ABSTRACT

INTRODUCTION

Alzheimer's disease (AD) and mild cognitive impairment (MCI) as its preclinical syndrome are characterized by a variety of cognitive deficits that can be assessed by using the neuropsychological test battery of the CERAD. The cerebral changes underlying the respective cognitive deficits, however, are only partly understood.

METHODS

In 75 patients with mild AD and MCI, cerebral changes were investigated by positron emission tomography with Fluorodeoxyglucose. A regression analysis was performed in order to investigate the respective associations of regional cerebral glucose metabolism with the CERAD test scores by statistical parametric mapping.

RESULTS

Episodic memory scores were significantly correlated with glucose metabolism in temporo-frontal and cingulate cortices. Verbal fluency and naming scores were significantly correlated with glucose metabolism predominantly in left temporo-parietal and frontal cortices whereas constructional praxis test scores correlated significantly with left temporal and right frontal cortices. Both subtests of delayed episodic memory were associated with a network including rather frontal association cortices.

CONCLUSION

Findings of the study demonstrate that neuropsychological deficits as assessed by the CERAD refer to different cerebral sites of both hemispheres, and underline the clinical validity of this clinical instrument.

Keywords: neural correlates, AD, MCI, CERAD, PET