Temporal lobe hypoperfusion in isolated amnesia with slow onset: a single photon emission computer tomography study

Area of Science:

• Neurology
• Neuroimaging
• Gerontology

Background:

• Early detection of neurodegenerative diseases like Alzheimer's disease (AD) is crucial.
• Mild cognitive impairment (MCI) patients, especially those with isolated amnesia, have a high conversion rate to AD.
• Single Photon Emission Computed Tomography (SPECT) can identify brain dysfunction.

Purpose of the Study:

• To characterize regional cerebral blood flow (CBF) in patients with isolated amnesia.
• To investigate early functional brain changes in individuals at high risk for AD.
• To assess the utility of SPECT in identifying preclinical AD markers.

Main Methods:

• SPECT-99mTc-d,l-HMPAO perfusion studies were conducted on 32 isolated amnesia patients and 15 healthy controls.
• Neuropsychological assessments and neuroimaging (MRI/CT) were performed on all participants.
• Semiquantitative SPECT values were calculated and statistically compared between groups.

Main Results:

• Patients with isolated amnesia exhibited significant hypoperfusion in multiple cortical regions compared to controls.
• The most prominent hypoperfusion was observed in the left temporal cortex.
• A trend towards globally reduced CBF was noted in patients, though not statistically significant.

Conclusions:

• SPECT reveals significant regional cerebral blood flow reductions in isolated amnesia patients.
• These findings suggest an early or preclinical stage of a progressive neurodegenerative illness.
• SPECT imaging may serve as a valuable tool for identifying at-risk individuals for AD.