Discrepancy Analysis Comparison after Brain Injury


Discrepancy Analysis

Discrepancy analysis is one of the cornerstones of neuropsychological assessment after brain injury. The theory of discrepancy analysis is that even though there was no neuropsychological evaluation done prior to the injury, that the pattern of scores can show a change as a result of trauma.

Neuropsychology – Discrepancy Analysis:

  • “Intraindividual comparison.”
  • “Relative weaknesses” for a given individual.

The problem for many TBI survivors and others in understanding neuropsychological reports is that scores are often not reported in percentage categories. The below chart helps to solve that problem.

 % Standard  T-Scores
 Very Superior Category
 98  130  70
 Superior Category
 91  120  60
 High Average Category
 75  110  50
 Average Category
 25  90  40
 Low Average Category
 7  80  30
 Borderline Category
 2  70
 Impaired Category
 below 2%

The Neurological Exam
The neurological exam is another effort at looking for a footprint of pathology, that something about the way in which the brain is functioning is not proper. A full neurological exam includes not only the classic tests to determine whether the nervous system is working properly, but also a rudimentary assessment of cognitive function and most important, a clinical interview.

Yet far too often in concussion cases, the exam is limited to a quick check for focal neurological deficits. Such an exam will rarely identify the type of deficits typically associated with a subtle brain injury, although the diligent neurologist may uncover focal deficits, which were missed at the time of the injury. Sadly, the one focal deficit which is most likely to be effected by a concussion, the sense of smell, is the one which is least often checked.

The neurological exam is often thought of as a objective evaluation as to whether the nervous system is working properly. While this conception may often be the way in which the exam is used for diagnostic purposes, the neurological exam is no more objective than other footprint type evaluations, nor is the good examination, limited to a physical exam.

NEXT: Discrepency Analysis Impeachment.

by Attorney Gordon Johnson