What is a concussion?

A concussion is a form of a traumatic brain injury that happens when the brain is shaken within the skull. Concussion is also known as mild traumatic brain injury (mTBI) but it does not typically result in structural brain injury identified on diagnostic imaging such as CT or MRI scans. The term mild does not diminish the impacts that concussion can have on your health and activities of daily living (ADLs).

While the majority of people recover within one month, in some cases symptoms resolve more slowly or may persist longer than expected. Prompt medical assessment and management can help diagnose concussions and ensure patients are provided with proper education and guidance as well as treatment as needed.

If you have suffered any trauma to your head and/or whiplash, and you experience symptoms of concussion, it is important to seek medical help. This includes if you have been in a traumatic accident; assaulted; fallen; or injured playing sports. National concussion guidelines recommend that all those with a suspected concussion undergo prompt medical assessment by a physician or nurse practitioner.

Topics in this section include:

Signs of a concussion

The following symptoms can occur after a concussion [1].

Please note: Most people will not experience all symptoms – but if you are experiencing symptoms after a physical injury, visit your doctor.

  • Headache/migraine
  • Dizziness and balance problems
  • Nausea
  • Fatigue
  • Sleep disturbance
  • Vision changes
  • Sensitivity to light or noise
  • Ringing in the ears
  • Seizure
  • Problems with smell/taste
  • Foggy-feeling
  • Difficulty remembering and focusing
  • Slower information processing
  • Trouble thinking clearly or finding your words
  • Difficulty making decisions or plans
  • Behavioural changes like depression, anxiety, irritability, aggression, or impulsivity

Who can diagnose a concussion?

There is no formal test to officially diagnose a concussion. A registered doctor or nurse practitioner are the medical professionals qualified to assess your symptoms to determine if you have a concussion.

Please note: there are some exceptions to this in Quebec and Manitoba. In Quebec, nurse practitioners are not able to make a concussion diagnosis. In Manitoba, physician assistants are licensed for medical assessments [2].

When to seek medical attention

You should see a doctor right away if you or someone you are caring for is experiencing the following symptoms after a traumatic event.

  • Significant neck pain or tenderness immediately after the injury
  • Double vision
  • Seizure or convulsion
  • Weakness or tingling/burning in arms and legs
  • Severe or increasing headache
  • Deteriorating conscious state
  • Repeated vomiting
  • Increase in restlessness, agitation or combative behaviour

If the person is experiencing these symptoms in extremes, call 911 and use emergency services.

For more information on treatment pathways after someone has sustained a concussion, see the full chart on the Concussion Awareness Training Tool. The difficulty with a concussion is that you may not recognize you have one right away. If you are experiencing symptoms of a concussion after an accident, instance of assault, or serious hit during sports, make an appointment to see a doctor.

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The Influence of Visual Triggers on Symptoms in Brain Injury and Concussion

By Karen Monet, Opticalm Visual Stress Solutions

Please note: As of 2022, this submitted article has been edited to reflect updated language related to brain injury. The information itself has not be altered.

Stress, both good and bad, is something that we all deal with. For many, managing stress is possible even though we may need help from supportive family, friends, coworkers, doctors, and therapists. The trauma of a brain injury, however, can cause a drastic change in our health, increasing the stress in our relationships, employment, finances, and lives in general. What was once manageable, may now be too overwhelming to manage.

It can be hard to identify everything contributing to this sense of overwhelm. This article aims to point out some of the environmental influences that may be contributing to stress and provide suggestion on how to modify these influences so that recovery and rehabilitation can be improved.

Too much information

Our brains are subject to a non-stop barrage of information – what we are sensing, what we are feeling, and what we are thinking about both. Visual information accounts for approximately 80% of the sensory information we take in, so if the brain is injured and becomes sensitive to visual information, too much energy can be used dealing with the results of this sensitivity, and there may not be enough left to work on recovery.

Tolerance to visual information often decreases following a brain injury and it may be difficult to pinpoint the specific visual information that is uncomfortable and triggering symptoms. Initially following a brain injury, it is recommended to briefly avoid stimulation, bright lights, and computers. If visual problems persist long-term, changes to the visual environment are necessary to decrease sensitives and encourage healing.

Visual stress and uncomfortable images

Visual stress is the term used to describe the overwhelm (hyper-excitement) the brain experiences in the presence of uncomfortable visual triggers. Uncomfortable images have been identified as those having a high spatial frequency such as those that are patterned and of high contrast. (Perception. 2008;37(7):1098-113. Uncomfortable images in art and nature. Fernandez D1, Wilkins AJ.) In addition, images that flicker or move quickly have been reported to be uncomfortable in those with hyper-excitable visual cortices (migraine, epilepsy, autism, head injury). (Wilkins et al. 1989 and Kowacs et al., 2004)

Functional magnetic resonance imaging (fMRI) has been used to demonstrate that “Most uncomfortable visual stimuli will reduce the sparseness of neural activity according to models of the visual cortex; and increase the amplitude of the haemodynamic response” (Arnold Wilkins, Discomfort and Hyper metabolism, Project October 22, 2016 ResearchGate)

Simplified, images that our brains find uncomfortable will:

  1. Increase the density of our brain activity, and
  2. Increase the energy (blood) sent to the area in response to the visual stimuli.
Visual cortex

This increased density and energy can lead to difficulty focusing, headaches, and perceptual distortions as the brain is overwhelmed with too much activity in one area. If the trigger to the hyperexcitement is not stopped and this brain activity and energy is not reduced, the effect then cascades into other areas of the brain. These same results have been shown using other brain imaging techniques including near infrared spectroscopy and QEEG, shown here.

