Archive for category Fatigue

[VIDEO] Traumatic Brain Injury: Understanding Fatigue – YouTube

The TBI Coach, Nathalie Kelly, explains cognitive fatigue in a way that everyone can understand. Brain fatigue is a huge debilitating issue for those with brain injuries and concusssions. See the full transcript below.

Hello my beautiful and courageous friends,

Do you find it hard to understand that at some moments someone with a TBI can appear to function pretty well, and a minute later they are stuttering and stumbling?

It’s called Cognitive Fatigue. Cognitive fatigue happens because the injured brain is working very hard . Since the old pathways are broken, your amazing brain is having to find new paths. when the brain is overloaded and it is like your brain switch being turned off. One minute you are there, and the next minute, it was too much, a fuse blew, and you are gone.

It can be so extreme of a contrast, that people get accused of faking their brain injury. That hurts!

The best explanation I have ever heard comes from Dr. Clark Elliott in his fabulous book “The Ghost in My Brain”. He came up with a great metaphor. It is as if we have 3 energy batteries, an A, B, C battery.

The most efficient battery is the A battery. For most people, it gets charged up each night with sleep,and lasts throughout the day. When the A battery gets used, we have to turn to our B battery. The B battery does not last as long and takes a lot longer to charge. When the B Battery runs down, we have to turn to our emergency battery, the C battery. The C battery should be for dire emergencies only. It only lasts a short while and it takes days to recharge. It’s kinda of like your laptop tells you you have 2% battery left. And then it shuts off and the screen goes black.

When you have a TBI, your A battery gets used up processing things that took no effort before. An enormous percentage of our brain’s energy goes toward processing vision. While it was no problem before, now Processing vision and sound, balance and motion, now takes most of your available energy. So your A batteries are always depleted.

You are now running on B batteries to do anything else, getting groceries, driving a car, going to work. They are not going to last long. And so you are dipping into the C batteries on a daily basis and not just during an emergency.

This is what it looks like when the C batteries are depleted. There will be days of sleep to pay for pushing it this far.

At the beginning of a brain injury when your brain is working really hard to find workarounds for the broken connections, you may be like this most of the time. Over time, as your brain slowly heals, your ability to process information improves and now your A battery has a little more capacity. As you get better you are tapping into you C battery less and less, perhaps only on rough days instead of everyday.

When you are fatigued, it is really important to sleep. That is the only way the batteries get charged again. And that is how our brain heals. New studies show that sleep is the process during which the brain dispels toxins so it can function at its best.

So, if someone you love has a Brain Injury and you can tell they are fatigued. What they need from you is an Immediate response. It takes less than a minute to go from one battery cell to the next, Take them out of the situation, the restaurant, the noise, and get them to quiet, dark, and rest ASAP. You do not want to linger. and You do not want to push the system into the C batteries.

Please share with our community your thoughts and experiences in the comment section below. What do you think of this A B C Battery metaphor? What helps you with cognitive fatigue?

Visit my website http://www.TheTBICoach.com for more helpful videos and tips and for my special report on 3 Things Everyone with a TBI Should Know.

via Traumatic Brain Injury: Understanding Fatigue – YouTube

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[Abstract] Post-stroke fatigue and daily activity patterns during outpatient rehabilitation: An experience sampling method study

Abstract

Objective

To advance our understanding of post-stroke fatigue by investigating its momentary and time-lagged relationship with daily activities

Design

Longitudinal observational study using the experience sampling method (ESM)

Setting

Outpatient rehabilitation care

Participants

Thirty individuals with stroke

Main outcome measures

ESM is a structured diary method that allows assessing real-time symptoms, behavior, and environment characteristics in the flow of daily life, thereby capturing moment-to-moment variations in fatigue and related factors. Using the mHealth mobile application PsyMateTM, individuals with stroke were followed during six consecutive days, and were prompted at 10 random moments daily to fill in a digital questionnaire about their momentary fatigue and current activity: type of activity, perceived effort and enjoyment, and physical activity levels.

