A clinicopathological study of CT scans in Alzheimer's disease.

OBJECTIVE: To investigate the accuracy of cranial computerized tomography (CT) scans in distinguishing patients with Alzheimer's disease from those with other dementing conditions. DESIGN: Retrospective clinicopathological correlation with pre-mortem CT scans. SETTING: Urban and rural hospitals and nursing homes in the Upper Midwest. PATIENTS: All 507 patients had clinical dementia diagnosed as Alzheimer's disease during life and the subsequent referral of their brains to a dementia brain bank. Of these, 375 patients had had CT scans as part of the diagnostic work-up for dementia. MAIN OUTCOME MEASURES: The presence of neuropathological evidence of Alzheimer's disease and the specific findings on CT scans. RESULTS: Of the 375 patients evaluated with a CT, 28% were misdiagnosed (lacked neuropathological evidence of Alzheimer's disease); of the 132 patients evaluated without a CT scan, only 18% were misdiagnosed (P less than 0.05). The degree of atrophy and other CT findings were similar in the correctly diagnosed and misdiagnosed groups except for increased ventricular size in the correctly diagnosed patients (P less than 0.05). CONCLUSION: Although CT scans do not usually contribute to the recognition of Alzheimer's disease, the presence of ventricular enlargement may help distinguish Alzheimer's disease from other dementias.

Risk factors in Alzheimer's disease: a clinicopathologic study.

We investigated potential risk factors for Alzheimer's disease (AD) in a clinicopathologic study of 407 patients with definite AD, 100 non-Alzheimer dementia patients, and 50 normal subjects. The AD patients had more first-degree relatives with dementia than the non-AD dementia group (odds ratio of 1.85, 95% confidence interval of 1.07-3.20) or the normal elderly (odds ratio of 3.60, 95% confidence interval of 1.50-8.64) but did not have significantly more head injuries, medical and psychiatric illnesses, or relatives with Down's syndrome. The AD patients with a family history of dementia had their dementia at a later age than those without an affected relative. These findings indicate a familial risk for AD that is greater than for other dementing illnesses and has age-related penetrance. This study does not support other putative risk factors for AD such as head trauma and familial Down's syndrome.

Dementia presenting with aphasia: clinical characteristics.

Dementia, a disorder of multiple cognitive functions, may atypically present as an aphasia. The clinical characteristics are reported of 13 patients with up to 14 years of progressive language impairment before developing dementia. In reviewing the literature, it was found that these patients were similar to those reported with progressive aphasia. It is concluded that dementia may present with an anomic, dysfluent language disorder due to the focal left sylvian onset of several dementing illnesses.

Neuropathologically confirmed Alzheimer's disease: clinical diagnoses in 394 cases.

In the absence of pathognomonic clinical features, the clinical diagnosis of Alzheimer's disease (AD) remains one of exclusion of other dementias. We investigated the clinical diagnoses among 394 neuropathologically confirmed AD cases in a dementia brain bank. Most patients were correctly diagnosed as AD (348 or 88%). Among the misdiagnosed patients, AD was mistaken for a primary depressive disorder in 14, multi-infarct dementia in 13, Parkinson's disease in nine, and alcoholic dementia in four. The number of misdiagnosed AD patients did not differ between physician specialties but was greater among AD patients with agitation, depression, paranoia, or delusions. This retrospective study suggests that the diagnostic sensitivity for AD is high among a cross-section of practicing physicians and that an important factor in mistaking AD for another illness is unfamiliarity with the potential psychiatric symptoms of AD.