TBI Guest Lecture Flashcards
Definition of TBI
an alteration in brain function or other evident brain pathology caused by an external force that is indicated by new onset or worsening of at least one of the following clinical signs, immediately following the event; an alteration in brain function is defined as 1 of the following clinical signs: any period of loss of or a decrease of consciousness (LOC/AOC), any loss of memory for events immediately before (retrograde amnesia) or after the injury (PTA), neurologic deficits (weakness, loss of balance, change in vision, dyspraxia paresis, sensory loss, aphasia etc), any alteration in mental state at the time in injury (confusion, disorientation, slowed thinking)
TBI Prevalence
nearly 1.7 million people sustain a tbi every year in america; 125,000 people each year are considered permanently disabled as a result of their TBI; 347,962 service members were diagnosed with TBI since 2000
Mechanics of TBI
External forces may include- being struck by an object, striking an object, acceleration or deceleration, foreign body penetrating, blast or explosive force, and other
Primary effects- bruised brain tissue, bleeding inside the brain, lacerations in brain, blood vessel injuries, neuronal and synapse damage, axonal injury
Secondary effects - neuroinflammation, fever, seizures, imbalance of neurological chemicals, medications
Physiological perturbations after concussion
- Ionic flux ——- Migraine, photophobia, phonophobia
- Energy crisis ——- Vulnerability to further injury
- Axonal injury & impaired neurotransmission ——- Impaired cognition, slowed processing, slowed reaction time
- Protease activation, altered cytoskeletal proteins, cell death ——- chronic atrophy, development of persistent impairments
Diffuse Axonal Injury
• Injury to axons within the white matter fiber tracts • Abrupt stretching * Damages axon cytoskeleton * Reduces elasticity * Impairs axonal transport • Retraction balls • Axonal swelling
- Delayed event that occurs over time
- Mostly affects: Gray-white matter junctions, BS, CC, cerebral & cerebellum peduncles, BG, thalamus, frontal & temporal white matter
Symptoms indicating emergency evaluation needed
- Worsening symptoms
- Diplopia or vision changes
- Decreased level of alertness
- Increased disorientation
- Repeated vomiting
- Seizures
- Unusual behavior
- Amnesia/memory problems
Mild TBI
79% of all TBIs
But even after a mild TBI,
• 47% moderate to severe physical disability (Thornhill et al., 2000)
• 43% cognitive difficulties
• 33% behavioral problems one-year post-injury (Bendictus, Spikman, & van der Naalt, 2010)
TBI imaging
- MRI and CT scan typically lack gross abnormalities (Niogi & Mukherjee, 2010; Tombaugh et al.,2007)
- fMRI and Diffusion Tensor Imaging may show changes in functional activation & white matter integrity (MacDonald et al., 2011; Matthews et al., 2011)
- Brain edema
- White matter hyperintensities
- Increased Ventricle-to-Brain Ratio (VBR)
- Brain volume loss
- Ventricular enlargement • Gyral shrinkage
- Sulcal enlargement
- Cerebral and hippocampal atrophy
- Hemosiderin (iron storage complex) deposits
TBI symptoms
Physical Symptoms • Headaches • Dizziness/imbalance • Nausea • Fatigue • Sleep disturbance • Blurred vision • Sensitivity to light • Hearing difficulties/loss • Sound sensitivity • Tinnitus • Seizure • Transient neurological abnormalities • Numbness/tingling
Cognitive Symptoms • Problems with attention • Problems with concentration • Problems with memory • Issues with processing speed • Issues with decision-making and executive control
Emotional Symptoms • Depression • Anxiety • Agitation • Irritability • Impulsivity • Aggression
CHRONIC TRAUMATIC ENCEPHALOPATHY (CTE)
• Progressive neurodegenerative disease associated with repeated head trauma
• Associated w/ long history of playing contact sports
• Frequency vs. severity
