Posts Tagged fatigue

[BLOG POST] 9 promising advances in the management of traumatic brain injury – The Neurology Lounge

 

Traumatic brain injury (TBI) is simply disheartening. It is particularly devastating because it usually affects young people in their prime, with the consequent personal, social, and economic consequences. This blog has previously touched a little on TBI with the post titled Will Smith and chronic traumatic encephalopathy? This was a light-hearted take on concussion in sports, but traumatic brain injury is nothing but a serious burden. So what are the big brains in white coats doing to take down this colossus? Quite a lot it seems. Here, for a taster, are 9 promising advances in the management of traumatic brain injury.

Better understanding of pathology

An amyloid PET imaging study by Gregory Scott and colleagues, published in the journal Neurology, reported a rather surprising link between the pathology seen in long-term survivors of traumatic brain injury, with the pathology seen in Alzheimers disease (AD). In both conditions, there is an increased burden of β-amyloid () in the brain, produced by damage to the nerve axons. The paper, titled Amyloid pathology and axonal injury after brain trauma, however notes that the pattern of  deposition in TBI can be distinguished from the one seen in AD. The big question this finding raises is, does TBI eventually result in AD? The answer remains unclear, and this is discussed in the accompanying editorial titled Amyloid plaques in TBI.

Blood tests to detect concussion

The ideal biomarker for any disorder is one which is easy to detect, such as a simple blood test. A headline that screams Blood test may offer new way to detect concussions is therefore bound to attract attention. The benefits of such a test would be legion, especially if the test can reduce the requirement for CT scans which carry the risks of radiation exposure. This is where glial fibrillary acidic protein (GFAP) may be promising. The research is published in the journal, Academic Research Medicine, with a rather convoluted title, Performance of Glial Fibrillary Acidic Protein in Detecting Traumatic Intracranial Lesions on Computed Tomography in Children and Youth With Mild Head Trauma. The premise of the paper is the fact that GFAP is released into the blood stream from the glial cells of the brain soon after brain injury. What the authors therefore did was to take blood samples within 6 hours of TBI in children. And they demonstrated that GFAP levels are significantly higher following head injury, compared to injuries elsewhere in the body. This sounds exciting, but we have to wait and see where it takes us.

Advanced imaging

Brain Scars Detected in Concussions is the attention-grabbing headline for this one, published in MIT Technology Review. Follow the trail and it leads to the actual scientific paper in the journal Radiology, with a fairly straight-forward title, Findings from Structural MR Imaging in Military Traumatic Brain Injury The authors studied >800 subjects in what is the largest trial of traumatic brain injury in the military. Using high resolution 3T brain magnetic resonance imaging (MRI), they demonstrated that even what is reported as mild brain injury leaves its marks on the brain, usually in the form of white matter hyperintense lesions and pituitary abnormalities. It simply goes to show that nothing is mild when it comes to the brain, the most complex entity in the universe.

Implanted monitoring sensors

Current technologies which monitor patients with traumatic brain injury are, to say the least, cumbersome and very invasive. Imagine if all the tubes and wires could be replaced with microsensors, smaller than grains of rice, implanted in the brain. These would enable close monitoring of critical indices such as temperature and intracranial pressure. And imagine that these tiny sensors just dissolve away when they have done their job, leaving no damage. Now imagine that all this is reality. I came across this one from a CBS News piece titled Tiny implanted sensors monitor brain injuries, then dissolve away. Don’t scoff yet, it is grounded in a scientific paper published in the prestigious journal, Nature, under the title Bioresorbable silicon electronic sensors for the brain. But don’t get too exited yet, this is currently only being trialled in mice.

Drugs to reduce brain inflammation

What if the inflammation that is set off following traumatic brain injury could be stopped in its tracks? Then a lot of the damage from brain injury could be avoided. Is there a drug that could do this? Well, it seems there is, and it is the humble blood pressure drug Telmisartan. This one came to my attention in Medical News Today, in a piece titled Hypertension drug reduces inflammation from traumatic brain injury. Telmisartan seemingly blocks the production of a pro-inflammatory protein in the liver. By doing this, Telmisartan may effectively mitigate brain damage, but only if it is administered very early after traumatic brain injury. The original paper is published in the prestigious journal, Brain, and it is titled Neurorestoration after traumatic brain injury through angiotensin II receptor blockage. Again, don’t get too warm and fuzzy about this yet; so far, only mice have seen the benefits.

Treatment of fatigue

Fatigue is a major long-term consequence of traumatic brain injury, impairing the quality of life of affected subjects in a very frustrating way. It therefore goes without saying, (even if it actually has to be said), that any intervention that alleviates the lethargy of TBI will be energising news. And an intervention seems to be looming in the horizon! Researchers writing in the journal, Acta Neurologica Scandinavica, have reported that Methylphenidate significantly improved fatigue in the 20 subjects they studied. Published under the title Long-term treatment with methylphenidate for fatigue after traumatic brain injury, the study is rather small, not enough to make us start dancing the jig yet. The authors have rightly called for larger randomized trials to corroborate their findings, and we are all waiting with bated breaths.

Treatment of behavioural abnormalities

Many survivors of traumatic brain injury are left with behavioural disturbances which are baffling to the victim, and challenging to their families. Unfortunately, many of the drugs used to treat these behaviours are not effective. This is where some brilliant minds come in, with the idea of stimulating blood stem cell production to enhance behavioural recovery. I am not clear what inspired this idea, but the idea has inspired the paper titled Granulocyte colony-stimulating factor promotes behavioral recovery in a mouse model of traumatic brain injury. The authors report that the administration of G‐CSF for 3 days after mild TBI improved the performance of mice in a water maze…within 2 weeks. As the water maze is a test of learning and memory, and not of behaviour, I can only imagine the authors thought-surely only well-behaved mice will bother to take the test. It is however fascinating that G‐CSF treatment actually seems to fix brain damage in TBI, and it does so by stimulating astrocytosis and microgliosis, increasing the expression of neurotrophic factors, and generating new neurons in the hippocampus“. The promise, if translated to humans, should therefore go way beyond water mazes, but we have to wait and see.

