‘Executive dysfunction‘ is not, perhaps, a particularly well known term, but the effects of brain injury that it covers are very common indeed. It is used to collectively describe impairment in the ‘executive functions’ – the key cognitive, emotional and behavioural skills that are used to navigate through life, especially when undertaking activities and interacting with others.
Although executive dysfunction is a common problem among many brain injury survivors, it is most commonly experienced following an injury to the frontal lobe.
The importance of executive functions is shown by the difficulties caused when they don’t work properly and someone has problems with executive dysfunction. Since the executive functions are involved in even the most routine activities, frontal injuries leading to executive dysfunction can lead to problems in many aspects of life.
Here we list the most common effects of executive dysfunction, with some examples of common issues that brain injury survivors can face:
Difficulties with motivation and organisation
Loss of ‘get up and go’, which can be mistaken for laziness
Problems with thinking ahead and carrying out the sequence of steps needed to complete a task
Difficulty in evaluating the result of actions and reduced ability to change behaviour or switch between tasks if needed
Poor problem solving
Finding it hard to anticipate consequences
Decreased ability to make accurate judgements or find solutions if things are going wrong
Acting too quickly and impulsively without fully thinking through the consequences, for example, spending more money than can be afforded
Difficulty in controlling emotions which may lead to outbursts of emotion such as anger or crying
Rapid mood changes may occur, for example, switching from happiness to sadness for no apparent reason
Difficulties in social situations
Reduced ability to engage in social interactions
Finding it hard to initiate, participate in, or pay attention to conversations
Poor judgement in social situations, which may lead to saying or doing inappropriate things
Finding it harder to concentrate
Difficulty with learning new information
Decreased memory for past or current events, which may lead to disorientation
Find out more
If you or someone you care for is affected by executive dysfunction, it is important to seek support. Speak to your doctor about your symptoms, and ask about referral to specialist services such as counselling, neuropsychology and rehabilitation.
As a translational neuroscientist, this work immediately piqued my interest. It has direct implications for the research my lab does: We transplant young neurons into damaged brain areas in mice in an attempt to treat epileptic seizures and the damage they’ve caused. Like many labs, part of our work is based on a foundational belief that the hippocampus is a brain region where new neurons are born throughout life.
If the new study is right, and human brains for the most part don’t add new neurons after infancy, researchers like me need to reconsider the validity of the animal models we use to understand various brain conditions – in my case temporal lobe epilepsy. And I suspect other labs that focus on conditions including drug addiction, depression and post-traumatic stress disorder are thinking about what the UCSF study means for their investigations, too.
Neurogenesis – the production of new neurons – was previously thought to only occur during embryonic life, a time of extremely rapid brain growth and expansion, and the rodent findings were met with considerable skepticism. Then researchers discovered that new neurons are also born throughout life in the songbird brain, a species scientists use as a model for studying vocal learning. It started to look like neurogenesis plays a key role in learning and neuroplasticity – at least in some brain regions in a few animal species.
Even so, neuroscientists were skeptical that many nerve cells could be renewed in the adult brain; evidence was scant that dividing cells in mammalian brains produced new neurons, as opposed to other cell types. It wasn’t until researchers extracted neural stem cells from adult mouse brains and grew them in cell culture that scientists showed these precursor cells could divide and differentiate into new neurons. Now it is generally well accepted that neurogenesis takes place in two areas of the adult rodent brain: the olfactory bulbs, which process smell information, and the hippocampus, a region characterized by neuroplasticity that is required for forming new declarative memories.
Adult neural stem cells cluster together in what scientists call niches – hotbeds for cultivating the birth and growth of new neurons, recognizable by their distinctive architecture. Despite the mounting evidence for regional growth of new neurons, these studies underscored the point that the adult brain harbors only a few stem cell niches and their capacity to produce neurons is limited to just a few types of cells.
With this knowledge, and new tools for labeling proliferating cells and identifying maturing neurons, scientists began to look for postnatal neurogenesis in primate and human brains.
