Traumatic+Brain+Injury+Prognosis

**How can initial neurocognitive assessment predict TBI outcome?**
By: Alyssa Champlin, Sarah Hedlund, Jake Reynolds, Lizzie Stierwalt

Inclusion Criteria

 * PubMed Clinical queries for prognosis factors
 * Primarily examining mortality vs. survival
 * Exclusion of studies that were too population specific
 * Articles with common research criteria
 * Attempting to capture the highest level of evidence

Traumatic Brain Injury

 * Defined as any trauma that disrupts normal brain function
 * TBI is a contributing factor to a third of all injury-related deaths in the United States
 * After a severe TBI, 50% of people will be moderately disabled [1]
 * With a severe TBI, importance in being able to determine extent of care and family counseling [1]
 * With a minor TBI, it is important to predict prognosis so you can determine whether they will benefit from rehabilitation [1]

Glasgow Coma Scale
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 * Most commonly used outcome scale based on level of consciousness (LOC) at admission [2]
 * Records the patient’s eye opening, verbal, and motor responses
 * The average Glasgow Coma Scale of patients who die is statistically lower than the patients who survived (p < 0.001) [1]
 * Scores:
 * 3-8 - severe injury
 * 9-12 - moderate
 * 13-15 - mild
 * The predictive value for poor outcome in patients with initial GCS 6–8 was 26% and for patients with GCS 5–3 was 77% [3]
 * The 1-point increase in Glasgow scale causes a 19% reduction in the chance of mortality of the patient [3]
 * Three month and one year outcomes are measured with Glasgow Outcome Scale classifications of:
 * Dead, Persistent Vegetative State, Severe Disability, Moderate Disability, Good Recover

Marshall Scale

 * CT is the most frequently used neuroimaging method [2]
 * Involves descriptive classification of morphological abnormalities as depicted on CT scan
 * CT is sensitive and specific for the presence of intracranial hemorrhage, extra-axial fluid collections, skull fractures, and also detects cerebral edema, swelling and signs of herniation [4]
 * The Rotterdam score, modified from the Marshall score, is based only on CT findings, such as the presence of subarachnoid or intraventricular hemorrhage, effacement of the basilar cisterns, midline shift >5 mm, presence/absence of hemorrhage, to predict 6-month mortality [4]
 * According to Marshall et al., the presence or absence of a mass lesion, compression of basal cisterns and midline shift were the three variables analyzed [3]
 * Marshall degree is statistically associated with mortality (p < 0.001) [3]
 * Despite exclusion of analysis Marshall I patients, any category above Marshall II increases the risk of death [3]
 * Midline deviation is a significant factor in increasing mortality (p < 0.001) [3]
 * A negative correlation was established between the Marshall/Rotterdam scores and three month outcomes, but was not predictive of one year outcomes [3]
 * Research supports the use of an initial CT evaluation as well as repeated measures 24hrs post. Patients originally not classified as severe worsened by the repeat scan [3]



MRI

 * MRI may be indicated in acute TBI when results on CT are normal and there are persistent unexplained neurologic findings [4]
 * MRI is the primary imaging modality for subacute to chronic TBI and has been repeatedly shown to be very sensitive for detecting and characterizing brain injuries, particularly brain atrophy in the chronic stage [4]
 * MRI is recommended only in the presence of new, persistent, or worsening symptoms in patients with subacute to chronic TBI [4]
 * The correct prediction of an unconscious patient returning to a minimally conscious state of an MRI was 90.4%. [5]



Anisocoria

 * Inequality in the size of the pupils of the eyes
 * Pupillary abnormalities were associated with higher mortality (p < 0.001) [3]
 * Patients with anisocoria have 67% higher chance of mortality [3]
 * The presence of anisocoria was related to 38% of mortality [3]
 * As demonstrated by Chesnut et al., 43% of patients with pupillary asymmetry > 3 mm had intracranial mass lesions [3]

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Intracranial Pressure

 * Normal ICP is between 5 and 15 mmHg at rest in an adult. [6]
 * TBI can cause swelling that can increase pressure and result in damage to the brain.
 * Common symptoms of increased intracranial pressure:
 * Behavior changes
 * Decreased consciousness
 * Headache
 * Lethargy
 * Neurological symptoms: weakness, numbness, eye movement problems, double vision, seizures
 * Vomiting
 * Patients with a Glasgow Coma Score between 3 and 8 must have their ICP monitored [7]
 * ICP has also been used to prognosticate the outcome of patients with a TBI [8]
 * However, ICP was not correlated with coma duration or treatment outcome 6 months after the trauma [8]



