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Visual hallucinations (VH) are common in dementia with Lewy bodies (DLB), and are among the core symptoms for its clinical diagnosis. VH have been associated with cognitive alterations, although research findings in this area are still limited. The present study aimed at investigating the cognitive correlates of VH in DLB, and the baseline neuropsychological features predicting the future development of VH. A cross sectional study compared the cognitive profile of 18 DLB patients with VH with that of 32 DLB without VH. A longitudinal study involved 34 DLB patients with no VH at baseline, among whom 17 developed VH and 17 remained without VH at follow-up. Logistic regression analyses were carried out to investigate what baseline cognitive variables independently predicted the development of VH at follow-up. DLB patients with VH had worse performance on the copy of the Rey complex figure, assessing visual construction/perception, than those without VH in the cross-sectional study (p = .001). Significant impairments in attention and visual memory delayed recall were also present. Baseline performance on the immediate prose memory was the only significant predictor of VH development in the longitudinal study (p = .03). DLB patients are more at risk of developing VH if presenting more severe immediate verbal memory impairment, and this might be related to a combination of (a) DMN-related dysfunctions, (b) impairment in medial temporal lobe-related functions, and (c) frontal abilities including long-term encoding of information and working memory. Differences between hallucinating and non-hallucinating patients in visual construction/perception, typical of DLB symptomatology, may be essential for VH to emerge in individuals with an at risk cognitive profile.

BACKGROUND Standard measures of commonly used memory tests may not be appropriate to distinguish different neurodegenerative diseases affecting memory. OBJECTIVE To study whether specific measures of verbal memory obtained with the Rey Auditory Verbal Learning test (RAVLT) could help distinguish dementia with Lewy bodies (DLB) from Alzheimer's disease (AD). METHODS Twenty-nine DLB and 32 AD patients participated in the study and were followed longitudinally for 3 years until the diagnosis was confirmed according to standard clinical criteria. Twenty-eight healthy elderly subjects served as controls. The following verbal memory measures were evaluated: verbal learning (VL), verbal forgetting (VF), percentage of verbal forgetting (VF%), and serial position effects of the immediate recall performance. RESULTS DLB and AD groups have comparable performances at the RAVLT immediate and delayed recall tasks. However, VL was higher in DLB than AD while VF% was greater in AD. With a VF% cut-off ≥75%, AD and DLB patients were differently distributed, with 58% of AD versus 21% of DLB above this cut-off. The recency effect was significant higher in AD than DLB. DISCUSSION DLB patients had a better performance in VL than AD, but worse VF and recency effect. These specific measures of verbal memory could be used as cognitive markers in the differential diagnosis between these two conditions.

BACKGROUND Alterations of the sleep-wake cycle are common features of neurodegenerative dementia. OBJECTIVES To study differences in sleep-wake profiles in dementia with Lewy bodies (DLB), Alzheimer's disease (AD), and healthy controls. METHODS 30 DLB and 32 AD patients, and 33 healthy elderly participants were studied. Patients were evaluated for global cognitive impairment, extrapyramidal signs, fluctuations of attention, and behavioral disorders. A comprehensive sleep-wake profile was obtained including a set of questionnaires [Pittsburgh Sleep Quality Index (PSQI), REM Sleep Behavior Disorder Single-Question screen (RBD1Q), Epworth Sleepiness Scale (ESS)] and 12-day sleep diaries. RESULTS Patients were matched for age, gender, and disease severity. DLB patients showed more severe daytime somnolence/dysfunction due to somnolence, and a higher proportion of RBD-like symptoms (70%) compared to AD and controls (p