What’s happening in adult human brains?
Many neuroscientists believe that by understanding the process of adult neurogenesis we’ll gain insights into the causes of some human neurological disorders. Then the next logical step would be trying to develop new treatments harnessing neurogenesis for conditions such as Alzheimer’s disease or trauma-induced epilepsy. And stimulating resident stem cells in the brain to generate new neurons is an exciting prospect for treating neurodegenerative diseases.
However, obtaining rigorous proof for adult neurogenesis in the human and primate brain has been technically challenging – both due to the limited experimental approaches and the larger sizes of the brains, compared to reptiles, songbirds and rodents.
But even when scientists saw evidence for new neurons in the brain, they tended to be scarce. Some neurogenesis experts were skeptical that evidence based on incorporating BrdU into DNA was a reliable method for proving that new cells were actually being born through cell division, rather than just serving as a marker for other normal cell functions.
Further questions about how long human brains retain the capacity for neurogenesis arose in 2011, with a study that compared numbers of newborn neurons migrating in the olfactory bulbs of infants versus older individuals up to 84 years of age. Strikingly, in the first six months of life, the baby brains contained lots of chains of young neurons migrating into the frontal lobes, regions that guide executive function, long-range planning and social interactions. These areas of the human cortex are hugely increased in size and complexity compared to rodents and other species. But between 6 to 18 months of age, the migrating chains dwindled to a thin stream. Then, a very different pattern emerged: Where the migrating chains of neurons had been in the infant brain, a cell-free gap appeared, suggesting that neural stem cells become depleted during the first six months of life.
Now the largest and most comprehensive study conducted to date presents even stronger evidence that robust neurogenesis doesn’t continue throughout adulthood in the human hippocampus – or if it does persist, it is extremely rare. This work is controversial and not universally accepted. Critics have been quick to cast doubt on the results, but the finding isn’t totally out of the blue.
So where does this leave the field of neuroscience? If the UCSF scientists are correct, what does that mean for ongoing research in labs around the world?
Because lots of studies of neurological diseases are done in mice and rats, many scientists are invested in the possibility that adult neurogenesis persists in the human brain, just as it does in rodents. If it doesn’t, how valid is it to think that the mechanisms of learning and neuroplasticity in our model animals are comparable to those in the human brain? How relevant are our models of neurological disorders for understanding how changes in the hippocampus contribute to disorders such as the type of epilepsy I study?
In my lab, we transplant embryonic mouse or human neurons into the adult hippocampus in mice, after damage caused by epileptic seizures. We aim to repair this damage and suppress seizures by seeding the mouse hippocampus with neural stem cells that will mature and form new connections. In temporal lobe epilepsy, studies in adult rodents suggest that naturally occurring hippocampal neurogenesis is problematic. It seems that the newborn hippocampal neurons become highly excitable and contribute to seizures. We’re trying to inhibit these newborn hyperexcitable neurons with the transplants. But if humans don’t generate new hippocampal neurons, then maybe we’re developing a treatment in mice for a problem that has a different mechanism in people.
Perhaps our species has evolved separate mechanisms for neuroplasticity, distinct from those used by species such as rats and mice. One possibility is that there are other sites in the human brain where neurogenesis occurs – its a big structure and more exploration will be necessary. If it turns out to be true that the human brain has a diminished capacity for neurogenesis after birth, the finding will have important implications for how neuroscientists like me think about tackling brain disorders.
Perhaps most importantly, this work underscores how crucial it is to learn how to increase the longevity of the neurons we do have, born early in life, and how we might replace or repair neurons that become damaged.
Precisely timed electrical stimulation to the left side of the brain can reliably and significantly enhance learning and memory performance by as much as 15 percent, according to a study by a team of University of Pennsylvania neuroscientists published in Nature Communications. It is the first time such a connection has been made and is a major advance toward the goal of Restoring Active Memory, a U.S. Department of Defense-sponsored project aimed at developing next-generation technologies to improve memory function in veterans with memory loss.
