Brain Trauma - Concussion International Concussion Conference - - PowerPoint PPT Presentation

Blaine Hoshizaki PhD

Neurotrauma Impact Science Laboratory

Brain Trauma - Concussion

International Concussion Conference District School Board of Niagara

May 4-5, 2018 Niagara Falls, Ontario

Disclosure

Faculty: Blaine Hoshizaki PhD

Granting agencies: CIHR, NSERC, NOCSAE, Harvard University Football Players Health Study.

Relationships with commercial interests:

– Employee of University Of Ottawa – CCM Hockey Company (research agreement) – Fluid Technologies ( U of O patents)

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Topics to be discussed

• 1. Measuring trauma that causes brain damage.
• 2. Understanding brain trauma in sport.
• 3. What do helmets protect against?

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Head Trauma & Biomechanics

Predisposition

• Genetic
• Psychological
• Anatomical
• Injury history

Injury Event

• Fall
• Collision
• Projectile
• punch

Head dynamic Response

• Linear Accel.
• Angular Accel.
• Duration

Brain Tissue Response

• Stress
• Strain
• Strain Rate

Brain Injury

* Emotions * Cognitive * executive T.B. Hoshizaki 2018

Brain Injury and Mechanisms

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Structural damage Molecular-cellular changes Metabolic changes Concussion Neurological Conditions

Long-term axonal damage

Chronic traumatic encephalopathy (CTE), Dementia pugilistica (Punch drunk), Chronic post concussion syndrome (CPCS), Chronic neurocognitive Impairment (CNI), Posttraumatic dementia, Posttraumatic Parkinsonism

Brain Trauma and Injury

Maximum Principle Strain

5 - 13% 14 - 35% 35+%

Traumatic brain injury Concussion Sub-concussion?

Neuron damage

“Head Impact”

location direction velocity mass event duration

Dynamic head response

translational rotational

Skull fractures Hematomas Focal neural and vascular injuries

Concussions

Subdural hematomas Diffuse brain injuries Neuron damage

Focal strains Diffuse strains

Predisposition Genetic Psychological Anatomical Injury history

Injury response

Prevention

Outcome

Protection equipment Play environment Game rules

Biomechanics Head Injury in Sport

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Injury management

Measuring Dynamic Response and Maximal Principal Strain

Impact: 1. Velocity 2. Compliance 3. Location 4. Mass

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Video Analysis

(impact: location, angle, velocity, mass, compliance)

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Injury reconstruction

(impact: location, angle, velocity, mass, compliance)

Dynamic Response

Crosby (7.5 m/s)

Maximal Principle Strain

Crosby (7.5 m/s)

A = 83.1g (10ms) α = 7974 rad/s2 (20ms) VMS = 20.23 kPa MPS = 41.7%

Measuring Head Trauma

1) Dynamic head response:

a) Peak linear acceleration b) Peak rotational/angular acceleration c) Rotational/angular velocity

2) Brain tissue trauma:

a) Maximal principal strain b) Strain rate c) Cumulative Strain Damage Measure (10%, 15%)

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Head Impact Event and Dynamic Response

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50 100 150 200 250 300 0.000 0.010 0.020 0.030 fall Shoulder Punch 5000 10000 15000 0.000 0.010 0.020 0.030 Fall Shoulder Punch

Linear Acc. (g) Rotational Acc. (rad/s2) Time (s) Time (s)

Head impact event and Dynamic response

The relationship between peak linear and rotational acceleration

500 3300

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Linear vs Rotational Acceleration and Concussion

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Relationship between linear and rotational acceleration and Maximum Principal Strain (John Hopkins FE model)

Wright R, Post A.*, Hoshizaki T.B. and Ramesh K.T., “A multiscale computational approach to estimating axonal damage under inertial loading of the head”, Journal of Neurotrauma, 30(2), 102-118, 2013.

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“time dependent” Visco-elastic Properties

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T.B. Hoshizaki 2018 Wayne State Tolerance Curve for Concussion

Gurdjian et al 1953(included dogs and primates)

10 20 30 40 50 60 100 200 300 400 500 600 700 10 20 30 40 DURATION (MS) Linear WSTC Angular

Unprotected falls Helmeted falls punches Padded Shoulder elbow

Linear Acceleration (G) Angular Acceleration (Krad/s2) NISL Tolerance Curve for real Concussion events in Sport

Tolerance curve for “concussions”

data

extrapolated

The effect of Compliance

Impact Location on Dynamic Response

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Where you get hit matters

Impact location and Rotational acceleration (rad/s2) head-to-boards impacts in hockey.

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Horizontal dotted lines reflect the reported range for a 50% probability of mTBI (Fréchède & McIntosh, 2009; Newman et al., 2000; Pellman, Viano, Tucker, Casson, Valadka, et al., 2003; L. Zhang et al., 2004).

Impact: (450 angle)

Concussion as a measure of Brain Trauma

• A large number of concussions are not diagnosed.
• Establishing the severity of a concussion is challenging.
• Brain injury not fully captured by concussion alone.

