Senile dementia may be defined as a peculiar state of mental deterioration, with or without delusions, resulting from cerebral lesions determined by senility.

Age is here, therefore, the great etiological factor; it is, however, not the sole factor. Many attain extreme old age without presenting any appreciable intellectual disorders; others, on the contrary, have scarcely passed over the threshold of senility when they are already veritable dements.1 The effects of age are the more powerful and the more precocious the more marked the predisposition. Heredity, the intoxications (alcoholism), overwork, violent and painful emotions, traumatisms, etc., are also given as causes.

Statistics furnish a rather small proportion of congeni-tally predisposed persons among senile dements, but this is perhaps partly due to the fact that it is frequently impossible to obtain reliable family histories in such cases.

Senile dementia is rare before the age of sixty years. Alcoholism sometimes brings about an analogous state of mental deterioration, appearing toward fifty or fifty-five years, which has been designated by the term sceniwn prcecox.2 Such cases are exceptional if we exclude ordinary alcoholic dementia.

1 Russell. Senility and Senile Dementia. Amer. Journ. of Insanity, 1902.

2 Cases essentially of premature senility have been described under the name of Alzheimer's disease. See Alzheimer. Ueber eigenartige

The onset sometimes follows some strong emotional shock, financial troubles, or a somatic affection. Almost always it is insidious, marked simply by a change of disposition and slight disorders of memory. When fully established the dementia presents the following fundamental elements:

(a) Impairment of attention and sluggishness of association of ideas, readily demonstrable by psychometry, as has been shown by the experiments of Rauschburg and Balint.1 (These authors performed their experiments upon cases of simple senile dementia without delusions.) A curious fact observed in these experiments is that associations of ideas were almost always determined by the sense of the words, and rarely by similarities of sound or by rhymes. It will be remembered that associations by similarities of sound are the result of automatic psychic activity; it seems, therefore, that mental automatism, instead of being exaggerated, as it is in certain psychoses (mania), is, like voluntary psychic activity, diminished, at least in simple senile dementia without delusions.

(6) Inaccurate and incomplete perception, the consequence of which is the production of numerous illusions and of disorientation of place.

(c) Disorders of memory, comprising:

(I) Amnesia of fixation (anterograde amnesia), which entails disorientation of time; krankheitsfdlle des spdteren Alters. Zeitschr. f. d. gesamte Neurol, u. Psychiatrie, Vol. IV, p. 365. - Perusini. Ueber klinisch und histolonisch eigenartige psychische Erkrankungen des spdteren Lebensalters. Nissl's Arbeiten, Vol. II, p. 297. - S. C. Fuller. A Study of the Miliary Plaques Found in Brains of the Aged. Amer. Journ. of Ins., Oct., 1911. - S. C. Fuller. Alzheimer's Disease (Senium Prazcox): The Report of a Case and Review of all Published Cases. Journ. of Nerv. and Ment. Dis., Vol. XXXIX, 1912. - S. C. Fuller and H. 1. Klopp. Further Observations on Alzheimer's Disease. Amer. Journ. of Ins., July, 1912. - W. J. Tiffany. The Occurrence of Miliary Plaques in Senile Brains. Amer. Journ. of Ins., Jan., 1914.

1 Ueber qualitative und quantitative, etc. Allgem. Zeitsch. fur Psychiat., 1900.

(II) Amnesia of conservation (retrograde amnesia), which is progressive and which follows almost perfectly the law of retrogression;

(III) Illusions and hallucinations of memory, which form the basis of pseudo-reminiscences, often absurd or puerile in character and varying from one instant to another.

(d) Impoverishment of the stock of ideas: old impressions disappear and are not replaced by new ones. This is the cause of the tiresome repetitions in the discourses of old dotards.

(e) Loss of judgment: the patient does not accept new points of view. He mourns for the good old times and shows a profound contempt for new ideas which he is incapable of assimilating. This contempt for the present is met with in many old people and not necessarily in combination with any appreciable mental deterioration.

The senile dement has no realization of his own condition. Often he boasts of his endurance, strong will, lucid mind, and declares that he is in no need of assistance from anyone and is quite able to manage his own affairs.

(/) Diminution of affectivity, morbid irritability: hence the indifference of senile dements for their relatives and their interests, their unprovoked outbursts of anger, their tyrannical tendencies, and their occasional emotionalism.

(g) Automatic character of reactions: from this point of view senile dements may be divided into two classes: the turbulent and the apathetic.

The turbulent are always moving, intrude everywhere, give unreasonable or contradictory orders, get up during the night and wander about the house with a candle in their hand at the risk of starting a fire. Their mood is either depressed or elated and hypomaniacal. Sexual excitement, most often purely psychic, is quite likely to be associated with this state, and, together with the mental deterioration, leads the patient to dangerous acts: attempts of rape, indecent exposures, etc.

