Kraepelin himself seems to be very uncertain as to the significance and the delimitation of these various presenile forms. It must be confessed that some of the types described very strongly suggest the condition formerly looked upon by him as involutional melancholia. It will be noted that he considers as possible etiological factors the disturbance of metabolism which may result from regressive or involutional processes. The differentiation from manic-depressive forms, from arteriosclerotic disorders and from senile psychoses must also be looked upon as presenting some difficulties which cannot be entirely disregarded. Many possibilities suggest themselves.
In the senile deteriorations Kraepelin notes particularly a loss in the capacity of apprehension and perception, with a sluggishness of the train of thought, a dulling of the emotions, a reduction of energy and the development of conduct disorders. Ranschburg in psychological tests noticed a lengthening of the reaction time, with a delay in the choice of action, the reading of words, the performance of addition, and the formation of judgment. The retardation was shown particularly in psychic processes and the association time. The reactions were, moreover, much more monotonous, irregular and unreliable than in the young. Memory tests also showed poor associations.
The most advanced form Kraepelin describes as senile dementia, a progressive mental enfeeblement in which the loss of apprehension and memory becomes a conspicuous feature. The perception of external impressions is diminished and delayed and there is a profound disorder of attention. Memory of the remote past is much better than it is for current events. Retrospective falsification is a common symptom. The patient is, moreover, unable to change old viewpoints or acquire new ones. Delusional manifestations such as childish egotism, foolish suspicions or notions of impending illness develop. Grandiose ideas often occur, delusions of great wealth being common. These symptoms are transitory and come and go without apparent reason. In some cases the hallucinations resemble those found in the alcoholic psychoses. Sooner or later there is a disturbance of consciousness leading to a dreamlike existence suggesting a delirium. There is a noticeable dulling of the emotional feelings. The patients become indifferent and apathetic, losing interest in their surroundings, and are often irritable and excitable. In a certain number of cases depressive states develop, sometimes with suicidal tendencies. The delusions may be hypochondriacal or nihilistic in character. Complaints of persecution are common. Some of the patients show a simple, childish deterioration with seclusive tendencies. Stuporous or cataleptic states may develop. Others become uneasy, wander in the streets, remove their clothes, collect rubbish, or show sexual excitement. Restlessness at night is especially suggestive.
Delirious excited states ("Senile Delirium") characterized a certain number of Kraepelin's cases. In these, clouding of consciousness is marked. The presbyophrenic complex described by Kahlbaum often occurs. These cases are fairly clear mentally at first, as far as their surroundings are concerned, but show memory disturbances, particularly for recent events. Orientation is lost very soon and they fail to recognize old friends and relatives. Fabrications are resorted to for the purpose of remedying these defects of memory and delusions are very common. Nevertheless, judgment about many things is well retained. In some instances, however, orientation for time, place and person is completely lost. Kraepelin is in doubt as to whether presbyophrenia should be looked upon as constituting a definite entity or only a form of senile insanity. It may last for years or terminate in a marked deterioration. In some of the senile cases arteriosclerotic changes in the cortex are very pronounced. This is more noticeable in the depressive and anxious forms and in the incoherent varieties. These individuals become clouded, incoherent, and deteriorate rapidly.
There is also a characteristic paranoid form of senile psychosis. Delusions of suspicion and jealousy are common in these cases. They usually develop persecutory trends and often exhibit hallucinations of hearing. They sometimes show partial disorientation and gaps in the memory. The mood is usually irritable and often anxious. There is very likely to be a disturbance of sleep and often signs of physical enfeeblement. There may be neurological symptoms caused by the arteriosclerotic complications, such as headache, pupillary changes, tremors of the tongue and disturbance of the reflexes. Tremors are also shown in the writing. Paraphasia occurs and there may be sensory aphasia or apraxia.
In severe cases of senile dementia Kraepelin expects to find definite lesions at autopsy. The brain weight is always decreased, sometimes to a very striking degree. The volume of the brain is reduced and the ventricles enlarged. The cortex is diminished in thickness, the frontal region being most affected. The parietal region may be involved, but not to any such extent as in general paresis. There may be localized areas of atrophy. Pachymeningitis and hemorrhagic membranes are often found. The microscope shows a proliferation of the glia cells and there is often some disturbance of the layering of the cortex. Cell alterations appear, with fatty degeneration, some neurones showing little more than a darkly colored nucleus. The glia cells are enlarged. There should be no marked changes in the vessels. Fatty changes in the ganglion cells are very noticeable. There is also some loss in the tangential fibres.
Quite characteristic of the senile brain is the occurrence of the miliary plaques or "drusen" described by Redlich in 1898. Fischer in 1907 reached the conclusion that these "drusen" were pathognomonic of presbyophrenia, as he did not find them in senile dementia, in other psychoses or in normal brains. Hübner, however, noted them in alcoholics and "circular" cases as well as in normal individuals. Oppenheim also found them in the brains of the aged when no psychoses were observed. The interior of the plaque is a homogeneous, dark-staining, structureless mass. Sometimes there is a clear space around this center, with club- or spindle-shaped bodies in the periphery, representing remnants probably of neurones, glia cells or axis cylinders. The whole structure is encapsulated in glia fibres. These so-called plaques were spoken of by Fischer as "miliare Nekrosen" and by Redlich as "miliare Sclerosen." Kraepelin is of the opinion that they are associated either with senile cases showing arteriosclerotic changes or presbyophrenia. Alzheimer has described a senile atrophy of the brain with wedgeshaped areas showing cell loss. This is due to a gradual occlusion of the smaller vessels extending down from the meninges into the cortex, and may result in a hemorrhage, a softening or merely an atrophic area characterized by an absence of ganglion cells. He has also described another group of cases showing characteristic cell changes.
This condition has been given the name "Alzheimer's disease" by Kraepelin.[160] It is marked clinically by a gradual senile deterioration with organic brain changes. These eases show some thought defect, loss of memory, confusion, and clouding. Later they become restless, talkative, sing and laugh, etc. Aphasic disturbances develop early, with paraphasia or apraxia. There are speech disturbances ending in a senseless jargon and writing becomes impossible. An advanced deterioration ensues. Physically there is a general weakness and uncertain gait, sometimes with epileptiform attacks. The pupillary reaction may be lost and evidences of arteriosclerosis usually appear. The disease may last for many years. At autopsy "drusen" are common in the cortex and almost a third of the nerve cells are found to be destroyed. These are replaced by darkly-staining fibril bundles. There is marked neuroglia reaction, particularly around the "drusen" and retrogressive changes are found in the vessel walls. This disease usually appears about the fortieth year and may be looked upon, Kraepelin says, as a "senium praecox," although its significance is not clear.
He finds the senile psychoses occurring usually between the ages of sixty-five and eighty, although they occasionally appear before sixty. Seven and sixty-seven hundredths per cent of his cases were between sixty and sixty-five years of age; ten per cent between sixty-five and seventy; thirty-five per cent between seventy and seventy-five; 27.8 per cent between seventy-five and eighty; 22.2 per cent between eighty and eighty-five; 10.5 per cent between eighty-five and ninety; and 2.78 per cent were over ninety years of age. Of 183 cases studied, twenty-three per cent were cases of presbyophrenia; sixty-three per cent of simple deterioration; eight per cent of arteriosclerotic origin; and the remainder, of delusional forms. More than half of the cases of presbyophrenia occurred in persons over seventy-five. The paranoid and arteriosclerotic forms occurred in younger individuals. In the alcoholic cases the Korsakow complex was common. The analysis of presenile psychoses made by Kraepelin is, to say the least, exceedingly interesting. Such clear-cut differentiations as he describes are, however, not always possible or necessary. Very few other writers have gone into the question so exhaustively, nor is his classification of these conditions generally accepted. Bleuler[161] in 1918 in discussing the presenile psychoses quotes Kraepelin's classification and also refers to Gaupp's anxious depressive forms. Under the senile deteriorations he describes "dementia senilis" and presbyophrenia. He also calls attention to the fact that Binswanger spoke of a "pre-senile dementia" occurring between the fortieth and fiftieth years of age and characterized by an emotional dulness and a diminished capacity for work. Bleuler speaks of the affective disturbances in advanced years as senile mania and melancholia, which he says may recover, the former frequently, the latter more rarely.
The American Psychiatric Association has only attempted to cover the principal groupings of the characteristic senile forms. The differentiation of these conditions as suggested in the statistical manual is as follows:—