Clinical criteria for the diagnosis of Alzheimer's disease include insidious onset and progressive impairment of memory and other cognitive functions. There are no motor, sensory, or coordination deficits early in the disease. The diagnosis cannot be determined by laboratory tests. These tests are important primarily in identifying other possible causes of dementia that must be excluded before the diagnosis of Alzheimer's disease may be made with confidence. Neuropsychological tests provide confirmatory evidence of the diagnosis of dementia and help to assess the course and response to therapy. The criteria proposed are intended to serve as a guide for the diagnosis of probable, possible, and definite Alzheimer's disease; these criteria will be revised as more definitive information become available.

https://n.neurology.org/content/neurology/34/7/939.full.pdf

Clinical diagnosis of Alzheimer's disease : report of the NINCDS-ADRDA Work Group under the auspices of Department of Health and Human Services Task Force on Alzheimer's Disease

A new interview schedule for the diagnosis and measurement of dementia in the elderly is described. The schedule named the Cambridge Mental Disorders of the Elderly Examination (CAMDEX), consists of three main sections: A structured clinical interview with the patient to obtain systematic information about the present state, past history and family history; a range of objective cognitive tests which constitute a mini-neuropsychological battery; a structured interview with a relative or other informant to obtain independent information about the respondent's present state, past history and family history. The CAMDEX is acceptable to patients, has a high inter-rater reliability and the cognitive section has been shown to have high sensitivity and specificity.

CAMDEX. A standardised instrument for the diagnosis of mental disorder in the elderly with special reference to the early detection of dementia.

Objective: To examine the relation of midlife raised blood pressure and serum cholesterol concentrations to Alzheimer9s disease in later life Design: Prospective, population based study Setting: Populations of Kuopio and Joensuu, eastern Finland Participants: Participants were derived from random, population based samples previously studied in a survey carried out in 1972, 1977, 1982, or 1987 After an average of 21 years9 follow up, a total of 1449 (73%) participants aged 65–79 took part in the re-examination in 1998 Main outcome measures: Midlife blood pressure and cholesterol concentrations and development of Alzheimer9s disease in later life Results: People with raised systolic blood pressure (≥160 mm Hg) or high serum cholesterol concentration (≥65 mmol/l) in midlife had a significantly higher risk of Alzheimer9s disease in later life, even after adjustment for age, body mass index, education, vascular events, smoking status, and alcohol consumption, than those with normal systolic blood pressure (odds ratio 23, 95% confidence interval 10 to 55) or serum cholesterol (odds ratio 21, 10 to 44) Participants with both of these risk factors in midlife had a significantly higher risk of developing Alzheimer9s disease than those with either of the risk factors alone (odds ratio 35, 16 to 79) Diastolic blood pressure in midlife had no significant effect on the risk of Alzheimer9s disease Conclusion: Raised systolic blood pressure and high serum cholesterol concentration, and in particular the combination of these risks, in midlife increase the risk of Alzheimer9s disease in later life What is already known on this topic Vascular risk factors may play an important part as risk factors for Alzheimer9s disease No population based studies have evaluated prospectively the impact of both midlife blood pressure and cholesterol concentration in both men and women on the subsequent development of Alzheimer9s disease What this study adds Raised systolic blood pressure and high serum cholesterol concentration, and in particular the combination of these risks, in midlife increased the risk of Alzheimer9s disease in later life Raised systolic blood pressure and hypercholesterolaemia may have a role in the pathogenesis of Alzheimer9s disease; more emphasis should be placed on identification and appropriate treatment of these conditions

https://www.bmj.com/content/bmj/322/7300/1447.full.pdf

Midlife vascular risk factors and Alzheimer's disease in later life: longitudinal, population based study.

Magnetic resonance imaging (MRI) has shown a great reduction in medial temporal lobe and hippocampal volume of patients with Alzheimer's disease as compared to controls. Quantitative volumetric measurements are not yet available for routine clinical use. We investigated whether visual assessment of medial temporal lobe atrophy (MTA) on plain MRI films could distinguish patients with Alzheimer's disease (n = 21) from age matched controls (n = 21). The degree of MTA was ascertained with a ranking procedure and validated by linear measurements of the medial temporal lobe including the hippocampal formation and surrounding spaces occupied by cerebrospinal fluid. Patients with Alzheimer's disease showed a significantly higher degree of subjectively assessed MTA than controls (p = 0.0005). Linear measurements correlated highly with subjective assessment of MTA and also showed significant differences between groups. Ventricular indices did not differ significantly between groups. In Alzheimer's disease patients the degree of MTA correlated significantly with scores on the mini-mental state examination and memory tests, but poorly with mental speed tests. This study shows that MTA may be assessed quickly and easily with plain MRI films. MTA shown on MRI strongly supports the clinical diagnosis of Alzheimer's disease, is related to memory function, and seems to occur earlier in the disease process than does generalised brain atrophy.

https://jnnp.bmj.com/content/jnnp/55/10/967.full.pdf

Atrophy of medial temporal lobes on MRI in “probable” Alzheimer's disease and normal ageing: diagnostic value and neuropsychological correlates

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(98)03086-4.pdf

Prevention of dementia in randomised double-blind placebo-controlled Systolic Hypertension in Europe (Syst-Eur) trial.

• Twenty-four patients of comparable age, blood pressure, and degree of dementia were classified by an "Ischemic Score" based on clinical features into "multi-infarct" and "primary degenerative" dementia. Regional cerebral blood flow (CBF) was measured by the intracarotid xenon 133 method. Both groups showed a decreased proportion of rapidly clearing brain tissue (largely gray matter). Cerebral blood flow per 100 gm brain per minute was normal in the primary degenerative group but low in the multi-infarct group. This suggests the blood flow is adequate for metabolic needs of the brain in patients with primary degenerative dementia but inadequate for those with multi-infarct dementia. There was no correlation between degree of dementia and CBF in the primary degenerative group but an inverse relationship existed in the multi-infarct group. Reactivity of blood vessels to reduction of arterial carbon dioxide pressure was normal in both groups.

E. Zilhka

Papers

Cerebral blood flow in dementia.