Laboratory Diagnosis in Neurology, 1 Ed.

11 Dementia and Other Psychiatric Disorders

M. Otto, M. Uhr

Dementia is the secondary loss of cognitive abilities. It may be the symptom of a great variety of neurological and psychiatric disorders.

Diagnostic criteria. The diagnostic criteria of dementia include memory impairment, personality changes, and impairment of abstract thinking, judgment, and speech as well as of the recognition and perception of reality. Focal neurological signs are usually absent in the early stages of developing dementia. If they do occur, they provide valuable clues for the differential diagnosis.

Cause-oriented differential diagnosis. Dementia can be subdivided into degenerative diseases of the nervous system, cerebrovascular diseases, infectious dementia, metabolic disorders involving the brain, endocrine dysfunction and deficiencies, toxic dementia, hydrocephalus, and trauma (Table 11.1). Neoplasia and demyelinating diseases (e. g., multiple sclerosis) can also cause dementia syndromes.

This chapter discusses Alzheimer's disease, multi-infarct dementia, Lewy body dementia, frontotemporal lobar degeneration, multiple system atrophy, and Creutzfeldt-Jakob disease (Table 11.2). The example of Creutzfeldt-Jakob disease has shown how, with concerted action, clinical, laboratory, and neuropathologic criteria that allow an early diagnosis can be established within a few years. Diseases that are not neurodegenerative but nevertheless cause dementia syndromes are also listed in Table 11.2. These diseases can mostly be excluded quite simply (Table 11.3).