Memory Loss Patterns Help in
Diagnosis of Alzheimers
Lead Researcher: Scott A. Small resources
Through a novel use of functional magnetic resonance imaging (fMRI),
P&S researchers have provided evidence of two distinct patterns
of memory decline in the elderly. Clinicians hope to use this
technique someday to diagnose patients in the very early stages
of Alzheimers disease so they can implement early interventions
to slow the conditions progression. Scott A. Small, assistant
professor of neurology, published his findings in the April 1999
issue of Annals of Neurology.
Memory decline with age is common, with some reports suggesting
that more than 40 percent of people over age 60 have some memory
impairment. But not all age-related memory decline inevitably
leads to the development of Alzheimers disease. "Both Alzheimers
disease and other age-dependent physiologic changes probably contribute
to memory decline in the elderly. A key question for researchers
is, How do we distinguish between these processes? A test that
could do so would be helpful in identifying individuals in the
early stages, when the main focus of treatment is halting progression,"
says Dr. Small.
Dr. Small and his colleagues used fMRI, a non-invasive modification
of traditional MRI, to analyze changes in the hippocampus region
of the brain during memory tests. Its been known for decades
that the hippocampus is integral to the brains memory function.
Other functional imaging techniques, such as positron emission
tomography (PET), have been used to study brain changes related
to memory function, but these techniques have been unable to selectively
assess different regions within the hippocampus and thus cannot
show how specific areas of the brain alter as memory declines.
The study led by Dr. Small is the first to document functional
changes in various areas in the hippocampal formation.
"The hippocampus is the first brain structure to be targeted by
Alzheimers disease; therefore, detection of changes in this area
would provide early diagnosis of the condition. Through the use
of fMRI, we were able to show two distinct patterns of age-related
memory decline in the healthy, non-demented elderly. We believe
that those individuals with dysfunction in the entorhinal region
of the hippocampus have early Alzheimers disease, while those
with dysfunction in other regions of the hippocampus do not,"
says Dr. Small.
The study first evaluated memory function in three groups of individuals
over age 64: four patients with normal memory, 13 with isolated
memory decline, and four with mild Alzheimers disease. All of
the study participants viewed photographic portraits for four
minutes while undergoing a brain MRI. Study participants were
selected from the Washington Heights Inwood Aging Project, a long-term,
community-based random aging project. They were followed for at
least three years. The research was funded by the National Institute