Factors Influencing Recovery after Brain Damage

Question 1

8 common misconceptions about recovery/damage

Answer 1

• Recovery from brain dysfunction depends largely on injured person’s efforts
• Someone with severe brain dysfunction can recover completely (apart from some persistent problems with memory)
• Misattributing behaviour (ie. Fatigue, aggression) that results from brain dysfunction to the person’s personality or life stage
• People are more forgiving of behaviour if they have bandage/visible scarring on head
• Emotional problems after brain injury are usually not related to brain dysfunction
• A second brain injury can restore lost memories in those with amnesia
• People with amnesia are totally normal in every other respect
• People with amnesia have no trouble learning new info (ie. They believe amnesia is entirely retrograde -> loss of memory for events prior to injury)

Question 2

Anosognosia

Answer 2

• May occur after stroke and hemiplegia (paralysis on one side of the body)
• May involve confabulation (making up a story that fits the current circumstances that are not reflective of reality) or somatoparaphrenia (identifying paralyzed limb as someone else’s; not their own)
• Often goes away after a few days-weeks after stroke
• Linked to various forms of dysfunction

Question 3

Forms of dysfunction linked to anosognosia

Answer 3

• Movement disorders
• Contralateral neglect
• Memory disorders
• Dysexecutive syndrome (‘frontal lobe syndrome’): Disinhibition, aggression, impulsiveness, and disruptions in planning and certain types of memory (i.e., working memory)

Question 4

4 studies describing importance of self-awareness in successful recovery

Answer 4

• Prigatano & Wong study: your ability to accurately predict your recovery increases likelihood of achieving your recovery goals
• Jehkonen study: those with initial anosognosia had poorer functional outcomes
• Gialanella study: rehabilitation progress not as strong when anosognosia is present
• Cheng & Man study: “Awareness Intervention Program” (AIP); AIP group showed improved self-awareness but was not associated with improved functional outcome

Question 5

effect of age on recovery

Answer 5

• In monkeys, removal of primary motor cortex in infancy results in less dramatic impairment than in adulthood
• In humans, brain injury resulting in aphasia before age 1 is associated with best recovery; recovery diminishes as age increases
• Prefrontal lesions before 16 months may be associated with an inability to learn social and moral rules later in life

Question 6

effect of damage on recovery

Answer 6

• Direct relationship between size of brain lesion and extent of recovery (Larger lesions -> more functional impairments)
• Patients with bilateral lesions show less recovery than patients with unilateral lesions
• • Ex. Bilateral hippocampal lesions -> severe anterograde amnesia; unilateral lesions -> less severe
• Differences due to Chronic vs. Acute Dysfunction

Question 7

effect of damage on recovery: chronic vs. acute dysfunction

Answer 7

• Massive slow-growing tumour (chronic) can have little impairment/functional deficit
• On the other hand, sudden stroke with associated damage of comparable size (acute) can result in functional devastation

Question 8

effect of environment on recovery

Answer 8

• Environmental factors may affect the amount of functional recovery following brain injury
• • Ex. Animal models in enriched environments recover better
• • Ex. Monkeys with focal strokes to the motor cortex were re-trained in skilled hand use

Question 9

Secondary Effects

Answer 9

• Edema

- Diaschisis

Question 10

Secondary effects: edema

Answer 10

• Swelling (edema) after stroke may mask or distort functions in essentially intact regions of the brain
• Dissipation of these effects may account for substantial early recovery (the regions were never broken, they just stop being distorted by edema)

Question 11

Secondary effects: Diaschisis

Answer 11

• Brain lesion can cause dysfunction in an area remote to it because of its strong connections with that area
• Thus, recovery can occur because of a spontaneous reduction of diaschisis (metabolic depression in cerebral areas remote to the lesion)

Question 12

Compensatory strategies

Answer 12

• Mainstay of rehabilitation of patients with brain dysfunction
• Recovery may not represent true restitution of function, but substitution of a new behaviour
• Patient learns strategies to adopt to his or her new motor, sensory, or cognitive impairments
• Ex. Rats use compensatory strategies to walk across beam

Question 13

Therapy dose

Answer 13

More therapy time, more recovery (even when controlling for time post-injury)

Question 14

What is Targeted Temperature Management (TTM)?

