is caused by a blow to the head or violent head movement similar to what happens in a high-impact motor vehicle accident.
TBI has to occure ____ not ____
after not during birth
An injury is considered a TBI when, and only when, there is....
Evidence of total or partial functional disability or psychological impairment or both.
developmental brain disorders and other neurological conditions.
List examples of non-traumatic brain injuries
Anoxic injuries caused by reduction in oxygen.
Infections of the brain (meningitis and encephalitis)
Stroges and other vascular accidents
Tumors of the brain
TBI can result in impairment of
speech/language functions and swallowing
Describe the ways TBI can occur
Penetrating injuries: An object striking the head can break through the skull and penetrate the brain (gunshot)
Diffuse Axonal Injuries (DAI): Brain is stretched and twisted within the skull
Focal Contusions/contact injuries: A blow to the head can bur is the brain
What is an open head injury vs closed head injury?
OHI: caused by accidents, falls abuse, assaults and surgical procedures that result in a penetrating wound to the brain (more focal)
CHI: caused by accidents, falls abuse, and assaults in which the membranes (meninges) surrounding the brain remain intact but damage to the brain comes from internal compression, stretching or shearing actions (more diffuse)
TBI severity rating refers to...
the amount of acute (immediate) disruption of brain physiology or structure.
You derive from clinical evaluations
Ratings predict course of outcome.
GLASGOW COMA SCALE
Describe the characteristics of a Mild TBI
Injury to the head arising from blunt trauma or acculturation or deceleration forces that results in one or more of the following:
- GCS 13-15
- Loss of consciousness <20 min.
- Post-traumatic amnesia + coma <1hr
- Injury is NOT visible with medical imaging
-Any disfunction of memory around the time of the injury
-Individual appears to be "fine"
10% of individuals with MILD TBI
experience long term consequences
Mild TBI =
does not equal mild impairment.
Describe the characteristics of a Moderate TBI
LOC 20 min- 36 hours
COma + PTA 1-24 hours
Individual may sustain fractures, bruises, or bleeding of the brain (subdural hematoma)
Injury is visible with medical imaging
1/3-1/2 of individuals will have lifetime difficulties with learning and daily activities.
Describe the characteristics of a Severe TBI
GCS 8 or less
LOC> 36 hours
Coma + PTA longer than 24 hours
80% of individuals will have lifetime disabilities
Long term support will be required at home, in school, and in the community and to sustain employment and independent living.
At least ___ people sustain a TBI each year?
Approximately ____ people died from a TBI
the entire family no just the patient.
What groups are at risk for a TIB?
Males are about 2x as likely as females to sustain a TBI
Infants and children aged o-4 and adolescents aged 15-19 years are the 2 age groups at highest risk for a TBI
Adults aged 75 years or older have the highest rates of TBI related hospitalization and death
TBI results in both primary and secondary brain injury- describe both
Primary injury: occurs immediately following impact and is related to instantaneous events directly caused by the blow.
Secondary injury: is characterized by a cascade of biochemical, cellular and molecular events involved in the evolution of secondary damage.
Describe what happens during a TBI
When the brain is injured, neuronal connections may be disrupted- some are stretched and some are completely torn.
There is evidence that new connections can be developed throughout life, and that "stretched" connections can heal
Broken connections cannot mend and the neurons cannot regenerate once dead.
When an injury occurs, the clean up process in the brain usually results in swelling around neurons, particularly around any stretched or bruised connections.
This swelling prevents those parts of the brain from working optimally and can last a long time up to three years following an injury
Describe neuronal death
Increases in extracellular potassium and glutamate
Brain rotates at an angle causing abrasions, lacerations and twisting/shearing forces resulting in diffuse axonal injury and hemorrhage and cranial nerve trauma
Most lesions occur in the deep white matter and brain stem
Describe a compression injury
Brain matter is compressed or deformed by pressure against the skull
Propagation of shock waves throughout the skull and brain can also occur and may result in small intracerebral hemorrhages
What is the skull-brain interface?
This is that it is common for contusions (bruising) to occur in cerebral regions adjacent to these skull regions where there is the greatest bone-brain interface.
Lacerations are often seen on the orbital frontal cortices and the tips of the frontal and temporal lobes.
What is the most common neuropathological consequence?
Damage to the hippocampus (memory) and other medial temporal lobe limbic (emotion) structures, resulting in post-traumatic memory disorder and emotional behavior changes.
with the skull brain interface, the superficial bruising of ____ are frequently found in the ___ regardless of the site or direction of initial impact
frontal and temporal regions
site or direction of initial impact.
