Preliminary evidence of validity of the revised criteria for alzheimer disease diagnosis: Report of 2 cases

Objective: Revised research criteria for the diagnosis of Alzheimer disease have been proposed to capture patients presenting with mild and not yet disabling symptoms, and currently classified as mild cognitive impairment (MCI). We describe 2 very mild cases of MCI and their clinical outcome. Methods: The 2 cases were selected as they had unequivocal preservation of daily activities and normal global cognitive performance (Mini-Mental State Examination 29/30) and were positive to all 3 markers. Cognitive profile was assessed with an extensive neuropsychologic battery, medial temporal atrophy with hippocampal volumetry, hypometabolism on F-deoxyglucose positron emission tomography and voxel-based statistical parametric mapping analysis, and tau and amyloid beta-42 in the cerebrospinal fluid with enzyme-linked immunosorbent assay. Results: Both patients had a poor performance in 2 out of 11 neuropsychologic tests. Both had hippocampal volumes at or below the first percentile of the age-specific distribution, retrosplenial glucose hypometabolism, and inversion of tau/amyloid beta-42 cerebrospinal fluid ratio. Both showed progression of the cognitive deficit over the following 12 months. Conclusions: These 2 patients with progressive MCI and positivity to all Alzheimer markers predicated by the new research criteria provide preliminary support to their validity. Future work will characterize the marker profile of the vast majority of patients with incomplete marker positivity.