Drugs to accelerate recovery

The idea behind using Etanercept to promote recovery from brain injury sound logical. A paper published in the journal, Clinical Drug Investigation, explains that brain injury sets off a chronic lingering inflammation which is driven by tumour necrosis factor (TNF). A TNF inhibitor will therefore be aptly placed to stop the inflammation. What better TNF inhibitor than Eternacept to try out, and what better way to deliver it than directly into the nervous system. And this is what the authors of the paper, titled Immediate neurological recovery following perispinal etanercept years after brain injury, did. And based on their findings, they made some very powerful claims: “a single dose of perispinal etanercept produced an immediate, profound, and sustained improvementin expressive aphasia, speech apraxia, and left hemiparesis in a patient with chronic, intractable, debilitating neurological dysfunction present for more than 3 years after acute brain injury”. A single patient, mind you. Not that I am sceptical by nature, but a larger study confirming this will be very reassuring.

Neuroprotection

And finally, that elusive holy grail of neurological therapeutics, neuroprotection. Well, does it exist? A review of the subject published in the journal, International Journal of Molecular Sciences, paints a rather gloomy picture of the current state of play. Titled Neuroprotective Strategies After Traumatic Brain Injury, it said “despite strong experimental data, more than 30 clinical trials of neuroprotection in TBI patients have failed“. But all is not lost. The authors promise that “recent changes in experimental approach and advances in clinical trial methodologyhave raised the potential for successful clinical translation”. Another review article, this time in the journal Critical Care, doesn’t offer any more cheery news about the current state of affairs when it says that the “use of these potential interventions in human randomized controlled studies has generally given disappointing results”. But the review, titled Neuroprotection in acute brain injury: an up-to-date review, goes through promising new strategies for neuroprotection following brain injury: these include hyperbaric oxygensex hormones, volatile anaesthetic agents, and mesenchymal stromal cells. The authors conclude on a positive note: “despite all the disappointments, there are many new therapeutic possibilities still to be explored and tested”.

What an optimistic way to end! We are not quite there yet, but these are encouraging steps.

via 9 promising advances in the management of traumatic brain injury | The Neurology Lounge

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[Image] Fatigue

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[ARTICLE] Muscle fatigue assessment during robot-mediated movements – Full Text

Abstract

Background

Several neuromuscular disorders present muscle fatigue as a typical symptom. Therefore, a reliable method of fatigue assessment may be crucial for understanding how specific disease features evolve over time and for developing effective rehabilitation strategies. Unfortunately, despite its importance, a standardized, reliable and objective method for fatigue measurement is lacking in clinical practice and this work investigates a practical solution.

Methods

40 healthy young adults performed a haptic reaching task, while holding a robotic manipulandum. Subjects were required to perform wrist flexion and extension movements in a resistive visco-elastic force field, as many times as possible, until the measured muscles (mainly flexor and extensor carpi radialis) exhibited signs of fatigue. In order to analyze the behavior and the characteristics of the two muscles, subjects were divided into two groups: in the first group, the resistive force was applied by the robot only during flexion movements, whereas, in the second group, the force was applied only during extension movements. Surface electromyographic signals (sEMG) of both flexor and extensor carpi radialis were acquired. A novel indicator to define the Onset of Fatigue (OF) was proposed and evaluated from the Mean Frequency of the sEMG signal. Furthermore, as measure of the subjects’ effort throughout the task, the energy consumption was estimated.

Results

From the beginning to the end of the task, as expected, all the subjects showed a decrement in Mean Frequency of the muscle involved in movements resisting the force. For the OF indicator, subjects were consistent in terms of timing of fatigue; moreover, extensor and flexor muscles presented similar OF times. The metabolic analysis showed a very low level of energy consumption and, from the behavioral point of view, the test was well tolerated by the subjects.

Conclusion

The robot-aided assessment test proposed in this study, proved to be an easy to administer, fast and reliable method for objectively measuring muscular fatigue in a healthy population. This work developed a framework for an evaluation that can be deployed in a clinical practice with patients presenting neuromuscular disorders. Considering the low metabolic demand, the requested effort would likely be well tolerated by clinical populations.

Background

Muscle fatigue has been defined as “the failure to maintain a required or expected force” [1] and it is a complex phenomenon experienced in everyday life that has reached great interest in the areas of sports, medicine and ergonomics [2]. Muscle fatigue can affect task performance, posture-movement coordination [3], position sense [4] and it can be a highly debilitating symptom in several pathologies [5]. For many patients with neuromuscular impairments, taking into account muscle fatigue is of crucial importance in the design of correct rehabilitation protocols [6] and fatigue assessment can provide crucial information about skeletal muscle function. Specifically, several neuromuscular diseases (e.g. Duchenne, Becker Muscular Dystrophies, and spinal muscular atrophy) present muscle fatigue as a typical symptom [7], and fatigue itself accounts for a significant portion of the disease burden. A systematic approach to assess muscle fatigue might provide important cues on the disability itself, on its progression and on the efficacy of adopted therapies. In particular, therapeutic strategies are now under deep investigation and a lot of effort has been devoted to accelerate the development of drugs targeting these disorders [8]. Therefore, the need for an objective tool to measure muscle fatigue is impelling and of great relevance.

