Neuroanatomical correlates of unawareness of memory deficits in early Alzheimer's disease

Department of Geriatric Medicine, Tokyo Medical University, Tokyo, Japan.
Dementia and Geriatric Cognitive Disorders (Impact Factor: 2.81). 02/2008; 25(4):347-53. DOI: 10.1159/000119594
Source: PubMed

ABSTRACT To investigate neuroanatomical substrates of unawareness of memory deficits in patients with early Alzheimer's disease (AD).
We compared regional perfusion deficits between AD patients with awareness (n = 19) and unawareness (n = 19). SPECT data were analyzed by statistical brain imaging method.
Statistical maps demonstrated a more extensive and severe reduction in perfusion in the unaware group than in the aware group. Quantitative analysis demonstrated a significant difference between the groups in the right subcallosal, anterior cingulate and cingulate gyri and left orbital, subcallosal, and anterior cingulate gyri.
Functional damage to the inferior, medial and orbital frontal lobes as well as the anterior cingulate gyri may be associated with the lack of awareness in patients with early AD.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Anosognosia is present in a large proportion of patients with mild Alzheimer's disease (AD), and its frequency increases with the progression of the illness. Several instruments have been validated to assess anosognosia in AD, but there is no consensus regarding the best diagnostic strategy. Anosognosia in AD is a significant predictor of apathy and is significantly related to lower depression and anxiety scores, more severe caregiver burden and dangerous behaviours. Studies using different imaging modalities have demonstrated an association between anosognosia and dysfunction in frontal, temporomedial and temporoparietal regions. The mechanism of anosognosia remains unknown, but it has been explained as a consequence of deficits of encoding and updating biographical memory, and dysfunction of comparator, executive and metacognitive systems. Copyright © 2014 Elsevier Ltd. All rights reserved.
    Cortex 12/2014; 61C:64-73. DOI:10.1016/j.cortex.2014.07.019 · 6.04 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Awareness of cognitive deficits may be reduced in mild cognitive impairment (MCI). This may have a detrimental effect on illness course and may be a predictor of subsequent conversion to AD. Although neuropsychological correlates have been widely investigated, no evidence of a neuroanatomical basis of the phenomenon has been reported yet. This study was aimed at investigating the neuroanatomical correlates of deficit awareness in amnestic MCI to determine whether they constitute risk factors for conversion to AD.
    Cortex 12/2014; 61:183-95. DOI:10.1016/j.cortex.2014.10.010 · 6.04 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To investigate, in a group of subjects at an early stage of cognitive impairment, the relationship between anosognosia and both cognitive and behavioral symptoms by exploring the various domains of insight. One hundred and eight subjects affected by cognitive impairment were consecutively enrolled. The level of awareness was evaluated by means of the Clinical Insight Rating Scale (CIRS). Psychiatric symptoms were evaluated using the Italian version of the Neuropsychiatric Inventory (NPI), whereas memory (memory index, MI) and executive (executive index, EI) functions were explored using a battery of neuropsychological tests and qualified by means of a single composite cognitive index score for each function. A significant positive correlation between the total NPI score and global anosognosia score was found. Furthermore, both the MI and EI scores were lower in subjects with anosognosia than in those without anosognosia (p < 0.001 and p < 0.007, respectively). When the single domains of the CIRS were considered, anosognosia of reason of visit correlated with the EI score (r = -0.327, p = 0.01) and night-time behavioral disturbances (r = 0.225; p = 0.021); anosognosia of cognitive deficit correlated with depression (r = -0.193; p = 0.049) and the MI score (r = -0.201; p = 0.040); anosognosia of functional deficit correlated with the MI score (r = -0.257; p = 0.008), delusions (r = 0.232; p = 0.015) and aberrant motor behavior (r = 0.289; p = 0.003); anosognosia of disease progression correlated with the MI score (r = -0.236; p = 0.015), agitation (r = 0.247; p = 0.011), aberrant motor behavior (r = 0.351; p = 0.001) and night-time behavioral disturbances (r = 0.216; p = 0.027). Our study suggests that, in the early stage of cognitive impairment, anosognosia is associated with both cognitive deficits and behavioral disorders according to the specific functional anatomy of the symptoms.
    01/2015; 5(1):42-50. DOI:10.1159/000367987