Traumatic Brain Injury (TBI)

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Traumatic Brain Injury (TBI)

Heterogenous injury that typically occurs as a result of a high-velocity or high-impact blow to the head

Brain damage results from external forces that cause the brain tissue to make direct contact with an object, rapid acceleration or deceleration forces, or blast waves from an explosion 

3 Classifications of TBI

1. Mild (majority)

2. Moderate

3. Severe

What is the most common cause of TBI hospitalizations? 

Unintentional falls 

Primary Brain Injury

Primary: due to direct trauma to the parenchyma

Secondary: results from a cascade of biochemical, cellular, and molecular events that evolve over time due to the initial injury and injury-related hypoxia, edema, and elevated ICP

Diffuse Axonal Injury (DAI) 

Caused by acceleration and deceleration that causes shearing, tensile, and compressive forces within the brain 

Commonly occurs in the corpus callosum, internal capsule, cerebral peduncles, and brainstem 

Can cause coma if severe enough 

Hypoxic-Ischemic Injury

Lack of oxygenated blood flow to the brain tissue, leading to death of cells in the brain 

Hypoxic-Ischemic Injury Causes

• Systemic hypotension

• Anoxia

• Vascular damage in the brain

• Cardiac arrest 

Epidural Hematoma

Accumulation of blood between the skull and dura matter

Typically caused by a temporal bone fractures that tears in the middle meningeal artery

Sx include brief LOC, headache, vomiting, seizure, can lead to coma

Subdural Hematoma

Accumulation of blood between the dura and arachnoid matter

Rupture of bridging veins; can be a slow bleed 

Can lead to brain damage or death if severe enough 

Sx include persistent headache, confusion, drowsiness, nausea, vomiting, slurred speech, visual changes, dizziness, loss of balance, difficulty walking, weakness, seizures, LOC and coma 

What are the 3 sites of hematomas?

1. Epidural

2. Subdural

3. Intracerebral

Traumatic Intracerebral Hemorrhage 

Bleed inside the brain caused by trauma to the head 

Associated with severe TBI

Higher risk of mortality and morbidity

Traumatic Subarachnoid Hemorrhage

Accumulation of blood in the subarachnoid space and CSF caused by damage to vessels in subarachnoid space from trauma 

Associated with moderate or severe TBI

Petechial Hemorrhage 

Bleeding in the white matter produced by shearing forces

Associated with diffuse axonal injury (DAI) 

What can occur as a result of severely increased ICP? 

Herniation of the brain or brain ischemia; requires prompt emergency treatment 

Coup-Contrecoup Injury

A type of TBI that occurs when the brain strikes both the initial impact site (coup) and the opposite side of the skull (contrecoup)

Coup

Contusion occurs to area of the brain under the direct, localized impact

Distorted then returns to usual shape

Contrecoup

Contusion located on the opposite side of direct impact

Occurs due to translational acceleration from inertial loading

True or False: Coup and contrecoup can occur separately 

True

Blast TBI

Trauma induced by exposure to a blast without a direct blow to the head

MOI not clear though usually blast waves that produce concussion or mild TBI

Sx include headache, fatigue, poor concentration, lethargy, anxiety, depression, insomnia

Diffuse Brain Injury Consequences

• Reduced thinking speed.

• Confusion

• Reduced attention and concentration

• Fatigue

• Impaired cognitive skills in all areas

Motor Control Impairments

• Paresis (focal or diffuse)

• Decreased selective motor control or increased coactivation

• Abnormal synergies

• Increased reaction times

• Altered coordination

Postural Control Impairments 

• Difficulties with alignment, steady state, anticipatory and reactive postural control 

• Sensorimotor processing 

• Abnormal timing, sequencing, coactivation resulting in disorganized postural motor synergies 

Primary Impairments

• Tone

• Sensory deficits

• Perception

• Visual

• Pain

• Speech, language, swallowing

• Cognition

• Behavioral

Secondary Impairments

• MSK involvement (!!!)

• CVP involvement

• Integumentary involvement

Priority Tests and Measures for Baseline 

• Muscle tone

• Functional mobility and task analysis 

• Visual fields 

• Perception 

• Joint integrity and PROM 

• Sensation 

• Cranial nerve integrity 

• Integument integrity (positioning) 

• Pain