TBI

TBI etiology

MOI = contact forces to skull and rotational acceleration forces, causing varying degrees of injury to the brain

Primary brain damage

- Diffuse axonal injury

- Focal injury

- Coup-contracoup injury

- Closed or open injury

Diffuse axonal injury

Disruption and tearing of axons and small blood vessels from shear-strain of angular acceleration; results in neuronal death and petechial hemorrhages

Focal injury

- Contusions

- Lacerations

- Mass effect from hemorrhage

- Edema (hematoma)

Coup-contracoup injury

- Injury at point of impact and opposite point of impact

Closed or open injury

- Associated with fracture of skull

Secondary brain damage

- Hypoxic-ischemic injury

- Swelling/edema

- Electrolyte imbalance and mass release of damaging neurotransmitters

Concussion

- Loss of consciousness, either temporary or permanent resulting from blow to head, with impaired functioning of the brainstem reticular activating system

- May see changes in HR, RR, BP

Structures within the frontal lobe

- Primary motor cortex

- Premotor area

- Prefrontal area

- Supplementary motor

- Middle frontal gyrus

- Motor speech area (Broca)

- Dorsolateral

- Orbifrontal

- Orbital gyri

Damage to frontal lobe: primary motor cortex

Contralateral paralysis and paresis (most pronounced in distal parts of limbs and lower part of face)

Damage to frontal lobe: premotor area

Apraxia or motor planning difficulties

Damage to frontal lobe: prefrontal area

Loss of specific motor plans

Damage to frontal lobe: supplementary motor

Loss of bilateral control of posture

Damage to frontal lobe: middle frontal gyrus

Transitory paralysis of conjugate eye movements to opposite side

Damage to frontal lobe: motor speech area (Broca)

Non-fluent aphasia

Damage to frontal lobe: dorsolateral

Bilateral lesions = impaired ability to concentrate

Damage to frontal lobe: orbitofrontal

Unstable emotions, unpredictable behaviors

Damage to frontal lobe: orbital gyri

Inability to discriminate odors

Structures within parietal lobe

- Postcentral gyrus/ primary somatosensory area

- Secondary somatosensory area

- Gustatory cortex

- Parietal lobe (right hemisphere)

Damage to parietal lobe: postcentral gyrus/ primary somatosensory area

Loss of contralateral stimulus location, intensity

Damage to parietal lobe: secondary somatosensory area

Tactile agnosia:

- Astereognosis

- Agraphesthesia

- Loss of 2-point discrimination

- Extinction

Damage to parietal lobe: gustatory cortex

Impairment of taste in contralateral side of tongue

Damage to parietal lobe: right hemisphere

- Visual spatial disorders

- Body scheme disorders

- Apraxias

- Tactile and auditory perceptual disorders

Structures within temporal lobe

- Primary auditory cortex

- Wernicke's area

- Superior temporal gyrus

- Temporal cortex (non-dominant side)

- Parahippocampal region

Damage to temporal lobe: primary auditory cortex

Subtle decrease in hearing and ability to localize sounds, both contra laterally

Damage to temporal lobe: Wernicke's speech area

Fluent aphasia

Damage to temporal lobe: superior temporal gyrus (left hemisphere)

Impairment of learning and memory

Damage to temporal lobe: non-dominant side & parahippocampal region

Profound memory loss of recent events, no new learning

Structures within occipital lobe

- Primary visual cortex

- Visual association cortex

- Posterior multimodal area

Damage to occipital lobe: primary visual cortex

- Contralateral homonymous hemianopsia

- Impairment of vision

Damage to occipital lobe: visual association cortex

Visual agnosia

Damage to occipital lobe: posterior multimodal area

Perceptual impairment

Standardized tests/outcome measures for patients with TBI

- GCS

- Rancho los amigos levels of cognitive functioning

- Rappaport's disability rating scale (DRS)

- Glasgow outcome scale (GOS)

- High-level mobility assessment

- Functional independence measure/functional assessment measure (FIM/FAM)

- Neurological outcome scale for TBI (NOS-TBI)

- Assessment of life habits

- Coma recovery scale

- Moss attention rating scale

Mild TBI

- LOC = 0-30 min

- Alteration of consciousness = brief; > 24 hours

- Posttraumatic amnesia = < 1 day

- GCS = 13-15

- Imaging = normal

Moderate TBI

- LOC = > 30 min but less than 24 hr

- Alteration of consciousness = > 24 hours

- Posttraumatic amnesia = >1 day but < 7 days

- GCS = 9-12

- Imaging = normal or abnormal

Severe TBI

- LOC = > 24 hr

- Alteration of consciousness = > 24 hr

- Posttraumatic amnesia = > 7 days

- GCS = < 9

- Imaging = normal or abnormal

Recovery stages from diffuse axonal injury

- Coma

- Unresponsive vigilance/ vegetative state

- Mute responsiveness/minimally responsive

- Confusional state

- Emerging independence

- Intellectual/social competence

- Patient can plateau at any stage or regress under stress

Examination for TBI

- Generalized signs of increased ICP

- Level of consciousness (GCS), cognitive functioning (LOCF--Ranchos)

- Cranial nerve function

- Changes in behavior: physical, verbal, sexual behaviors; poor judgement; irritability, aggression, impulsivity, depressed mood

- Speech and communication

- Sensory deficits

- Motor function

- Functional mobility skills, ADLs

- Level of general reconditioning

- Sympathetic storming

Sympathetic storming

Result of hypothalamic stimulation of the SNS with an increase in circulating corticoids and catecholamines (stress response)

Management based on decreased response levels (LOCF I-III)

- Maintain ROM

- Maintain skin integrity

- Maintain respiratory status

- Provide appropriate stimulation for arousal and to elicit movement and function

- Promote early return of FMS

Management based on mid-level recovery (LOCF IV-VI)

- Provide structure, prevent overstimulation for confused, agitated patient, daily schedules and memory logs, relaxation techniques

- Provide consistency

- Engage patient in task-specific training

- Provide verbal or physical assistance

- Control rate of instruction; provide frequent orientation

- Emphasize safety, behavioral management techniques

- Model calm, focused behavior

Management based on high-level recovery (LOCF VII-VIII)

- Allow for increasing independence

- Assist patient in behavioral, cognitive, emotional reintegration

- Enhance motor learning and promote independence in functional tasks

- Improve postural control, symmetry, and balance

- Encourage active lifestyle

- Provide emotional support, encourage socialization, behavioral control, and motivation