P2–215: Episodic memory performance is associated with neuropathology in primary progressive aphasia

Primary Progressive Aphasia (PPA) is an aphasic dementia syndrome commonly caused by frontotemporal lobar degenerations (FTLD). Ho wever, 30–40% of PPA cases are caused by atypical Alzheimer's disease (AD) neuropathology where neurofibrillary tangles show greater leftward asymmetry and less entorhinal prominence (Rogalski & Mesulam, 2008; Gefen et al., 2012). Episodic memory is impaired in dementia associated with typical AD neuropathology, and thus might represent a clinical marker of AD versus FTLD neuropathology in PPA. This study is an archival analysis of performance on the Three Words Three Shapes Test in a sample of PPA patients with post mortem AD (PPA-AD, N=14) or FTLD neuropathology (PPA-FTLD, N=8). The test assesses verbal and nonverbal copy, recall, and recognition in the visual modality. Recall is tested under conditions of effortless encoding and after effortful learning trials and a delay. Data were analyzed using ANOVAs with neuropathology diagnosis as the between-subjects variable and material (words vs. shapes) as the within-subjects variable. PPA-AD and PPA-FTLD groups did not differ significantly based on age at test, education, symptom duration, age at death, or activities of daily living (all p s > 0.05). Consistent with previously reported findings in a living sample (Weintraub et al., 2013), all patients had better recall of shapes than of words following effortless encoding (p < 0.001) and delayed recall (p < 0.05). However, word recall in both conditions was better for PPA-FTLD than for PPA-AD patients (effortless encoding, p < 0.05; delayed recall p < 0.05). FTLD neuropathology was associated with greater capacity for both online storage (effortless encoding) and long-term storage and retrieval (delayed recall) of words than AD neuropathology in patients with clinical PPA. Findings suggest that PPA-AD patients show more amnestic features than PPA-FTLD patients on an episodic memory test.