou Ding, Ph.D., of the J. Crayton Pruitt Family department of biomedical engineering in the Herbert Wertheim College of Engineering, served as the study’s other senior author. The project is part of a larger investigation involving Thomas Mareci, Ph.D., of the department of biochemistry and molecular biology in the College of Medicine and the Evelyn F. and William L. McKnight Brain Institute; Hari Parvataneni, M.D., of the department of orthopaedics and rehabilitation in the College of Medicine; Ilona Schmalfuss, M.D., of the department of radiology in the College of Medicine; Mark Rice, M.D., and Cynthia Garvan, Ph.D., of the department of anesthesiology in the College of Medicine; and Ann Horgas, Ph.D., of the department of biobehavioral nursing science in the College of Nursing. The research was supported by funding from the National Institutes of Health.

Press release source.

Reference

Huang H, Tanner J, Parvataneni H, Rice M, Horgas A, Ding M, Price C (2018) Impact of Total Knee Arthroplasty with General Anesthesia on Brain Networks: Cognitive Efficiency and Ventricular Volume Predict Functional Connectivity Decline in Older Adults. J Alzheimers Dis 62, 319-333.

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Collaborative Learning: The Example of Quizlet

One of the benefits of the internet and world wide web are the opportunities for collaborative learning and work. The distributed structure of the internet mirrors the brain in many ways. While specific parts of the brain are specialized for specific tasks, wide areas of the brain are needed to do just about anything. The interconnectedness of major brain networks are visualized in the following image.

brain_networks

Portions of the internet have also been visualized in similar ways, such as this image produced in 2010 by AT&T Labs.

ATT_internet_map

What does this have to do with collaborative learning?

One example is the site Quizlet.com (I have no affiliation with them). Quizlet is a site billing itself as providing “Simple tools for learning anything. Search millions of study sets or create your own. Improve your grades by studying with flashcards, games and more.”

People can create study sets (digital flashcards) about just about any topic. The site is particularly helpful for middle and high school students who can access content created by others or provide their own content.

Do you need to study vocabulary words for the SAT? There is a study set with words that might appear on the test.

Do you need to study for an AP Psychology test? Here’s a set of terms that might be helpful.

Whether you are lazy and don’t want to create your own study materials, are interested in learning something new, have a big test coming up, or want to help other people, sites like Quizlet provide opportunities for collaborative learning.

Image sources

Hagmann P, Cammoun L, Gigandet X, Meuli R, Honey CJ, Wedeen VJ, Sporns O (2008) Mapping the structural core of human cerebral cortex. PLoS Biology Vol. 6, No. 7, e159.

http://www.research.att.com/export/sites/att_labs/groups/infovis/news/img/ATT_Labs_InternetMap_0730_10.pdf

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Memory Problems in Some With Parkinson’s Disease

From a recent news release by Jill Pease at the University of Florida.

Using a combination of neuropsychological testing and brain imaging, University of Florida researchers have discovered that in a group of recently-diagnosed patients with Parkinson’s disease, about one quarter have significant memory problems.

Parkinson’s disease is commonly known as a movement disorder that leads to tremors and muscle rigidity, but there is growing recognition of cognitive problems associated with the disease. One of the most common is slower thinking speed that causes patients to have trouble quickly retrieving information. The UF study identifies a subset of patients who have a different kind of cognitive issue — memory problems, or difficulty learning and retaining new information.

The findings were published July 24 in the journal PLOS ONE.

“While a large proportion of people with Parkinson’s will experience slower thinking speed, which may make them less quick to speak or have difficulty doing two things at once, we now know that there are a subset of individuals with Parkinson’s disease who have memory problems,” said Catherine Price, Ph.D., the study’s senior author and an associate professor in the UF College of Public Health and Health Professions’ department of clinical and health psychology, part of UF Health. “It is important to recognize which people have issues with learning and memory so we can improve diagnostic accuracy and determine if they would benefit from certain pharmaceutical or behavioral interventions.”

For the UF study, 40 people in the early stages of Parkinson’s disease and 40 healthy older adults completed neuropsychological assessments and verbal memory tests.

About half the participants with Parkinson’s disease struggled with an aspect of memory, such as learning and retaining information, or recalling verbal information, said lead author Jared Tanner, Ph.D., an assistant research professor in the UF department of clinical and health psychology who conducted the study as part of his dissertation research for a UF doctoral degree in clinical psychology.

“And then half of those participants, or nearly one quarter of all participants with Parkinson’s, were really having a difficult time consistently with their memory, enough that it would be noticeable to other people,” said Tanner, adding that researchers were encouraged by the fact that most participants in the initial stages of Parkinson’s were not having significant memory problems.

All participants received brain scans, which used new imaging techniques that allowed the scientists to navigate the pathways of white matter fibers, the tissue through which messages travel across the brain. The methodology was developed by the research group ofThomas Mareci, Ph.D., a professor of biochemistry and molecular biology in the UF College of Medicine, and is described in a paper published July 14 in PLOS ONE.

Experts have theorized that cognitive problems in Parkinson’s are caused by a shortage of the brain chemical dopamine, which is responsible for patients’ motor issues. But with the help of imaging, the UF researchers were able to spot changes in the brain’s gray and white matter that appear unrelated to dopamine loss and are specific to those patients with Parkinson’s who have memory problems.

“Not only is gray matter important for memory, in Parkinson’s disease white matter connections between the temporal lobe and a region in the posterior portion of the brain called the retrosplenial cortex were particularly important in the recall of verbal information,” Tanner said. “People with Parkinson’s disease who had stronger connections between these areas of the brain did better at remembering information.”