Currently, in clinical practice muscle fatigue is evaluated by means of qualitative rating scales like the 6-min walk test (6MWT) [9] or through subjective questionnaires administered to the patient (e.g. the Multidimensional Fatigue Inventory (MFI), the Fatigue Severity Scale (FSS), and the Visual Analog Scale (VAS)) [10]. During the 6MWT patients have to walk, as fast as possible, along a 25 meters linear course and repeat it as often as they can for 6 min: ‘fatigue’ is then defined as the difference between the distance covered in the sixth minute compared to the first. Obviously, such a measure is only applicable to ambulant patients and this is a strong limitation to clinical investigation because a patient may lose ambulatory ability during a clinical trial, resulting in lost ability to perform the primary clinical endpoint [11]. It should also be considered that neuromuscular patients, e.g. subjects with Duchenne Muscular Dystrophy, generally lose ambulation before 15 years of age [12], excluding a large part of the population from the measurement of fatigue through the 6MWT. Since neuromuscular patients often experience a progressive weakness also in the upper limb, reporting of muscle fatigue in this region is common. A fatigue assessment for upper limb muscles could be used to monitor patients across different stages of the disease. As for the questionnaires, the MFI is a 20 items scale designed to evaluate five dimensions of fatigue (general fatigue, physical fatigue, reduced motivation, reduced activity, and mental fatigue) [13]. Similarly, the FSS questionnaire contains nine statements that rate the severity of fatigue symptoms and the patient has to agree or disagree with them [14]. The VAS is even more general: the patient has to indicate on a 10 cm line ranging from “no fatigue” to “severe fatigue” the point that best describes his/her level of fatigue [15]. Despite the ease to administer, such subjective assessments of fatigue may not correlate with the actual severity or characteristics of fatigue, and may provide just qualitative information with low resolution, reliability and objectivity. Considering various levels of efficacy among the methods currently used in clinical practice, research should focus on the development of an assessment tool for muscle fatigue, that is easy and fast to administer, even to patients with a high level of impairment. Such a tool, should provide clear results, be easy to read and understand by a clinician, be reliable and objectively correlated with the physiology of the phenomenon.

In general, muscle fatigue can manifest from either central and/or peripheral mechanisms. Under controlled conditions, surface electromyography (sEMG) is a non-invasive and widely used technique to evaluate muscle fatigue [16]. Certain characteristics of the sEMG signal can be indicators of muscle fatigue. For example during sub-maximal tasks, muscle fatigue will present with decreases in muscle fiber conduction velocity and frequency and increases in amplitude of the sEMG signal [16]. The trend and rate of change will depend on the intensity of the task: generally, sEMG amplitude has been observed to increase during sub-maximal efforts and decrease during maximal efforts; further it has been reported that there is a significantly greater decline in the frequency content of the signal during maximal efforts compared to sub-maximal [17]. Accordingly, spectral (i.e. mean frequency) and amplitude parameters (i.e. Root Mean Square (RMS)) of the signals, can be used to measure muscle fatigue as extensively discussed in many widely acknowledged studies [161819], however, context of contraction type and intensity must be specified for proper interpretation. A significant problem with the majority of existing protocols is that they rely on quantifying maximal voluntary force loss, maximum voluntary muscle contraction (MVC) [182021] or high fatiguing dynamic tasks [1922] that cannot be reliably performed in clinical practice, especially in the case of pediatric subjects. Actually, previous works pointed out that not only the capacity to maintain MVC can be limited by a lack of cooperation [2324], but also, that sustaining a maximal force in isometric conditions longer than 30 s reduces subject’s motivation leading to unreliable results [25]. Besides, neuromuscular patients might have a high level of impairment and low residual muscular function thus making even more difficult, as well as dangerous for their muscles, sustaining high levels of effort or the execution of a true MVC. In order to overcome this issue, maximal muscle contractions can be elicited by magnetic [10] or electrical stimulation [26]. Although such procedures allow to bypass the problem mentioned above, these involve involuntary muscle activation and not physiological recruitment of motor units [24]; moreover, they can be uncomfortable for patients and can require advanced training, which makes them difficult to be included in clinical fatigue assessment protocols. As for the above mentioned problem with children motivation, work by Naughton et al. [27] showed that the test-retest coefficient of variation of fatigue index during a Wing-Gate test, significantly decreased when using a computerized feedback game linked to pedal cadence, suggesting that game-based procedures may ensure more consistent results in children assessment.

In recent years, the assessment of sensorimotor function has been deepened thanks to the introduction of innovative protocols administered through robotic devices [28293031]. These methods have the ambition to add meaningful information to the existing clinical scales and can be exploited as a basis for the implementation of a muscle fatigue assessment protocol. In order to fill the gap between the need of a quantitative clinical measurement protocol of muscle fatigue and the lack of an objective method which does not demand a high level of muscle activity, we propose a new method based on a robotic test, which is fast and easy to administer. Further, we decided to address the analysis of muscle fatigue on the upper limb as to provide a test suitable to assess patients from the beginning to the late stages of the disease, regardless of walking ability. Moreover, we focused on an isolated wrist flexion/extension tasks to assess wrist muscle fatigue. This ensured repeatability of the tests and prevented the adoption of compensatory movements or poor postures that may occur in multi-segmental tasks, involving the shoulder-elbow complex. In the present work, we tested the method on healthy subjects with the specific goal to evaluate when during the test the first meaningful symptoms of fatigue appaered and not how much subjects are fatigued at the end of the test. The most relevant and novel features of the proposed test include the ability to perform the test regardless of the subjects’ capability and strength, the objectivity and repeatability of the data it provides, and the simplicity and minimal time required to administer.[…]

 

Continue —->  Muscle fatigue assessment during robot-mediated movements | Journal of NeuroEngineering and Rehabilitation | Full Text

Fig. 1

Fig. 1 Experimental setup. Participant sitting on a chair with the forearm secured to the WRISTBOT while performing the wrist rotation reaching task. The visual targets of the reaching task are shown on a dedicated screen

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[ARTICLE] Effort and Fatigue-Related Functional Connectivity in Mild Traumatic Brain Injury – Full Text