• Diagnosis - only determined by post-mortem exam
• Dementia syndrome accompanied by Parkinsonian
and cerebellar motor signs
• Gradual, subtle onset
• Typically occurs in middle age
• Survival after onset of neurologic or cognitive impairment is variable (7-35 years)
• Neuropathological features: Cerebral and hippocampal atrophy, Neurofibrillary tangles (common marker of Alzheimer’s), Reduced brain weight, Cavum septum pellucidum, Enlargement of ventricles, Thinning of the corpus callosum
Manifestations:
- cognitive (slowed thinking, confusion, executive dysfunction, etc)
- behavioral (mood swings, disinhibition, paranoia, irritability)
- motor function (tremor, dysarthria, mild imbalance)
TBI co-morbidities
- Pain
- Sleep disturbances
- Anxiety/PTSD
- Depression
- Substance abuse
- Limb injuries/amputations • Auditory impairments
- Visual impairments
- Spinal Cord Injury
POST-TRAUMATIC STRESS DISORDER (PTSD)
• Definition: Mental health condition that’s triggered by a terrifying event, either experiencing it or witnessing it – Mayo Clinic
PTSD symptoms: • Sleep problems • Emotionally withdrawn/numb • Lack of interest in things they previously enjoyed • Easily startled • Irritability/aggressiveness • Avoidance of situations that remind them of the traumatic event • Flashbacks • Substance abuse
TBI Management
- Sleep and pain first!
- What’s most troubling to the patient?
- Substance abuse problems
- Anxiety/depression
- Compensatory strategies and short visits
- Possible malingering or exaggeration
If prolonged, persistent symptoms, consider: • Psych issues • Medications/drugs/alcohol • Sleep issues • Lack of psychosocial support • Negative illness expectations • Compensation/ litigation
TBI AND EFFECTS ON AUDITORY FUNCTION
• Auditory symptoms typically secondary to medical conditions/ symptoms
• Auditory problems may not be apparent immediately post-injury; may have delayed onset or be progressive in nature
• Failure to ID auditory dysfunction: Misdiagnosis, Quality of life, Rehab success, Fitness for duty (combat effectiveness and
survival)
87% of Veterans with TBI reported some degree of disturbance of daily living due to hearing difficulty.
As severity of TBI increases, incidence of auditory dysfunction increases.
Ear is most vulnerable organ to suffer injury from a blast or pressure-wave!
38% of OIF individuals with blast-related TBI reported tinnitus
78% reported greater difficulties hearing speech in noisy environments after their blast exposure
• Most common ear complaints immediately s/p blast: Otalgia, Tinnitus, Aural fullness, Dizziness, Sensitivity to sound, Distorted hearing, Hearing loss
Auditory Damage • Outer ear • Middle ear • Temporal Bone fractures • Inner ear • Central auditory (BS and cortex) • Tinnitus
Vestibular Damage • Semi-Circular Canals • Otolith organs • BS • Cerebellum
Outer Ear Damage • Wounds to pinna and ear canal • Risk for infection • Malformations of pinna • Implications for funneling of sound • Limitations for fitting with amplification, if needed
Middle Ear Damage • TM perforation • Most common • May lead to infection and/or cholesteatoma • Causes conductive hearing loss • May require surgical repair • Ossicular Chain Discontinuity • Dislocation, distortion or fracture of M.E. bones • Causes conductive hearing loss • May require surgical repair
Tinnitus more common than HL Hyperacusis/sound sensitivity also quite common
CAUSES OF AUDITORY PROCESSING DISORDERS
- Neurological lesions or compromise of the CANS
- Neoplasms
- Degenerative processes (e.g.., multiple sclerosis)
- Seizure disorders
• Head trauma • Cerebrovascular accidents • Metabolic disorders • Benign CANS dysfunction • Cerebromorphological abnormalities • Neuromaturational delays in the development of the CANS, often secondary to auditory deprivation • Age-related changes in CANS function • Blasts/explosions
