Outcome of Mild Head Injury and Persistent Post-concussion Syndrome

1. Outcome of Mild Head Injuryand Persistent Post-concussion Syndrome

2. Brain Injury and Law • Worker’s Comp Law • 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

3. 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

4. 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 sxbc they tend to occur in everyday life Mitterberg et al., 1992

5. 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

6. 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

7. 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

8. 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)

9. 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

10. 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

11. 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.)

12. 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

13. 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

14. “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

15. “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

16. “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