Epilepsy Information

2010
American Epilepsy Society Poster (Abst. 1.331)

Comparison of the assessment of effort in patients with psychological non epileptic seizures and refractory partial epilepsy using the Test of Memory Malingering


Authors: J. Kanter, Lorna Myers, K. Perrine, J. Politsky and M. Lancman

Rationale:
The Test of Memory Malingering (TOMM) was originally developed as a symptom validity measure to assess effort and possible malingering of memory deficits, especially in litigating traumatic brain injury cases. Studies of patients with verified neurologic disorders such as dementia generally show that patients with substantiated poor memory “pass” this test. Patients with psychological non-epileptic seizures (PNES) have extensive cognitive complaints that are so profound as to sometimes appear exaggerated , but verification with symptom validity testing is rarely performed. The current study examines TOMM performance in an outpatient sample of adults with refractory partial epilepsy vs. PNES.

Methods:

A retrospective chart review was performed to identify all patients who had taken the TOMM; this measure has been part of our standard neuropsychological battery since 2008. Forty-nine PNES patients and 31 epilepsy patients (consecutive with refractory partial epilepsy-taking 2 or more antoconvulsants) were included in the study. Neuropsychological testing was conducted on an outpatient or inpatient basis. Diagnosis of epilepsy vs. PNES was made by epileptologists following review of video-EEG monitoring. Independent t test was used for statistical comparison.

Results:
Analysis of performance on Trial 1 of the TOMM revealed that 15 of 49 (31%) PNES patients failed trial one of the TOMM (mean score 42.6 - 1.2) compared to 3 of 31 (< 10%) of the epilepsy patients (mean score 46.4 - 0.8) (p<0.01). However, closer case review revealed that 6 of these persons had clear secondary gain associated to their symptoms (e.g. litigation following a motor vehicle accident, Worker’s Compensation, and school avoidance). In another case, testing was discontinued due to significant fluctuation in arousal levels. When these patients were removed from the sample, the mean score was 44.8 -1.0 and the difference between the groups was not significant (p<0.239).

Conclusions:
Patients with PNES with no verifiable secondary gain do not differ significantly from an epilepsy sample. Symptom validity testing is an important part of the standard PNES neuropsychological battery. Scores from these measures have the potential of providing important diagnostic information. These scores serve the purpose of alerting the clinician to possible secondary gain and may assist in the discrimination between conversion/somatization disorders (PNES) and malingering (NES).



 

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