Brain Trauma - Concussion International Concussion Conference District School Board of Niagara May 4-5, 2018 Blaine Hoshizaki PhD Niagara Falls, Neurotrauma Impact Science Laboratory 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) T.B. Hoshizaki 2018
Topics to be discussed 1. Measuring trauma that causes brain damage. 2. Understanding brain trauma in sport. 3. What do helmets protect against? T.B. Hoshizaki 2018
Head Trauma & Biomechanics Predisposition • Genetic Injury Event • Psychological Head dynamic • Fall • Anatomical Response • Collision • Injury history Brain Tissue • Projectile • Linear Accel. Brain Injury Response • punch • Angular Accel. * Emotions • Stress • Duration • Strain * Cognitive • Strain Rate * executive T.B. Hoshizaki 2018
Brain Injury and Mechanisms Chronic traumatic encephalopathy (CTE), Dementia pugilistica (Punch drunk), Chronic post concussion syndrome Neurological (CPCS), Chronic neurocognitive Impairment (CNI), Posttraumatic dementia, Posttraumatic Parkinsonism Long-term Conditions Concussion axonal damage Molecular-cellular Metabolic changes Structural damage changes T.B. Hoshizaki 2018
Brain Trauma and Injury Maximum Principle Strain Traumatic brain injury 35+% Concussion 14 - 35% Sub-concussion? 5 - 13% Neuron damage
Biomechanics “Head Impact” Head Injury in Sport location direction velocity Predisposition mass Genetic event duration Psychological Anatomical Skull fractures Injury history translational Dynamic Focal strains Hematomas Focal neural and vascular injuries head response rotational Diffuse strains Concussions Subdural hematomas Diffuse brain injuries Neuron damage Prevention Injury response Protection equipment Play environment Game rules Injury management T.B. Hoshizaki 2018 Outcome
Measuring Dynamic Response and Maximal Principal Strain Impact: 1. Velocity 2. Compliance 3. Location 4. Mass T.B. Hoshizaki 2018
Injury reconstruction Video Analysis (impact: location, angle, velocity, mass, compliance) (impact: location, angle, velocity, mass, compliance) T.B. Hoshizaki 2018
Dynamic Response Crosby (7.5 m/s)
Maximal Principle Strain Crosby (7.5 m/s) A = 83.1g (10ms) α = 7974 rad/s 2 (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%) T.B. Hoshizaki 2018
Head Impact Event and Dynamic Response T.B. Hoshizaki 2018
Head impact event and Dynamic response Linear Acc. (g) Rotational Acc. (rad/s 2 ) 300 15000 fall Fall 250 Shoulder Shoulder Punch Punch 200 10000 150 100 5000 50 0 0 0.000 0.010 0.020 0.030 0.000 0.010 0.020 0.030 Time (s) Time (s) T.B. Hoshizaki 2018
The relationship between peak linear and rotational acceleration 3300 500 T.B. Hoshizaki 2018
Linear vs Rotational Acceleration and Concussion T.B. Hoshizaki 2018
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 T.B. Hoshizaki 2018 approach to estimating axonal damage under inertial loading of the head”, Journal of Neurotrauma, 30(2), 102-118, 2013.
Visco-elastic Properties “time dependent” T.B. Hoshizaki 2018
Tolerance curve for “concussions” Wayne State Tolerance Curve for Concussion NISL Tolerance Curve for real Concussion events in Gurdjian et al 1953(included dogs and primates) Sport Unprotected Padded Shoulder Helmeted falls falls elbow punches Angular Acceleration (Krad/s 2 ) 700 60 Linear Linear Acceleration (G) 600 WSTC 50 Angular 500 40 data 400 30 300 20 extrapolated 200 10 100 0 0 0 10 20 30 40 DURATION (MS) The effect of Compliance T.B. Hoshizaki 2018
Impact Location on Dynamic Response Where you get hit matters T.B. Hoshizaki 2018
Impact location and Rotational acceleration (rad/s 2 ) head-to-boards impacts in hockey. Impact: (45 0 angle) 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). T.B. Hoshizaki 2018
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. T.B. Hoshizaki 2018
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 ➢ of 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. T.B. Hoshizaki 2018
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 T.B. Hoshizaki 2018
High speed Falls
Bike Racing T.B. Hoshizaki 2018
Professional football T.B. Hoshizaki 2018
Youth football T.B. Hoshizaki 2018
Professional Hockey T.B. Hoshizaki 2018
Peewee hockey T.B. Hoshizaki 2018
Measuring Trauma in Sport “linear dependent variables for concussions” Peak linear acceleration HIC 15 50 % Concussion 50 % Concussion T.B. Hoshizaki 2018
Measuring Trauma in Sport “rotational and MPS dependent variables for concussions” Peak rotational acceleration Maximum principal strain 50 % 50 % Concussion Concussion Brain trauma T.B. Hoshizaki 2018
People are dying, we need helmets! 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. T.B. Hoshizaki 2018
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. T.B. Hoshizaki 2018
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”
Hockey Helmet Protection Helmet Maximum principle strain % No helmet concussion brain trauma 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 Standard tested at 5 m/s
Hockey Goalie Helmet Protection concussion brain trauma Goal tender mask
Baseball Baseball Helmet Protection helmets Baseball helmets Major League Acceleration loading curves for baseball helmets (a&c) vs professional (b&d) for the side impact.
Managing Risk with Helmets Work quite well Doesn’t work so well Neurological Disorders Concussive injuries Traumatic 1. Transient (symptoms). 1. Chronic traumatic encephalopathy 1. Skull fractures (linear) (linear/ rotation ) (CTE) 2. Intracranial bleeds (linear) 1.Typically concussions 2. Dementia pugilistica (Punch drunk) resolve in the first three days. 3. Chronic post concussion syndrome 2.Disability from concussion (CPCS) is hard to predict? 4. Chronic neurocognitive Impairment 2. Persistent (linear/ rotation ) (CNI) 1.May result in serious and 5. Posttraumatic dementia permanent disability . 6. Posttraumatic Parkinsonism Helmets
The Future MIPS 6- d gel pads Fluid technologies Hövding MIPS/Fluid: 11 – 12 mps Conventional: 14 – 22 mps Click View then Header and Footer to change this footer
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