I often use the analogy of blushing to explain this concept – when triggered by something embarrassing, our cheeks fill with blood, become red, burn with heat, and the skin can actually sting as the blood makes the area firm. Until we remove ourselves from the trigger experience and start to calm down, this can be very uncomfortable. And the same goes for our brain.

So what can be done?

Start by evaluating the visual environment. Look for images that are uncomfortable that you avoid looking at. The idea is to find these items/images and make changes where possible, even if the changes are only temporary until the original environment is more tolerable. A good rule of thumb is things that are similar to those found in nature will be comfortable and anything unnatural will likely be uncomfortable. And while wearing dark sunglasses may be a go-to solution, consider this: wearing dark sunglasses will block out almost all the visual information leading to eye strain. This is similar to having to strain to hear something through noise cancelling headphones.

1. Reduce High Contrast Images

Find and remove items in your visual environment with high contrast. This is not just black against white, but also colours that are opposite like red/green, purple/yellow, and blue/orange. Also remove dark/light contrast images as they have the same effect that black/white has on hyperactivating the visual cortex. Difficulty reading is a commonly reported post-injury symptom. To reduce the contrast of black text on white paper, select a comfortable colour of paper and write on it with a similarly coloured pen or print on it with a closely coloured font. Reducing the contrast on your computer screen or phones is possible with specific software and apps that tint screens and change font colours.

2. Reduce Patterns

Repetitive narrow patterns like stripes are one of the most uncomfortable images, and the biggest triggers to visual stress.  Look at patterns around you in artwork, clothing, carpets, flooring, fabrics, and window coverings. Text is also a pattern. Things that were liked and tolerated before the injury may now be causing discomfort simply because of the pattern. The more these items are present in the visual environment, the more the visual stress accumulates. Change out highly patterned artwork, cover patterned carpets or flooring with solids, and soften items with sharp corners and edges with plants, blankets, or curtains. Think soft curves of nature. A local rehabilitation centre changed their high contrast tile flooring because of complaints from patients who felt uncertain walking on it and afraid they would fall. Similarly, a local physiotherapy clinic with a highly patterned carpet must lay towels over the carpeting to reduce nausea for clients looking down from the therapy beds.

3. Reduce Flicker

Flicker is the on/off presentation of an image. It could be the flicker of a computer screen, fan blade, light reflecting off moving water, images moving past the car window, etc. Think about how you feel when looking at these flickering images and do what you can to avoid looking at them. There are specialty filters for computer screens and blade-less fans.  As well, there are specific filter lenses that can be worn to reduce the effects of visual images that cannot be changed.

Another source of flicker is lighting, specifically fluorescent.  For those who have experienced a brain injury, sensitivity to this flicker may be heightened and can be perceived even if others around do not notice it. The compact fluorescent lights bulbs that were put into lamps and lights can be contributing to discomfort. Look instead for dimmable and tunable colour LED bulbs to replace them. These bulbs can also be used at the office for task and ambient lighting if the overhead fluorescent tubes can be turned off.

Blinds are both patterned and create a contrast with the bright light coming through the darker blind. When the windows are open, the breeze may move the blinds, causing flicker. We suggest keeping blinds all the way closed or all the way open to reduce this trigger or use an un-patterned drape or roll blind material instead.

4. Wear precision tinted filters

While you can make modifications to your own environment, you can’t change the world to suit your needs, so an important option is to get tested for visual stress and have your unique visual filters identified. Everyone has a different optimal filter to improve visual perception, just as everyone has a different prescription to improve vision refraction.

Experience a reduction in symptoms

Making these changes can reduce commonly reported symptoms of brain injury, such as:

  • Visual sensory problems: light/glare sensitivity, movement sensitivity
  • Visual processing problems: reading difficulties (word movement, intermittent blurring), and balance difficulties (world appears off balance)
  • Cognitive difficulties: fatigue, concentration, comprehension
  • Physical difficulties: headache, eye pain, nausea

These modifications suggested above may provide a more tolerable visual environment and reduce symptoms, leading to an increased ability to focus on other important aspects of recovery and rehabilitation. It is important to continue with other visual and physical therapies as these will help your brain get back to tolerating life and all the stresses that were managed before brain injury.

Cindy McNaughton

Cindy-survivorMy name is Cindy McNaughton, and I have lived with the effects of concussion since September 2015. This is my experience and it isn’t to scare you: it’s so you feel normal if this has happened to you.

