Confabulations on Episodic and Semantic Memory Questions Are Associated With Different Neurologic Backgrounds in Alzheimer Disease

Lee, Eunjoo; Kinomura, Shigeo; Meguro, Kenichi; Akanuma, Kyoko; Meguro, Mitsue; Fukuda, Hiroshi

doi:10.1097/wnn.0b013e3181a7226c

Cited by 22 publications

(38 citation statements)

References 34 publications

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“…There is consistent evidence of greater executive and/or ‘frontal’ dysfunction in AD patients with psychotic symptoms (Koppel et al ., 2014b; Lee et al ., 2009; Lee et al ., 2007; Paulsen et al ., 2000a; Paulsen et al ., 2000b), including patients who present solely with persecutory delusions (Nagata et al ., 2009). Inconsistent findings have however been reported across other cognitive domains (Reeves et al ., 2012).…”

Section: Introductionmentioning

confidence: 99%

Cognitive phenotype of psychotic symptoms in Alzheimer's disease: evidence for impaired visuoperceptual function in the misidentification subtype

Reeves

Clark-Papasavas

Gould

et al. 2015

Int J Geriatr Psychiatry

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BackgroundEstablishing the cognitive phenotype of psychotic symptoms in Alzheimer's disease (AD) could localise discrete pathology and target symptomatic treatment. This study aimed to establish whether psychotic symptoms would be associated with poorer performance on neuropsychological tests known to correlate with striatal dopaminergic function and to investigate whether these differences would be attributed to the paranoid (persecutory delusions) or misidentification (misidentification phenomena +/− hallucinations) subtype.MethodsSeventy patients with probable AD (34 psychotic and 36 nonpsychotic) were recruited to the study. Analysis of covariance was used to compare motor speed and the rapid visual processing test of sustained visual attention, after adjusting for potential confounding factors. Multivariate analyses were used to compare performance across other cognitive domains. Significant findings were explored by separating patients on the basis of subtype.ResultsRapid visual processing performance accuracy was reduced in patients with psychotic symptoms (F 1,58 = 5.94, p = 0.02) and differed significantly across subtypes (F 2,51 = 3.94, p = 0.03), largely because of poorer performance in the misidentification compared with nonpsychotic group. Multivariate analyses (corrected for multiple comparisons) showed poorer performance on the incomplete letters task in psychotic patients (F 1,63 = 8.77, p = 0.004) and across subtypes (F 2,55 = 10.90, p < 0.001), similarly attributed to the misidentification subtype.ConclusionsThese findings provide further support of the involvement of dopaminergic networks in the psychosis endophenotype in AD and, in addition, implicate the ventral (temporo‐occipital) pathway in the misidentification subtype. Future studies should investigate the early trajectory of neuropathological change in vivo across psychosis subtypes.© 2015 The Authors. International Journal of Geriatric Psychiatry published by John Wiley & Sons, Ltd.

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Section: Introductionmentioning

confidence: 99%

Cognitive phenotype of psychotic symptoms in Alzheimer's disease: evidence for impaired visuoperceptual function in the misidentification subtype

Reeves

Clark-Papasavas

Gould

et al. 2015

Int J Geriatr Psychiatry

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“…However, our study could not find any abnormalities in the frontal lobe corresponding to psychotic factors. Recent studies using neuroimaging have shown that the right side of either the frontal or temporal lobe is critical for delusions in AD patients 14,54,55. A possible reason is that the limited types of questions for delusions may not be sufficient to analyze the neural basis underlying various types of delusions, such as misidentification delusions.…”

Section: Discussionmentioning

confidence: 99%

Neural basis of three dimensions of agitated behaviors in patients with Alzheimer disease