“Our study has two novel aspects,” said Youssef Ezzyat, a senior data scientist in Penn’s psychology department in the School of Arts and Sciences and lead author on the paper. “We developed a system to monitor brain activity and trigger stimulation responsively based on the subject’s brain activity. We also identified a novel target for applying stimulation, the left lateral temporal cortex.”
In previous work by the Penn team, led by Michael Kahana, professor of psychology and RAM program principal investigator, and Daniel Rizzuto, director of cognitive neuromodulation, electrical pulses were delivered at regular intervals, independent of a subject’s success at learning. For example, during a free-recall memory task, researchers presented words on a screen for the patient to learn, and they applied brain stimulation with every other word in an effort to improve the outcome. In this case, the stimulation was not in response to specific brain-activity patterns.
In the current study, they took a different tack, one that included monitoring a patient’s brain activity in real time during a task. As the patient watched and attempted to absorb a list of words, a computer tracking and recording brain signals would make predictions based on those signals and then prompt an electrical pulse, at safe levels and unfelt by the participants, when they were least likely to remember the new information.
“During each new word the patient viewed, the system would record and analyze brain activity to predict whether the patient had learned it effectively. When the system detected ineffective learning, that triggered stimulation, closing the loop,” Ezzyat said.
After stimulation was turned off, the system would again listen to the subject’s brain activity, waiting for the next appropriate opportunity to generate the pulse.
The study involved 25 neurosurgical patients receiving treatment for epilepsy. Patients participated at clinical sites across the country, including the Hospital of the University of Pennsylvania, Thomas Jefferson University Hospital, University of Texas Southwestern, Emory University Hospital, Dartmouth-Hitchcock Medical Center and Mayo Clinic. All subjects had already had electrodes implanted in their brains as part of routine clinical treatment for epilepsy.
To build the models that used brain activity to make predictions, each participant performed the free-recall memory task during at least three 45-minute sessions before the Penn team introduced any closed-loop stimulation; multiple sessions increased the confidence that the brain activity linked to ineffective learning reflected a true pattern rather than an accidental blip. Patients then took part in at least one session involving brain stimulation.
“By developing patient-specific, personalized, machine-learning models,” Kahana said, “we could program our stimulator to deliver pulses only when memory was predicted to fail, giving this technology the best chance of restoring memory function. This was important because we knew from earlier work that stimulating the brain during periods of good function was likely to make memory worse.”
With this finding, the four-year RAM project comes closer to a fully implantable neural monitoring and stimulation system. The researchers said they believe there is great potential for the therapeutic benefits of this stimulation, particularly for people with traumatic brain injury and Alzheimer’s disease.
“Now we know more precisely,” Rizzuto said, “where to stimulate the brain to enhance memory in patients with memory disorders, as well as when to stimulate to maximize the effect.”
Michael Sperling, clinical study investigator at Thomas Jefferson University Hospital, added, “We are now able to monitor when the brain seems to be going off course and to use stimulation to correct the trajectory. This finding took an incredible amount of effort by not only the researchers but also by our patients, who were extraordinarily dedicated to participating in this project so that others might be helped.”
Youssef Ezzyat et al. Closed-loop stimulation of temporal cortex rescues functional networks and improves memory, Nature Communications (2018). DOI: 10.1038/s41467-017-02753-0
Tickling the brain with low-intensity electrical stimulation in a specific area can improve verbal short-term memory. Mayo Clinic researchers report their findings in Brain.
The researchers found word recall was enhanced with stimulation of the brain’s lateral temporal cortex, the regions on the sides of the head by the temples and ears. Patients recalled more words from a previously viewed list when low-amplitude electrical stimulation was delivered to the brain. One patient reported that it was easier to picture the words in his mind for remembering.
“The most exciting finding of this research is that our memory for language information can be improved by directly stimulating this underexplored brain area,” says Michal Kucewicz, Ph.D., a Mayo Clinic researcher in the Department of Neurology and co-first author. Dr. Kucewicz compares the stimulation to “tickling” the brain.
