Perspective taking to assess self-personality: What's modified in Alzheimer's disease?

in Neurobiology of Aging (2009), 30(10), 1637-1651

Personality changes are frequently described by caregivers of patients with Alzheimer's disease, while they are less often reported by the patients. This relative anosognosia of Alzheimer disease (AD ... [more ▼]

Personality changes are frequently described by caregivers of patients with Alzheimer's disease, while they are less often reported by the patients. This relative anosognosia of Alzheimer disease (AD) patients for personality changes might be related to impaired self-judgment and to decreased ability to understand their caregiver's perspective. To investigate this issue, we explored the cerebral correlates of self-assessment and perspective taking in patients with mild AD, elderly and young volunteers. All subjects assessed relevance of personality traits adjectives for self and a relative, taking either their own or their relative's perspective, during a functional imaging experiment. The comparison of subject's and relative's answers provided congruency scores used to assess self-judgment and perspective taking performance. The self-judgment "accuracy" score was diminished in AD, and when patients assessed adjectives for self-relevance, they predominantly activated bilateral intraparietal sulci (IPS). Previous studies associated IPS activation with familiarity judgment, which AD patients would use more than recollection when retrieving information to assess self-personality. When taking a third-person perspective, patients activated prefrontal regions (similarly to young volunteers), while elderly controls recruited visual associative areas (also activated by young volunteers). This suggests that mild AD patients relied more on reasoning processes than on visual imagery of autobiographical memories to take their relative's perspective. This strategy may help AD patients to cope with episodic memory impairment even if it does not prevent them from making some mind-reading errors. [less ▲]

Neural correlates of fast and slow ocular sequence learning

in NeuroImage (2005), 26(Suppl. 1),

Two Aspects of Impaired Consciousness in Alzheimer's Disease

in Progress in Brain Research (2005), 150(Boundaries of Consciousness: Neurobiology and Neuropathology), 287-98

Alzheimer's disease (AD) is a degenerative dementia characterized by different aspects of impaired consciousness. For example, there is a deficit of controlled processes that require conscious processing ... [more ▼]

Alzheimer's disease (AD) is a degenerative dementia characterized by different aspects of impaired consciousness. For example, there is a deficit of controlled processes that require conscious processing of information. Such an impairment is indexed by decreased performances at controlled cognitive tasks, and it is related to reduced brain metabolic activity in a network of frontal, posterior associative, and limbic regions. Another aspect of impaired consciousness is that AD patients show variable levels of anosognosia concerning their cognitive deficits. A discrepancy score between patient's and caregiver's assessment of cognitive functions is one of the most frequently used measures of anosognosia. A high discrepancy score has been related to impaired activity in the superior frontal sulcus and the parietal cortex in AD. Anosognosia for cognitive deficits in AD could be partly explained by impaired metabolism in parts of networks subserving self-referential processes (e.g., the superior frontal sulcus) and perspective-taking (e.g., the temporoparietal junction). We hypothesize that these patients are impaired in the ability to see themselves with a third-person perspective (i.e., being able to see themselves as other people see them). [less ▲]

Festina lente: evidences for fast and slow learning processes and a role for sleep in human motor skill learning.

in Learning & Memory (Cold Spring Harbor, N.Y.) (2003), 10(4), 237-9