Background-We examined whether cerebral metabolic rates for glucose (CMRglc) on 2-[ 18 F] fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET) and cerebrospinal fluid (CSF) markers of Alzheimer's disease (AD) are altered in cognitively normal apolipoprotein E (ApoE) E4 carriers with subjective memory complaints (SMC).

Deposition of β-amyloid (Aβ) is an early pathogenic event in Alzheimer’s disease (AD). We measured Aβ42 and Aβ40 in cerebrospinal fluid (CSF) in a population-based sample of 85-year-olds, 27 demented and 35 non-demented. During the following 3 years, 7 of the 35 non-demented individuals had developed dementia, while 28 remained non-demented. Reduced CSF levels of both Aβ42 (p = 0.001) and Aβ40 (p = 0.0001) were found in patients with manifest AD and vascular dementia at the age of 85. Non-demented individuals who developed dementia during follow-up had lower levels of CSF- Aβ42 (p = 0.003), but not CSF-Aβ40 (p = 0.96), than those who remained non-demented. The odds ratio for development of dementia was 8.2 (p = 0.027) for individuals in the lower 50th percentile of CSF-Aβ42, while none of those in the highest 33rd percentile of CSF-Aβ42 developed dementia during follow-up. There were no significant differences between carriers and non-carriers of the apolipoprotein E Ε4 allele regarding CSF-Aβ42or CSF-Aβ40.Our study suggests that low CSF-Aβ42 is found also in an unselected population-based sample of old demented patients and provides the first evidence of a disturbance in the metabolism of Aβ, specifically involving Aβ42, before the onset of clinical symptoms in AD.

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The aim was to study the frequently found white-matter changes on computerized tomography (CT) in patients with dementia and to relate these changes to clinical regional brain symptomatology, vascular factors, albumin ratio [indicator of blood-brain barrier (BBB) function] and other CT changes. The study included 85 patients, average age 71 ± 8, with Alzheimer’s disease (n = 56) and vascular dementia (n = 29), who underwent CT (Siemens Somatome DR 1) of the brain. They were inpatients in a psychiatric department specialized in dementia investigations. The degree of CT white-matter changes (absence, mild-moderate, severe) was the basis for the division of the patients into three groups. As the patients without white-matter changes were significantly younger than those with such changes, all statistical analyses were controlled for age. Subcortical symptomatology was significantly more frequent in the group with severe white-matter changes, whereas the reverse was true for parietal symptomatology. Diabetes mellitus, hypertension, ischemic cardiac disease and lacunas were significantly more common in patients with white-matter changes, whereas the freqeuncy of transient ischemic attack/stroke episodes did not differ significantly between the groups. The albumin ratio was significantly higher in the groups with white-matter changes and highest in the group with severe white-matter changes. The findings indicate that white-matter changes in demented patients are at least partially an age- and stroke-independent disease manifestation of the vascular system and is associated with a specific symptom pattern. BBB dysfunction may be the link between the vasculature and the tissue damage.

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