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Scientific Research and Evidence

Here is a compilation of scientific articles demonstrating the positive effects of brain cooling as a treatment for concussion.

Future Medicine / SHL PolarCool Study

Selective head–neck cooling after concussion shortens return-to-play in ice hockey players

Anna Gard, Yelverton Tegner, Mohammad Fazel Bakhsheshi & Niklas Marklund

Summary

The scientific publication is an analysis of data from the study with Svenska Hockeyligan AB (SHL) and HockeyAllsvenskan. The result shows significant positive effects in the form of shortened Return-To-Play (median 7 days for intervention vervus 12.5 days for control) and reduced proportion of long-term absence (7% in intervention vervus 25% in control) for players cooled with PolarCap® System.

Highlights

  • After the study, 2 PolarCap® Systems have been available at all SHL games, where data has been continually collected in a follow-up-study.
  • The result was then further strengthened when data from the 2019/2020 season were included where the number of cases increased to 129.
  • The result showed stronger significance, especially regarding the considerably reduced proportion of long-term absence among treated players (absence 3 weeks or more, 8%of treated, 28% of control, p = 0.003).
  • Return to play, 31% faster among treated players compared to non-treated players.

Read the article  

In addition to the extensive study with SHL and HockeyAllsvenskan, below are several other studies that demonstrates positive effects of brain cooling on concussion. These studies point to positive effects of cold treatment for concussions, something that the robust study with SHL now confirms with its strong result.

University of Miami

Mild Hyperthermia Worsens the Neuropathological Damage Associated with Mild Traumatic Brain Injury in Rats

Atsushi Sakurai, Coleen M. Atkins, Ofelia F. Alonso, Helen M. Bramlett, and W. Dalton Dietrich

Summary

Experimental study from the University of Miami shows that mild hypothermia in rats (39°C) gives significant more symptoms than at 37 °C. See attached full article.

Highlights

  • In conclusion, we have demonstrated the increased vulnerability of the mildly traumatized brain to periods of elevated temperature. Elevating the brain and core temperature immediately prior to mTBI produced more severe changes in contusion volume and damage to dentate hilar neurons. This finding would suggest that strategies that include the critical measurement and management of temperatures before or following an mTBI or concussion could be beneficial in limiting tissue vulnerability and subsequent behavioral deficits.

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University of Miami

Emergence of Cognitive Deficits after Mild Traumatic Brain Injury due to Hyperthermia

David J. Titus, Concepcion Furones, Coleen M. Atkins, and W. Dalton Dietrich

Summary

Follow-up experimental study from the University of Miami shows both biological positive effects and cognitive long-term effects after cooling. See attached full article.

Highlights

  • mTBI alone did not result in significant, long-term cognitive deficits
  • mTBI while hyperthermic resulted in long-term learning and memory deficits
  • Cooling after hyperthermic mild TBI prevented development of cognitive deficits
  • Cortical contusions were decreased by cooling after hyperthermic mTBI

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Penn State University

Neurobiological effect of selective brain cooling after concussive injury

AlexaWalter, Katie Finelli, Xiaoxiao Bai, Brian Johnson, Thomas Neuberger, Peter Seidenberg , Timothy Bream, Mark Hallett & Semyon Slobounov

Summary

Clinical study with a functional MRI from Penn State University that shows increased blood flow to the brain after cold treatment, where a negative effect of concussion is precisely a reduced blood flow. In the study, Penn State athletes suffering from concussions were cold-treated 3 to 8 days after injury. The study was conducted at the Center for Sport Concussion Research and Service. See attached full article.

Highlights

  • “fMRI showed global increase of relCBF after brain cooling”
  • “Changes in subjects’ performance on spatial memory, reaction time and balance task after cooling.”
  • ” Considering the existing evidence of metabolic crisis after concussive injury (e.g., reduced blood flow and increased demands for glucose etc., metabolism) (Giza and Hovda 2001) and the observed increase of blood flow (ASL data) in concussed individuals after 30 min of brain cooling administration, we can conclude that brain cooling may potentially be implemented as a treatment modality in the acute phase of injury”.

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Auckland University of Technology

Effect of Selective Head-Neck Cooling on Signs and Symptoms of Sport Originated Brain Injury in Amateur Sports: A Pilot Study

Doug King, Patria A Hume, Karen Hind and Trevor Clark

Summary

Clinical study from New Zealand on 35 athletes, of which 23 women, cold-treated for 20-30 minutes showing reduced acute concussion symptoms for treated individuals. Equal effect between men and women.

Highlights

  • “During contact sports, body temperature can elevate to between 38.9°C and 40.0°C at the peak of activity.”
  • “The key finding observed and most pronounced was an immediate reduction in post-injury event clinical symptoms in both male and female players who wore the head-neck cooling device. Whilst players who did not elect to use the head-neck cooling device, demonstrated no change in symptom scores measured via the CSS. Interestingly, females recorded a similar symptom score in all the symptom scale clusters when compared with males for both the selective and no head-neck cooling groups. However, they did record a higher severity in most, but not all of the symptom clusters which was similar to previous studies.”

Read the article  

Further scientific reading

Dynamic blood brain barrier regulation in mild head trauma

O'Keeffe, Eoin & Kelly, Eoin & Liu, Yuzhe & Giordano, Chiara & Wallace, Eugene & Hynes, Mark & Tiernan, Stephen & Meagher, Aidan & Greene, Chris & Hughes, Stephanie & Burke, Tom & Kealy, John & Doyle, Niamh & Hay, Alison & Farrell, Michael & Grant, Gerald & Friedman, Alon & Veksler, Ronel & Molloy, Michael & Campbell, Matthew. (2019).

