Neuropsychological assessment is most useful in patients with more subtle cognitive deficits . It is also useful for detecting deficits in patients with particularly high premorbid intelligence levels in which bedside type clinical testing may be insensitive to mild alterations. Single Photon Emission Computed Tomography (SPECT) with the tracer 99m Tc-hexamethyl propyleneamine oxime (HMPAO) provides imaging allowing semiquantitative estimation of regional cerebral blood flow (rCBF) . In normal aging persons, reduced cerebral blood flow could be responsible for age-related changes in cognitive functions.