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BRAIN TRAUMA EXPOSURE PROFILE

Magnitude Frequency Interval Duration

peak #/day seconds #season location #/week hours #years volume #/year days

(MPS >7%) (game/day/week/season/life) (minutes/hours/days/weeks) (years) T.B. Hoshizaki 2018

Summary

1. Understanding brain trauma and injuries in sport – not just concussion! ➢ Brain Injuries are complex, representing: cellular and molecular damage, disruption

• f physiological processes (concussion) and structural damage.

2. Impact events and brain injury risk. ➢ Head impact events vary, creating neural damage in unique ways. 3. Predicting the risk of neurological injuries using brain trauma profiles. ➢ Impact: magnitude – frequency – interval – duration of exposure, are all contributors to neural damage and resulting neurological disorders.

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Head Trauma in Sport

In the coming slides I would like you to remember these are sports. These are activities that are planned, managed and for the most part include trained athletes

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High speed Falls

Bike Racing

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Professional football

Youth football

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Professional Hockey

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Peewee hockey

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Peak linear acceleration HIC15

Measuring Trauma in Sport

“linear dependent variables for concussions”

50 % Concussion 50 % Concussion

50 % Concussion

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Maximum principal strain Peak rotational acceleration

Measuring Trauma in Sport

“rotational and MPS dependent variables for concussions”

Brain trauma

50 % Concussion

People are dying, we need helmets!

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1905: “18 student-athletes died … in one season, primarily from skull fractures.” President Theodore Roosevelt 1956: William "Pete" Snell, a popular sports car racer who died of head injuries he received when the racing helmet he wore failed to protect his head. 1968: Masterton playing hockey was knocked backward in a collision and landed on his head. He wasn't wearing a helmet. Thirty hours later, he was dead in hospital.

Yes, helmets do help prevent accidental death.

Sport helmets and Concussion

Sport helmets were originally intended to prevent deaths. Helmet certification standards were developed to accomplish this. Helmets are designed to meet the standard. For the most part sport helmets do decrease the risk of severe injuries including death.

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Cycling Helmets

74% of fatal cycling accidents involve head injuries. 97% of fatal cycling accidents involving head injuries were not wearing helmets. Helmet use among cyclists with serious injuries was as low as 13% Those killed 3% were wearing helmets.

Helmet categories

Multiple Impact helmets Mid energy helmets Single Impact helmets High energy management “crash helmets”

Helmet No helmet

Maximum principle strain %

concussion

Falls, elbow, shoulder: 1, 2 - 3 m/s Falls, elbow, shoulder: 3, 4 - 5 m/s Falls, elbow, shoulder: 5, 6 – 7 m/s Puck: 1,2 - 20 m/s Puck: 3,4 - 30 m/s Puck: 5,6 – 40 m/s

brain trauma

Hockey Helmet Protection

Standard tested at 5 m/s

Goal tender mask

brain trauma

concussion

Hockey Goalie Helmet Protection

Acceleration loading curves for baseball helmets (a&c) vs professional (b&d) for the side impact.

Baseball helmets

Baseball helmets Major League

Baseball Helmet Protection

Managing Risk with Helmets

Concussive injuries

1. Transient (symptoms). (linear/rotation) 1.Typically concussions resolve in the first three days. 2.Disability from concussion is hard to predict? 2. Persistent (linear/rotation) 1.May result in serious and permanent disability.

Traumatic

1. Skull fractures (linear) 2. Intracranial bleeds (linear)

Neurological Disorders

1. Chronic traumatic encephalopathy (CTE) 2. Dementia pugilistica (Punch drunk) 3. Chronic post concussion syndrome (CPCS) 4. Chronic neurocognitive Impairment (CNI) 5. Posttraumatic dementia 6. Posttraumatic Parkinsonism Helmets

Work quite well Doesn’t work so well

The Future

Click View then Header and Footer to change this footer

6- d gel pads Fluid technologies MIPS Hövding

MIPS/Fluid: 11 – 12 mps Conventional: 14 – 22 mps

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Bigger Helmets

CCM FL 500 6D Helmets VICIS Zero 1

Future

1. Integrated risk management of sports that account for the limitations of helmets.

• 2. Improved helmet certification tests.

Improved testing methods to include non-centric and higher impact energies Improved dependent variables to include rotational measure and strain.

• 3. Improved helmet technology that manages rotational acceleration
• 4. Customized helmets to protect trauma reflective of risks specific for age group, sex

and competitive level.

Observation

The brain is vulnerable to damage at low energy impacts. A big part of concussion research is focused on developing better ways to diagnose, treatment and return to play. Millions of dollars are spent on developing better helmets. Why do we put our children’s mental health at risk by allowing head impacts that create high risk for neurological damage in sports? - Remove head impacts in sport, especially for youth.

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• Dr. Scott Delaney

McGill University

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Seen here explaining his nick name: “hands of stone”

Thank you

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