Answer 14

therapeutic cooling of the human body used for neuroprotection

Question 15

What are the mechanisms of TTM?

Answer 15

• One mechanism:
• • lowers brain metabolism (glucose and O2 consumption) ->
• • lower risk of energy failure (prevents failure of sodium pumps and potassium influex) ->
• • decreased risk of cell death
• Another mechanism:
• • Decreases pressure by reducing inflammation and cerebral blood volume

Question 16

3 phases of TTM

Answer 16

• Induction: rapid application of ice packs and cold IV fluids (4 degrees C)
• Maintenance: advanced cooling technology device applied to maintain core body temperature
• Rewarming: re-heating body at ~0.25 degree C/hour -> most dangerous phase

Question 17

What forms of acute brain injury is TTM useful for?

Answer 17

• Ischaemic stroke

- Maybe TBI (but studies haven’t shown it to be very effective yet)

Question 18

dose-response relationship for rehabilitative therapy following stroke

Answer 18

• dose = total time scheduled for therapy
• response = improved function or reduced impairment
• the more dose, the better response (time spent in therapy is strong predictor of recovery across different types of therapies)
• this effect exists regardless of time between stroke and start of therapy (though starting extremely early is not always better, sometimes it may hinder recovery)

Question 19

Jessica’s story - initial damage

Answer 19

• Hematoma in right frontal temporal lobe size of tennis ball, no contracoup injury
• 4 on Glasgow coma scale (no motor response to pain, no motor reflexes or verbal response, eyes open in response to pain , no improvement after 24 hours)
• could not walk/talk, 70% chance of death

Question 20

Jessica’s story - initial recovery

Answer 20

• Within a week, cognitive ability skyrocketed -> due to swelling going down
• Still had issues w/balance (contusion approached cerebellum) and short-term memory
• Weird complications -> grew 9 inches, salt-deficient
• Signs of depression -> active kid who could no longer be active; wouldn’t sleep, anxious

Question 21

Jessica’s story - 10-year follow-up

Answer 21

• Scar tissue on brain & cerebellum
• Dead tissue in areas that didn’t have bleeding
• Brain shifted during swelling, right ventricle smushed, volume loss in hippocampus
• Memorizing things and balance is still an issue (changes in gait -> compensatory strategy)
• Anxiety (study found that head trauma as a child can lead to anxiety 10-15 years later)
• Insomnia

Question 22

In what patient populationis anosognosia most common?

Answer 22

Patients with strokes affecting the right hemisphere (esp. Right frontal parietal strokes) leading to paralysis to left side of body

Question 23

Other theories about anosognosia and why people engage in denial

Answer 23

• Normal people engage in denial to protect ego (ex. saying you don’t engage in denial = denial)
• Evolutionary explanation: When you lie, deception is easy to see. But if you lie to yourself and convince yourself to believe the lie, you’re no longer lying -> harder to detect, easier to deceive
• • Problem: self-deception isn’t effective (ie. if you self-deceive about the location of food, you’ll no longer know where it is)

Question 24

VS Ramachandran’s theory of anosognosia

Answer 24

• based on hemispheric specialization
• As you go through life and experience events, they influence your belief system. When you find something that doesn’t fit your belief system, you either have to re-write the system (if it’s major) or ignore it (if it’s minor) -> left hemisphere does this
• Right hemisphere tells you when the thing is major enough that you need to re-write the script -> damage to right hemisphere influences ability to do this (and remember that anosognosia only happens to people with right hemisphere damage)

Question 25

Virtual reality box

Answer 25

• showed that contralateral neglect is not a mechanism of anosognosia
• Using mirror box, asked patient to put gloved hand in it and move it up and down to beat of metronome
• Asked to close eyes, mirror flips and RA puts gloved, stationary hand in box -> patient sees RA’s hand but thinks it’s his own -> normal people freak out
• When this is done on people with anosognosia (on their right hand that is not paralyzed), they do not freak out when they see the RA’s stationary hand -> denies it
• • Unable to register discrepancy (right frontal parietal region is involved in identifying discrepancies -> damaged in those with anosognosia)

Question 26

anosognosia experiment: the choice between unscrewing a lightbulb for $5 or tying a shoe for $10

Answer 26

• People without paralysis pick shoe
• People with paralysis but not anosognosia pick light bulb
• People with paralysis and anosognosia pick shoe