RehabSci 3060 Lecture 1 TBI Questions with 100% correct answers + detailed rationales

TBI

Traumatic Brain Injury

Epidemeology

the incidence, distribution, and control of diseases that are prevalent among a population at a specific time

Etiology

the study of the causes of diseases

Pathology

Processes, causes, and effects of a disease

what is a traumatic brain injury

occurs when an external force disrupts the normal structure or function on the brain. something from outside the body causes the brain to move, strike the inside of the skull, or otherwise become injured

can mild injuries impact daily life?

yes

4 areas affected by TBI

1. cognition

2. physical

3. communication

4. emotional/behavioural

cognition

memory, attention, problem solving

physical

strength, balance, coordination

communication

speech and language

emotional/behavioural

mood, personality, impulse control

what are the parts of the severity spectrum

mild, moderate, severe

mild

concussions: headache, dizziness, confusion, brief loss of consciousness

moderate-severe

prolonged unconsciousness: significant neurological deficits, coma

what factors contribute to the classification of the severity of a TBI?

consciousness, loss of consciousness duration, post traumatic amnesia, Glasgow Coma Scale score

Primary injury

at moment of impact, the immediate physical damage cause by the external force causing bruising of the brain tissue, bleeding, stretching/tearing of tissue

secondary injury

minutes to days after, cascade of biological processes causing swelling, reduced blood flow, lack of oxygen, chemical/metabolic changes, increased intracranial pressure

what is a primary goal of care for a TBI

preventing harm from secondary injury

leading causes of TBI

1. falls

2. motor vehicle collisions

3. sports and recreation

4. workplace accidents

key trends with TBI

- increasing assault related TBI

- creates economic burden

- surveillance gap/underestimates of total TBIs

epidemiology of TBI in Canada

- 456 Canadians sustain a serious brain injury every day (1 every 3 min)

- 18,000 + hospitalizations for TBI per year

- about 800k Canadians living with TBI

- by 2031, TBI is expected to be among the most common neurological conditions in Canada

Sex differences in TBI risk

males have higher rates overall, especially in younger age groups - linked to risk taking behaviour, contact sports, and occupational hazards

what are some high risk occupations

construction, mining, agriculture, manufacturing, transport

is the gender gap narrowing?

yes

what factors are influencing increasing TBI rates in female

- greater participation in sports and recreational actives, including contact sports

- improved recognition and diagnosis, especially of concussions

- increased awareness of TBI related to intimate partner violence

- broader workforce participation, including entry into higher risk occupations

common causes of TBI in young adults

- sports and recreational activities

- motor vehicle collisions

higher exposure to risky activities

common causes of TBI in older adults

- falls are the leading cause

- driven by population aging

- higher vulnerability to injury

age influences TBI risk in 2 key ways:

younger individuals have higher exposure to injury, while older adults have higher vulnerability with worse consequences

what is the leading cause of TBI in Canada

falls

why are older adults at a higher individual risk to TBI

impaired balance, muscle weakness, vision decline, medications, chronic conditions

what percentage of people experiencing homelessness have a history of TBI

about 50%

what kind of relation is there between TBI and homelessness

bidirectional relationship

TBI --> homelessness

- cognitive impairments

- behavioural changes

- difficulty with memory

- loss of employment

- weakened social functioning

homelessness --> TBI

- exposure to violence

- substance use

- unsafe environments

- limited healthcare access

- lack of prevention resources

what are the most common TBIs in the homeless population

moderate to severe TBIs are disproportionately common in this group

3 regions of the frontal lobe

1. prefrontal cortex and anterior cingulate cortex

2. primary motor cortex and premotor cortex and supplementary motor area

3. broca's area

prefrontal cortex

thinking and control, main role: executive function (planning and organizing, decision making, problem solving, working memory, impulse control, social behaviour, self awareness and judgement)

emotionally labile

reactions much stronger than expected

anterior cingulate cortex

motivation and monitoring, main role: drive, attention, error detection (motivation and initiation, apathy, sustaining attention, error monitoring, emotional regulation)

map of executive function

- planning and organizing --> deciding what to do first

- working memory --> remembering what you still need to do

- attention --> not getting distracted

- cognitive flexibility --> adjusting if plans change

what is the result of impaired planning and organization

difficulty completing ADLs and iADLs

poor impulse control

blurting out inappropriate comments, risky decision making, aggressive or socially inappropriate behaviour

difficulty with task initiation and motivation

patient sits for long periods without starting tasks, appears lazy but its neurological not motivational

what is apathy

reduced motivation, decreased interest, and less emotional engagement

what is associated with emotional dysregulation

sudden anger, crying spells, irritability, reduced frustration tolerance

primary motor cortex

responsible for planning, controlling, and executing voluntary movements

motor homunculus describes:

topographical organization

where is the lower body represented on the motor homunculus

more medially

where is the upper body represented on the motor homunculus

more laterally

where is the face and mouth represented on the motor homunculus

most lateral portion

what does contralateral control mean

damage to the left frontal lobe may result in weakness or loss of movement on the right side of the body

