Outcome of Mild Head Injury and Persistent Post-concussion Syndrome

Brain Injury and Law Worker’s Comp Law Tort of Emotional Distress Worker must demonstrate injury or disability that arises out of and during the course of employment and is accidental Need to establish physical or mental stimulus (e.g., extreme stress) that causes the mental injury Sometimes hard to determine whether there was a preexisting condition Tort of Emotional Distress Relies on judicial proceedings exclusively, rather than administrative decision-making Case law vs. statutory law Damages set by a jury, rather than fixed schedule

Mild TBI and Forensic NP Mild TBI most common type of case seen by forensic NP in personal injury setting (torts) Many cases of mTBI or post-concussion syndrome don’t show acute injury characteristics consistent with TBI mTBI refers to alteration of ongoing mental processing either due to loss of consciousness (59mins or less) or post-traumatic amnesia (not beyond 24hrs) For non-complicated mTBI, expect full NP recovery ~3mo post-trauma Larrabee & Rohling, 2013

Post-concussion Syndrome Cluster of sx including: memory/concentration difficulty headache vertigo depression/anxiety/irritability/fatigue blurred vision/photophobia hyperacoustism Cause is controversial Cerebral dysfunction vs. psychogenic origin Now more commonly seen as somatoform-esque Incidence is unrelated to severity of injury or NP status Issue is lack of specificity of PCS sx bc they tend to occur in everyday life Mitterberg et al., 1992

Post-concussion Syndrome Mittenberg et al. (1992) asked pts with TBI & healthy controls (who imagined they had a TBI) what symptoms they experienced/expected 6 mo following an injury Number of sx TBI pts reported wasn’t significantly different from what controls expected Headaches and visual difficulties were expected more often than they occurred Irritability, fatigue, and difficulty with memory occurred more often than controls expected However, there was a tendency of TBI to attribute premorbid sx to TBI Mitterberg et al., 1992

Financial Incentives after Head Injury Controversy in the field about whether financial incentives maintain disability and symptoms after closed-head injury Mild head trauma w/post-concussion syndrome (PCS) has been called “compensation neurosis” that clears after settlement of litigation Binder & Rohling, 1996

Financial Incentives after Head Injury Meta-analysis of financial incentives on disability, symptoms, and objective findings Reviewed 17 articles, total of 2,353 individuals Found overall moderate effect size (0.47) ^ report of abnormality and disability in patients with financial incentives, even with less severe injuries Monetary incentives are more powerful for mild TBI Findings suggest that considering secondary gain is important in an NP eval, especially for mild TBI Binder & Rohling, 1996

So What Symptoms are Legit? Factors that can affect sx: Severity of injury (e.g., length of coma, nonreactive pupils, mass lesions, CNS complications) Time from injury to testing Patient’s personal characteristics (e.g., mood, personality)

mTBI Post-Injury Outcomes At one week post-trauma: domains with greatest effect size were WM, verbal and visual learning/memory At 93 days: only WM was significantly different from 0 Larrabee & Rohling, 2013

NP Outcomes at 1-Year Post Injury Head injuries requiring hospitalization are associated with NP impairments at 1-year post injury Significant dose-response relationship No one value or range of Impairment Index that can classify all TBI Impairments are shifted about 25%ile points down from GT controls Selective impairments in attention and memory start to emerge as head injury increases in severity With ^ severity, most domains become affected More reliable differences noted on measures like Finger Tapping, PIQ, and overall NP performance, rather than attention or memory only Significant NP impairment due to a mild head injury is very unlikely Dikmen et al., 1995

Should we be more stringent about test procedures to discriminate potential psychogenic PCS vs. organically-based PCS? (e.g., should NP testing or trials for compensation only be done after 1-year, etc.)

Dangers of Incorrectly Diagnosing Impairments Self-fulfilling prophecy Patients believe they are incapable of getting better or lack control over progress Potential mistreatment Expensive or labor-intensive treatments that are unnecessary Unnecessary management services Bauer, 1997

Relevance to Forensic NP Clinical eval of mental injury similar in torts and WC Aside from assessing whether there is an injury, need to understand whether it was due to work or a result of the action by the defendant; also, need to comment on prognosis

“Deadly Sins” of Forensic NP in Brain Damage Cases (According to Dr “Deadly Sins” of Forensic NP in Brain Damage Cases (According to Dr. Bauer in 1997) It’s elementary If a test result is abnormal, must mean the person has brain damage What you see is what you get - Ecological validity of NP tests 3. Two deficits are worse than one Taking each domain as an independent sample of behavior; failing to interpret the overall pattern 4. All people are created equal - All people should fall ≥ average

“Deadly Sins” of Forensic NP in Brain Damage Cases (According to Dr “Deadly Sins” of Forensic NP in Brain Damage Cases (According to Dr. Bauer in 1997) 5. The proof is in the pudding If neuroradiological evidence is absent, just means NP is more sensitive 6. One man’s ceiling is another man’s floor All NP data are subject to interpretation of the professional 7. You can use a wedge to putt from the fringe, as long as you blade it correctly NP tests can be applied in all settings and whoever can administer/interpret 8. If the patient complains, it must hurt All info that the patient reports must be true

“Deadly Sins” of Forensic NP in Brain Damage Cases (According to Dr “Deadly Sins” of Forensic NP in Brain Damage Cases (According to Dr. Bauer in 1997) 9. What I don’t know won’t hurt me NP data and interview are enough to infer past functioning 10. It’s all in the name You can tell what a test measures by looking at its name Three words to remember: localization, localization, localization Every test has its own special location in the brain