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What Is a Subconcussion?

| By Dr. Jennifer Hunnicutt

New Research Aims to Highlight Information on this Tricky Head Injury

You’ve heard of concussions, but have you heard of subconcussions?

Subconcussions are head injuries that do not present with clinical symptoms. Therefore, they can be pretty tricky to identify and treat!

A research group representing many parts of the U.S. sought to shed light on subconcussions through a recently published literature review. (1) Their goal was to improve the understanding of this head injury among healthcare providers. An enhanced understanding and recognition of subconcussion will allow for earlier intervention and ultimately improve outcomes for athletes or other individuals affected by head injuries.

What is a subconcussion?

A subconcussion is an injury to the head that does not present with clinical symptoms. The impact injury produces metabolic and physiological changes in the brain, but it does not reach the threshold that would produce the standard clinical symptoms of a concussion. In other words, a brain injury occurs but you can’t tell it is there!

Even though clinical symptoms do not present, subconcussions should still be considered a possibility after a blow to the head or upper body, especially in younger athletes or patients.

While a single subconcussion may not be detrimental, the compounding effects of subconcussions can be very serious, just like with concussions.

How are subconcussions diagnosed?

Because subconcussions do not display clinical symptoms, they are very difficult to diagnose. There currently is not a standard form of diagnosis outside of standard assessments of concussion (symptom tracking, balance testing, neurocognitive testing, etc.)

If a subconcussion is suspected, perform the standard assessments of a concussion and refer to a specialized healthcare provider for further evaluation and diagnosis.

How are subconcussions treated?

If a subconcussion is suspected, it should be treated following the same protocols as a concussion.

The current best practice for subconcussions is to remove the athlete from play – “when in doubt, sit them out.” (2) The researchers suggest this is the best preventative measure.

Subconcussions, especially a multitude of subconcussions (i.e., repetitive head injuries/impacts), may affect learning. Therefore, it is important to treat patients with repeated head injuries conservatively – err on the side of caution and follow standard return-to-learn protocols.

Future Research on Subconcussions

There is exciting research being conducted to better identify subconcussions and how they differ from concussions. Most of these studies are preclinical, meaning they are being conducted in animals before they are conducted in humans.

Just because clinical symptoms do not present in patients with subconcussion does not mean that the subconcussion is benign. We just don’t have the tools yet that are sensitive and specific enough to identify the lower threshold of subconcussion symptom presentation or the effects of repetitive subconcussive injury. This is why future research is so important. It will help healthcare providers learn more about subconcussions, identify and treat subconcussions, and ultimately improve outcomes for athletes or patients affected by subconcussions and repetitive head injuries.

References

  1. Dioso E, Cerillo J, Azab M, Foster D, Smith I, Leary O, Goutnik M, Lucke-Wold B. Subconcussion, Concussion, and Cognitive Decline: The Impact of Sports Related Collisions. J Med Res Surg. 2022;3(4):54-63. doi: 10.52916/jmrs224081. Epub 2022 Jul 20. PMID: 35966951; PMCID: PMC9371364.
  2. Responding to a Concussion and Action Plan for Coaches. Accessed at: https://www.cdc.gov/headsup/.
Dr. Jennifer Hunnicutt
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