Results

Based on all completed digital questionnaires (N = 1013), multilevel regression analyses showed that fatigue was significantly associated with type of activity and that fatigue was higher when participants had engaged in physical activity. Fatigue was also higher during activities perceived as more effortful and during less enjoyable activities. Time-lagged analyses showed that fatigue was also predicted by physical activity and perceived effort earlier during the day. Importantly, the relationship between these daily activity characteristics and fatigue differed substantially across individuals.

Conclusions

This study illustrates the need for ESM to design personalized rehabilitation programs and to capture fatigue and other patient reported outcomes in daily life.

Source: https://www.archives-pmr.org/article/S0003-9993(20)30026-5/fulltext?rss=yes

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[VIDEO] Managing Fatigue After A Brain Injury – YouTube

via Managing Fatigue After A Brain Injury – YouTube

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[BLOG POST] Five Reasons Fatigue Isn’t Like Normal Tiredness (Proving Most People Don’t Get It)

When you’re dealing with a chronic illness, there are a lot of things non-sick people say that are annoying. Things such as, “Aren’t you better yet?” Of course not. This is a chronic illness, not a you-have-it-for-a-week-and-then-it’s-over-with illness. You don’t say that, though. You smile and say, “unfortunately not.” Or friends and family might make a comment about how you’ve taken a lot of time off work lately, as if it was your life plan to become disabled. Or they might mention that you don’t go out much anymore…because clearly you prefer to stay in laid up in bed.

But the most jerkish thing people do is act like the fatigue you’re dealing with—the bone wearying, debilitating, sometimes disabling fatigue—is equivalent to how they felt when they ran a 10k that one time. “Just get more sleep,” they’ll tell you. Or, “You need to push through it. We all get tired.” If you weren’t so fatigued you’d punch the guy right in the face. But you are, so you smile and nod.

Even worse than thoughtless friends spouting this nonsense, is when you get the same thing from doctors. You’d think someone medically trained would be taught the difference between fatigue and normal tiredness, but they’re not. There aren’t even terms to differentiate the two, really. So for medical professionals and non-medical professionals alike, I’ve created a list of the top five reasons that fatigue and normal tiredness should not even be considered in the same sentence. (Other than that one, of course.) Feel free to share it with anyone who doesn’t get it.

5. Sleeping “cures” tiredness; it’s only mildly helpful for fatigue.

When you have chronic fatigue, the number one piece of advice you get from well-meaning non-sick people is to get more sleep. It makes sense. They reflect on their own life and think, “You know, when I feel tired, if I get a good night’s sleep I feel better. Sally should try that.” But that doesn’t work for Sally, and you know why? Because Sally has fucking lupus or Ehlers Danlos Syndrome or Rheumatoid Arthritis. Feeling tiredness in your muscles because you ran some extra errands today is resolved by getting a good eight hours of sleep, but do you know what is not cured by sleeping? Sjogren’s Syndrome. Multiple Sclerosis. Umm, cancer.

While it’s true that getting plenty of rest is good self-care that can reduce flares, it’s not a cure-all, and to suggest that it is is belittling. Especially considering that many people with chronic fatigue are often already sleeping much of the day. Some chronic illnesses sufferers can sleep for sixteen or twenty hours a day and still feel fatigued. Or even if they’re sleeping a normal eight hours, they may feel their worst in the morning, just when you’d predict they’d feel best if their issue was lack of sleep. And all of this ignores the fact that for some people…

4. Fatigue can actually keep you awake.

Sounds stupid, doesn’t it? After working hard all day, most people can lay their head on their pillow and be out within five minutes. Not the case with fatigue. I, myself, have a condition called lupus. It’s an autoimmune disorder, which means that my immune system literally attacks my body rather than outside invaders. It’s sort of like friendly fire in a war. My immune cells are like, “Sorry kidney! Didn’t mean to murder you when I was trying to take out that cold virus. My bad.”

So the fatigue I get stems from the fact that my body is working really hard against the onslaught from…my own body. This sort of fatigue can be so overwhelming that it’s uncomfortable. It’s almost like the tiredness equivalent of pain. It simply doesn’t feel the same as what you experience after doing a lot of cardio. It feels more like your entire life force has been sucked out of your body. It’s disconcerting.

You know that indescribable symptom you get when you have the flu? Not the runny nose or congestion. The feeling that you’re just “sick.” It’s like that feeling amplified. And that feeling is uncomfortable even if there’s not actual pain associated with it (which, with most chronic illnesses, there is anyway). This horrible feeling of fatigue can overcome you and actually make it difficult to fall asleep.

If this seems stupid and horribly counterproductive, you’re right! It feels that way to the sick person too. There’s nothing worse than being horribly fatigued, and yet not being able to fall asleep. That’s why a person with chronic fatigue will recoil at your advice to get more sleep. They’re trying and reminding them of their failure only makes them want to cut you.

3. Pushing through tiredness means you get extra work done; pushing through fatigue means you’re out of commission for a week.

This is probably the biggest pet peeve of the chronically ill: the suggestion that they should just suck it up and push through it. That is actually the worst single piece of advice you could give a chronically ill person, and this is why. People possessing average energy stores and bodies that aren’t falling apart can go for a day or week or even month where they’re not getting enough sleep. Sure they’ll feel crappy, but once they take a weekend to really rest, their body will be back to normal. For a healthy person, it might be totally reasonable to push through some tiredness to get extra work done.

Not so for chronically ill people. Being chronically ill is sort of like starting every day on three hours of sleep, regardless of how much sleep you’ve actually gotten. Strike that. It’s like starting the day on three hours of sleep plus you have the flu. A flu that might never go away or get better. (I’m a bundle of laughs at parties, let me tell you.) If a chronically ill person tries to “push through” their fatigue, they could actually make themselves substantively sicker. The immune system that was just sort of nibbling on their kidneys will now go on full attack, or the moderate pain they had in their joints will be turned up to eleven. And, as you can imagine, that increase of symptoms doesn’t just last during the period that they’re “pushing through” their fatigue. It can last for weeks because now they’ve actually made themselves sicker. Telling a chronically ill person to just suck it up and push through the fatigue is like telling a lung cancer patient to just have another five cigarettes. Go ahead! Suck that smoke through your throat hole. It won’t hurt you.

2. Tiredness is to fatigue as a pimple is to face herpes.

Hopefully this article has already made this clear, but fatigue is far far worse than being tired. Have you ever been so tired after a hard day’s work that you literally couldn’t talk? I haven’t, and I’ve worked very physical jobs. I used to set up stages and sound systems for concerts, lifting super heavy stuff in the heat for sixteen hours at a time. I’d be sore and I’d want to get in the hot tub at the end of the day, but I could always talk. Not so with lupus. Sometimes I am literally so fatigued that it is too much exertion to open my mouth and talk. If you knew me, you’d know what a personal tragedy this is. I am a talker. There is nothing I like more than shooting the shit. My husband wooed me by staying up until noon talking to me all night. On, like, fifteen occasions. That’s how much I love talking.

Recently I created a fatigue scale after I realized that doctors don’t have one. It is as follows:

Tiredness for me maxes out at around a 4. No matter how tired I am, I could always make myself run errands if I had to. When I’m fatigued, though, it’s not just that running errands is a bad idea (which it is). Sometimes I literally don’t have the strength, coordination, or mental capacity to do it. So for any non-sick person who’s never experienced fatigue beyond a four, your advice, while well meaning, is useless because you literally don’t get it.

1. Fatigue is a daily struggle; tiredness is a temporary inconvenience.

Finally, one of the worst things about struggling with chronic fatigue is that you don’t know if it’ll ever end. Most doctors don’t take complaints of fatigue seriously, and even when they do, there’s not much they can do for it anyway. We don’t have an opioid-equivalent fatigue reliever. We don’t even have a tylenol equivalent. When a non-sick person feels tired, they know that if they get a good night’s rest or take a vacation, they’ll feel better. There is no vacation from fatigue. You could fly to Aruba and you’d be just as debilitated.

That’s why the douchy “just get a good night’s sleep” comments sting so badly. If you had even half an understanding of what it’s like to live with this sort of fatigue, there’s no way you’d suggest that. Do you really think someone is this debilitated and they hadn’t even considered, umm, I don’t know, sleeping more. Of course they’ve tried sleeping more! They’re sick, not a moron.