Memory impairments are a prevalent, costly problem in many brain diseases. Medication and behavioral therapies have limited effectiveness in many cases. “While electrical stimulation of the brain is emerging as potential therapy for a wide range of neurological and psychiatric diseases, little is known about its effect on memory,” says Gregory Worrell, M.D., Ph.D., a Mayo Clinic neurologist and senior author of the article.
The Mayo researchers are part of a multicenter collaboration led by Michael Kahana, Ph.D., University of Pennsylvania in Philadelphia. This collaboration includes seven academic medical centers.
“The next step for this project is to determine how to best apply electrical current in terms of the exact location within this area of the brain, timing and parameters of stimulation,” says Brent Berry, M.D., Ph.D., a Mayo Clinic researcher in the Department of Physiology and Biomedical Engineering and co-first author.
In this Brain paper, Drs. Kucewicz and Berry, and colleagues focused their study on four areas of the brain known to support memory for facts and events that can be consciously recalled.
The memory testing was done with patients undergoing evaluation for surgery to address seizures. These patients agreed to have their memory investigated using the electrodes implanted in their brains for surgical evaluation. It is common for people with epilepsy to have memory problems because the brain circuits that underlie memory function often are affected by epilepsy.In the study, patients were instructed to read a list of words—one at a time—from a computer screen. Electrical stimulation was applied some of this time. Patients then attempted to freely recall the words in any order.
Among 22 patients, the researchers found enhanced memory performance in the four patients with stimulation of the lateral temporal cortex but not among those with the other brain regions stimulated.
“These findings may lead to new stimulation devices that treat deficits in memory and cognition,” says Jamie Van Gompel, M.D., a Mayo Clinic neurosurgeon specializing in brain stimulation and an author in the study.
The authors note study limitations include pain and seizure medications that may affect patient performance, the hospital setting that may disrupt patients‘ sleep and wake cycles, and the fact that epilepsy affects memory.
Regardless of how mild or severe these memory problems may be, they are definitely distressing and can affect an individual’s quality of life.
New research from the Semel Institute for Neuroscience and Human Behavior at the University of California, Los Angeles suggests that there is a relatively easy way of keeping your brain in top shape as you grow older: take a moderately long walk every day.
This could boost your attention, the efficiency with which you process information, and other cognitive skills, say first study author Prabha Siddarth and colleagues.
The research findings were recently published the Journal of Alzheimer’s Disease.
Cortical thickness to assess cognitive health
Siddarth and team initially recruited 29 adults aged 60 and over, of which 26 completed the study over a 2-year period. The participants were split into two distinct groups:
a low physical activity group, comprising people who walked 4,000 or fewer steps each day
a high physical activity group, made up of people who walked more than 4,000 steps per day
All the participants reported a degree of memory complaints at baseline, but none of them had a dementia diagnosis.
In order to explore the potential effect of physical activity on cognitive ability, the researchers used MRI to determine the volume and thickness of the hippocampus, which is a brain region associated with memory formation and storage, and spatial orientation.
Previous research suggested that the size and volume of this brain region can tell us something about cognitive health. For instance, a higher hippocampal volume has been shown to indicate more effective memory consolidation.
“Few studies have looked at how physical activity affects the thickness of brain structures,” says Siddarth.
“Brain thickness,” she notes, “a more sensitive measure than volume, can track subtle changes in the brain earlier than volume and can independently predict cognition, so this is an important question.”
Walk more every day for a resilient brain
In addition to the MRI scans, the participants also underwent a set of neuropsychological tests, to consolidate the assessment of their cognitive capacity.
It was found that those in the high physical activity group — who walked more than 4,000 steps (approximately 3 kilometers) each day — had thicker hippocampi, as well as thicker associated brain regions, when compared with that of the those falling under the low physical activity category.
The highly active group was also found to have better attention, speedier information processing abilities, and more efficient executive function, which includes working memory. Working memory is the resource that we tap into on a daily basis when we need to make spontaneous decisions.