Mental fatigue in healthy individuals is typically observed under conditions of high cognitive demand, particularly when effort is required to perform a task for a long period of time—thus the concepts of fatigue and effort are closely related. In brain injured individuals, mental fatigue can be a persistent and debilitating symptom. Presence of fatigue after brain injury is prognostic for return to work/school and engagement in activities of daily life. As such, it should be a high priority for treatment in this population, but because there is little understanding of its behavioral and neural underpinnings, the target for such treatment is unknown. Here, the neural underpinnings of fatigue and effort are investigated in active duty military service members with mild traumatic brain injury (mTBI) and demographically-matched orthopedic controls. Participants performed a Constant Effort task for which they were to hold a pre-defined effort level constant for long durations during fMRI scanning. The task allowed for investigation of the neural systems underlying fatigue and their relationship with sense of effort. While brain activation associated with effort and fatigue did not differentiate the mTBI and controls, functional connectivity amongst active brain regions did. The mTBI group demonstrated immediate hyper-connectivity that increased with effort level but diminished quickly when there was a need to maintain effort. Controls, in contrast, demonstrated a similar pattern of hyper-connectivity, but only when maintaining effort over time. Connectivity, particularly between the left anterior insula, rostral anterior cingulate cortex, and right-sided inferior frontal regions, correlated with effort-level and state fatigue in mTBI participants. These connections also correlated with effort level in the Control group, but only the connection between the left insula and superior medial frontal gyrus correlated with fatigue, suggesting a differing pattern of connectivity. These findings align, in part, with the dopamine imbalance, and neural efficiency hypotheses that pose key roles for medial frontal connections with insular or striatal regions in motivating or optimizing performance. Sense of effort and fatigue are closely related. As people fatigue, sense of effort increases systematically. The data propose a complex link between sense of effort, fatigue, and mTBI that is centered in what may be an inefficient neural system due to brain trauma that warrants further investigation.

Introduction

A signature injury of service members deployed during the conflicts in Iraq and Afghanistan is traumatic brain injury (TBI). Of the approximately 360,000 service members who suffer from TBI, 70% are classified as mild injuries (mTBI; DVBIC Quarterly Reports). At least 19% of the service members with mTBI have persistent symptoms that contribute to difficulty engaging in social and work activities. The consequences of persistent fatigue in mTBI pose a real challenge to rehabilitation (1). High levels of mental fatigue commonly persist and relate to failure to return to work and loss of productivity (23). In fact, presence of fatigue is the strongest predictive factor of poor outcomes following TBI (1). Despite the prevalence of fatigue in TBI, our understanding of its behavioral and neural underpinnings is lacking.

Mental fatigue is a complex process that is operationally defined by time on task and increased mental effort. When performance suffers (reaction time, accuracy, etc.) over time, presumably from fatigue, there tends to be fairly diffusely increased brain activity (4). Simultaneously, there may also be decreased motivation under high effort (5). According to Kahneman’s “resource capacity theory,” the amount of effort needed to perform a task is related to the complexity of the task and an individual’s limited general capacity to perform mental work [i.e., resource capacity, (67)]. When a task is difficult, the demand for resources is high, and performance suffers when resources near depletion. When a person recognizes that performance is suffering, tasks are perceived as more difficult, and require greater effort, which Kahneman equates with the experience of mental fatigue.

Brain imaging in mTBI indicates an increase in brain activity with increased time on task regardless of the type or demand requirements of the task (8). In contrast, healthy individuals have decreased activation over time without a serious decrement in performance, and without reporting significant fatigue. This brain response in TBI may suggest a perception of higher levels of effort when the task is long, or that individuals with TBI inefficiently regulate cognitive control and exert more mental effort to maintain a high-level of performance, resulting in fatigue.

While there is a plethora of literature reporting that task demand causes degradation of performance in mTBI, few have investigated whether task demand results in fatigue more so than in healthy controls, or how this fatigue manifests in behavior or in neural function. The few available studies have small sample sizes [e.g., (9)] limiting their generalizability. The brain networks implicated in effort and fatigue include frontostriatal circuitry, or the ventromedial prefrontal cortex more specifically. Damage to these brain regions is thought to diminish resource capacity and impair allocation of resources, resulting in an increased perception of expended effort (1012). Additionally, fatigue related to lack of motivation to engage and maintain performance on a task, or to predict and manage change in performance based on feedback about performance, is associated with the integrity of the ventromedial prefrontal cortical. That is, individuals with larger lesions of this brain region report more fatigue and apathy (1314). The frontostriatal network is involved in coding the incentive value for an expected outcome (15), and is mediated by dopaminergic frontostriatal networks (131619). Breakdowns in ventromedial prefrontal cortex-related network connectivity may disrupt the ability to appropriately detect, monitor, and self-correct errors or to adequately motivate behavior (2021). For example, the anterior cingulate cortex is associated with monitoring and detecting errors, the pre-supplementary motor area with engaging in task, and the connectivity amongst these two regions is related to fatigue (22).

One gap in the existing literature on fatigue is that paradigms infer “probable” fatigue [exception is Wylie et al. (22)], rather than directly measuring it. In the present study, we investigate brain activity and network connectivity in mTBI participants while they perform a task explicitly designed to study the relationship between task-related effort and fatigue. We assess fatigue with a questionnaire about fatigue over the week prior to scanning (trait) as well as with task manipulation during brain imaging [state, Constant Effort Task [CE]]. For Constant Effort, subjects are asked to squeeze a bulb to a prescribed effort level and hold it constant for a discrete period of time. The task is considered a general index of central fatigue as it is not specific to motor system engagement (2324). Varying effort levels result in predictable changes in the ability to maintain pressure on the bulb such that the time it takes to fatigue is slower at low effort levels than at higher effort levels. Performance on the CE task during functional fMRI allowed for identification of the neural systems underlying effort and fatigue as well as the differences in these systems in mTBI relative to control. We hypothesize that fatigue in mTBI arises when there is an altered perception of the amount of effort needed to perform the task, either because there is a failure to:

a) update the amount of effort given to the task based on internal feedback about performance, which is assessed by contrasting performance across effort levels,

b) sustain a given effort level, which is assessed via time on task, or

c) both.

Because estimating and maintaining effort are likely a result of a complex network of interacting brain regions, we examined not only brain activation during task performance, but also functional connectivity (FC) amongst the regions active during the task. We predict that mTBI participants will demonstrate increased pre-frontal and anterior cingulate cortex activation, as well as increased connectivity of these regions to ventral-striatal regions relative to Control participants.[…]

 

Continue —> Frontiers | Effort and Fatigue-Related Functional Connectivity in Mild Traumatic Brain Injury | Neurology

Figure 1. Effort and Fatigue in the Constant Effort task demonstrated differing regional effects with effort associated with caudal, medial prefrontal cortex (red) while fatigue was associated with rostral prefrontal cortex as well as postcentral and posterior cingulate cortex (blue). Controls demonstrated significantly higher activity than mTBI in a small area of the right medial prefrontal cortex (green) while mTBI had more activity in the posterior occipital cortex, but there were no other significant group effects. When these regions were used in computing functional connectivity, it was only the connectivity amongst the regions of the effort effect (red) that demonstrated group differences in connection strength. For example, the connection between the left insula (A) and the right inferior frontal gyrus (B, pars orbitalis) was significantly stronger in the TBI group for time on task at 75% effort.

