Neuro-biological findings
Recent neurobiological advances as a result of enhanced
imaging have uncovered mechanisms in the brain involved in
memory loss associated with ageing. The hippocampus
(located in the medial temporal lobe of the brain) is responsible
for learning and memory (Lister & Barnes 2009). Lister
and Barnes (2009) studied the literature on changes in the
hippocampus, confirming that structural and functional
deficits occurred in normal ageing. Through positron
emission tomography (PET) imaging, Mormino et al. (2008)
confirmed that deposits of beta-amyloid plaques (commonly
observed in the brain cortex of patients with Alzheimer
disease) correlated with atrophy in the hippocampus, but
could also be seen in people without dementia. The findings
of Mormino et al. suggest that even small deposits of
beta-amyloid may represent an early stage of Alzheimer disease,
but that atrophy in the hippocampus must reach a
threshold before pathological impairment of memory occurs.
Stroke and cerebral small vessel disease
Garcia-Molina et al. (2006) found memory impairment to be
the most commonly-affected cognitive domain on neuropsychological
testing in people who had suffered anoxic brain
injury (i.e. stroke). However, in a longitudinal study (n = 832)
in which stroke was an exclusion criterion, Prins et al. (2005)
found no association between memory loss and structural
magnetic image resonance (MRI) changes seen in cerebral
small vessel disease (specifically white matter hyperintensities
resulting from chronic hypertension, diabetes, smoking and/or
ageing of the vasculature). This study did, however, show an
association with small vessel disease (very common in older
adults), slowed processing time and impaired executive
functioning (responsible for both planning and abstract
thinking).
Neuro-biological findings
Recent neurobiological advances as a result of enhanced
imaging have uncovered mechanisms in the brain involved in
memory loss associated with ageing. The hippocampus
(located in the medial temporal lobe of the brain) is responsible
for learning and memory (Lister & Barnes 2009). Lister
and Barnes (2009) studied the literature on changes in the
hippocampus, confirming that structural and functional
deficits occurred in normal ageing. Through positron
emission tomography (PET) imaging, Mormino et al. (2008)
confirmed that deposits of beta-amyloid plaques (commonly
observed in the brain cortex of patients with Alzheimer
disease) correlated with atrophy in the hippocampus, but
could also be seen in people without dementia. The findings
of Mormino et al. suggest that even small deposits of
beta-amyloid may represent an early stage of Alzheimer disease,
but that atrophy in the hippocampus must reach a
threshold before pathological impairment of memory occurs.
Stroke and cerebral small vessel disease
Garcia-Molina et al. (2006) found memory impairment to be
the most commonly-affected cognitive domain on neuropsychological
testing in people who had suffered anoxic brain
injury (i.e. stroke). However, in a longitudinal study (n = 832)
in which stroke was an exclusion criterion, Prins et al. (2005)
found no association between memory loss and structural
magnetic image resonance (MRI) changes seen in cerebral
small vessel disease (specifically white matter hyperintensities
resulting from chronic hypertension, diabetes, smoking and/or
ageing of the vasculature). This study did, however, show an
association with small vessel disease (very common in older
adults), slowed processing time and impaired executive
functioning (responsible for both planning and abstract
thinking).
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