Journal of Neurotrauma. DOI: 10.1089/neu.2019.6483.

Understanding the Consequences of Repetitive Subconcussive Head Impacts in Sport: Brain Changes and Dampened Motor Control Are Seen After Boxing Practice

Di Virgilio Thomas G., Ietswaart Magdalena, Wilson Lindsay, Donaldson David I., Hunter Angus M.

Frontiers in Human Neuroscience.

Cold Blooded: Evaluating Brain Temperature by MRI During
Surface Cooling of Human Subjects

Eric J. Curran, Daniel L. Wolfson, Richard Watts and Kalev Freeman

Neurocrit Care (2017) 27:214–219, DOI 10.1007/s12028-017-0389-4

Longitudinal Performance of Plasma Neurofilament Light and Tau in Professional Fighters: The Professional Fighters Brain Health Study

Charles Bernick, Henrik Zetterberg, Guogen Shan, Sarah Banks, and Kaj Blennow

Journal of Neurotrauma. 35:2351–2356 (October 15, 2018)

Association of Acute Increase in Plasma Neurofilament
Light with Repetitive Subconcussive Head Impacts: A Pilot Randomized Control Trial

Angela Wirsching, Zhongxue Chen, Zachary W. Bevilacqua, Megan E. Huibregtse, and Keisuke Kawata

Journal of Neurotrauma. 36:548–553 (February 15, 2019)

Consequences of Repeated Blood-Brain Barrier Disruption in Football Players

Marchi N, Bazarian JJ, Puvenna V, Janigro M, Ghosh C, Zhong J, Zhu T, Blackman E, Stewart D, Ellis J, Butler R, Janigro D. PLoS One, 2013

March

Meta-analysis of Therapeutic Hypothermia for Traumatic Brain Injury in Adult and Pediatric Patients

Crompton EM, Lubomirova I, Cotlarciuc I, Han T, Sharma S, Sharma P. Critical Care Medicine.

April 2017 – Volume 45 – Issue 4 – p 575–583.

The effect of sub-concussive collisions on brain integrity in colleagiate football players over a single football season: A multi-modal neuroimaging study

Slobounov SM, Walter A, Breiter HC, Zhu DC, Bai X, Bream T, Seidenberg P, Mao X, Johson B, Talvage TM Neuroimage Clinical 2017

March; 10.1016/j.nicl.2017.03.006

Noninvasive Selective Brain Cooling by Head and Neck cooling is Protective in Severe TBI

Qiu W, Shen H, Zhang Y, Wang W, Liu W, Jiang Q, Luo M, Manou M.

Journal of Clinical Neuroscience. 2006 Dec;13(10):995-1000.

Effects of Therapeutic Hypothermia on Inflammasome Signaling After Traumatic Brain Injury

Tomura S, de Rivero Vaccari JP, Keane RW, Bramlett HM, Dietrich WD.

Journal of Cerebral Blood Flow & Metabolism. 2012 Oct;32(10):1939-47.

Post-Traumatic Brain Hypothermia Provides Protection from Sensorimotor and Cognitive Behavioral Deficits

Bramlett HM, Green EJ, Dietrich WD, Busto R, Globus MY, Ginsberg MD.

Journal of Neurotrauma. 1995 Jun;12(3):289-98.

Post-Traumatic Brain Hypothermia Reduces Histopathological Damage Following Concussive Brain Injury in the Rat

Dietrich WD, Alonso O, Busto R, Globus MY, Ginsberg MD.

Acta Neuropathologica. 1994;87(3):250-8.

Neuroprotective Mechanisms of Hypothermia in Brain Ischaemia

Yenari MA, Han HS.

Nature Reviews Neuroscience. 2012 Feb 22;13(4):267-78.

A Military-Centered Approach to Neuroprotection for Traumatic Brain Injury

Shear DA, Tortella FC.

Frontiers in Neurology. 2013 Jun 12;4:73.

Prophylactic Hypothermia for Traumatic Brain Injury: a Quantitative Systematic Review

Fox JL, Vu EN, Doyle-Waters M, Brubacher JR, Abu-Laban R, Hu Z.

Canadian Journal of Emergency Medicine. 2010 Jul;12(4):355-64.

Prophylactic Hypothermia for Traumatic Brain Injury: a Quantitative Systematic Review

Fox JL, Vu EN, Doyle-Waters M, Brubacher JR, Abu-Laban R, Hu Z.

Canadian Journal of Emergency Medicine. 2010 Jul;12(4):355-64.

A Military-Centered Approach to Neuroprotection for Traumatic Brain Injury

Shear DA, Tortella FC.

Frontiers in Neurology. 2013 Jun 12;4:73.

Neuroprotective Mechanisms of Hypothermia in Brain Ischaemia

Yenari MA, Han HS.

Nature Reviews Neuroscience. 2012 Feb 22;13(4):267-78.

Post-Traumatic Brain Hypothermia Reduces Histopathological Damage Following Concussive Brain Injury in the Rat

Dietrich WD, Alonso O, Busto R, Globus MY, Ginsberg MD.

Acta Neuropathologica. 1994;87(3):250-8.

Noninvasive Selective Brain Cooling by Head and Neck cooling is Protective in Severe TBI

Qiu W, Shen H, Zhang Y, Wang W, Liu W, Jiang Q, Luo M, Manou M.

Journal of Clinical Neuroscience. 2006 Dec;13(10):995-1000.

Effects of Therapeutic Hypothermia on Inflammasome Signaling After Traumatic Brain Injury

Tomura S, de Rivero Vaccari JP, Keane RW, Bramlett HM, Dietrich WD.

Journal of Cerebral Blood Flow & Metabolism. 2012 Oct;32(10):1939-47.