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Abstract:
Abstract: Recent evidence suggests that a large proportion of
older individuals diagnosed with mild cognitive impairment (MCI)
may develop neurodegenerative conditions such as Alzheimer's
disease (AD). MCI patients display deficits on neuropsychological
measures that require the formation and consolidation of new
memories. Both medial temporal and frontal lobes may play an
important role in the performance of such tasks. In the current
study, we sought to determine the relative contributions of these
areas to the cognitive deficits associated with MCI. Cognitive
neuropsychological measures of associative learning (AL) and
executive function (EF) were administered to a group of 25 MCI
patients and 25 controls. MCI patients displayed a severe deficit
on AL measures, which resembles that seen in AD patients and
patients with hippocampal lesions, a result which supports the
hypothesis that MCI represents the preclinical stages of AD.
Specifically, MCI patients were unable to transfer knowledge
learned very recently to a parallel task in which one of two
stimulus features were modified. A mild EF deficit was also
observed in the MCI group; however, this was only evident on a
measure with a large memory component. While disruption to a medial
temporal- frontal lobe network may cause a variety of memory
complaints, the current results suggest that the deficits
associated with MCI are attributable to deterioration of the
hippocampal formation.
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