Abstract
Fabricating cognitive deficits seems to be a convenient way to gain financial benefits or avoid imprisonment. We assume, that with an increasing presence of Alzheimer's disease (AD), the amount of people, who mimic its symptoms for their own benefit, will increase.
This is a problem, as faked symptoms are hard to distinguish from real ones. Visual recognition tests can be used to categorize the difference between the two.
Overall, 161 people went through a complex battery of neuropsychological tests regularly used at the General University Hospital in Prague. Furthermore, participants were tested on a visual recognition test, Delayed Matching to Sample 48 (DMS 48). 31 patients were diagnosed with dementia due to AD and 54 with amnestic mild cognitive impairment (aMCI).
A group of 76 healthy controls were divided into 30 "malingerers" faking symptoms and 46 norms. We found, that malingerers scored significantly worse on the DMS 48 when compared to other participants.
Memory tests failed to detect malingering. Moreover, patients and norms scored lower on the Geriatric Depression Scale than malingering group.
Further ROC analysis was performed on the DMS 48 using values of specificity and sensitivity to determine cut-off scores. We propose a cut-off of 39 to 40 points to distinguish malingering from dementia due to AD and aMCI.