I was leaving work for the day. I worked as a letter carrier with Canada Post. The loading dock door was left 3/4 of the way open. I was looking in my bag for my keys and when I lifted my head, I walked into the steel bar on the bottom of the dock door.

I remember excruciating pain, blacking out and coming to in a crouched position. I split the bridge of my nose and had a very large goose egg on the left side of my forehead. I also somehow managed to jar my jaw in such a way that I loosened my two front teeth.

I was fortunate one of my supervisors was familiar with concussions, but I had a different supervisor go to the hospital with me. They left to pick up their child before I was seen. I can’t stress enough how important it is to have someone there who will wait with you and be your advocate to make sure everything gets checked over thoroughly, make sure they ask questions about what to expect, resources to help and what to watch for after the person with the concussion leaves the hospital. The ER doctor suspected I had a concussion and I just remember him telling me I shouldn’t drive. For how long? I don’t remember that part.

It is still very emotional for me to remember that day because moving forward, my life changed so much. Honestly, I really only remember the very beginning of my injury. The next few months is just gone.

I had a very hard time with any noise, lights, and being around crowds and people. I was tired all the time and I was beyond irritable with the smallest things. My short-term memory was fairly nonexistent. I hated talking on the phone and it was so frustrating being asked all the time how I was because there was so many things happening with me, I couldn’t pinpoint what I was feeling.

My cousin, who I am so grateful for, came to help me for a week with my daughter. I can’t even recall what she did, other than let me sleep. At some point months later, I thought I would be okay quickly. But that wasn’t the case and it scared me to think that I actually had a concussion for this long. I started Googling signs and symptoms and there were so many I had. I felt a sense of relief that what I was feeling was part and parcel of a concussion.

I saw a physiotherapist who helped me with tracking things, as my eyes and brain just wouldn’t line up and it made me so nauseous. The exercises I was given tired out my brain so much I would nap for hours after. One of the hardest symptoms for me was my memory loss. Everyone noticed that I would say something and two minutes later forget. I used so many sticky notes, but they were what helped me remember. Another very frustrating symptom – that I still have four years later – is having a word on the tip of my tongue and for the life of me I can’t think of it. I can remember the longer or different version of the word and I use a thesaurus to figure out the right word. I just hope it will still get better over time.

I did eventually return to work. I have been a registered massage therapist since 2002 and dropped down to part time while I worked at the Post. I was a casual there for 7 years. I took a three month leave of absence after my concussion, but if I took any longer I would lose my seniority. I wasn’t 100% functioning at optimum and didn’t have it in me to negotiate more time, so I went back and ended up spraining my ankle badly. I knew I needed more time to heal and being at the Post was not going to facilitate that, so I decided to open a massage clinic and handed in my resignation in October 2016. I should’ve fought harder but didn’t have anyone to help. So, I did return to work, but it’s a huge blank. I don’t remember any of the small details, but it was for less than a year.

I use a lot of coping strategies like the sticky notes and the thesaurus. Another coping strategy is letting everyone I know well that I’ve had a concussion, so things don’t run as smoothly in my brain as they once did. I also saw a physiotherapist who dealt with concussions and worked on my tracking with my brain and eyes, balance, hand eye coordination and really let me know I was “normal” with the symptoms I was experiencing. The biggest strategy is I’m patient with myself, which was not always the case. I’m not who I was. My brain doesn’t work the same although it’s getting better, but if I forget something or can’t do roller coasters anymore with my daughter, it is my way of life and I accept that.

Time is what heals. Be patient with yourself and be open with everyone on the struggles you have so they can help you. Always take the help.

Chronic Traumatic Encephalopathy (CTE)

Chronic Traumatic Encephalopathy (CTE) is a neurodegenerative disease that can occur in people who have a history of multiple head injuries [1]. This includes athletes and veterans. CTE is caused by the accumulation of abnormal protein tau that spreads throughout the brain and kills cells. CTE is associated with a number of changes including memory and thought processing problems, as well as changes in personality such as aggression and impulsivity. Eventually people with advanced CTE develop dementia [2]. Symptoms of CTE don’t normally appear until several years after the head injuries.

How is chronic traumatic encephalopathy (CTE) diagnosed?

There is no test to confirm whether someone has CTE while they are alive. A diagnosis can only be made after the person has passed away through an examination of brain tissue. Knowledge and research into CTE is ongoing. At this time, there is evidence that multiple hits to the head is the most important risk factor for developing CTE. People who are most at risk are contact sports athletes [3], military personnel and in some cases victims of intimate partner violence [4] because of the high risk of multiple head injuries. However, it may also be possible in individuals who sustained concussions in motor vehicle crashes [5]. It is important to note that not every person with a history of multiple head injuries will develop CTE.

This is the most current information about CTE. There are ongoing research projects to learn more about this condition. It should be noted that many current research projects, such as the CTE study at the Canadian Concussion Centre, are focusing on professional athletes. If you have questions about CTE, you should speak with your doctor about being referred to a neuro-specialist.

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