B - 80 The Long-Term Memory Sign in Adults Referred for Neuropsychological Evaluation

Objective We investigated the clinical utility of the newly described long-term memory (LTM) sign in adults referred for neuropsychological evaluation. Individuals with dementia often report short-term episodic memory decline or no memory decline, but rarely report long-term episodic memory decline. The LTM sign refers to patient self-report of long-term episodic memory decline, that is equivalent to/or greater than, subjective short-term episodic memory decline. Method The LTM sign was endorsed on a pre-visit intake form and established during clinical interview in 568 patients (M age = 63, SD = 14.3) referred for neuropsychological evaluation at a large medical center in the Northwest United States. Results In our sample of 568 patients, 79 (14%) reported the LTM sign. In 79 patients with the LTM sign, 45 were diagnosed with a primary psychiatric disorder (57%), 23 were diagnosed with mild neurocognitive disorder (29%), seven had no cognitive or psychiatric diagnosis (9%), and four had dementia (5%). The LTM sign was most common in those with a history of trauma in childhood or adolescence (52/79, 66%) and substance use disorders (50/79, 63%). Conclusions The LTM sign was rare in dementia, but common in those with a current psychiatric diagnosis. These findings support the literature on episodic memory decline in dementia populations and suggests that encoding of early memories and/or retrieval of old memories is negatively impacted by a current psychiatric disorder, traumatic events in childhood and adolescence, and lifetime history of substance use disorder. The LTM sign is a valuable addition to the clinical interview of neuropsychological patients.