Later, it becomes evident that the patient is easily distracted by every passing incident. He no longer finds it possible to think about or discuss a problem with customary clarity or to comprehend all aspects of complex situations. The ability to make proper deductions and inferences from given premises are greatly reduced. One feature of a situation or some relatively unimportant event may become a source of unreasonable concern or worry. Tasks that require several steps cannot be accomplished, and all but the simplest directions cannot be followed. The patient may get lost, even along habitual routes of travel. Day-to-day events are not recalled, and perseveration or impersistence in speech, action, and thought becomes evident. Diminished capacity for abstraction, attention, planning, and problem solving may be observed as the degenerative process continues. The last of these is subsumed under the term disorder of “executive functions.”
In yet other instances, an early abnormality may be in the nature of emotional instability, taking the form of unreasonable outbursts of anger, easy tearfulness, or aggressiveness. A change in mood becomes apparent, deviating more toward depression than elation. Apathy is common. Some patients are irascible; a few are cheerful and facetious. The direction of the mood change is said to depend on the patient’s previous personality rather than on the character of the disease, but one can think of glaring exceptions to this statement from clinical experience. Excessive lability of affect may also be observed—for example, easy fluctuation from laughter to tears on slight provocation.
A considerable group of patients come to the physician with physical complaints, the most common being dizziness, a vague mental “fogginess,” and nondescript headaches. The patient’s inability to give a coherent account of his symptoms bears witness to the presence of dementia. Sleep disturbances, especially insomnia, are prominent in some cases and a particular disorder relating to the acting out of dreams during REM sleep marks some of the degenerative dementia. Sometimes the mental failure is brought to light more dramatically by a severe confusional state attending a febrile illness, a concussive head injury, an operative procedure, or the administration of some new medicine, as discussed in the following text and in Chap. 19. As noted there, the family almost uniformly, but mistakenly, dates an abrupt onset of dementia to the time of the intercurrent illness, a fall, or an operation.
Loss of social graces and indifference to social customs may occur, but usually much later in the course of illness. Judgment becomes impaired, early in some, late in others. At certain phases of the illness, suspiciousness or frank paranoia may develop. Although more typical of advanced cases, on occasion the first indication of an oncoming dementia is the expression of paranoia—for example, relating to being robbed by employees or to the infidelity of a spouse. When the patient’s condition is probed by an examination, there are no signs of depression, hallucinations, or illogical ideas, but memory and problem solving are found to be deficient. The troublesome paranoid ideas then persist throughout the illness. Also more typical of late disease but an early feature of certain degenerative dementias, visual and auditory hallucinations, sometimes quite vivid in nature, may be added. Wandering, pacing, and other aimless activities are common in the intermediate stage of the illness, while other patients sit placidly for hours. By this point, these patients have little or no realization of the changes occurring within themselves; that is, they lack insight into the problem.
As the condition progresses, all intellectual faculties become impaired; but in the most common degenerative diseases, as stated earlier, memory is most affected.
Deference to a spouse or child when the patient is unable to answer the examiner’s questions is characteristic. Up to a certain point in the illness, memories of the distant past are relatively well retained at a time when more recently acquired information has been lost (the earlier mentioned Ribot’s law). Eventually, patients also fail to retain remote memories, to recognize their relatives, and even to recall the names of their children.