Lacerations are ..... which can lead to ....
They usually heal and leave ....
hemorrhagic lesions which can lead to edema and necrosis within the brain.
Yellow brown atrophic scars that are easily recognized on autopsy.
What are the types of primary damage associated with OHI?
Low velocity: Concentrated force causes fracture of the skull with debris entering the brain--destruction of tissue at the site of impact is often substantial
High velocity: a projectile enters the brain-causes destruction of tissue around the projectile path
Main areas of damage from primary involvement are surface contusion, anterior and inferior frontal and temporal damage, bilateral temporal damage, frontolimbic damage, brain stem damage, basal ganglia damage.
what are impression traumas and ellipsoidal deformation that are associated with OHI?
Non-acceleation is a moving object that hits the head
Impression trauma: Meninges and cortex at site of impact are damaged as skull is deformed by a rapid blow. Negative pressure created by the rebound of skull may contribute to damage.
Ellipsoidal defomation: A slow moving object with a large surface area deforms the skull from oval to circular shape--brain tissue moves outward from center resulting in stretching and tearing of central structures such as the basal ganglia.
What is secondary damage with CHI?
Ischemic brain damage
The cranial cavity is partitioned by the ...
tentorium cerebelli and falx cerebri.
When part of the brain is compressed by a subdural hematoma or is expanded because of a contusion, it is displaced (herniates) from one cranial compartment to another.
what is edema as secondary damage?
increase in brain volume due to an accumulation of excess water in the brain tissue. Caused by increase in permeability of capillaries allowing water to exclude out into extracellular spaces. Results in raised intra-cranial pressure (ICP)(NOT IN VENTRICLES)
What is ischemic brain damage as secondary brain damage with CHI?
Hypoperfusion (low blood supply in brain) and herniation lead to further brain damage in the form of pressure necrosis and infarction, often remote from the site of the primary injury--diaschisis.
What is hemmorrhage as secondary brain damage with CHI?
Extracerebral: Bleeding into the meninges (epidurla, subdural, subarachnoid)
Epidural (or extradural): usually results from laceration from bone fracture, may develop quickly and need immediate evacuation to avoid disability
Subdural (veins): develop more slowly.
Intracerebral: bleeding into brain tissue--associated with diffuse axonal injury.
If a hemorrhage is not treated...
results in drowsiness, paralysis down one side of the body, compression of 3rd cranial nerve
compression of brain stem, herniation, fatal due to compression of vital centers in the brainstem.
What is the medical management of a Tbi?
control increasing ICP
Prevention of hypotension/hypoxia
maintain cerebral perfusion
What are Post-traumatic complications?
Residual disability or new developing complication (seizure disorder) can be from impact damage or secondary processes
Focal injuries often leave residual focal neurological deficits such as hemiplegia, hemiparesis, hemianopsia, aphasia.
Cranial nerve abnormalities often arise when cranial nerves are damaged when the skull is fractured or when the brain is thrown about dying acceleration/decleration injury.
Post traumatic eplilepys
What are the post-traumatic complications caused by?
Diffuse (widespread) injury; other by focal injury
What is the most severe form of diffuse damage
chronic or persistent vegetative state- affecting 5% of head injury survivors.
Post traumatic epilepsy is more probable after?
depressed fracture with dural tear
amnesia of > 24 hours
usually develops within the first 2 years post-injury
Describe post traumatic vertigo
may last for days, weeks, or months
What is the most common and most complex sequelae of HI?
PTS-Post Traumatic Syndrome
It uses headaches, dizziness, difficulty concentrating, host of vague behavioral symptoms such as anxiety, depression, and nervous instability.
More common with slight trauma than serious
lasts a few weeks to a few months- symptoms gradually disappear and are exacerbated by strenuous physical activity, emotional stress, and use of alcohol,
rest and symptomatic treatment are usually required.
What are cognitive deficits following TBI?
