Role of stroke in dementia

Epidemiology of clinically diagnosed Alzheimer's disease

This report reviews the current status of descriptive and analytic epidemiology of clinically diagnosed Alzheimer's disease (AD). Since AD can be diagnosed with certainty only at autopsy, currently available epidemiological data are based on a presumed clinical diagnosis. Current data indicate that AD represents a major health problem, at least in the developed countries. The prevalence ratio for AD ranges between 1.9 and 5.8 cases per 100 population aged 65 and over. Moreover, its prevalence is likely to increase in the next twenty years as a consequence of current demographic trends. The prevalence ratio for AD increases steeply with age and is higher in females. Incidence rates show a similar pattern, suggesting that AD should not be subdivided in a presenile and a senile form based on age of onset alone. Annual incidence rates of 2.4 cases per 100,000 population between ages 40 and 60, and 127 cases per 100,000 population after age 60 have been reported. Several case-control studies show that the occurrence of either dementia or Down's syndrome in other family members, advanced age of the mother at subject's birth, and head injury are possible risk factors.

Validity of clinical diagnosis in dementia: a prospective clinicopathological study

With neuropathological diagnosis as the point of reference, the accuracy of clinical diagnosis was studied in a series of 58 demented patients. Alzheimer's disease and multi-infarct dementia were recognised with sensitivities and specificities exceeding 70%, whereas combined dementia as a separate group was relatively unreliably diagnosed. The value of Hachinski's Ischaemic Score in differentiating between Alzheimer's disease and vascular dementias was demonstrated. Its performance was to some extent improved by assigning new weights to the items. In a logistic regression model, fluctuating course, nocturnal confusion, and focal neurological symptoms emerged as features with the best discriminating value, and helped to diagnose correctly 89% of the Alzheimer and 71% of the vascular dementia patients.

Cerebrovascular disease in dementia: the importance of atrial fibrillation

The relationship between cardiovascular disease and cerebral infarction was analysed in a prospectively assessed post mortem series of 48 demented patients. Hypertension was rare in this group of patients whose mean age was 82.7 y. Atrial fibrillation was the most important underlying cardiac abnormality. It is suggested that atrial fibrillation is more important than hypertension in the aetiology of cerebral infarction in the very aged and that this may be relevant to the pathogenesis of cerebrovascular dementia.

Accuracy of clinical diagnosis in primary degenerative dementia: correlation with neuropathological findings

Neuropathological features and causes of death are presented in 27 deceased patients belonging to a prospective series of 71 hospitalised patients with primary degenerative dementia. The clinical criteria for primary degenerative dementia used in the present study were accurate enough to exclude patients with multi-infarct dementia. At necropsy, 82% of the cases had neuropathological changes of Alzheimer's disease. The clinical features of patients with other neuropathological changes are described. The most common immediate cause of death was bronchopneumonia which accounted for 59% of deaths in Alzheimer's disease.

Alzheimer's disease and senile dementia of Alzheimer type. A comparative study

Clinical and neuropsychological findings, EEG, and several blood and CSF parameters were investigated in 36 patients with Alzheimer's disease (AD) and 35 patients with senile dementia of Alzheimer type (SDAT). There were more women among senile patients and more familial cases among presenile patients. The average duration of the symptoms was longer in presenile patients (6.1 years) than in senile patients (3.9 years). This could be due to the lower resistance to the disease process in the senile group. Extrapyramidal signs, especially rigidity, were found in over 60% of all patients and in practically all patients with advanced dementia. Tremor was found in three patients only. Four presenile (11%) and two senile (6%) patients had epileptic seizures. All patients had abnormal EEG recordings, mainly in form of diffuse slowing. A positive correlation was found between the EEG abnormality and the severity of dementia in AD but not in SDAT. However, the difference between the correlation coefficients in AD and SDAT was insignificant. Between EEG and the duration of the disease there was no correlation. EEG was not more abnormal in very severe dementia than in severe dementia. Other findings were similar in AD and SDAT. It is concluded that it is artificial to separate AD and SDAT at the age of 65 and that they clinically compose a single entity. This entity could well be called Alzheimer's disease.

CNS cysticercosis--a problem of differential diagnosis

Although a well-known disease worldwide, cerebral cysticercosis in European countries is a rare event. Due to increased travel to East-Asian and Latin American countries it is possible that the occurrence of brain cysticercosis will become more frequent. These facts should remind us of the possibility of cysticercosis of the nervous system. A case of cerebral and spinal cord cysticercosis is presented, causing symptoms of progressive dementia with ventricular occlusion and hydrocephalus. Differential diagnosis causes a major problem. It is shown that myelography may demonstrate characteristic features of the disease.

Is idiopathic dementia a regional vitamin deficiency state?

We hypothesize that some cases of idiopathic dementia are due to a gradual undernourishment of the brain with water-soluble vitamins. This occurs because the choroid plexus and possibly other transport loci in the central nervous system become unable to transport water-soluble vitamins from blood into the central nervous system in adequate amounts. If this testable hypothesis is correct, direct injections of vitamins into the ventricular cerebrospinal fluid should ameliorate the development of dementia.