The apathetic senile dements have an indifferent, stupid aspect. The patient's mouth, half open, allows the saliva to dribble; he remains motionless upon the chair where he has been placed; he is docile, obedient, and very suggestible. In the hands of unscrupulous persons he allows himself without protestation to be swindled and maltreated, and unconsciously yields to inveiglements for imprudent disposal of his property.

In advanced stages of the disease turbulent as well as apathetic senile dements frequently become filthy, often soiling and wetting themselves.

Sleep is diminished and often even absent in the excited forms. On the other hand, constant somnolence is frequent in the apathetic cases.

Together with the dementia there are the regular signs of senility. The skin is wrinkled and discolored; the hairy system is undergoing atrophy; the patellar reflexes are sometimes abolished, but more frequently exaggerated; the pupils are slightly myotic and paretic; arcus senilis is well marked; there is hypoaesthesia of all the senses; all movements are awkward and uncertain; there is diminution of the muscular power; senile tremors affect the entire body and especially the head, consisting of coarse oscillations.

The cardio-vascular symptoms are of great importance.

The frequent association of senile dementia with arteriosclerosis has already been mentioned. Vascular disease is, however, not invariably present and is often but slight: senile atrophy is a process essentially independent of arteriosclerosis.

The appetite is diminished, or, on the contrary, it may be exaggerated to a degree constituting voracity. In the latter case the patient's diet should be carefully regulated to prevent grave gastro-intestinal disturbances.

Delusional Forms

The delusions bear the stamp of dementia: they are absurd, changeable, and present little or no tendency to systematization. They may be of the following varieties:

(a) Ideas of persecution, which in their mildest form manifest themselves by mere suspiciousness such as is always common in old persons. Their form is varied: ideas of poisoning, theft, jealousy, fear of being killed, etc.

Persecutory ideas are more likely to become systematized than any others, though the systematization is very imperfect; and more likely to be accompanied by hallucinations, chiefly of hearing and vision. Sometimes these delusions appear long before any evidences of dementia, constituting the presenile paranoid state (Prceseniler Beein-trachtigungswahn) of Kraepelin.

(6) Melancholy ideas of all possible types: ideas of self-accusation, of ruin, etc. Ideas of negation are very frequent.

(c) Ideas of grandeur, which are at times absurd, resembling those of general paralytics.

The delusions are associated with a corresponding state of the emotions and of the reactions. Three principal forms of delusional senile dementia may be distinguished:

(1) Persecutory form: ideas of persecution; reactions of self-defense which may at times be violent.

(2) Depressed form: melancholy ideas, psychic pain, depression, anxiety, suicidal ideas.

(3) Maniacal form: euphoria, ideas of grandeur, variable moods, impulsive reactions, sometimes flight of ideas, erotic tendencies, etc.

Senile dementia is sometimes marked by acute attacks characterized by complete disorientation and hallucinations, closely resembling certain phases of general paralysis, but especially delirium tremens (senile delirium). These attacks, usually very brief, terminate either in death or in a return to the previous condition. They may occur in old persons independently of senile dementia (Wernicke).

The principal complications of senile dementia are:

Apoplectic and sometimes epileptic seizures (senile epilepsy), hemiplegia, aphasic phenomena, etc.

Alcoholism in the form of episodic accidents (delirium tremens) or of alcoholic dementia may be associated with senile dementia.

The prognosis is fatal. The affection always follows a progressive course. Remissions are very rare and never complete. Death usually supervenes at the end of from three to five years, as a result of senile cachexia, some intercurrent disease (pneumonia), or apoplexy.

Not all psychoses occurring at an advanced age are senile dementia. Old men present attacks of manic-depressive psychoses, paranoia, and other psychoses which differ in no way from those observed in younger people.1

The diagnosis is based upon the pathognomonic features of the dementia.

Involutional melancholia and manic-depressive psychoses may be distinguished by the absence of mental deterioration, by the preservation of lucidity, and by the intensity of the affective phenomena - psychic pain or euphoria.

General paralysis may be differentiated by the more rapid development of dementia and by its special physical signs.

Alcoholic dementia shows the physical signs of chronic alcoholism: muscular pain, tremors, gastric disorders, etc. Senile dementia and alcoholic dementia may exist together. ' The anatomical lesions arise from a process of wear and atrophy: atheroma of the cerebral arteries, thickening of the meninges, diminution of the weight of the brain, which may sometimes fall below 1000 grams; thinning of the cortex; numerous miliary plaques; diminution of the number of nerve-cells, chromatolysis, pigmentary degeneration, atrophy; disappearance of a large number of tangential fibers.

The treatment, purely symptomatic, consists chiefly in hygienic measures. Commitment is but seldom necessary. The majority of cases are best treated in special asylums for the aged or in private homes.

1 Thivet. Contribution a l'etude de la folie chez les vieillards. These de Paris, 1889. - Regis. Psychoses de la vieillesse. Ann. med. psych., March-April, 1897. - Ritti. Les psychoses de la vieillesse. Congres des mddecins alienistes et neurologistes, 1896.