Difficulty focusing and sustaining attention
delayed response time
decreased ability to organize information
difficulty with simultaneous processing
limited ability to generalize
rigid/concrete problem solving
decreased concept formation
altered perceptual/spatial function
What are the behavioral issues with a brain injury
poor self control
limited insight into deficits
lack of initiative
decreased understanding of social rules
low threshold for over stimulation
low frustration tolerance
Describe the physical functions of TBI
difficulty with coordination, balance, and movement
changes in sense of smell and taste
chronic pain, headaches, dizziness
visual or auditory changes
fine motor coordination
paralysis or spasticity
What are the speech/language functions?
speed, accuracy, and coordination of speech
impaired breath support for speech
How do you determine the prognosis of a TBI
GCS Motor score (higher=better)
Presence of epidural hematoma vs subdural hematoma on CT (less direct damage to brain, more likely to be evacuated)
Premorbid cognitive function
What are the positive indicators of prognosis
Limited imaging findings
No dural penetration
No pupillary response abnormalities
No systemic complication
What are the negative indicators of Prognosis
Pupillary response abnormalities
Ocular Motor abnormalities
Secondary systemic complications
REMEMBER: The severity of the injury....
does not always equate to the functioning level of the patient.
What is cognition?
the study of the thinking mind is concerned with how we attend and gain information about the world, how that information is stored in memory by the brain and how that knowledge is used to solve problems, to think, and to formulate and use language.
What is attention?
The concentration of mental effort on sensory or mental events.
What are the three components of attention?
Arousal, vigilence, selective attention
What is arousal?
physiological state underlying a general readiness to act or to receive and process incoming information.
can be hypo (coma/sleep) or hyperaroused (ptsd)
other forms of attention depend on optimal level of arousal
orienting to sensory events.
What is vigilence
state whereby attention is sustained over a fairly long period of time (sustained attention)
Maintaining attention to driving or holding a conversation
Selective attention depends on it
What is selective attention?
Intention:governs which actions are performed ("executive attention")
Attention: Ability to select for further processing
Early vs late selection
Controlling access to memory and awareness
Attention is limited by?
the amount of information we can hold in our immediate attention (working memory)
Performing simultaneous tasks can interfere with each other in the same modality or in different modalities
Describe the Bottleneck theory of attention
Theories that attempt to explain how people select information when some information processing stage becomes overloaded with too much information
Point in information processing where only ne piece of information processed at a time (serial processing --> only one thing done at a time
Describe the famous example of the bottleneck theory
The cocktail party effect: found people were not sensitive to what they were told to ignore. played two different inputs and asked to listen to one. People were good at selecting what to listen to.
Describe the capacity theories
Minds have limited amount of mental fuel; different tasks share the amount of mental fuel available
can do two tasks in parallel, if enough mental fuel available (divided attention)
A person has considerable control over how this limited capacity can be allocated to different activities (driving and talking)
Thought you don't have to do serial processing.
Describe the allocation of capacity
supply and demand- when the supply of attention does not meet the demand, level of performance declines.
Compare and contrast bottleneck vs capacity
The capacity model was proposed to supplement the bottleneck theories not replace them
both types of theories predict that simultaneous activities are likely to interfere with each other, but they attribute the interference to different causes.
compare and contrast automatic vs controlled processes
automatic mental processes are those that require little or no mental effort (riding bike, tying shoes)
Controlled mental processes are those that require mental effort.
Describ the strop test
This is when words of colors appear and the color of the word does not match the word.
What are characteristics of automatic processes?
unavailable to consciousness
occur without intention
do not require mental resources
What are characteristics of controlled processes.
not well practiced
EX: obstacle course, driving in unfamiliar place
What is memory?
Means by which we draw on our past experiences in order to use this information in the present.
As a process, memory refers the the dynamic mechanisms associated with retaining and retrieving information about past experience.
What are the 3 operations identified in memory?
Encoding: during this process you transform sensory data into a form of mental representation (acquisition and consolidation)
Storage: you keep encoding information in memory
Retrieval: you pull out or use information stored in memory
What are the memory subfields?
Describe the sensory or immediate stage of memory
approximatly 1 sec. Bridge between perception and memory opportunity to organize and categorize incoming info. Nothing stored here.
Describe iconic memory
Sperling's experiments indicate the existence of a brief visual sensory memory-known as iconic memory or iconic store
Infromation decays rapidly (after a few hundred milliseconds) unless attention transfers items to short term-memory
Analogous auditory store: echoic store
STM is a ...
limited capacity store for information - place to rehearse new information from sensory buffers
Items need to be rehearsed in STM...
before entering long term memory. Probability of encoding in LTM directly related to time in STM
Describe the recency effect and the primacy effect?
Remembering things most recently scene
First times scene in a list.
What are serial position effects
Explanation from atkinson and shiffrin model:
Early items can be rehearsed more often (more likely to be transferred to long-term memory
Last items of list are still in short term memory (with no distractor task)
they can be read out easily from short-term memory
What are the pros and cons of modal memory model
Pro: provides good quantitative account of many findings
Con: Assumtion that all information must go through STM is probably wrong
Model proposes one kind of STM but evidence suggests we have multiple kinds of STM stores
Describe Baddley's working memory model
WM contains information that can be acted on and processed
A unitary STM was insufficient to explain the processing and maintenance of information over short periods.
