Imaging Techniques and Neuropsychological Testing in Dementia with Severe White Matter Changes

Multi-infarct dementia (MID), as originally described by Hachinski [21] is thought to be the consequence of repeated, clinically apparent cerebrovascular infarctions. The Hachinski Ischemic Scale [21] is used to separate vascular from nonvascular dementias, according to this operational definition. Not all cerebral infarctions are clinically apparent, however. Recent reports suggest that 11%–30% of all cerebral infarctions are asymptomatic [8,37]. Moreover, the concept of cerebrovascular dementia has evolved to include patients with subcortical arteriosclerotic dementias (SAD) where clinical stroke is inapparent [9,35]. Patients with SAD form a subgroup of slowly progressive dementing illnesses which differ pathophysiological from the dementia of Alzheimer type (DAT) and MID groups, by virtue of having predominantly small vessel cerebrovascular disease and central white matter demyelination [33,35]. The cognitive deficits, however, bear no unique characteristics that reliably distinguish them from DAT or MID [7,9,33,35,36].