So please. If you’re someone who’s lucky enough not to struggle with chronic fatigue, don’t be a douche. It’s really easy. Just treat the person you’re talking to with respect and assume they have as much common sense as you do.

 

via Five Reasons Fatigue Isn’t Like Normal Tiredness (Proving Most People Don’t Get It) — Miss•Treated

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[BLOG POST] Perfectly Imperfect For The Holidays – TBI Survivor Tips and Observations

By Bill Herrin

Living with a TBI is a reality all its own, and as I reiterate in many posts – it’s different for everyone, including how people around you act, react, overact, act up, or don’t react to you at all. With the Holidays now “officially” here, and Thanksgiving already passed – it’s the time of year that many people dread, and for many good reasons.

The way some people celebrate seems so perfectly “normal” from the outside – the whole family gets together, they have dinner together, or they open gifts, or they have a wonderful party…and that can happen, but from the outside it seems much more “perfect” than anything that we experience in our life. Why is that? Well, living with TBI overshadows a lot of our being, and it’s no wonder…it’s changed who we are in some ways.

It can change us immensely and visibly, or it can change us in a less obvious way – and sometimes, people don’t see what it’s done to a survivor at all. Either scenario can be very frustrating for the survivor of TBI, stroke, concussion, mild TBI, acquired brain injuries, etc.

Making The Holidays More Positive

On one hand, getting together with family and friends during the Holidays after TBI can be an annual test of wills due to lack of patience or empathy for one another, misread intentions, disagreements, or just a lack of understanding for each other.

On the other hand, all families, no matter how perfect things appear on the surface, can have similar issues. Yes, some actual families do get along great, and the Holidays are a positive experience for them – but don’t be dismayed, because (at the end of the day) we’re all perfectly imperfect people. Brain injury or no brain injury!

The point being made is plain and simple – although TBI survivors bear a load of issues in situations with people around, many times they still are left to shoulder the weight of inconsideration, improper actions, comments and more. Being the bigger person is hard to do (especially under the circumstances) but it’s worth the effort!

A Little Empathy Goes A Long Way…

Whether you’re reading this as a TBI Survivor, a caregiver, or as a friend or family member – it’s important to always work toward being empathetic toward each other.

As a survivor, knowing that everyone hasn’t experienced what you have been through is a good rule of thumb for overlooking things that could easily get under your skin. As a friend or family member, remember that you have no clue what it’s like to have a TBI is a good starting point, and overlooking things (that are said) can keep things on an even keel.

The same goes for a TBI survivor that fields negative comments or verbal jabs…working to focus on being together is the point! Enjoying each other’s company is a rarity and should be treated that way – as perfectly imperfect as any of us are.

Some Suggestions

Here are some suggestions to help make the Holidays less frustrating, and hopefully a better experience for a TBI Survivor (and their friends & family):

• Avoid alcoholic drinks (especially when using medications)

• Noise-canceling headphones or earplugs to bring noise levels down to a manageable level

• Bring someone with you that understands your needs when you go shopping, to a party, or for dinner at home (or elsewhere) with others

• Be careful to avoid sensory overload, and act accordingly at an event if necessary (retreat for a bit, leave early if needed, etc.)

• Be rested before any Holiday party, gathering, parade, etc. – if you know that a Holiday parade or program is going to be overwhelming, you may be better off skipping it altogether

• Do your Holiday shopping (along with a friend or family member, etc.) when crowds are at a minimum

• If blinking or bright holiday lights bother you, plan (in advance) to have sunglasses handy, or even a place that you can retreat to if necessary

• Unless you’re certain that a fireworks display is ok to attend, it may be best to skip it (New Year’s Eve, etc.)

• Movies, concerts, outdoor events with lots of lights can all cause issues for Survivors…base your decisions to go on previous experience when possible. If not, do you best to plan in advance on how you (with a friend or loved one) will have an action plan to deal with it

• Try to avoid situations that may overstimulate your senses. Noise, crowds, lights, etc. can trigger anxieties (fear, panic, etc.) and even fatigue – when your brain is overloaded by too many things going on at once

• Another good thing to keep in mind is to ask for assistance if you need it – taking on too much by yourself is asking for trouble, and if you have someone willing and able to help you, let them!

