Assessing brain activity and blood flow regulation following concussion


Even though the brain is small it uses a lot of energy at rest. This lopsided use of nutrients occurs as a result of the brain having a limited ability to store energy. However, it has been shown concussion can change this functional ability. Therefore, understanding how the brain controls its nutrient supply is essential following injury. When this control system is disrupted, a person is at risk of fainting or in extreme cases, stroke. This may also play a role in symptoms present following concussion. As such, maintaining brain blood flow control is of critical importance for humans.

Precise control of brain blood flow occurs through a series of regulatory actions. Changes related to blood pressure are known as cerebral autoregulation (CA). Changes to providing food/energy to brain tissue is known as neurovascular coupling (NVC). Changes in oxygen and carbon dioxide levels in our body is known as cerebrovascular reactivity (CVR). Most of research in this area has been focused on healthy adult males. This has also been primarily measured using transcranial Doppler ultrasound (TCD). This measures the speed of blood flow in deep brain blood vessels. A second technique is functional near-infrared spectroscopy (fNIRS). This measures the amount of oxygen within the blood in the outer regions of the brain. A third technique is electroencephalography (EEG). This measures the amount of brain activity occurring in the outer regions of the brain.

Using these techniques together will allow us to understand how brain regions communicate with each other. This will reveal how brain function is changed following concussion. People following concussion also experience headaches, dizziness, and other symptoms when exercising. It is unknown how these symptoms link to brain blood flow deficits.

This study is exploring how brain blood flow control is affected following concussion. If you agree to take part, you will perform various tasks that will alter the control of brain blood flow. These tasks are safe and have been completed in healthy and clinical populations. You will also be invited to perform an exercise test.

The aims of this study are:

1) Understand brain blood flow control and how it relates to brain activity between healthy and concussed participants.
2) Examine differences in heart function between healthy and concussed participants.
3) Understand how brain blood flow relates to concussion symptoms and these are affected by exercise.

Please contact us for more details about this study.


Currently recruiting participants: Yes

Eligible gender: Male, Female, Transgender, Other

Eligible ages: 12 to 65

Accepts healthy participants: Yes

Inclusion criteria:

We are looking to include 360 participants in this study. 180 people who have experienced concussion and 180 control participants who have not experienced concussion.

Female and male participants will be included if:

1) they are between the ages of 12-65 years

2) have no history of cerebrovascular, cardiorespiratory, and/or musculoskeletal conditions

3) are able to perform exercise and orthostatic protocols

4) provide informed consent.

Exclusion criteria:

Participants will be excluded if they: '

1) are obese (body mass index >35 kg/m^2), have a history of regular smoking in the previous 5 years, are hypertensive (systolic >145 mmHg and diastolic >90 mmHg), or have a history of substance abuse

2) are pregnant or attempting to become pregnant

3) have a previous history of syncope

4) are not able to communicate in English.


Fill out the following form if you want to participate in this research

Method of contact

Additional information

Contact information

Please contact the Cerebrovascular Concussion Lab at UCalgary for more information about this study

Principal investigator:

Jonathan Smirl

Clinical trial: