SLHS 539: 4/21 "Traumatic Brain Injury"

What is TBI?

TBI is caused by a blow to the head or violent head movement (similar to what happens in a high-impact motor vehicle accident.)

The term “TBI” is only utilized when there is evidence of…

Total or partial functional disability or psychological impairment, or both.

Is TBI developmental or acquired?

Acquired

What can cause TBI?

• blow to head

  • causes blood vessels to tear, resulting in a hematoma putting pressure on a specific part of the brain or causing a blood clot

• an object striking to the head

  • can break through the skull and penetrate the brain or push bone fragments into the brain

—>contusion: blow to the head can bruise the brain, damaging tissue located under the point of impact

What are some examples of non-traumatic brain injuries? (5)

• Anoxic injuries caused by anesthetic accidents, hanging, choking, near-drowning, severe blood loss

• Infections of the brain like Meningitis and Encephalitis

• CVA (stroke)

• Brain tumors

• Metabolic disorders that affect the brain such as insulin shock, liver and kidney diseases

What is the prevalence of TBI?

• How many individuals sustain a TBI each year?

• How many die from TBI?

• How many experience the onset of a long-term disability due to a TBI?

• 1.5 million

• 50, 0000

• 80-90,000

What groups have the highest risk of sustaining a TBI?

• In every age group, are TBI rates higher in males than females?

• children age 0-4

• teens 15-19

• adults 75+

What is an SLP’s role in TBI?

SLPS’s are involved in screening, assessment, and treatment of persons with TBI

• identifying risk factors for TBI

• providing prevention information

• conducting comprehensive assessment

• advocating for individuals with TBI and their families

• educating other professionals

T/F: A cerebrovascular accident is a type of TBI.

False

TBI: Primary Injury Types

When the injury causes the TBI directly

• Nonacceleration Injuries

• Acceleration Injuries

  • linear acceleration forces

  • rotational acceleration forces

Nonacceleration Injuries

• Primary Injury (directly causes TBI)

• Moving object strikes stationary object

• Relatively rare

• Tends to be less severe

Acceleration Injuries

• Primary Injury

• Linear Acceleration Forces

  • mvt of the brain inside the skull

  • will cause a coup (where hit your head) and contrecoup (damage at opposite site due to the brain’s inertia - where your brain bounces around - imagine brain like jello inside skull)

• Rotational Acceleration Forces

  • skull is halted by impact; brain continues to rotate with skull

  • leads to diffuse axonal injury

Examples of Primary Damage from TBI (occurs at moment of trauma)

• diffusion axonal injury

• coup and contrecoup injuries

• intracranial hemorrhages

  • extra-axial

  • intra-axial

Pathophysiology of Traumatic Brain Injury: Diffuse Axonal Injury (DAI)

• Diffuse Axonal Injury (DAI): caused by a significant acceleration/deceleration injury

  • ex. a fall from greater than 6 ft. a fall with high angular momentum or a major motor vehicle accident

Pathophysiology of Traumatic Brain Injury: Focal (3)

• Contusions

• Lacerations

• Hematomas (subdural and epidural)

What are the different types of diffuse axonal injuries?

• compression

• tension (pulled apart)

• shearing force (twisted)

Angular Acceleration Injuries

• Define

• Where do most lesions occur?

• The brain rotates at an angle that causes abrasions, lacerations, and twisting/shearing forces —> diffuse axonal injury and hemorrhage and cranial nerve trauma

• Most lesions occur in deep white matter (neuronal fibers that interconnect with different brain regions and brain stem.

Where are the most at risk regions for TBI in the brain? (2)

• Orbital Frontal Cortex

• Anterior Temporal Poles

Acquired Sociopathy

• Damage in Orbital Frontal Cortex

• Deficits in social cognition

B

A

• What happens when part of the brain is compressed by a subdural hematoma or is expanded because of a contusion?

• What do hypoperfusion and herniation lead to?

• It is displaced (and can herniates) from one cranial compartment to another.

• Can lead to further brain damage in the form of pressure necrosis and infaraction, often remote from the site of the primary injury diaschisis.

Decompressive Craniectomy

A neurosurgical procedure involving the removal of a large section of the skull to relieve severe, refractory intracranial pressure (ICP) and prevent fatal brain herniation, usually caused by traumatic brain injury (TBI) or stroke

Hemorrhage vs Hematoma

• Extra-Axial vs. Intra-Axial Hemorrhages

• Hemorrhage = the event —> there has been a bleed

• Hematoma = the result —> collection of blood in places it shouldn’t be (the bruise)

• Extra-Axial = epidural hemorrhage, subdural hemorrhage, subarachnoid hemorrhage

• Intra-Axial = intracerebral hemorrhage, intraventricular hemorrhage

What are some examples of secondary damage from TBI?

• Cerebral Edema: swelling

• Infection

• Hypoxia

• Alterations in:

  • volume of cerebral blood flow

  • release of neurotransmitters

  • neural sensitivity

  • metabolic processes

What does “TBI Severity” refer to?

• Where are assessments of severity derived from?

• Are the boundaries between classifications of mild, moderate,

The amount of acute disruption of brain physiology or structure.

• They are derived from clinical evaluations

  • longer LOC (loss of consciousness) = more severe

What are the initial presentation clinical features of mild traumatic brain injury?

• How long does LOC last?

• Period of Confusion

• Symptoms

• Are there typically focal findings on the remainder of the neurological examination?

• no longer than thirty minutes

• period of confusion (post-traumatic amnesia, PTA) = up to 24 hours

• any combination of headaches, neck ache, dizziness, and nausea

• typically there are no focal findings throughout the remainder of the neurological examination

Neural Injury

Cognitive deficits (attention, memory, and executive function)

Non-Neural Injury

• Systemic Deficits (head/neck ache, dizziness, poor sleep)

• Behavioral Deficits, Mental Health Issues (depression, anxiety)

• Someone who has mild TBI usually recovers within… (how much time)

• If the injury is more severe, recovery can take... (how much time)

• Modal Patient (LOC < 1 minute, PTA (Post-traumatic amnesia) 20-40 minutes, usually recovers within 3 months

• If injury is more severe (LOC > 10 minutes, PTA > 4-6 hrs) recovery can take months to years or not at all

Persistent Post-Concussive Syndrome (PPCS)

When mild TBI patients have symptoms at 1 year

What are the initial presentation clinical features of moderate traumatic brain injury?

• How long does LOC last?

• What type of injuries might the individual sustain?

• Is imaging visible with medical imaging?

• 1/3 to ½ of individuals will have lifetime difficulties with…

• 6 hours

• Fractures, bruises, bleeding (subdural hematoma)

• injury is visible with medical imaging

• learning and daily activities

What are the initial presentation clinical features of severe traumatic brain injury?

• Coma duration

• What percentage of individuals will have lifetime disabilities

• longer than 6 hours

• 80%

T/F: The severity of the injury does not equate to the functioning level of the patient.

True

What are the symptoms of a concussion?

• Dizziness

• Nausea

• Dazed feeling

• Visual symptoms

• Irritability

T/F: Mild brain injury, mild traumatic brain injury (MTBI), mild head injury (MHI), minor head trauma, and concussion may be used interchangeably.

T

Mild traumatic brain injury vs. Concussion

• MTBI/concussion = short-lived loss of brain function due to head trauma that resolves spontaneously

• concussion = function interrupted but no visible structural damage to the brain

How are concussions diagnosed?

• Simple Concussion: symptoms gradually resolve, and the patient returns to normal function in 7-10 days

• Complex Concussion: symptoms persist and thought processes are affected

Patients with repeated concussions would fall into which category diagnosis of concussion?

Complex Concussion

When can repeated concussions result in cumulative neurologic and cognitive deficits?

Repeated mild brain injuries occurring over extended period (ex. months or years) can result in cumulative neurologic and cognitive deficits.

When can repeated concussions be fatal?

Repeated mild brain injuries occurring within a short period (ex. hours, days, weeks) can be fatal.

Second Impact Syndrome

An individual sustains a second head injury before the symptoms from the first head injury have resolved.

What is the leading cause of death in sports-related accidents?

TBI