Traumatic Brain Injury

Mild TBI

• normal imaging

• LOC 0-30 mins

• AOC up to 24 hrs

• PTA up to one day

• GCS 13-15

Moderate TBI

• normal or abnormal imaging

• LOC greater than 30 mins, less than 24 hrs

• AOC greater than 24 hrs

• PTA 1-7 days

• GCS 9-12

Severe TBI

• normal or abnormal imaging

• LOC greater than 24 hrs

• PTA over 7 days

• GCS 3-8

Penetrating Injuries

• An object breaks through the skull and enters the brain

• Damage is usually localized to the area of entry

  • Ex. Gunshot wound, Stab injury

Non-penetrating injuries

• The skull is not broken

• Brain is injured by movement inside the skull

• Acceleration and non-acceleration injuries

  • Ex. Falls, Car accidents, Sports injuries

Secondary Injuries

Subsequent to initial insult. Effects evolve over time.

● Cerebral edema (swelling)

● Raised intracranial pressure

● Meningitis

● Biochemical changes (changes in levels of neurotransmitters,

sodium, potassium, etc.).

Attention (Selection)

• attending to one aspect of a situation/stimulus and ignoring others

Attention (Capacity Limitation)

• Only so much information can be consciously attended to, or held and manipulated in memory.

• resource allocation theory

• related to working memory (active manipulation of info)

Clinical Models of Attention

● Focused: basic ability to attend, even momentarily.

● Sustained: maintaining focus over time.

● Selective: maintaining focus in the presence of distraction.

● * Alternating: shifting focus back and forth between tasks.

● * Divided: “multi-tasking”.

• alternating and divided considered the same

Attention and Neural Networks

Attention is a whole brain phenomenon, but certain areas are crucial. Some areas associated with attention:

● Alerting: achieving and maintaining a

high sensitivity to incoming stimuli.

● Orienting: selecting information from

sensory input.

● Executive attention: monitoring and

resolving conflict among thoughts,

feelings, and responses.

Attention and TBI

Diffuse and bilateral injury to: neocortex, limbic system, and brain stem areas.

• Sensory selective attentional system (Parieto-temporo-occipital area).

• Arousal, sustained attention and vigilance system (Midbrain reticular activating system and limbic structures).

• Anterior system for selection and control of responses (Frontal lobes, anterior cingulate gyrus, basal ganglia, thalamus)

Frontal Lobe Syndrome/Dysexecutive Syndrome

• cluster of behavioral, affective, and cognitive symptoms resulting from frontal lobe damage

• executive function and pragmatic deficits

• personality change

Concussion

• mildest form of TBI

Short-Term Memory

● Maintaining information for a short time.

● Chunking is good for short-term memory.

● Limited capacity (e.g.,“magic number” of 7 ±2)

Sensory Memory

● Traces of sensory input that persist only briefly.

● Sensory memories typically only last a few seconds.

● It allows us to select what to pay attention to next.

Long-Term Memory

• storage of information for an extended period

Retrospective Memory

• Memory of people, words, events, etc. encountered or experienced in the past

Declarative/Explicit Memory

• type of long term memory

• type of retrospective memory

  • knowledge you can consciously access

Episodic Memory

• type of long term memory

• type of retrospective memory

• type of declarative memory

  • for events involving contextual information (experiences)

Semantic Memory

• type of long term memory

• type of retrospective memory

• type of declarative memory

  • word/lexical knowledge

  • memory independent of learning context

Non-Declarative Memory

• type of long term memory

• type of retrospective memory

  • knowledge you cannot consciously access

Procedural Memory

• type of long term memory

• type of retrospective memory

• type of non-declarative memory

  • motor or automized cognitive skills

Conditioning Memory

• type of long term memory

• type of retrospective memory

• type of non-declarative memory

  • neutral stimulus becomes linked with a meaningful stimulus, and this association is stored in memory.

Prospective Memory

• type of long term memory

• remembering to remember

• Usually triggered by cues:

  • Certain time of day.

  • Certain event occurring or location.

  • Strength and salience of cues affect success.

• proper (e.g., buying groceries en route home)

• habitual (e.g., taking same medication every day)

• vigilance (e.g., preventing a kettle from boiling over)

• Supported by routines and external memory aids

Memory and TBI

• In TBI, there is generally diffuse and bilateral injury to many regions, including

  temporal and basal-frontal regions, hippocampus

  • Memory problems (Acute) ~69-80% of cases.

  • Memory problems (Chronic) ~35-75% of severe cases