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[BLOG POST] Antidepressants help us understand why we get fatigued during exercise

In general, the term ‘fatigue’ is used to describe any exercise-induced decline in the ability of a muscle to generate force. To identify the causes of fatigue, it is common to examine two divisions of the body that might be affected during exercise. The central component of fatigue includes the many nerves that travel throughout the brain to the spinal cord. The peripheral component predominantly reflects elements in the muscle itself. If there is a problem with either of these components, the ability to contract a muscle might be compromised. For many years, there has been suggestion that central fatigue is heavily influenced by neurotransmitters that get released in the central nervous system (such as dopamine and serotonin). However, little research has been performed in this area.

Serotonin is a chemical that can improve mood, and increasing the amount of serotonin that circulates in the brain is a common therapy for depression. However, serotonin also plays a vital role in activating neurons in the spinal cord which tell the muscle to contract. With the correct amount of serotonin release, a muscle will activate efficiently. However, if too much serotonin is released, there is a possibility that the muscle will rapidly fatigue. Recent animal studies indicate that moderate amounts of serotonin release, which are common during exercise, can promote muscle contractions (Cotel et al. 2013). However, massive serotonin release, which may occur with very large bouts of exercise, could further exacerbate the already fatigued muscle (Perrier et al. 2018).

Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed antidepressants. These medications keep serotonin levels high in the central nervous system by stopping the chemical from being reabsorbed by nerves (reuptake inhibition). Instead of using SSRIs to relieve symptoms of depression, we used them in our recent study (Kavanagh et al. 2019) to elevate serotonin in the central nervous system, and then determine if characteristics of fatigue are enhanced when serotonin is elevated. We performed three experiments that used maximal voluntary contractions of the biceps muscle to cause fatigue in healthy young individuals. Our main goal was to determine if excessive serotonin limits the amount of exercise that can be performed, and then determine which central or peripheral component was compromised by excessive serotonin.

WHAT DID WE FIND?

Given that SSRIs influence neurotransmitters in the central nervous system, it was not surprising that peripheral fatigue was unaltered by the medication. However, central fatigue was influenced with enhanced serotonin. The time that a maximum voluntary contraction could be held was reduced with enhanced serotonin, whereby the ability of the central nervous system to drive the muscle was compromised by 2-5%. We further explored the location of dysfunction and found that the neurons in the spinal cord that activate the muscle were 4-18% less excitable when fatiguing contractions were performed in the presence of enhanced serotonin.

SIGNIFICANCE AND IMPLICATIONS

The central nervous system is diverse, and the fatigue that is experienced during exercise is not just restricted to the brain. Instead, the spinal cord plays an integral role in activating muscles, and mechanisms of fatigue also occur in these lower, often overlooked, neural circuits. This is the first study to provide evidence that serotonin released onto the motoneurones contributes to central fatigue in humans.

PUBLICATION REFERENCE

Kavanagh JJ, McFarland AJ, Taylor JL. Enhanced availability of serotonin increases activation of unfatigued muscle but exacerbates central fatigue during prolonged sustained contractions. J Physiol. 597:319-332, 2019.

If you cannot access the paper, please click here to request a copy.

KEY REFERENCES

Cotel F, Exley R, Cragg SJ, Perrier JF. Serotonin spillover onto the axon initial segment of motoneurons induces central fatigue by inhibiting action potential initiation. Proc Natl Acad Sci U S A. 110:4774-4779, 2013.

Perrier JF, Rasmussen HB, Jørgensen LK, Berg RW. Intense activity of the raphe spinal pathway depresses motor activity via a serotonin dependent mechanism. Front Neural Circuits. 11:111, 2018.

AUTHOR BIO

Associate Professor Justin Kavanagh is a researcher and lecturer at Griffith University. His team explores how the central nervous system controls voluntary and involuntary movement, and he has particular interests in understanding how medications can be used to study mechanisms of human movement.

via Antidepressants help us understand why we get fatigued during exercise – Motor Impairment

 

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[BLOG POST] Brain Injury, Social Skills, and the Holidays – BrainLine

Ask the Expert: Social Skills and the HolidaysQuestion:

My husband fell off a ladder almost a year ago now and sustained a brain injury. I’ve noticed that his communication and social skills tend to get worse at parties, especially during the holiday season. Why is this? And what can I do to help

Answer:

The holidays can be fraught with pitfalls for someone with a brain injury. The fact that your husband’s communication and social skills worsen at parties is not unusual. For starters, routines are disrupted and there can be an increased number of social functions with less time to rest in between.

TBI related fatigue could cause a decline in social skills. Things can get even more challenging if alcohol is added to the mix. And for individuals prone to seizure activity, holiday lighting — particularly flashing lights — could increase the risk of a seizure.

A social setting, like a party with many people engaged in conversation, eating, and drinking, can easily become over-stimulating and even upsetting to a person with TBI. To help your husband deal with all these issues, you might try limiting the number of engagements during the holidays. And when in a social setting, help support your husband’s conversations by introducing easy topics, and repeating or rephrasing questions asked by others.

You know your husband better than anyone else, and when you hear him having difficulty using the right words, or even slurring his speech, it’s time to go home. All the activity has probably tired him out. For someone with TBI, it can be exhausting trying to converse in crowds, with strangers, and in over-stimulating settings.