pre motor cortex

helps plan and prepare movements before they are executed by the primary motor cortex (movements that are triggered by something we see or interact with in the environment)

what is apraxia

difficulty planning and performing purposeful movements (incorrect, awkward, slowed, poorly coordinated), not due to weakness or lack of understanding

supplemental motor area

helps plan and prepare well learned internally generated motor sequences (writing signature, typing on keyboard, playing instruments)

what important role does the SMA play in movement

coordinating sequences of movements that require both hands (bimanual coordination), buttoning shirt, tying shoe laces

what does akinesia mean

damage leads to difficulty initiating movement

Broca's area location

left frontal lobe anterior to pre central gyrus

what critical role does Broca's area play

speech production and language expression (form words, organize words, produce fluent language)

what is damage to Broca's area called

Broca's aphasia or expressive aphasia (able to understand language but difficulty with producing speech and written language which is frustrating because they know what they want to say but can't say it)

What is the parietal lobe responsible for?

processing sensory imformation

primary somatosensory cortex

senses touch, pressure, pain, temperature, body position

proprioception

our sense of body position

parietal lobe deficits

- reduced, absent or abnormal sensations (contralateral)

- impaired spatial awareness (difficulty judging distances, understanding position of their body, sensory ataxia)

- perception (gestermann syndrome: cluster of damage to left parietal lobe)

Dyscalculia

difficulty with math

agraphia

difficulty writing

finger agnosia

inability to distinguish between fingers

left/right disorientation

inability to distinguish right from left

ideomotor apraxia

motor planning disorder - difficulty with performing purposeful movements

left side of brain responsible for:

language: reading and math

right side of brain responsible for:

spatial relations: recognize shapes, negative environment, interpreting pictures/maps

what is the temporal lob primarily responsible for

hearing (auditory cortex), memory (anterograde amnesia), language comprehension (receptive/Wernicke's aphasia) especially with left damage, emotional processing (amygdala, connections with limbic system)

temporal lobe deficits

- difficulty forming new memories

- Wernicke's aphasia (left side only)

- auditory processing

- difficulty regulating emotions (anxiety, mood swings, irritability, emotional outbursts, inability to recognize emotions in others, reduced fear response)

what is the occipital lobe primarily responsible for

visual processing (interprets features: colour, shape, movement, spatial orientations)

occipital lobe deficits

- visual field loss (homonymous hemianopia)

- cortical blindness

- visual agnosia

- general difficulties with visual perception and interpretation

anosognosia

lack of awareness of deficits

confabulation

fabricating details to fill in missing information

Anton's syndromes

cortically blind and unaware

prosopagnosia

face blindness

3 main parts of the brainstem

1. midbrain

2. pons

3. medulla

the brainstem controls basic life functions, including:

breathing, BP, HR, sweating, digestion, arousal, consciousness

what is the primary responsibility of the cerebellum

coordination and fine tuning of movement (balance, posture, motor learning)

cerebellar deficits

- ataxia (uncoordinated movement)

- poor balance and unsteady gait

- dysmetria (inaccurate movement distance)

- intention tremor

- ataxic dysarthria (slurred, irregular speech)

Diplopia

double vision - seeing two images of a single object

damage to the brainstem (double vision)

cause eyes to move out of sync, misaligning images

damage to the cerebellum (double vision)

disrupts coordination, contributing to double vision

brain receiving information regarding double vision

the brain receives two different visual signals it cannot merge into one image, leading to the perception of seeing double

associated symptoms of double vision

difficulty focusing, blurred vision, headaches, dizziness, balance problems

nystagmus

involuntary, repetitive eye movements

what does the vestibular system do

regulates balance and spatial orientation

how does nystagmus occur following a TBI

damage disrupts coordination --> eyes move uncontrollably or rhythmically, producing nystagmus

3 types of nystagmus

1. horizontal nystagmus

2. vertical nystagmus

3. rotory nystagmus

what is a diffuse axonal injury

a primary injury that involves widespread damage throughout the brain

what does a diffuse injury result from

- rapid acceleration, deceleration, or rotational forces

- different parts of the brain move at slightly different speeds thus creating shearing forces

do patients often experience immediate loss of consciousness when a diffuse injury occurs?

yes

After a diffuse injury, could a CT scan look normal?

yes as damage is often microscopic and spread out

4 occurrences with secondary brain injury

1. cerebral edema

2. cerebral ischemia

3. excitotoxicity

4. inflammation and oxidative stress

describe the biochemical cascade

minutes to days after initial trauma excessive glutamate release, calcium flooding into neurons, mitochondria dysfunction, free radical production, blood-brain barrier breakdown

why does understanding secondary injury matter clinically?

secondary injury is potentially preventable

what does acute treatment focus on to prevent secondary injury

- managing intracranial pressure

- maintaining oxygen and blood flow

- limiting secondary cascades

what months are critical after a TBI

the first 6 months