However, Siddarth and colleagues reported no significant differences between the high activity and low activity groups when it came to memory recall.
The next step from here, the researchers suggest, should be to undertake a longitudinal analysis in order to test the relationship between physical activity and cognitive ability over time.
They also note the need to better understand the mechanisms behind cognitive decline in relation to hippocampal atrophy.
Whether you’re awake or asleep, your brain is continuously active. Vast amounts of information—thoughts, moments, feelings, etc.—are sent to your brain, where they are filtered and stored, and it’s important for your brain to be working properly in order to place them in the right spots.
After surviving a stroke, there is a possibility that some of the brain’s vital functions could be damaged, which makes its processes more difficult to carry out, potentially causing harmful issues for the patient. In many stroke cases, issues with thinking and memory are likely to occur, but there are ways to rebuild brain power and regain a healthy lifestyle over time.
Common Problems After a Stroke
Due to physical trauma to the brain, it’s common to experience a variety of issues. Daily actions, like executing a simple task or reacting to external situations, can become difficult to navigate. These kinds of challenges may include watching a television show, reading a book, following through with a task from start to finish, remembering what others have just told you, troubles with directions, executing simple instructions, and even cooking for yourself. If these don’t sound cumbersome enough, along with a slew of physical hurdles lies a deeper obstacle of impaired cognition.
Continue reading our previous post Most Common Questions Answered for more common stroke recovery questions & answers.
Cognitive Problems After a Stroke
Impairments dealing with cognition refer to mental actions and operations that the brain cannot fully sort out. Basically, there is a lack of communication when it comes to gaining information and understanding through vital pathways—thoughts, experiences, and the senses. Because of this, a stroke survivor can possibly mimic symptoms of someone who has dementia or memory loss.
Depending on which side of the brain is most affected by a stroke, different symptoms can occur. For example, someone with a right-brain stroke can exhibit complications with problem solving. In addition, they may confuse information or muddle up the order of details of an event. For those who are left-brain impacted, there may be a significant change to their short-term memory. In this case, a survivor may have a hard time learning new things and will most likely have to be reminded of something many times. That being said, there are ways to help improve cognitive abilities with patience and repetition, and it all starts with rebuilding memory.
Memory Loss After a Stroke
Not only is it common for stroke survivors, but memory loss can be an issue for anyone. Factors like old age and physical accidents can contribute to its deterioration, so understanding its processes can provide a better scope of what to expect.
Visual confusion with faces, objects, and directions
Trouble with new information and tasks
Inability to think clearly
Although these issues may seem challenging, keep in mind that one’s memory has the capability to heal itself over time with the help of mental exercises. Daily routines of mental stimulation may aid in rebuilding awareness and focus, and the best part is that these activities can be enjoyable. There are ways to incorporate a variety of exercises into your life that can make a big difference towards a healthy recovery. Remember, memory symptoms have the potential to last for years, so it’s unlikely that progress will be made overnight, but consistency can set the pace for improvement.
Something else to keep in mind is that techniques for improving after memory loss are considered experimental. In most stroke cases, treatments are designed to help prevent further damage, so if you or a loved one feel like treatments aren’t working, consult with your doctor about taking medications that may assist in rehabilitation.
Ways to Stimulate the Brain
The good news is that there are many options to increase your brain power, and they are all useful in more ways than one! For instance, taking up a new hobby that involves both the mind and body is a great way to work your brain muscles. In addition, performing various physical movements shows a huge correlation with growth in mental and physical strength. Along with these methods, great improvements of mental health can be made by following a routine. Simple tasks like writing things down, designating certain spots for items, and overall repetition provide stability and reassurance.
Rather than focusing all your attention on classic methods of brain stimulation, try technology; it can be an immediate and fun way to see results. On a smartphone or tablet you’ll find countless apps available that can help improve memory and speech, set reminders for medications and appointments, and help manage other illnesses or issues that you may have. With today’s growing technology, apps are both widely accessible and easy to use, giving you freedom to develop your own regiment of “app rehab.”