 

via Brain Injury, Social Skills, and the Holidays | BrainLine

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[BLOG POST] One day at a time. Cognition and Caregiving after a TBI

By Bill Herrin

Thinking comes so naturally that most people take it for granted, but after a traumatic brain injury – many times, thinking can be more of a deliberate action. It takes focus and effort to put a series of thoughts together after TBI, to speak clearly, or to even move. Simply put, the brain (like the body) takes time to heal. Since no two brain injuries are identical, there is no clear path to better cognition. There are, however, certain broad directives that can get you moving in the right direction in most situations. The hardest part of this is to accept your “new normal”. Acceptance, once you come to terms with it, gives you the desire to work toward the goal of better cognition, coordination, memory, anger management, judgement, attention, and other challenges. Once you accept your situation isn’t going to change overnight, you can start the process of healing, along with testing your limitations. Although finding your limitations is difficult, knowing what they are is a huge step towards improvement in areas that need changing. When a person lacks enough cognition to be self-aware or to strive towards improvement, that’s a test for the caregiver’s guidance and patience. Sometimes just being there for your friend, spouse, or loved one is all you can do.

As a caregiver, high expectations from a TBI survivor shouldn’t be overly discouraged, as they can bring progress through their desire to improve. They may not reach the goal they wanted to, but they’ll make strides towards it! That is positivity in its purest form. Nobody wants to be working through such a huge change in their life without encouragement – cheer them onward and upward! Even if they fail, they are trying, and that shows initiative. Their desire to improve should never be underappreciated.

When cognition is in the early stages of improvement, the changes may be noticed more by the family or caregiver than they are by the survivor. Sometimes incremental change is just too subtle for survivors to realize, but pointing out the changes to them is incredibly positive reinforcement. The following tips on cognition are excerpted from Lash & Associates’ tip card titled “Cognition – Compensatory strategies after brain injury”

Cognitive fatigue is one of the most common consequences of brain injury. The survivor’s brain is simply working harder to think and learn. Cognitive rest is just as important – maybe even more important – as physical rest after the brain has been injured. Cognitive fatigue can have a ripple effect. You may have a shorter temper, find it harder to concentrate, make more errors, misplace things or forget appointments. You may feel like you can’t think straight no matter how hard you try. Many survivors describe cognitive fatigue as “hitting the wall”.

Do you…

• Feel tired after mental exertion?

• Have a harder time thinking after working on longer or more complex tasks?

• Need more sleep than usual?

• Find it hard to get through the day without napping?

 

Tips on compensatory strategies…

• Take breaks.

• Schedule rest periods.

• Stay organized.

• Use a daily planner.

• Use time management strategies.

• Eat nutritious meals on a regular schedule.

• Go to bed at a consistent time.

– Create a weekly exercise routine.

• Request a medical evaluation.

• Discuss medications that may help with a physician specializing in brain injury rehabilitation.

There are a plenty of great suggestions for compensatory strategies for survivors and their caregivers in the tip card referenced above. Here’s a link to it here!

 

When it comes to cognitive functional rehabilitation – seek professional advice first (of course), but when the TBI survivor is at home with a caregiver, clinician, friend or family member, there are some great approaches to working on communication, social interaction, organization, reading, attention, problem solving, and rebuilding other deficits through consistent application by any or all of the people involved in the care of the TBI survivor.

Referencing the book titled “Cognition Functional Rehabilitation Activities Manual” (Developed by Barbara Messenger, MEd, ABDA and Niki Ziarnek, MS, CCC-SLP/L), I’m sharing an excerpt that provides a glimpse into the workbook’s approach to helping a person with cognitive challenges. Many of the exercises use interaction and documentation to assess where the TBI survivor is at (cognitively speaking) on an ongoing basis. Remember, this is a workbook, and there are plenty of exercises that build activities and responses ongoing. Here is the example of how the manual challenges a TBI survivor with structured and specific activities:

Task: Provide awareness training.

Procedure:

  1. Prompt participant to work on awareness training.
  2. Ask why participant is here receiving rehabilitation.
  3. Ask what skills/activities are harder since the brain injury.
  4. Ask what participant does to compensate for these difficulties and which therapies address them.Ask what participant’s strengths are (what is participant good at?).
  1. Ask the participant how the brain injury and difficulties affect daily activities.
  2. Provide answers and examples when needed.
  3. Provide positive reinforcement for strengths, being receptive to information regarding brain injury, for participating in the task, and for being motivated to participate in rehabilitation.

Staff Reminder: (clinician, caregivers, family, etc.)

Provide a complete description of this activity in the Functional Rehabilitation Documentation Form.

Last words…

By asking specific questions, and recording the corresponding answers, this workbook is a great tool for tracking progress – and the exercises can be done more than once, to check and see how/if the answers have changed. So, what’s the takeaway from this excerpt? It illustrates that structure and consistency of care and treatment by family/caregivers and professionals can overlap and create a solid overview of cognitive deficits, and improvements.

In closing, the main goal of this post is to address the expectations of TBI survivors and their caregivers, to encourage them to strive for progress and to offer resources for compensatory strategies, and cognitive rehabilitation. If all parties work in tandem with the common goal of helping a TBI survivor make it to the next level, they’re all closer to the goal…and the whole team wins. That’s the goal!

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[BLOG POST] One day at a time. Cognition and Caregiving after a TBI

By Bill Herrin

Thinking comes so naturally that most people take it for granted, but after a traumatic brain injury – many times, thinking can be more of a deliberate action. It takes focus and effort to put a series of thoughts together after TBI, to speak clearly, or to even move. Simply put, the brain (like the body) takes time to heal. Since no two brain injuries are identical, there is no clear path to better cognition. There are, however, certain broad directives that can get you moving in the right direction in most situations. The hardest part of this is to accept your “new normal”. Acceptance, once you come to terms with it, gives you the desire to work toward the goal of better cognition, coordination, memory, anger management, judgement, attention, and other challenges. Once you accept your situation isn’t going to change overnight, you can start the process of healing, along with testing your limitations. Although finding your limitations is difficult, knowing what they are is a huge step towards improvement in areas that need changing. When a person lacks enough cognition to be self-aware or to strive towards improvement, that’s a test for the caregiver’s guidance and patience. Sometimes just being there for your friend, spouse, or loved one is all you can do.

As a caregiver, high expectations from a TBI survivor shouldn’t be overly discouraged, as they can bring progress through their desire to improve. They may not reach the goal they wanted to, but they’ll make strides towards it! That is positivity in its purest form. Nobody wants to be working through such a huge change in their life without encouragement – cheer them onward and upward! Even if they fail, they are trying, and that shows initiative. Their desire to improve should never be underappreciated.