Tanner’s study is part of a larger research project supported by a $2.1 million grant from the National Institute of Neurological Disorders and Stroke of the National Institutes of Health. Researchers led by Price are using imaging and cognitive testing to determine profiles for the cognitive problems that most commonly affect patients with Parkinson’s. The information gleaned from the research could help clinicians foreshadow the type of cognitive impairment a patient may experience over time, if any, and tailor treatment plans accordingly.

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GABA receptor role in postoperative cognitive decline

About 20-30% of older adults (age greater than 60) undergoing major surgery experience temporary (generally reversed) memory and thinking deficits after major surgery, particularly heart and orthopedic. A small minority (<5%, probably much less) might not return to cognitive baseline (how they were before surgery). The cause of this decline in cognition is unclear, although many attribute it to the anesthesia used. So far, however, research has been inconclusive as to specific causes of cognitive difficulties after surgery. This is because surgeries are major events that affect most parts of the body, not just what is being operated upon. They are stressful – physically and emotionally.

Newly published research proposes one mechanism for causes of memory problems after surgery – anesthesia acting on ɣ-aminobutyric acid type A receptors (ɣ5GABAaR). This new research suggests that the function of these receptors does not return to baseline until much later than previously believed. This means that the normal function of chemicals in the brain, particularly ones important for memory, might be disrupted for longer than expected, and might play a role in memory problems that some individuals experience after major surgery.

Reference

Zurek, A. A., Yu, J., Wang, D. S., Haffey, S. C., Bridgwater, E. M., Penna, A., … & Orser, B. A. (2014). Sustained increase in ?5GABA A receptor function impairs memory after anesthesia. The Journal of clinical investigation, 124(12).

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Modeling the Human Brain

Wired has an article about Dr. Henry Markram’s goal to simulate an entire human brain within 10 years. While his goal will not be met within that time-frame, this is important work to do. If we can have a way to simulate brain development or function, it can help us understand how brain disorders occur and help with the treatment of them.

One of the great things about the project is the collaborative nature of it: “‘But the only way you can find out is by building it,’ [Markram] says, ‘and just building a brain is an incredible biological discovery process.’ This is too big a job for just one lab, so Markram envisions an estimated 6,000 researchers around the world funneling data into his model…. Neuroscientists can spend a whole career on a single cell or molecule. Markram will grant them the opportunity and encouragement to band together and pursue the big questions.”

Read the Wired article for more information about the project and the 1 billion Euro grant Markham received.

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Intelligence and Neurological Conditions

Intelligence is an interesting concept. We have tests that measure what we call intelligence but such tests are limited and culture-centric (not that that is necessarily a negative thing). However, for the sake of discussion I will operationally define aptitude (i.e., intelligence) as Intelligence Quotient so as to have a standard metric as foundation for this post.

I spend time assessing people’s memory and thinking abilities. I almost always try to get some measure of baseline aptitude either by estimating it (e.g., years of education, vocabulary knowledge, word reading ability) or by formally measuring via an intelligence test. Granted, this has limitations but it allows me to estimate how well an individual’s brain should function across multiple domains of thinking (e.g., problem-solving, reasoning, memory, language, and so forth). In other words, the higher a person’s general aptitude (abilities), the better he generally will do across most cognitive domains barring brain insult. This is certainly not a rule codified in stone and in triplicate but it serves as a rubric to follow.

Intelligence as measured by IQ is generally quite stable across the lifespan but can improve modestly with  diligence in informal or formal education. Intelligence as denoted by IQ can also decrease modestly if people are intellectually inactive, although such declines are slight. What can happen though is as brains age or if damaged by a pathological process or an injury, components of IQ can decrease. My primary clinical and research focus is in understanding how brains and cognition change in old age – both naturally and in the presence of neurological (brain) insult. Remarkably, the measures we use for intelligence tend to be rather insensitive to aging and even neurological insult, at least some of the components of intelligence are generally insensitive to brain insult. However, this leads to one area where our conceptualization of intelligence as IQ starts to break down.

As they age, the brains of people almost universally slow down. Wear and tear on the brain over decades of life affects how well and quickly we can think. Blood, which is essential for life and for the functioning of the brain, happens to be toxic to brain cells. Sometimes the protections in the brain that keep blood far enough from brain cells (neurons) to protect them but near enough to feed and maintain brain cells start to break down over time. This can injure the brain and start to reduce how well the brain works, even lowering IQ. Now, does that mean that a person’s intelligence decreases? If IQ = intelligence, then yes, it does. Contrary to how I operationalized intelligence earlier, intelligence is not synonymous with IQ. IQ can be a useful concept but it is far from perfect, particularly if by using it one argues that someone is less intelligent simply because his head was injured in an accident or because she developed dementia or suffered a stroke.

This is an area that demonstrates the limitations of our current research and clinical conceptualizations of intelligence. However, understanding how IQ changes over time and how it is affected by neurological conditions is important information to have, as it can help localize areas of pathology.

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The Magic of Deep Brain Stimulation Surgery

Deep brain stimulation (DBS) is a neurosurgery where an electrode (or electrodes) is implanted within the deep portions of the brain with the hope of changing an abnormally functioning brain. DBS is used to treat Parkinson’s disease, essential tremor, multiple sclerosis, and even some intractable depression and obsessive-compulsive disorder. It is an exciting area of research and clinical work. Here is a video of a neurosurgeon and a neurologist talking about their work with DBS. It almost seems like magic. Like magic, it can be dangerous without proper controls. It does wonders for many people though.

 

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