Banno¹,

Nakaaki²,

Sato³

et al. 2014

NDT

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BackgroundAgitated behaviors are frequently observed in patients with Alzheimer disease (AD). The neural substrate underlying the agitated behaviors in dementia is unclear. We hypothesized that different dimensions of agitated behaviors are mediated by distinct neural systems.MethodsAll the patients (n=32) underwent single photon emission computed tomography (SPECT). Using the Agitated Behavior in Dementia scale, we identified the relationships between regional cerebral blood flow (rCBF) patterns and the presence of each of three dimensions of agitated behavior (physically agitated behavior, verbally agitated behavior, and psychosis symptoms) in AD patients. Statistical parametric mapping (SPM) software was used to explore these neural correlations.ResultsPhysically agitated behavior was significantly correlated with lower rCBF values in the right superior temporal gyrus (Brodmann 22) and the right inferior frontal gyrus (Brodmann 47). Verbally agitated behavior was significantly associated with lower rCBF values in the left inferior frontal gyrus (Brodmann 46, 44) and the left insula (Brodmann 13). The psychosis symptoms were significantly correlated with lower rCBF values in the right angular gyrus (Brodmann 39) and the right occipital lobe (Brodmann 19).ConclusionOur results support the hypothesis that three different agitated behaviors may represent distinct neural networks in AD patients.

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“…Recently, a more specific frontal deficit causing confabulating retrieval has been proposed, operating in conjunction with memory impairment [29]. Paralleling behavioral observations, neuroimaging of lesions in confabulating patients also suggests the involvement of multiple systems, the ventromedial prefrontal cortex [28, 29, 30] as well as more posterior cortical areas, in memory processes [31]. Our findings on GC are generally in agreement with those reported in the literature on VC, pointing to a dysexecutive-amnesic involvement.…”

Section: Discussionmentioning

confidence: 99%

“…However, the relative weight of the frontal and memory deficits in determining GC seems to be variable in different cognitive syndromes. Previous evidence on VC in AD [11, 32] indicates that they are related to memory impairment rather than to frontal dysfunction, while a recent paper [31] reported that episodic confabulation is affected by delusion related to frontal dysfunction, and semantic confabulation is more closely associated with memory disorder. In our sample, GC is limited to demented patients, while VC also presented in MCI patients, suggesting that in this form of confabulation memory deficits are critical, with the dysexecutive component being less important.…”

Section: Discussionmentioning

confidence: 99%

When Rey-Osterrieth’s Complex Figure Becomes a Church: Prevalence and Correlates of Graphic Confabulations in Dementia

Pelati

Castiglioni

Isella

et al. 2011

Dement Geriatr Cogn Disord Extra

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Verbal confabulation (VC) has been described in several pathological conditions characterized by amnesia and has been defined as ‘statements that involve distortion of memories’. Here we describe another kind of confabulation (graphic confabulation, GC), evident at the recall of the Rey-Osterrieth complex figure (ROCF). In a retrospective study of 267 patients with mild-to-moderate dementia, 14 patients (4.9 %) recalled the abstract ROCF as drawings with recognizable semantic meaning. VC was evident at the story recall test in 19.8% of the study participants. VC and GC were homogeneously distributed among the different types of dementia. VC has been proposed to originate from complex interactions of amnesia, motivational deficit and dysfunction of monitoring systems. On the contrary, GC seems to be the result of a deficit in visual memory replaced by the semantic translation of isolated parts of the ROCF along with a source monitoring deficit.

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Confabulations on Episodic and Semantic Memory Questions Are Associated With Different Neurologic Backgrounds in Alzheimer Disease

Abstract: Different mechanisms are involved in confabulations between semantic and episodic memories in AD. Episodic confabulation is affected by delusion related to frontal dysfunction, and semantic confabulation is associated with cognitive dysfunction.

Cited by 22 publications

References 34 publications

Cognitive phenotype of psychotic symptoms in Alzheimer's disease: evidence for impaired visuoperceptual function in the misidentification subtype

Cognitive phenotype of psychotic symptoms in Alzheimer's disease: evidence for impaired visuoperceptual function in the misidentification subtype

Neural basis of three dimensions of agitated behaviors in patients with Alzheimer disease

When Rey-Osterrieth’s Complex Figure Becomes a Church: Prevalence and Correlates of Graphic Confabulations in Dementia

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