When cognition is in the early stages of improvement, the changes may be noticed more by the family or caregiver than they are by the survivor. Sometimes incremental change is just too subtle for survivors to realize, but pointing out the changes to them is incredibly positive reinforcement. The following tips on cognition are excerpted from Lash & Associates’ tip card titled “Cognition – Compensatory strategies after brain injury”

Cognitive fatigue is one of the most common consequences of brain injury. The survivor’s brain is simply working harder to think and learn. Cognitive rest is just as important – maybe even more important – as physical rest after the brain has been injured. Cognitive fatigue can have a ripple effect. You may have a shorter temper, find it harder to concentrate, make more errors, misplace things or forget appointments. You may feel like you can’t think straight no matter how hard you try. Many survivors describe cognitive fatigue as “hitting the wall”.

Do you…

• Feel tired after mental exertion?

• Have a harder time thinking after working on longer or more complex tasks?

• Need more sleep than usual?

• Find it hard to get through the day without napping?

Tips on compensatory strategies…

• Take breaks.

• Schedule rest periods.

• Stay organized.

• Use a daily planner.

• Use time management strategies.

• Eat nutritious meals on a regular schedule.

• Go to bed at a consistent time.

– Create a weekly exercise routine.

• Request a medical evaluation.

• Discuss medications that may help with a physician specializing in brain injury rehabilitation.

There are a plenty of great suggestions for compensatory strategies for survivors and their caregivers in the tip card referenced above. Here’s a link to it here!

When it comes to cognitive functional rehabilitation – seek professional advice first (of course), but when the TBI survivor is at home with a caregiver, clinician, friend or family member, there are some great approaches to working on communication, social interaction, organization, reading, attention, problem solving, and rebuilding other deficits through consistent application by any or all of the people involved in the care of the TBI survivor.

Referencing the book titled “Cognition Functional Rehabilitation Activities Manual” (Developed by Barbara Messenger, MEd, ABDA and Niki Ziarnek, MS, CCC-SLP/L), I’m sharing an excerpt that provides a glimpse into the workbook’s approach to helping a person with cognitive challenges. Many of the exercises use interaction and documentation to assess where the TBI survivor is at (cognitively speaking) on an ongoing basis. Remember, this is a workbook, and there are plenty of exercises that build activities and responses ongoing. Here is the example of how the manual challenges a TBI survivor with structured and specific activities:

Task: Provide awareness training.

Procedure:

  1. Prompt participant to work on awareness training.
  2. Ask why participant is here receiving rehabilitation.
  3. Ask what skills/activities are harder since the brain injury.
  4. Ask what participant does to compensate for these difficulties and which therapies address them.Ask what participant’s strengths are (what is participant good at?).
  1. Ask the participant how the brain injury and difficulties affect daily activities.
  2. Provide answers and examples when needed.
  3. Provide positive reinforcement for strengths, being receptive to information regarding brain injury, for participating in the task, and for being motivated to participate in rehabilitation.

Staff Reminder: (clinician, caregivers, family, etc.)

Provide a complete description of this activity in the Functional Rehabilitation Documentation Form.

Last words…

By asking specific questions, and recording the corresponding answers, this workbook is a great tool for tracking progress – and the exercises can be done more than once, to check and see how/if the answers have changed. So, what’s the takeaway from this excerpt? It illustrates that structure and consistency of care and treatment by family/caregivers and professionals can overlap and create a solid overview of cognitive deficits, and improvements.

In closing, the main goal of this post is to address the expectations of TBI survivors and their caregivers, to encourage them to strive for progress and to offer resources for compensatory strategies, and cognitive rehabilitation. If all parties work in tandem with the common goal of helping a TBI survivor make it to the next level, they’re all closer to the goal…and the whole team wins. That’s the goal!

 

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[WEB SITE] How to keep your brain healthy and avoid cognitive fatigue

The Globe and Mail and Morneau Shepell have created the Employee Recommended Workplace Award to honour companies that put the health and well-being of their employees first. Read about the 2018 winners of the award at tgam.ca/workplaceaward.

Registration is now open for the 2019 Employee Recommended Workplace Awards at www.employeerecommended.com.

Morneau Shepell is hosting a free webinar on Thurs. Sept. 13 from 1 p.m. ET to 2 p.m. ET to discuss seven ways to improve mental health in your workplace. If you would like to participate, click here to register.

Think back to your school days, especially postsecondary school, and how your brain felt after cramming all night for a tough exam. Remember that? When you felt like your brain had been pushed to the limit and was no longer functioning properly? That is called cognitive fatigue.

Cognitive fatigue can be defined as a decrease is one’s cognitive abilities due to prolonged mental demands, brought on by excessive wear and tear on the brain. It’s not simply being sleep-deprived, although sleep is important and necessary for healthy brain functioning.

Sometimes the challenges we take on, such as work-related commitments and education goals, can be stressful, challenging and require a high level of cognitive demand over an extended period of time.

Daniel Goleman reports that cognitive exhaustion can occur due to extended periods of focus, and the brain, like any muscle, can be pushed to the point of exhaustion. When this happens, the brain’s capacity to perform to its full potential can be dramatically decreased.

Understanding cognitive fatigue can help us know the actions we can take to reduce the risk and increase our capacity to manage high-demand mental task when necessary. When we’re not aware that cognitive fatigue is happening, we can be at increased risk for being distracted, anxious and irritable.

This micro skill provides some ideas to mitigate risk for cognitive fatigue. The focus is on people who engage in some form of activity (such as work or school) that requires a high level of concentration over an extended period.

Awareness

People who have suffered a head injury or some form of mental illness can be at increased risk for experiencing cognitive fatigue. Research shows that cognitive fatigue can significantly impair physical performance that could put a person at increased risk for making mistakes.

Common signs of cognitive fatigue include a decrease in motivation, creativity and ability to analyze and think clearly. Someone who’s experiencing any of these symptoms may not be able to process what’s happening, so they need to learn the concept of cognitive fatigue and what actions to take if they’ve reached that point.

