Sports Concussion: Immediate, short- and long-term effects on the brain Gary Solomon, Ph.D., FACPN...

Vanderbilt Sports Concussion Center

Sports Concussion: Immediate, short- and long-term effects on the brain

Gary Solomon, Ph.D., FACPNAssociate Professor of Neurological Surgery, Psychiatry,

and Orthopaedic Surgery & RehabilitationCo-Director, Vanderbilt Sports Concussion Center

Team Neuropsychologist, Nashville PredatorsConsulting Neuropsychologist, Tennessee Titans

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• I receive consulting fees from the Nashville Predators and

Tennessee Titans.

• I am involved in beta testing a new version of ImPACT and receive free use of the test during the testing; I am a member of the ImPACT Professional Advisory Board and am reimbursed for travel expenses to Board meetings

• This presentation is not endorsed by any organization with which I am affiliated.

Disclosures/Competing Interests

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Objectives:

1. Overview of the brain

2. What happens in the brain during a concussion--- immediate, short, and long-term effects

3. How long it takes for the brain to recover from a concussion

4. Potential long-term effects a. Post-Concussion Syndrome (PCS) b. Chronic Traumatic Encephalopathy (CTE)

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Average Adult Human Brain

Weight = 1350 g (~3 lbs.)

Width = 140 mm (5.6”)

Length = 167 mm (6.68”)

Height = 93 mm (3.72”)

Brain = 2% of Total Body Weight

Average Adolescent Brain is Smaller

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We can think of the brain as a computer

it is composed of hardware (structure)

and software (function)

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Hardware (Structure) = brain tissue

Software (Function) = Electrical and chemical processes ongoing within the brain tissue that allows us to sense, think, feel, and act

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Sports related concussions rarely cause a hardware problem (structural injury)

When structural injuries do occur, they are usually due to tearing of a blood vessel (resulting in an epidural or subdural hematoma) or in some cases, tearing of nerve cells (traumatic axonal injury)

However, these structural injuries are extremely rare in sports.This is why the structural CT or MRI scan is normal 99+% of the time after a sports concussion

Sports concussion usually causes a disruption in brain function (software problem), which leads to the signs and symptoms described previously

The disruption in brain function hasbeen termed “the chemical cascade”

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The Chemical Cascade of Concussion

Blood flow to the brain is reduced immediately after a concussion

The brain operates on 2 kinds of fuel: glucose and oxygen

The brain gets glucose and oxygen from the blood supply

But because the brain is getting less blood flow after a concussion, the brain is not getting the typical amount of fuel (energy)

The difference between the energy the brain is getting and what the brain needs to operate fully results in an energy crisis and the symptoms

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PET Scans in Head Injury (Glucose)

Marvin Bergsneider, M.D., and David Hovda, Ph.D.UCLA School of Medicine

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fMRI Scan (Oxygen)

Drs. Mark Lovell and Micky Collins University of Pittsburgh Medical Center

Drs. Victoria Morgan and Megan Strother, Vanderbilt

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The short term effects of concussion are age- andpossibly gender dependent

Younger athletes take longer to recover than older athletes, probably because the brain is not fully developed physically until about age 23

Many studies have indicated that females may take longer to recover than males, although a recent VSCC study did not support this

Other factors affecting the duration and intensity of symptoms after a concussion can include concussion history and co-existing disorders such as ADHD, learning disabilities, sleep disorders, psychiatric illness, and migraine headaches

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To get back to the computer analogy, when we have a software problem, we usually shut down the computer and re-boot it.

After a concussion the brain typically repairs (re-boots) itself.

But how long does it take?

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First, there is no FDA-approved medication for concussion, although many drugs are used to treat the symptoms of concussion

In general and on average, the short term effects of concussion resolve within: 7 days for professional athletes 7-10 days for collegiate athletes 7-14 days for high school athletes 7-21 days for younger athletes

>90% of athletes with sport-related concussions recover within a month

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Second Impact Syndrome (SIS)

However, if an athlete does not recover fully from an initial concussion and sustains another concussion before the first has cleared completely, then he may be at risk for Second Impact Syndrome (SIS)

SIS is a very rare condition and typically occurs in teen aged males

SIS has never been reported in females or in professional athletes

SIS occurs when an athlete sustains an initial concussion that is unrecognized, not reported, or has not fully healed

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The brain remains in a vulnerable state from the initial concussion (energy crisis)

The athlete then sustains a second concussion which causes additional chemical changes in the brain that lead to severe brain swelling

The brain is encased in a hard skull and can only expand within certain limits

SIS usually results in permanent disability or death

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__________________________________________________________Effective January 1, 2014

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Sports Concussion: Long Term Effects

Post-Concussion Syndrome (PCS)

Chronic Traumatic Encephalopathy (CTE)

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Post-Concussion Syndrome (PCS)

The term was first used by an article by Strauss and Savitsky in 1934

Multiple definitions abound and vary somewhat, but all involve a constellation of symptoms after a blow to the head

Symptoms common to most definitions include a persistence of the initial concussion symptoms, including headaches, dizziness, fatigue, irritability, forgetfulness, poor concentration, blurred vision, sensitivity to light and noise, frustration, sleep disturbance, difficulty thinking, nausea, depression, increased emotionality

The diagnosis is made anywhere from 6 weeks to 3 months post-injury

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Most of the scientific research on PCS has been done on civilians, and more recently, on military personnel experiencing blast injuries Studies of PCS in athletes are now being conducted

In general, less than 10% of athletes are diagnosed with PCS

Most of these athletes recover within 6-12 months, although there is a small group that remains symptomatic longer

PCS typically involves multiple factors and usually requiresa multi-disciplinary treatment approach

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Chronic Traumatic Encephalopathy (CTE)

Punch-Drunk Syndrome: Martland, 1928, JAMA

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CTE has receive a resurgence of interest due to several professional athletes (especially football players) being diagnosed with CTE after death

The current definitions of CTE are somewhat different but common elements include the appearance of a tau protein in brain tissue, found on autopsy

Mood, behavioral, and cognitive changes occur priorto death

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CTE is an evolving area of study and merits close scientific investigation with well designed, well controlled research

CTE, like most neurodegenerative disorders, is a multi-faceted brain disease that involves a variety of genetic, athletic exposure, and lifestyle factors

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“…a cause and effect relationship has not yet been demonstrated between CTE and concussions or exposureto contact sports.”

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Thanks to all of you for being here today, and

special thanks to Rawlings for their support