Here are some of our favorite apps to try out:
What’s the Difference?
In this game, two pictures will appear on the screen, and it’s your job to use your finger and circle any differences you spot on the image below compared to the image above. As you move from one level to the next, the differences will be harder to find! This game will improve your awareness and perception skills with every round.
Thinking Time Pro
Designed by Harvard and UC Berkeley neuroscientists, this app uses four different scientific games to enhance your memory, attention, reasoning, and overall cognitive skills. The best part about this app is that you can set the difficulty level to move at your own pace.
Fit Brains Trainer
Ranked as one of the best educational apps in the world, Fit Brains Trainer stimulates your cognitive and emotional intelligence through a variety of brain games, workout sessions, and personalized status reports based on your performance.
For the ultimate boost in memorization, Eidetic utilizes a technique known as “spaced repetition” to aid you in memorizing loads of information. Whether you want to remember someone’s phone number or a recipe you just found online, this app will do the trick.
Support Leads to Progress
If you or a loved one is suffering from issues pertaining to thinking and memory, know that there are treatments out there to make improvements. With patience and understanding, a stroke survivor can eventually reach a level of fulfillment in life, but it’s difficult to get there alone. More than anything, a survivor will need encouragement in order to believe that progress can be made. With the support of friends and family, and help from various exercises and technologies, development is certainly possible
Having a Vagus Nerve Stimulator implanted can be a tough decision. Is it right for you? Will it work? What are the side effects and consequences?
I did some research and got the low-down on what it is, how it works and some interesting statistics. (If you are already acquainted with the VNS and are on the fence, you might want to just skip down to risks and benefits sections.)
How it works
Vagus Nerve Stimulation (VNS) has been used to treat more than 30,000 epilepsy patients worldwide. It’s designed to prevent or interrupt seizures or electrical disturbances in the brain for people with hard to control seizures. Used in conjunction with anti-seizure medications, the VNS uses electrical pulses that are delivered to the vagus nerve in the neck and travel up into the brain.
The good news is that the vagus nerve has very few pain fibers, so it’s…
How does brain injury affect memory? Learn about memory impairment following brain injury in this video featuring NeuroRestorative’s Tori Harding. Following a brain injury, the deeply embedded and long-term memories usually remain intact while short-term memory may significantly be affected. Learn about the three memory system areas and strategies that can help a survivor improve their memory.
We review investigations of whether tDCS can facilitate motor skill learning and adaptation.
We identify several caveats in the existing literature and propose solutions for addressing these.
Open Science efforts will improve standardization, reproducibility and quality of future research.
Motor skills are required for activities of daily living. Transcranial direct current stimulation (tDCS) applied in association with motor skill learning has been investigated as a tool for enhancing training effects in health and disease. Here, we review the published literature investigating whether tDCS can facilitate the acquisition, retention or adaptation of motor skills. Work in multiple laboratories is underway to develop a mechanistic understanding of tDCS effects on different forms of learning and to optimize stimulation protocols. Efforts are required to improve reproducibility and standardization. Overall, reproducibility remains to be fully tested, effect sizes with present techniques vary over a wide range, and the basis of observed inter-individual variability in tDCS effects is incompletely understood. It is recommended that future studies explicitly state in the Methods the exploratory (hypothesis-generating) or hypothesis-driven (confirmatory) nature of the experimental designs. General research practices could be improved with prospective pre-registration of hypothesis-based investigations, more emphasis on the detailed description of methods (including all pertinent details to enable future modeling of induced current and experimental replication), and use of post-publication open data repositories. A checklist is proposed for reporting tDCS investigations in a way that can improve efforts to assess reproducibility.
The four-page guide defines executive functions and how they are affected by traumatic brain injury (TBI), and describes the unique challenges that students with TBI face in the college environment. The guide also offers specific academic strategies that may be helpful for deficits in executive function. The guide was developed in collaboration with Chapman University.