In closing…

In closing, if you’re a TBI Survivor – try to pace yourself during the holidays when there’s so much going on, and not get too overloaded with things to do, places to go, and people to see. As a friend, family member, or caregiver of a person with TBI – keep this in mind as well!

Helping advocate for a TBI Survivor is very important, and they will do much better with you as their “overload avoidance” point person (or team). Happy Holidays to all, and we’ll see you in 2020.

 

via Perfectly Imperfect For The Holidays – TBI Survivor Tips and Observations

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[ARTICLE] Follow-up after 5.5 years of treatment with methylphenidate for mental fatigue and cognitive function after a mild traumatic brain injury – Full Text

Objective: Prolonged mental fatigue and cognitive impairments are common after a mild traumatic brain injury (TBI). This sets limits for rehabilitation and for regaining the capacity for work and participation in social life.

Method: This follow-up study, over a period of approximately 5.5 years was designed to evaluate the effect and safety of methylphenidate treatment for mental fatigue after a mild TBI. A comparison was made between those who had continued, and those who had discontinued the treatment. The effect was also evaluated after a four-week treatment break.

Results: Significant improvement in mental fatigue, depression, and anxiety for the group treated with methylphenidate (p < .001) was found, while no significant change was found for the group without methylphenidate. The methylphenidate treatment group also improved their processing speed (p = .008). Withdrawal produced a pronounced and significant deterioration in mental fatigue, depression, and anxiety and a slower processing speed. This indicates that the methylphenidate effect is reversible if discontinued and that continued methylphenidate treatment can be a prerequisite for long-term improvement. The effect was found to be stable and safe over the years.

Conclusion: We suggest methylphenidate to be a possible treatment option for patients with post-TBI symptoms including mental fatigue and cognitive symptoms.

Introduction

Long-term mental fatigue and cognitive impairment are common after a mild, moderate or severe traumatic brain injury (TBI) and these can have a significant impact on work, well-being and quality of life (1). Fatigue and concentration deficits are acknowledged as being one of the most distressing and long-lasting symptoms following mild TBI (1). There is currently no approved treatment (2), although the most widely used research drug for cognitive impairments after TBI is methylphenidate (3). A few studies have used methylphenidate for mental fatigue after TBI with promising results including our own (4,5). Other clinical trials of drugs have reported improvements in mental fatigue ((−)-osu6162 (6)) or none ((−)-osu616, modafinil (79)).

In our feasibility study of methylphenidate (not placebo controlled) we reported decreased mental fatigue, improved processing speed and enhanced well-being with a “normal” dose of methylphenidate compared to no methylphenidate for people suffering from post-traumatic brain injury symptoms (4). We tested methylphenidate in two different dosages and found that the higher dose (20 mg three times/day) had the better effect compared to the lower dose. We also found methylphenidate to be well tolerated by 80% of the participants. Adverse events were reported as mild and the most commonly reported side-effects included restlessness, anxiety, headache, and increased heart rate; no dependence or misuse were detected (10). However, a careful monitoring for adverse effects is needed, as many patients with TBI are sensitive to psychotropic medications (11).

Participants who experienced a positive effect with methylphenidate were allowed to continue the treatment. We have reported the long-term positive effects on mental fatigue and processing speed after 6 months (12) and 2 years (13). No serious adverse events were reported (13)(Figure 1). In a 30-week double-blind-randomized placebo-controlled trial, Zhang et al. reported that methylphenidate decreased mental fatigue and improved cognitive function in the participants who had suffered a TBI. Moreover, social and rehabilitation capacity and well-being were improved (5). Other studies evaluating methylphenidate treatment after TBI have focused only on cognitive function reporting improved cognitive function with faster information processing speed and enhanced working memory and attention span (1421). A single dose of methylphenidate improved cognitive function and brain functionality compared to placebo in participants suffering from post-TBI symptoms (22,23). Most of these have been short-term studies covering a period between 1 day and 6 weeks and included participants suffering from mild or more severe brain injuries.

