Effects of concussion more subtle and longer-lasting than conventional tests show

  • More evidence comes from several studies of more subtle brain damage that isn't captured in conventional tests of concussions.
  • A new brainwave monitor finds brain impairments in ice hockey players that had been cleared to return to play after concussions, as well as signs of impairment from players experiencing sub-concussive impacts
  • A new way of analyzing brain images has found clear brain changes six months after female rugby players suffered concussions
  • Young adults suffering multiple concussions showed brainwave changes accompanied by poorer cognitive control more than a month after the last concussion
  • Detailed scans found hockey players cleared to return to play showed loosened myelin (the insulating substance around brain wiring)
  • However one study of young football players showed no association between sub-concussive impacts and neurocognitive performance (but were their tests sensitive enough?)

New method finds undetected brain impairments in ice hockey players with and without diagnosed concussions

A hockey concussion study tracking the brain function of 47 Junior A male ice hockey players using a new brainwave monitoring method called "brain vital signs", has found that this more sensitive measure detected neurophysiological impairments, such as attention and cognitive processing deficits, in players who had been diagnosed with concussions and were cleared for return-to-play. Surprisingly, the team also found significant delays in cognitive processing for players who were not diagnosed with concussions at any time during the season (sub-concussive effects).

The new method is easy and quick to use, taking less than 10 minutes and being easily and fully deployable within a variety of sporting settings.

https://www.eurekalert.org/pub_releases/2019-01/cpr-bvs011519.php

New technique confirms persistent brain changes after concussion

A brain imaging study of 52 female athletes from a women's varsity rugby team, including 21 who suffered a concussion, has used a technique that combines multiple imaging measures to produce a much more sensitive and complete picture of concussion injury.

The study identified three unique signatures — one that shows acute brain changes after an athlete has suffered a concussion, another that can identify persistent brain changes six months after the concussion, and a third that shows evidence of concussion history.

Confirming growing evidence of persistent changes in the brain that last well beyond clinical recovery and clearance to return to play, the study showed clear brain changes in both structure and function that persisted six-months after injury.

https://www.eurekalert.org/pub_releases/2018-12/uowo-mts121918.php

Paper available at https://www.sciencedirect.com/science/article/pii/S2213158218303759?via%3Dihub

Lasting impact of concussions on young adults seen in brainwaves & cognitive control

A study involving 21 young adults (18-24) with a history of two or more concussions and 21 age- and gender-matched controls has revealed that those in the concussion group performed significantly worse on a task-switching activity. This was accompanied by greater desynchronization of brainwaves in relevant brain areas. It’s suggested that a change in neural communication occurs and persists after concussion.

All concussions were at least a month earlier.

https://www.eurekalert.org/pub_releases/2018-12/uonh-urf_1121918.php

Sub-concussive impacts in one football season not linked to cognitive harm

A prospective study following 112 youth football players age 9-18 found that sub-concussive impacts were not correlated with worsening performance in neurocognitive function.

The pre- and post-season assessments used to measure outcomes included:

  • Neuropsychological testing
  • Symptoms assessment
  • Vestibular and ocular-motor screening
  • Balance testing
  • Parent-reported ADHD symptoms
  • Self-reported behavioral adjustment

Sensors placed in the helmets recorded sub-concussive head impacts during practices and games.

https://www.eurekalert.org/pub_releases/2018-10/nch-csi101118.php

Concussions loosen insulation around brain cells

Detailed scans of concussed university hockey players found that myelin (the protective fatty tissue surrounding brain cell fibers) was loosened two weeks after the injury — even though the athletes felt fine and were deemed ready to return to the ice.

Myelin speeds the transmission of electrical signals between brain cells, and previous animal research has shown that this loosened myelin can completely deteriorate with subsequent blows. This is the first evidence in humans.

Conventional brain scans do not reveal myelin loosening.

Happily, the myelin had returned to normal after two months, but the findings provide more evidence that more time is needed before concussed athletes return to play.

https://www.eurekalert.org/pub_releases/2018-09/uobc-cli083118.php

Paper available at https://www.frontiersin.org/articles/10.3389/fneur.2018.00575/full

Reference: 

Manning, K.Y. et al. 2019. Linked MRI signatures of the brain's acute and persistent response to concussion in female varsity rugby players. NeuroImage: Clinical, 21, 101627.

[4371] Barlow, S. E., Medrano P., Seichepine D. R., & Ross R. S.
(2018).  Investigation of the changes in oscillatory power during task switching after mild traumatic brain injury.
European Journal of Neuroscience. 48(12), 3498 - 3513.

Rose SC, Yeates KO, Fuerst DR, Ercole PM, Nguyen JT, Pizzimenti NM. 2018. Head impact burden and change in neurocognitive function during a season of youth football. The Journal of Head Trauma Rehabilitation. [Epub ahead of print.]

Weber, A.M.et al. 2018. Pathological Insights From Quantitative Susceptibility Mapping and Diffusion Tensor Imaging in Ice Hockey Players Pre and Post-concussion. Frontiers in Neurology, 9, 575.

 

 

 

Related News

A randomized clinical trial involving 103 teenage athletes who sustained concussions while playing sports found that those who underwent a supervised, aerobic exercise program took significantly less time to recover compared to those who instead engaged in mild stretching.

The American Academy of Pediatric now supports children and teens engaging in light physical activity and returning to school as they recover. It also now advises against complete removal of electronic devices, such as television, computers and smartphones, following a concussion.

Can stronger necks reduce concussion risk & severity?

A review of nearly 2.8 million patient cases in Denmark found that the risk of dementia in individuals with a history of TBI was 24% higher than those without a history of TBI, after accounting for other risk factors.

A study showing that a certain type of instructor-led brain training protocol can stimulate structural changes in the brain and neural connections even years after a traumatic brain injury (TBI) challenges the widely held belief that recovery from a TBI is limited to two years after an injury.

Key points that are new in the 5th International Consensus statement on concussion in sport:

A small study involving 71 adults who struggled with persistent cognitive difficulties after suffering a traumatic brain injury at least four months before has compared two cognitive training programs with and without drug therapy.

The two six-week programs were

A systematic literature review of computerized training for attention and executive function in adults who suffered a brain injury (TBI or stroke) has concluded that there is encouraging evidence that such programs can help.

In the study, mice were repeatedly given extremely mild concussive impacts while anesthetized. The brain's response to a single concussion was compared with an injury received daily for 30 days and one received weekly over 30 weeks.

We know that traumatic brain injury increases the risk of later developing neurodegenerative disorders such as Alzheimer's disease, but we haven't known why. New mouse studies suggest a reason.

Pages

Subscribe to Latest newsSubscribe to Latest newsSubscribe to Latest health newsSubscribe to Latest news