Language functions are impaired almost from the beginning of certain forms of dementia, the primary progressive aphasias discussed in the following text and in Chap. 38, but fragments of this problem are apparent in nondescript and amnestic forms of dementia as well. Apraxias and agnosias are early and prominent in one special group of degenerative conditions, occurring only later in Alzheimer disease. These defects may alter the performance of the simplest tasks, such as preparing a meal, setting the table, or even using the telephone or a knife and fork, dressing, or walking.
Furthermore, several clinical variants of dementia in which memory is relatively spared have long been recognized, and in recent years three of them—frontotemporal dementia (Pick disease), primary progressive aphasia, and semantic dementia—have been subsumed under the summary term frontotemporal lobar degeneration. Several consensus statements on the clinical diagnostic criteria for these syndromes have been published, although not all writings on this subject are in agreement (see Morris).
Lost in some aphasic cases is the capacity to understand nuances of the spoken and written word, as are the suppleness and spontaneity of verbal expression. Or, vocabulary becomes restricted and conversation may become rambling and repetitious. The patient gropes for proper names and common nouns and no longer formulates ideas with well-constructed phrases or sentences. Instead, there is a tendency to resort to clichés, stereotyped phrases, and exclamations, which hide the underlying defect during conversation. Paraphasias and difficulty in comprehending complex conversations later become prominent. Subsequently, more severe degrees of aphasia, dysarthria, palilalia, and echolalia may be added to the clinical picture. As pointed out by Chapman and Wolff, there may be loss also of the capacity to express feelings, to suppress impulses, and to tolerate frustration and restrictions.
A common clinical syndrome in this group is characterized by features that would be expected of degeneration of the frontal lobes: early personality changes, particularly apathy or disinhibition, euphoria, perseveration in motor and cognitive tasks, ritualistic and repetitive behaviors, and laconic speech leading to mutism—all with relative preservation of memory, orientation, and visuospatial capability. With anterior temporal lobe involvement, hyperorality, excessive smoking, or overeating occur, and there may be added anxiety, depression, and anomia.
In the advanced stages of some dementias, restraining the patient leads to disagreeable behavior, petulance, agitation, shouting, and whining. Well known to physicians is nighttime confusion and inversion of the normal sleep pattern, as well as increased confusion and restlessness in the early evening (“sundowning”), as described in Chap. 19. Any febrile illness, drug intoxication, anesthesia, surgery, or metabolic upset is poorly tolerated, leading to severe confusion and even stupor—an indication of the precarious state of cerebral compensation.
It would be an error to think that the abnormalities in the degenerative dementing diseases are confined to the intellectual sphere. In advancing stages, the patient’s appearance and the physical examination yield highly informative data. The first impression is often revealing; the patient may be unkempt and unbathed. He may look bewildered, as though lost, or his expression may be vacant, and he does not maintain a lively interest or participate in the interview. There is a kind of psychic inertia. Movements may be slightly slow, sometimes suggesting an oncoming parkinsonian syndrome.