How many things can be stored in short term memory
The STM holds 7 units-letters or words +/- two
Individual letters should fill each slot, whereas letters that composed words/acronyms etc. were chunked into 1 word unit. occupying only 1 slot in Stm. Chuncking is therefore greatly expands the capacity of STM
Describe the phonological Loop- phonological store
Auditory presentation of words has direct access
Visual presentation only has indirect access
Affected by phonological similarity
converts visually presented words into inner speech that can be stored in phonological store
affected by word length
Describe reading rate and recall
Reading rate seems to determine recall performance
Phonological loop stores 1.5-2 seconds worth of words
Working memory and language differences
different language have different # syllables per digit
Therefore, recall for numbers should be differennt across languages
Occurs if info is not rehearsed. info processing leaves a trace with disuse these fade-use it or loose it. LTM
Assumes that forgetting reflects the disruption of the memory trace by other traces w/ the degree of interference depending on the similarity of the 2 mutually interfering memory traces STM
Memory performance is a combination of active rehearsal and storage in STM
If active rehearsal is prevented by the counting-backward task, the items decay from STM
Interference is at a process level-counting interferes with rehearsal
Muscles contract to create constrictions in the oral cavity to produce varying sounds.
What are the three types of nerve fibers?
Commissural association projection
What are commissural fibers
connect the two cerebral hemispheres.
Ex: corpus callosum
What are association fibers
connect areas of the brain whiten the same hemisphere. Long association fibers are known as fascicle. Fasciculi are large large bundles of axons. There are three major fascicle,
EX: Arcuate fasciculus
What are projection fibers?
Connect areas of the cortex with lower levels of nervous system
Descrive projection fibers
Efferent projection fibers are motor (they carry info from the cortex)
Afferent fibers are sensory (they carry info to the cortex)
Efferent motor fibers originate in the pre-central gyrus and in the area of the frontal lobe anterior to the pre-central gyrus. They innervate cranial nerve nuclei in the brainstem or cells in the spinal cord
Afferent sensory projection fibers originate in sensory receptor cells and their destination in the post-central gyrus
What are the four major devisions of the motor system>
The final common pathway (lmn)
The direct activation pathway (UMN or pyramidal tract)
the indirect activation pathway (extrapyramidal tract -direct contact with LMNs)
The control circuits (basal ganglia and cerebellum-no direct contact with LMNs)- Basal ganglia and cerebellum
UMNs are part of the ___ and LMNs are part of the ___
UMNs originate in the ____ and synapse onto the ______ in the contralateral brainstem or onto ____ in the contralateral spinal cord
cranial nerve nuclei (corticobulbar tract)
cells (corticospinal tract)
The ____ and ____ are also called the pyramidal tract
the main pathway for nearly all voluntary muscle activity.
Comprised of UMNs
It is a bundle of axons, which changes names as it courses from cortex to muscles
This is a crossed pathway. At the level of the pyramids in the medulla, approx. 80-90 % of the fibers in the tract cross the other side of the brainstem; therefore they descend in the opposite side of the spinal cord from where they originate.
The corticobulbar tract
is comprised of UMN
originates in the motor cortex
crosses to the opposite side of the brain at various levels of the brainstem
innervates cranial nerve nuclei at various levels of the brainstem
corticobulbar projections to most cranial nerve nuclei is bilateral but corticobulbar projections to some cranial nerve nuclei is contralateral
Discuss projection fibers
Thus, if UMNs are damaged, you get spasticity as well as not being able to initiate skilled motor movements.
Spasticity: increased muscle tone. A babinski sign signals the presence of UMN damage. Reflexes are exaggerated.
If LMNs are damaged, you end up with flaccid paralysis
Flaccidity: decreased muscle tone. Atrophy of muscles. Reflexes are diminished or absent.
The type of dysarthria from TBI is dependent on...
type and site of lesion
Due to the nature of TBI, there is wide variability of presenation
The most common type of dysarthria in CHI is>
spastic, due to bilateral UMN damage resultin in reduced range and force of movement and muscle spasticity.
What are the characteristics of spastic dysarthria?
Describe what happens with damage to the extrapyramidal system
basal ganglia, may result in forms of hypo or hyperkinetic dysarthria
Less common in TBI
Describe that characteristics of hypo kinetic dysarthria
repetition of phonemes
rushes of speech
delayed response initiation
EX: Parkinsons disease
What are the characteristics of Hyperkinetic dysarthria?
