A - 134 Consistent Failed Performance on Performance Validity Tests in Early-Onset Alzheimer’s Disease Confirmed by Lumbar Puncture

Abstract Objective This case study expands the literature of failed performance validity tests (PVTs) in individuals with confirmed biomarkers for early-onset Alzheimer’s disease (ad). Method The case presents a 56-year-old right-handed white male with a history of depression and onset of cognitive symptoms beginning in his early 50’s. He reported difficulties remembering appointments, tasks, and events, and difficulties with orientation while driving. Brain PET-MRI displayed mild to moderate atrophy of temporal lobes, and moderate hypometabolism in the bilateral temporal and partial lobes and posterior cingulate gyri. Following neuropsychological testing, a cerebrospinal fluid (CSF) analysis was consistent with ad biomarkers. Results Upon neuropsychological testing, the patient obtained below cutoff scores on freestanding and embedded PVTs. The Dot Counting Test (DCT) and the TOMM yielded below cutoff scores. Embedded validity indicators on the WAIS-IV and the RBANS were also suggestive of suboptimal effort. Impaired performances were seen on test of visuomotor speed and set-shifting. In contrast, he obtained scores within normal limits on tasks of visuospatial perception, basic auditory attention, and confrontation naming. Conclusion Failures on multiple PVT’s were evidenced on testing with no apparent external motivating factors. While below cutoff PVT performances are concerning for suboptimal engagement, positive CSF markers for ad raise concern for possible false positive classification of suboptimal effort vs genuine cognitive impairment. This case provides further insight into PVT performance in early ad, especially with symptom onset at a younger age.