Brain Injury Lawyer

Last month, I discussed a number of studies regarding the Word Memory Test (WMT) and testing efforts in traumatic brain injury patients.  As you will recall, the WMT was developed by Dr. Paul Green who has asserted that this test, which he developed, has consistently been found to be close to or actually 100% accurate in classifying simulators versus good effort volunteers.
 
According to Dr. Green’s most recent study, the Word Memory Test (WMT) is “meant to be virtually insensitive to all but the most extreme forms of impairment of learning and memory.”  The rationale of this and other symptom validity measures is that the tests are so easy that even patients with brain damage should be able to pass the test, scoring above the accepted cut-off point for failure and poor effort.  Dr. Green and others assert that the WMT and other SMTs place “only minimal cognitive demands on subjects, because of their simplicity thereby explaining why even patients with severe brain injury are able to pass these measures.”
 
Recently, Dr. Erin D. Bigler from Bingham Young University called into question the validity of the WMT’s foundation.  The researchers scanned four males age 22 - 26 with fMRI who received no compensation.  The males first were given the computerized version of Green’s WMT,  Participants underwent fMRI scanning during the delayed recognition phase.  The participants were also scanned while performing a control block which was chosen because it “matches the motor activity of the test task and because it clearly required minimal cognitive effort compared with the DR task.”
 
The researchers hypothesized that if the WMT “were to place only minimal cognitive demands on subjects because of its simplicity, little fMRI activation should be observed except in areas directly involved in the sensory processing of the task.  However, the fMRI data rejected this hypothesis as it showed that the WMT significantly taxed cognitive symptoms known to be involved in mental effort, where activation was found in areas consistently associated with increases in task difficulty, memory lobe and other forms of cognitive effort.  The researchers concluded that their findings “constituted compelling evidence against the notion that the WMT is an effortless cognitive test.”
 
The authors stated:
 
 Given that the greatest likelihood for damage in TBI, including mild TBI, occurs with frontotemporal and limbic regions, these are the very regions involved in cognitive effort shown in the fMRI study....
 
 This study raises serious questions about whether one can make straightforward inferences about cognitive effort from SVT performance alone.  Future structural and functional neuroimaging research is needed to better understand what the true meaning is of poor effort especially in TBI and other patient populations with distinct SNC lesions.