Neuroanatomical correlates of unawareness of memory deficits in early Alzheimer's disease.
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.
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ABSTRACT: Unawareness or diminished awareness is present when a patient's perception of obvious disease manifestations and impact differ from that of observers such as clinicians or family members. We examined studies that specifically investigate unawareness in Huntington disease (HD). Unawareness of motor, cognitive, behavioral, and functional aspects of HD has been documented throughout the disease course. This can occur at motor and cognitive onset but is more pronounced as the disease progresses. We discuss the implications for diagnosis, symptom report at presentation, timing of diagnosis, acceptance of symptomatic care strategies, and reporting in clinical trials. Assessments of work place competency, discrimination, driving, and the particular challenges of isolated patients without caregivers are described. Engaging with a person who is unaware of their disease or its impact presents a number of conflicts, including maintaining the right to autonomy, privacy, confidentiality, and independence while recognizing concerns for the wellbeing of the vulnerable person with HD and their caregiver when the unaware person refuses assistance. Unawareness is seen increasingly as neurologically based due to the impairment of functional networks, predominantly in nondominant frontostriatal pathways.Tremor and other hyperkinetic movements (New York, N.Y.). 01/2014; 4:257.
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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. · 6.04 Impact Factor
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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. · 6.04 Impact Factor