Performance of Patients with Epilepsy or Psychogenic Non-Epileptic Seizures on Four Measures of Effort

Abstract

Exaggeration of cognitive symptoms or poor effort on cognitive testing has been addressed primarily in the traumatic brain injury literature. The present investigation aims to extend the evaluation of effort to the epilepsy monitoring setting, where base rates of failure on effort testing remain unknown for patients with intractable epilepsy (ES), psychogenic nonepileptic seizures (PNES), or both conditions (ES+PNES). In addition, this investigation explores how well four measures of effort (DMT, LMT, TOMM, PDRT) distinguish between these diagnostic groups. Results show that 20% of the combined sample failed one or more effort measure. When examining failure rates for each diagnostic group, 22% of epilepsy patients, 24% of PNES patients, and 11% of ES+PNES patients performed suboptimally on one or more measure of effort. The utility of these effort measures to differentiate between these diagnostic groups appears limited. Further research is needed to clarify the base rate of poor effort in the epilepsy monitoring unit setting in general and in these three diagnostic groups specifically.

ACKNOWLEDGEMENT

The authors thank Chantel M. S. Dearth and Chris Miara for their help with data collection. Thank you to Christi Patten for her comments on an earlier draft of this manuscript. This project was supported by the Epilepsy Foundation through the generous support of the American Epilepsy Society.

Notes

Note. ES = epilepsy; PNES = psychogenic non-epileptic seizures; ES + PNES = epilepsy plus psychogenic non-epileptic seizures; SD = standard deviation; AED = anti-epileptic drug. Values with the same superscript do not differ.

Note. ES = epilepsy; PNES = psychogenic non-epileptic seizures; ES + PNES = epilepsy plus non-epileptic seizures; LMT = Letter Memory Test; DMT = Digit Memory Test; PDRT-27 = Portland Digit Recognition Test short form; TOMM = Test of Memory Malingering.

Note. ES = epilepsy; PNES = psychogenic non-epileptic seizures; ES + PNES = epilepsy plus non-epileptic seizures; LMT = Letter Memory Test; DMT = Digit Memory Test; PDRT-27 = Portland Digit Recognition Test—27-item version; TOMM = Test of Memory Malingering.

Note. ES = epilepsy; PNES = psychogenic non-epileptic seizures; ES + PNES = epilepsy plus psychogenic non-epileptic seizures.

Note. Edu = years of education, Onset = age of seizure disorder onset, Freq = frequency of seizures per month, Past AEDs = number of AEDs failed before admission, Curr AEDs = number of AEDs prescribed at the time of admission, HI = history of head injury, Psych = psychiatric history, Disability = on or seeking disability income due to seizures, F = female, M = male, LMT = Letter Memory Test, DMT = Digit Memory Test, TOMM (%/%) = Test of Memory Malingering (trial 2%correct/retention trial% correct), PDRT-27 = Portland Digit Recognition Test—27-item version.

The majority of the data in this paper are from the first author's master's thesis. Portions of these data were presented at the 29th Annual International Neuropsychological Society Conference, Chicago, IL, February 14–17, 2001.

These participants are also included in the larger patient sample reported in Cragar, D. E., Schmitt, F. A., Berry, D. T. R., Cibula, J. E., Dearth, C. M. S., & Fakhoury, T. A. (2003). A comparison of MMPI-2 decision rules in the diagnosis of nonepileptic seizures. Journal of Clinical and Experimental Neuropsychology, 25, 793–804.

Additional information

Notes on contributors

Dona E. Cragar

Dona E. Cragar is now Dona E. C. Locke, and is at the Department of Psychiatry and Psychology, Mayo Clinic, Scottsdale, AZ.

Jean E. Cibula

Jean E. Cibula is now at Mount Carmel Medical Center, Columbus, OH.