Anosognosia in mild cognitive impairment: Relationship to activation of cortical midline structures involved in self-appraisal

• Published in: Journal of the International Neuropsychological Society 2007-05, Vol.13 (3), p.450-461
• Main Authors: RIES, MICHELE L., JABBAR, BRITTA M., SCHMITZ, TAYLOR W., TRIVEDI, MEHUL A., GLEASON, CAREY E., CARLSSON, CYNTHIA M., ROWLEY, HOWARD A., ASTHANA, SANJAY, JOHNSON, STERLING C.
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Aging; Agnosia; Agnosia - etiology; Agnosia - pathology; Alzheimer disease; Alzheimer's disease; Appraisals; Brain; Brain Mapping; Case-Control Studies; Cerebral Cortex - blood supply; Cerebral Cortex - pathology; Cognition Disorders - complications; Cognition Disorders - psychology; Correlation analysis; Deficits; Female; Humans; Image Processing, Computer-Assisted; Investigations; Magnetic Resonance Imaging; Male; Medical imaging; Neocortex; Neuropsychological Tests; Oxygen - blood; Patients; Regression Analysis; Sample size; Self assessment (Psychology); Self Concept; Severity of Illness Index; Studies
• ISSN: 1355-6177; 1469-7661
• DOI: 10.1017/S1355617707070488

Awareness of cognitive dysfunction shown by individuals with Mild Cognitive Impairment (MCI), a condition conferring risk for Alzheimer's disease (AD), is variable. Anosognosia, or unawareness of loss of function, is beginning to be recognized as an important clinical symptom of MCI. However, little is known about the brain substrates underlying this symptom. We hypothesized that MCI participants' activation of cortical midline structures (CMS) during self-appraisal would covary with level of insight into cognitive difficulties (indexed by a discrepancy score between patient and informant ratings of cognitive decline in each MCI participant). To address this hypothesis, we first compared 16 MCI participants and 16 age-matched controls, examining brain regions showing conjoint or differential BOLD response during self-appraisal. Second, we used regression to investigate the relationship between awareness of deficit in MCI and BOLD activity during self-appraisal, controlling for extent of memory impairment. Between-group comparisons indicated that MCI participants show subtly attenuated CMS activity during self-appraisal. Regression analysis revealed a highly significant relationship between BOLD response during self-appraisal and self-awareness of deficit in MCI. This finding highlights the level of anosognosia in MCI as an important predictor of response to self-appraisal in cortical midline structures, brain regions vulnerable to changes in early AD. (JINS, 2007, 13, 450–461.)