Unpredictable, involuntary movements
manifest in any or all of the respiratory, phonatory, resinatory, and articulatory aspects of speech.
Can be generalized or affect a small group of muscles
Affects prosodic aspects of speech rhythm and rate of speech.
May include abrupts inhalations/exhilations, momentary voice arrests and strain or strangled vocal quality.
Describe dysarthria and TBI
Frequently involves simultaneous damage to multiple brain areas and can result in MIXED dysarthria
Most frequent toy of dysarthria following TBI is mixed
Specific deficits depend on the site and extent of damage
Increased severity in the mixed types,
Spastic-flaccid is very common
Hypokinetic is not as common because it deals with basal ganglia.
What are the most frequently occurring dysarthria features following a TBI?
Reduced normal pitch variation
reduced breath support
abnormal stress battern
Less common dysarthria features are..
reduced loudness variation and prolonged intervals
impaired overal intelligibility.
what are speech and language problems following head injury?
Controversy about the nature of these problems especially whether the patients are aphasic or not
Describe the work by Heilman, saffron and Geschwind (1971)
Studied 13 patients with aphasia after a CHI
Found 9 cases with anomic aphasia, fluent speech output, normal comprehension and repetition and verbal paraphasias and poor object naming
the other 4 had fluent paraphasic speech output and poor comprehension and repetition-very like classic wernickes aphasia
There were no Broca's or global aphasics.
Describe the Groher (1977)
Studied the progression of language deficits over time
CHI average 17 days in a coma
Patients were assessed as soon as consciousness was reached, then reassessed every 30 days for 4 months
when they were acute, their gestural skills were worse than graphic skills, and those were worse then verbal than verbal skills.
By the final assessment, all could make needs known and converse.
What is amimia?
A disorder of language characterized by an inability to make gestures or to understand the significance of gestures.
What are the arguments against language deficits in aphasia being the same as those in TBI?
Some of the initial language problems may be due to post traumatic amnesia, when people are confused and don't form memories of this time
Language problems due to pts being confused, with a poor stm lack of understanding of the environment and disorientation.
Speech can thus be irrelevant in content while still be fluent and syntactical.
Why is there a controversy?
Due to use of nomenclature associated with aphasia to classify linguistic deficits observed in TBI -E.g. anomic and wernicke's
inherent variability (level of skills are diverse across patients and this affects studies) in TBI population
Inconsistencies in methodological parameters used in studies
Relative rarity of deficits (as measured by standardized assessments)
What are the 3 ways that Audry Holland described TBI to be different than stroke patients
TBI is diffuse brain injury with pervasive memory and cognitive deficits.
Rehavilitation of CHI is more interdisciplinary than that of stroke
There is a big demophraphic difference.
TBI has confabulations and mis-namings in addition to circumlocutions and paraphasias.
TIB can have a sensory deficit.
Most different in pragmatics
Aphasia is a disorder of ___ while TBI show a disorder of ___ thus....
there can be a problem in orientation explanations, visual attention and utilization of contextual cues as well as reasoning.
What are the 3 time course patterns following injury?
Full language function recovered if initial injury was mild
After some mild head injury expressive deficits can remain for at least 6 months post onset with anomia
More severe damage, with diffuse swelling and bilateral hematoma correlated with persistent expressive and receptive impairment in at least one tear post injury with residual anomia, and non-verbal and verbal deficits.
What is the prognosis for TBI?
Most linguistic recovery occurs within the first 6 months, especially in the first 1 month
memory problems tend to resolve first
There is disagreement about the best way of predicting outcome. Some studies find a correlation between coma length and severity of linguistic problems, others do not . (NOT CONCRETE)
*Cognition recovery goes with language recovery.
What is the assessment and TX of speech and language disorders following TBI?
The integrity of an individuals communication(ability to make needs known or orient self) skills subsequent to TBI is often critical in determining post injury QOL
The S-L deficits may impose substantial social and vocational ramifications
What is the adult impact of S-L skills with TBI?
account for social isolation, academic failure and/or vocational demotion
What are the child impacts of S-L in TBI
account for immediate communication deficits, potential for predisposition to speech and or language impediments during the formative years...Infants fail to meet milestones
What are linguistic deficits with TBI
Despite performing largely WNL on standardized batteries, TBI patients suffer some degree of dysfunction within the language realm.
These deficits, while present, are often not enough to allow criteria to stand taxonomies to be met.