Relationships between neuropsychiatric symptoms and cognitive profiles in Alzheimer's disease and related syndromes.

OBJECTIVES: To investigate the rate of occurrence of neuropsychiatric symptoms (NPS) and their relationship with age, sex and cognitive performance in subjects with Alzheimer's disease and related dementias (Alzheimer's disease and related dementias [ADRD]). METHODS: This is a retrospective matched case-control study. Data from memory clinic patients included demographic information presence of NPS, and cognitive testing of Orientation, Immediate and Delayed Memory, Visuospatial Function, Working Memory, Attention, Executive Control and Language. Participants were Individuals with subjective cognitive impairment (n = 352), mild cognitive impairment (MCI) (n = 369), vascular MCI (n = 80), Alzheimer's disease (n = 147), vascular dementia (n = 41), mixed dementia (n = 33), and healthy controls (n = 305). Logistic regression was used to investigate the relationship between the presence of NPS, age and sex. A generalised additive model was used to investigate the relationship between presence of NPS, age and cognitive impairment. Analysis of variance was used to investigate differences in cognition between younger and older groups with and without NPS. RESULTS: We found an increased likelihood of occurrence of NPS in younger individuals and females across cohorts. Anxiety, depression, agitation, and apathy were associated with higher overall rate of NPS. We also found that individuals under 65 years of age with NPS had worse cognitive scores than their counterpart without NPS. CONCLUSION: The younger group with ADRD and NPS had lower cognitive scores, probably reflecting more aggressive neurodegenerative disease. Further work will be needed to elicit the degree to which imaging or mechanistic abnormalities distinguish this group.

Episodic memory decline is associated with deficits in coherence of discourse.

This study investigates coherence of discourse in the production of autobiographical narratives by individuals with aMCI. Autobiographical interviews were analyzed to determine whether reduced episodic recall was related to deficits in discourse coherence. A coherence rating scale was used to evaluate relatedness of the autobiographical details produced by participants to the topic of discourse. Interviews were transcribed, segmented into details, and divided into sets of episodic, semantic, or supplementary information, which were subsequently analysed with the coherence rating scale. We predicted that the known episodic deficits observed in aMCI could also affect the retrieval of coherent episodic information. The results revealed deficits in coherence could be found in both episodic and semantic information in the aMCI group. These results suggest that the cognitive deficits experienced by individuals with aMCI may go beyond their known difficulty in recalling episodic details, as they also affect the controlled retrieval of both episodic and semantic information.

Impaired coherence for semantic but not episodic autobiographical memory in semantic variant primary progressive aphasia.

Language deficits, including word-finding difficulties and impaired single-word comprehension, have been found in patients with semantic variant primary progressive aphasia (svPPA). These deficits characterize the linguistic abilities of patients with svPPA on a micro-linguistic level (word and sentence level). On a macro-linguistic level (discourse level), svPPA patients' discourse has been described as "empty". Few studies have considered the contribution of a linguistic impairment to the difficulty of producing autobiographical narratives. In the present study, we assessed svPPA patients' discourse coherence during autobiographical narratives in order to characterize the nature of their speech on a macro-linguistic level and to investigate the relationship between discourse production and memory in a naturalistic context. We collected samples of discourse in which svPPA patients and healthy controls (matched in age, education, sex and handedness) reported autobiographical events. Their narratives were assessed with a rating scale to evaluate global coherence of discourse. The protocols were also analysed using the Autobiographical Interview method (Levine, Svoboda, Hay, Winocur, & Moscovitch, 2002) and categorized as episodic (information about events at a specific time and place), semantic (general knowledge), or supplementary details (metacognitive statements, repeated information, editorializing). Where possible, patients were assessed longitudinally at three time points over two years. Patients with svPPA produced a reduced number of episodic details, while the number of semantic details produced was comparable to controls. However, the episodic information produced by patients was coherent with the topic of discourse, while semantic information was not. These results suggest that svPPA patients produce semantic information comparable to controls in quantity but not quality, whereas the opposite is the case for episodic information.