[Memory symptom exaggeration in a patient with progressive multiple sclerosis outside any medico-legal context]

Memory symptom exaggeration or malingering in the forensic neuropsychological evaluation of well-documented brain pathology is seldom described. For some, documented neuropathology and malingering are considered to be mutually exclusive.

We report an original clinical observation of an amnesic factitious disorder in a patient with progressive multiple sclerosis. This patient, who was seen for a routine comprehensive neuropsychological evaluation, demonstrated a severe memory encoding deficit in a classical standard episodic memory test. This amnesic syndrome was not in agreement with the neurological condition where deficits in retrieval memory processes are essentially observed. Moreover, his performance at two symptom validity tests fell below the admitted cut-off scores. In fact, the patient obtained an accuracy score of 3 (cut-score<10) in the Rey's 15-Items Test, a well known malingered amnesia measure. His performance in the 21-Items Test French adaptation was well below the proposed cut-off score of 15/21 and inferior to the results obtained by an Alzheimer patients group (n=30). A clinical approach of memory symptom exaggeration is described. We discuss the diagnosis of this false disorder.

This case report demonstrates unequivocally that memory symptom exaggeration or malingering can and does occur in patients seen without litigious contexts and who have a well-documented neurological pathology. Failure to address malingering may compromise neuropsychological clinical findings. Nevertheless, there is a lack of up-to-date standard French-language documentation in this topic.