Is Mild Cognitive Impairment Prodromal for Vascular Dementia Like Alzheimer’s Disease?

Abstract

Background and Purpose-Individuals with mild cognitive impairment (MCI) are at increased risk of Alzheimer's disease (AD) and probably other forms of dementia. Some subtypes of vascular dementia (VaD) may possess minor neuropathological changes of AD that may contribute to cognitive impairments. It was posited that MCI, identified by criteria described here, might present as a prodrome for VaD and AD. Methods-Serial Mini-Mental State Examination was administered at 3-to 6-month intervals, and neuroimaging was performed annually. Subtle cognitive dysfunctions were weighted and measured according to MCI criteria defined here. Subjects identified with MCI were then followed up for an additional 3.88Ϯ3.01 years. Diagnoses of VaD and AD were made according to established criteria. Results-During 3.72Ϯ2.94 years of follow-up of the original normative subjects, 73 of 291 (25.1%) developed MCI. Of the 27 subjects who developed VaD, 15 (55.6%) had prodromal MCI. Of these, two thirds were subclassified as having small-vessel dementia. The remaining 12 patients with VaD (44.4%) were diagnosed directly from a cognitively normal status without preceding MCI. These were predominantly multi-infarct or strategic-infarct dementia (66.7%). An additional 35 MCI subjects (47.9%) developed AD. Both VaD and AD diagnosed after MCI prodromes manifested similar spectral domains of cognitive impairments, which included memory, during their MCI stages. Conclusions-In some VaD subtypes, particularly those caused by subcortical microvascular disease, dementia may be preceded by MCI, which has similar domains of cognitive impairment and a similar progressive course that may mimic AD.

Patterns of neuropsychological impairment in MCI patients with small subcortical infarcts or hippocampal atrophy

“…Lopez et al (2007) have, indeed, rightly noted that when the subject's cognitive deficits could be due to nondegenerative conditions (such as a small-vessel subcortical pathology), a greater proportion of MCI patients remain cognitively stable or return to a normal baseline. These reasons could contribute to explain the conflicting results of previous studies dealing with the patterns of cognitive impairment observed in VD and DAT patients (e.g., Desmond, 2004;Laukka et al, 2004;Looi & Sachdev, 1999;Meyer et al, 2002;Reed et al, 2007). It is also possible that the absence of a clear neuropsychological pattern in vascular MCI patients was due to their small sample size (and hence to insufficient statistical power ) but this hypothesis is at variance with the fact that a clear and consistent neuropsychological pattern was found in the even smaller group of atrophic MCI patients.…”

White matter hyperintensities, executive function and global cognitive performance in vascular mild cognitive impairment

“…One of the most prevalent subtypes (36-67%, according to different authors), the subcortical ischemic vascular disease (SIVD), is due to gradually progressive microvascular changes that might cause insidious and subtle cognitive impairments before diagnostic of VaD becomes established. Most (83.3%) subcortical small-vessel dementias might exhibit prodromal MCI, similar to what occurs in Alzheimer's disease (AD) 5 . On magnetic resonance imaging (MRI), SIVD usually appears as periventricular and deep white-matter signal hyperintensities (WMHs), visible on T2 and FLAIR images, and lesions in the prefrontal subcortical circuits are known to be involved in executive function, including control of working memory, organization, language, mood, regulation of attention, and constructional skills 3 .…”

“…To date, diagnostic criteria developed to characterize cognitive syndromes associated with vascular disease require evidence of CVD or stroke previous to cognitive impairment, focal signs on physical examination, fluctuating stepwise course or dementia onset within three months of a stroke 4 . Although the need for a temporal association between stroke and cognitive changes may be relevant in cases of post-stroke dementia, it does not apply to cases of SIVD, in which cognitive decline may be slowly progressive rather than stepwise 5 . Therefore, diagnostic criteria for VCI due to SIVD should embrace cognitive impairments associated to deep white matter changes.…”

Treinamento auditivo em idosos com comprometimento cognitivo leve

“…Diversos estudos mostram que portadores de CCL apresentam maior risco de desenvolver quadros demenciais (Meyer et al, 2002;Sarazin, Dubois, 2002;Lopez, Dekoski, 2003). Cerca de 10 a 15% desses idosos tendem a apresentar a doença de Alzheimer em um ano, o que ressalta a importância da identificação desses casos.…”