Age

 * Many studies demonstrated that older age is associated with poorer outcome and the threshold values varying between 30 and 60 years [3]
 * The chance of an adverse outcome increases with patient age in a stepwise manner, especially after the 60 years [3]
 * Luerssen et al.published a relevant study that compared the impact of age on patients with severe TBI and pediatric patients had lower mortality when compared to adults (28% versus 47%). [3]
 * Effect of Age on Working Memory
 * Difficulty with working memory is often reported with cases of TBI [9]
 * Functional MRI uses blood oxygen levels to determine cerebral brain activation [9]
 * All patients had a Glasgow of 15 [9]
 * Young patients were 21-30 and the older patients were 51-68 [9]
 * Post-concussion syndrome(PCS) was assessed at the initial evaluation and at the 6 week follow-up. PCS symptoms included headache, tiredness, dizziness, loss of concentration, depression, sleep disturbance, memory impairment, disorientation, irritability, and anxiety. [9] [[image:https://lh3.googleusercontent.com/9mul_cOdKjIMKNiqMcthguTc27K3q8V-zShYgbHtFNK3ew5FQZa-KV0BQ-rxSztO761FOaMAg3hHzxCaxZEb4dpXw9EVBZBTOeCDlt5C1MrYT2FAG9Uhf1hU5ZNITP5zLslnQPboh9I width="300" height="175" caption="[9]"]]
 * Higher activation in injured young patients was associated with greater PCS which may be due to an association of increased hyperactivity and a more severe head trauma. There was no such relationship with the older patients [9]
 * Different post-concussion symptoms and functional MR imaging between younger and older patients confirmed the important role of age in the activation, modulation, and allocation of WM processing resources after mild TBI [9]
 * The results reinforced the assertion that younger patients have more neural plasticity and greater clinical recovery when compared to older patients.
 * The prognostic finding of this study are shown as hyperactivation during WM tasks in younger patients within 1 month of injury may indicate greater severity of brain injury and neuronal dysfunction [9]
 * Traumatic Brain Injury in Young Children
 * Severe TBIs in young children can have a great effect on the IQ of the child as they grow. The study found that 10 years post the severe TBI group was 18-26 points lower than the uninjured children [10]
 * There can be a disruption of brain development and although the child may recover relatively normal development the gap created by the injury will not be filled [10]
 * However the children that were categorized as mild or moderate saw much less differences at the 10 year follow up implying there might be an injury threshold for children of these ages [10]
 * Age at injury for the sample ranged from 2 to 7 years [10]
 * Other Age Related Prognostic Factors
 * Age continues to have negative effects on mortality past 60 years with those over 75 being 1.7 times more likely to die from a traumatic brain injury [11]
 * For people over 60 the mortality rate for moderate and severe TBIs are similar although still significantly different from the mild scores 13-15, this implies that the GCS may not be the best assessment tool for the elderly [11]
 * CTs are not a great predictor of future success on the Glasgow Outcome Scale Extended. The greatest correlation for mild TBIs and positive outcomes were age, extracranial injuries, and ethanol intoxication [12]

Multivariate Analysis

 * A logistic regression analysis was undertaken to define the adjusted weight of each independent variable in the outcome [3]
 * Logistic regression equation:
 * logit (p) = −1.36 + (age * 0.03) + (GCS * −0.2) + (MS 4,6 or 6 * 0.72) + (anisochoria * 0.58). Probability = 1/1 + e–logit (p).
 * This means that the death probability of a patient aged 65, with a GCS of 7, a MS of 4, with no anisocoria is estimated to be around 47.7% [3]

Beta Coefficients

 * Variables included in the model: adjusted weight of each independent variable in the outcome [3]
 * || OR || IC 95% || Coefficient || p ||
 * Age (years) || 1.03 || 1.02–1.03 || 0.03 || 0.0001 ||
 * Glasgow Coma Scale (3–15) || 0.81 || 0.77–0.84 || −0.2 || 0.0001 ||
 * Marshall Scale 4, 5, 6 (0: no; 1: yes) || 2.07 || <span style="background-color: transparent; color: #5c5c5c; font-family: Arial; font-size: 14pt; vertical-align: baseline;">1.50–2.85 || <span style="background-color: transparent; color: #5c5c5c; font-family: Arial; font-size: 14pt; vertical-align: baseline;">0.72 || <span style="background-color: transparent; color: #5c5c5c; font-family: Arial; font-size: 14pt; vertical-align: baseline;">0.0001 ||
 * <span style="background-color: transparent; color: #5c5c5c; font-family: Arial; font-size: 14pt; vertical-align: baseline;">Anisocoria (0: no; 1: yes) || <span style="background-color: transparent; color: #5c5c5c; font-family: Arial; font-size: 14pt; vertical-align: baseline;">1.79 || <span style="background-color: transparent; color: #5c5c5c; font-family: Arial; font-size: 14pt; vertical-align: baseline;">1.17–2.72 || <span style="background-color: transparent; color: #5c5c5c; font-family: Arial; font-size: 14pt; vertical-align: baseline;">0.58 || <span style="background-color: transparent; color: #5c5c5c; font-family: Arial; font-size: 14pt; vertical-align: baseline;">0.006 ||

So What?

 * When a patient has had a severe TBI and does not have any chance of recovering or even slightly improving, physical therapy is not appropriate.
 * However, if a reliable measure predicts that a patient may improve or have a good prognosis, early intervention is crucial.
 * Since the Marshall Scale, anisocoria, and Glasgow Coma Scale are good predictors of prognosis after a TBI, their results can lead to a more informed decision on the treatment plan for the patient.