In order to decide how the sense of "self" of an AD patient is affected by the disease, it is necessary to decide what constitutes personality. In this discussion, the set of behaviors that an individual associates with the self of that individual will be considered as expressions of the personality of the individual. There is strong support for the idea that personality is controlled by the functions of the central nervous system (CNS) (2). The specific area(s) of the CNS that controls the "self" can be labeled the I-function (2). An examination of the sense of "self" of a paraplegic suggests that the I-function may be specifically related to the functions of the brain, however, other areas of the CNS may still be involved with the I-function (2).
The study of the effects of Alzheimer's disease on the personality of AD patients suggests that the notion of an I-function within the brain regulating personality is quite reasonable. Alzheimer's disease causes the death of large numbers of brain cells over a period of time; this results in the mental deterioration, dementia, and eventual death of the afflicted individual (1). The symptoms include the loss of short-term memory, loss of long-term memory, difficulty with abstract thinking, impaired social and language skills, and personality changes (3). The personality changes can be alarming. A gentle, artistic mother can suddenly exhibit violent behavior (4). AD patients, often inappropriately, may also exhibit hypersexuality (5). Increased apathy, social reclusion, erratic moods, paranoia, and other general personality changes may also result from the onset of AD (6). These personality changes, and other symptoms of AD, can all be linked to the gradual degeneration of the patient's brain. As the brain deteriorates, so do the functions controlled by the brain, such as spatial orientation, bladder control, and personality. Linking personality to the functions of the brain raises the question of whether deterioration of the brain due to Alzheimer's disease changes the "self" of an AD patient with respect to the disease. Although it is hard to make concrete judgements, logically it is possible to consider the "self" unchanged. As an individual progresses from infant to adult, that individual is still considered to be the same person. Yet a great many changes have gone on in the brain of that person, corresponding to a gradual change in personality. These changes are normally due to education and experience, and the personality associated with the adult is assumed to be a mature version of the personality of the infant. Therefore, both the infant and the adult are considered the same "self". Alzheimer's disease seems to act in a similar manner, only in reverse order. An AD patient loses basic abilities in a similar order to that in which the abilities were learned: handling finances, choosing clothes, bathing oneself, control over bodily functions, feeding oneself, speech, the capacity to walk, and even the capacity to sit up (6). The effect of AD on the brain seems to be the opposite of the effect of learning on the brain. As a young child acquires knowledge, the amount and specificity of the neural connections of the brain are increased (7). As a result the depth and character of the young child's personality changes. Similarly, as the brain of an individual afflicted with AD deteriorates, their personality deteriorates as well.
This deterioration is not solely found in AD patients, although it is heightened and accelerated in them. Normal aging bears a significant resemblance to dementia, which is what makes diagnosing Alzheimer's disease so difficult (6). The impairment of memory, vision, spatial capacity, attention span, language skills and other symptoms of AD are all also side effects of the normal aging process (6). If the sense of "self" of an individual remains constant during the generative processes of learning in the brain, then the sense of "self" should also remain constant during the degenerative processes of AD, and normal aging, in the brain. Young children often say and do certain things that are inappropriate, such as throwing temper tantrums over minor disappointments. The ability to discern appropriate behavior is acquired. Similarly, individuals with Alzheimer's disease may exhibit inappropriate behavior, such as severe emotional reactions to minor irritations (6). Some behaviors exhibited by AD patients, however, seem out of character for the individual irrespective of the maturity or immaturity of their personality. The onset of Alzheimer's disease causes the sufferer's perception and understanding of reality to be distorted, which may explain apparently uncharacteristic behavior. An AD patient may be forced to react to reality, as they understand it (8). The son of an AD patient understood his mother's behavior as a problem of differing realities, "...I often felt [the uncharacteristic violence] was a response to what she perceived as reality, e.g., can you imaging how the sufferer feels when they are stripped and placed in water...they may have no perception of why, we understand it is a bath...we know why...they no longer understand...in my mother's case I often felt this was her response to what she felt was a threat" (4). The exhibited behavior of an AD patient may not be uncharacteristic if the reality the patient believes he or she is responding to is understood.
This also leaves open the possibility that personality may be influenced by more than simply the brain. The brain may be the mechanism through which the personality expresses itself, but not the sole influence on personality. Without the cooperation of the brain in expression of personality, it is difficult to ascertain the existence of personality in the absence of the brain. Other areas of the CNS may play a vital role in an individual's personality but are unable to communicate this role. Or the "self" associated with an individual may not depend solely on the CNS at all. "Memories in the Making", a collection of paintings by AD sufferers which is sponsored by the Alzheimer's Association of Orange County seeks to allow sufferers to express their personality through art (9). Selly Jenny, who produces the art exhibit, believes that AD patients actually do manage to express some aspect of their personality through their artwork (9). It is not clear whether the patients still have personalities to express through art simply because their brains have not deteriorated enough, or whether the personality of an AD patient can exist, to some extent, independently from the brain.
(1) FACT SHEET: ALZHEIMER'S DISEASE
(2) Grobstein, Paul. Lecture-Neurobiology and Behavior. Bryn Mawr College. January 29, 1998
(3) DEMENTIA (ALZHEIMER'S): AMERICAN DESCRIPTION
(6) DEMENTIA (ALZHEIMER'S): MENTAL HEALTH OF THE ELDERLY
(7) Deciphering the Miracles of the Mind , by Robert Lee Hotz of the LA Times
(9) Memories in the Making, a program of creative art expression for Alzheimer patients
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