Accountability

Sometimes we may order more food at a restaurant than we can eat. The same can happen when we want to achieve something. We focus on the end goal and may not consider the ongoing effort or commitment we’ve made to achieve it.

To reduce the risk for cognitive fatigue, you need to not only be aware of your capacity and the potential for cognitive fatigue, you need to set realistic expectations. For example, you wouldn’t commit to running a marathon unless you trained and worked up to it. The mind needs the same consideration. If you want to do something in your career or education that will be a challenge, it’s helpful to make a commitment to train your brain and rest it like any other muscle. You want to develop it to be as strong as possible.

Action

Here are some actions you can take to reduce your risk for cognitive fatigue.

Prepare for challenges – Accept that for your brain to work to its full potential it needs to be trained and prepared. If you’re taking a course that requires lots of studying over a period of a year or two, develop a capacity-building plan that may involve increasing your daily reading or taking a study strategy program to maximize your study habits.

Create a schedule and stick to it – Schedule periods in your day when you’ll focus, and rest periods above and beyond getting your required sleep. The purpose is to provide times in your day when your mind can rest and enjoy other activities.

Develop a daily resiliency plan – Too much caffeine or alcohol can hurt your brain’s ability to perform while exercise and strong coping skills – the strategies that enable us to solve problems under stress – can help your brain stay strong when its being stressed. A resiliency plan is a minimum commitment to provide the mind and body the most opportunity to have the energy it needs to push through daily challenges as well as to reduce risk for cognitive fatigue. A daily plan may include:

  • Getting seven to nine hours’ sleep
  • Drinking no more than two cups of coffee – and no other sources of caffeine
  • Taking a 10-minute break every 90 minutes
  • Eating three healthy meals, with healthy snacks between them
  • Exercising 30 minutes each day
  • Drinking at least 2.5 litres of water
  • Meditating for 15 minutes first thing in the morning to kick off the day
  • Journaling at the end of the day to process the day’s challenges and acknowledge things to be grateful for
  • Spending a minimum of 30 minutes with your partner to catch up on life

Bill Howatt is the chief research and development officer of work force productivity with Morneau Shepell in Toronto.

You can find all the stories in this series at tgam.ca/workplaceaward

via How to keep your brain healthy and avoid cognitive fatigue – The Globe and Mail

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[Systematic Review] Complementary and alternative interventions for fatigue management after traumatic brain injury: a systematic review – Full Text

We systematically reviewed randomized controlled trials (RCTs) of complementary and alternative interventions for fatigue after traumatic brain injury (TBI).

We searched multiple online sources including ClinicalTrials.gov, the Cochrane Library database, MEDLINE, CINAHL, Embase, the Web of Science, AMED, PsychINFO, Toxline, ProQuest Digital Dissertations, PEDro, PsycBite, and the World Health Organization (WHO) trial registry, in addition to hand searching of grey literature. The methodological quality of each included study was assessed using the Jadad scale, and the quality of evidence was evaluated using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. A descriptive review was performed.

Ten RCTs of interventions for post-TBI fatigue (PTBIF) that included 10 types of complementary and alternative interventions were assessed in our study. There were four types of physical interventions including aquatic physical activity, fitness-center-based exercise, Tai Chi, and aerobic training. The three types of cognitive and behavioral interventions (CBIs) were cognitive behavioral therapy (CBT), mindfulness-based stress reduction (MBSR), and computerized working-memory training. The Flexyx Neurotherapy System (FNS) and cranial electrotherapy were the two types of biofeedback therapy, and finally, one type of light therapy was included. Although the four types of intervention included aquatic physical activity, MBSR, computerized working-memory training and blue-light therapy showed unequivocally effective results, the quality of evidence was low/very low according to the GRADE system.

The present systematic review of existing RCTs suggests that aquatic physical activity, MBSR, computerized working-memory training, and blue-light therapy may be beneficial treatments for PTBIF. Due to the many flaws and limitations in these studies, further controlled trials using these interventions for PTBIF are necessary

Fatigue is a common phenomenon following traumatic brain injury (TBI), with a reported prevalence ranging from 21% to 80% [Ouellet and Morin, 2006Bushnik et al. 2007Dijkers and Bushnik, 2008Cantor et al. 2012Ponsford et al. 2012], regardless of TBI severity [Ouellet and Morin, 2006Ponsford et al. 2012]. Post-TBI fatigue (PTBIF) refers to fatigue that occurs secondary to TBI, which is generally viewed as a manifestation of ‘central fatigue’. Associated PTBIF symptoms include mental or physical exhaustion and inability to perform voluntary activities, and can be accompanied by cognitive dysfunction, sensory overstimulation, pain, and sleepiness [Cantor et al. 2013]. PTBIF appears to be persistent, affects most TBI patients daily, negatively impacts quality of life, and decreases life satisfaction [Olver et al. 1996Cantor et al.20082012Bay and De-Leon, 2010]. Given the ubiquitous presence of PTBIF, treatment or management of fatigue is important to improve the patient’s quality of life after TBI. However, the effectiveness of currently available treatments is limited.

Although pharmacological interventions such as piracetam, creatine, monoaminergic stabilizer OSU6162, and methylphenidate can alleviate fatigue, adverse effects limit their usage and further research is needed to clarify their effects [Hakkarainen and Hakamies, 1978Sakellaris et al.2008Johansson et al. 2012b2014]. Therefore, many researchers have attempted to identify complementary and alternative interventions to relieve PTBIF [Bateman et al. 2001Hodgson et al. 2005Gemmell and Leathem, 2006Hassett et al. 2009Johansson et al. 2012aBjörkdahl et al. 2013Sinclair et al. 2014]. In this study, we aimed to systematically review randomized controlled trials (RCTs) that evaluated treatment of PTBIF using complementary and alternative medicine (CAM) to provide practical recommendations for this syndrome. […]

 

Continue —>  Complementary and alternative interventions for fatigue management after traumatic brain injury: a systematic review – Gang-Zhu Xu, Yan-Feng Li, Mao-De Wang, Dong-Yuan Cao, 2017

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