Mild Traumatic Brain Injury, Invalid Effort, and Causation
Ms. P, 45, is a plaintiff in a motor vehicle collision case. She was rear-ended at 35 mph 18 months ago, had a brief emergency department visit, no loss of consciousness, and returned to work as a bookkeeper after four days. She now reports headaches, forgetfulness, and inability to work. Her neuropsychological testing shows a full-scale IQ of 92, impaired memory scores, and a TOMM score below the recommended cutoff on both trials. The MMPI-2-RF shows elevated F-r and RBS, and she has a history of depression treated with sertraline before the crash. Her neurologist diagnosed 'post-concussion syndrome' based on symptoms alone, and the defense asks you to opine on causation and effort.
1. How should the validity test results be interpreted, and what do they mean for the neuropsychological findings?
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The TOMM below cutoff on both trials is a strong indicator of invalid performance, and the MMPI-2-RF overreporting scales add converging evidence that symptom reporting is exaggerated. Neither result proves malingering by itself; depression, pain, fatigue, and test anxiety can affect effort, and the base rate of invalid performance in medico-legal settings matters. But the combination of failed performance validity and overreported symptoms substantially reduces confidence in the memory scores. I would not interpret the impaired memory as evidence of brain injury without valid effort.
I would review embedded validity indicators, behavioral observations, inconsistency across tests, and collateral reports. If effort remains invalid, the cognitive data are uninterpretable rather than evidence of impairment. I would explain this distinction clearly: invalid performance does not mean the person has no symptoms or no distress, but it does mean the test scores cannot be used to support a cognitive diagnosis or causation opinion. A repeat evaluation with valid effort would be necessary before drawing neuropsychological conclusions.
2. What causal opinion can be offered about the claimed cognitive and psychiatric problems?
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Causation requires a plausible injury mechanism, a credible clinical course, and an alternative explanation analysis. Here, there was no loss of consciousness, the emergency department visit was brief, and Ms. P returned to work within four days-findings that are not typical of a severe traumatic brain injury. Her neurologist's diagnosis of post-concussion syndrome appears to rest on symptom reports alone, which is circular when those reports are exaggerated. Her pre-existing depression is an alternative explanation for headaches, fatigue, and concentration problems.
Given invalid effort and the weak injury markers, I could not opine to a reasonable degree of psychological certainty that the collision caused her cognitive complaints. I would state that the current data do not support a neurocognitive disorder attributable to the crash, while acknowledging that she may experience genuine distress. I would recommend obtaining pre-crash records, treating the depression, and repeating testing with valid effort. The report should distinguish what is known, what is uncertain, and what would be needed to reach a firmer opinion.
3. How would you structure the report to avoid overstepping and remain helpful to the court?
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I would separate the report into clearly labeled sections: background and records reviewed, interview and behavioral observations, test results, validity analysis, diagnostic impressions, causation analysis, limitations, and recommendations. I would explain validity in plain language so the court understands why the memory scores cannot be trusted, without accusing Ms. P of dishonesty. I would identify alternative explanations-pre-existing depression, pain, sleep disruption, litigation stress-and weigh them explicitly.
I would avoid ultimate legal conclusions such as 'the defendant caused the injury' or 'the plaintiff is malingering.' Instead, I would offer psychological opinions with stated confidence and explain the basis. I would note that a diagnosis of post-concussion syndrome is not the same as proof of brain injury, and that symptom validity is central to the analysis. I would recommend treatment and, if appropriate, a re-evaluation. This structure helps the court without turning the psychologist into an advocate for either side.