This clinical follow-up study was designed to evaluate the long-term effect and safety of methylphenidate treatment. We also evaluated the effect after a four-week treatment break and compared the subjective and objective effects with and without methylphenidate. Patients who had discontinued methylphenidate during this long-term study were also included in this follow-up, as it was our intention to compare the long-term effects on mental fatigue in patients with and without methylphenidate treatment.

[…]

 

Continue —->  Follow-up after 5.5 years of treatment with methylphenidate for mental fatigue and cognitive function after a mild traumatic brain injury: Brain Injury: Vol 0, No 0

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[Review] Ketogenic Diet and Epilepsy – Full Text PDF

Abstract

Currently available pharmacological treatment of epilepsy has limited effectiveness.
In epileptic patients, pharmacological treatment with available anticonvulsants leads to seizure control in <70% of cases. Surgical intervention can lead to control in a selected subset of patients, but still leaves a significant number of patients with uncontrolled seizures. Therefore, in drug-resistant epilepsy, the ketogenic diet proves to be useful. The purpose of this review was to provide a comprehensive overview of what was published about the benefits of ketogenic diet treatment in patients with epilepsy. Clinical data on the benefits of ketogenic diet treatment in terms of clinical symptoms and adverse reactions in patients with epilepsy have been reviewed. Variables that could have influenced the interpretation of the data were also discussed (e.g., gut microbiota). The data in this review contributes to a better understanding of the potential benefits of a ketogenic diet in the treatment of epilepsy and informs scientists, clinicians, and patients—as well as their families and caregivers—about the possibilities of such treatment. Since 1990, the number of publications on attempts to treat drug-resistant epilepsy with a ketogenic diet has grown so rapidly that it has become a challenge to see the overall trajectory and major milestones achieved in this field. In this review, we hope to provide the latest data from randomized clinical trials, practice guidelines, and new research areas over the past 2 years.

[…]

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[Abstract] Poststroke Fatigue Is Related to Motor and Cognitive Performance

Abstract

Background and Purpose: Poststroke fatigue (PSF) is a common debilitating and persistent symptom after stroke. The relationship between PSF and motor and cognitive function remains inconclusive partly due to lack of control for effects of depression and use of insensitive measures. We examined the relationship between PSF and motor and cognitive performance using a comprehensive set of behavioral measures and excluding individuals with depression.

Methods: Fifty-three individuals poststroke (16 female) were included (median age: 63 years, median months poststroke: 20 months). Poststroke fatigue was quantified using the Fatigue Severity Scale (FSS) and cognitive performance was measured with the Montreal Cognitive Assessment, simple and choice reaction time (SRT and CRT) tasks. Lower extremity motor performance included Fugl-Meyer Motor Assessment, 5 times sit-to-stand test (5 × STS), Berg Balance Scale, Functional Ambulation Category, and gait speed. Upper extremity motor performance was indexed with Fugl-Meyer, grip strength, and Box and Block test. Spearman correlation and stepwise linear regression analyses were performed to examine relationships.

Results: Two motor performance measures, Berg Balance Scale and Functional Ambulation Category, were significantly correlated with FSS (ρ = −0.31 and −0.27, respectively) while all cognitive measures were significantly correlated with FSS (ρ = −0.28 for Montreal Cognitive Assessment, 0.29 for SRT, and 0.29 for CRT). Regression analysis showed that Berg Balance Scale was the only significant determinant for FSS (R2 = 0.11).

Discussion and Conclusions: Functional gait, balance, and cognitive performance are associated with PSF. Fatigue should be considered when planning and delivering interventions for individuals with stroke. Future studies are needed to explore the potential efficacy of balance and cognitive training in PSF management.

Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A287).

 

via Poststroke Fatigue Is Related to Motor and Cognitive Perform… : Journal of Neurologic Physical Therapy

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[Quotation] I Feel Like I’m Already Tired Tomorrow

Relationships Quotes Top 337 Relationship Quotes And Sayings 120

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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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