Traumatic Brain Injury (TBI) and Chronic Traumatic Encephalopathy (CTE)

Question 1

traumatic brain injury (TBI)

Answer 1

• occurs when a force to the head causes neuropathological damage and impairement of brain function
  
  • mild vs. moderate/severe
  • mild TBI (mTBI) is often used interchangeably with concussion

Question 2

chronic traumatic encephalopathy (CTE)

Answer 2

progressive neurodegenerative disorder usually caused by repetitive head trauma

Question 3

TBI - primary injury

Answer 3

stage of closed head injury

occurs at the time of impact

focal
- contusions/brusing

diffuse
- diffuse axonal injury

Question 4

TBI - secondary injury

Answer 4

stage of closed head injury

occurs after impact

several pathologies, mostly leading to increased intracranial pressure, bleeds, and cell death

can lead to:
- edema
- ischema
- hemorrage
- seizures

Question 5

open head injury

Answer 5

aka penetrating head injury
- penetration from outside resulting in focal damage (e.g. gunshot wound, stabbing)

Question 6

closed head injury

Answer 6

no open wound with damage resulting in diffuse damage (e.g. fall or car accident)

Question 7

edema

Answer 7

swelling resulting in increased intracranial pressure

Question 8

ischema

Answer 8

disruption of cerebral blood flow

leads to hypoxia/anoxia

Question 9

hemorrhage

Answer 9

bleeding or development of blood clots

Question 10

moderate/severe TBI & memory (Rigon et al., 2020)

Answer 10

spatial reconstruction/relational memory task

WORSE IN:
- accuracy
- misplacement

-compared to healthy comparison participants, individuals with a history of moderate-severe TBI performed significantly worse on a relational memory task

-more individuals were identified as memory impaired on the spatial reconstruction task than the standard neuropsychological measure of episodic memory (CVLT)

Question 11

mild TBI and memory (Monti et al., 2013)

Answer 11

• compared to matched controls, individuals who had an mTBI decades ago were less accurate on a face-scene relational memory task (middle aged groups)

-c ompared to matched controls, individuals who had an mTBI decades ago had smaller hippocampi bilaterally

• compared to matched controls, there was no impairment evident in memory or neuroimaging in individuals with recent mTBI (young groups)
• these findings implicate the combination of aging and a history of mTBI as the source of the deficit observed in the MI group, rather than mTBI alone

Question 12

TBI and aging

Answer 12

• moderate to severe TBI raises risk of developing AD later in life
  * whether these cases are actually CTE masquerading as AD remains to be seen
• CTE seems to be due to repeated mTBIs/concussions and sub-concussive blows to the head
  • not just the big hits

Question 13

CTE and aging

Answer 13

• symptoms typically appear in middle-age
• approx in 40’s but can be earlier or later
• usually symptoms onset after retirement
• symptoms can occur while still playing (generally more mild)
• diseases gets worse with progressing age

Question 14

emergence of CTE?

Answer 14

many NFL players commit suicide in a way to preserve brain

Question 15

brain changes after one season of football (Hivard et al., 2019)

Answer 15

• 38 football players wore accelometers on helmet all season and had MRIs pre and post season

FINDINGS:
- decrease in integrity of corticospinal tract in right midbrain
- the biggest changes that were happening in brain were individuals who had highest # of rotational hits

Question 16

CTE time course

Answer 16

• symptoms typically appear in middle-age
  
  • approx in 40s, but can appear earlier or later
    ** usually symptoms onset after retirement
    ** symptoms can occur while still playing (generally more mild)

Question 17

CTE cognitive changes

Answer 17

• main complaints seem to be of memory loss and later, executive dysfunction
• memory loss seems to be greatest for recent events
  *difficulty forming new memories
• also have difficulty with planning, judgement

Question 18

CTE psychological changes

Answer 18

• major affective/emotional component present in all stages of disease
  * depression
  * rage/anger
  * lack of inhibition leading to outbursts
• motor dysfunction also common
  * gait disturbances (e.g. some difficulty walking smoothly)

Question 19

tau depositions

Answer 19

earliest accumulation of deposition occurs in:
* depths of cortical sulci
* near blood vessels (perivascular regions)

in moderate stages tau is found in hippocampus and MTL

Question 20

axon damage

Answer 20

in addition to NFT formation, axon damage is seen in all four stages of CTE

** possible that this damage is accounting for any clinical symptoms observed in the early stages, as NFT formation is not that dense

Question 21

differentiating CTE and AD – patient history

Answer 21

former football player with multiple TBIs more likely to have CTE than a librarian

Question 22

differentiating CTE and AD – age of onset of symptoms

Answer 22

CTE affects people younger than AD
- CTE onset approx 40s w more variability
- AD onset typically above age 65, with risk increasing greatly into 70s and 80s

Question 23

differentiating CTE and AD – memory deficit

Answer 23

in the early stages of CTE research, it seems memory probs may be somewhat similar to those of AD
- initial symptoms of difficulty for recent, declarative memories

Question 24

differentiating CTE and AD – emotional/affective symptoms

Answer 24

• both can have depression, but seems more common in CTE
• explosive anger, rage, and impulsivity more common in CTE

Question 25

differentiating CTE and AD – more symptoms

Answer 25

gait disturbances and movement problems more common in CTE, though not unheard of in AD

Question 26

differentiating CTE and AD – pattern of tau deposition

Answer 26

AD-earliest deposition in hippocampus and entorhinal cortex, then spreading to cortical areas

CTE-earliest deposition in depths of cortical sulci and around blood vessels, then spreading to hippocampal region and other cortical areas

Question 27

differentiating CTE and AD – amyloid deposition

Answer 27

much more common in AD

CTE patients seems to have little amyloid in brain