The Effects of Alzheimer's Disease on Language

Table of Contents

1. Introduction

2. The Alzheimer's Disease – A medical overview
2.1 A short history of Alzheimer’s Disease
2.2 Impairments of body and brain due to A.D
2.3 The different stages of A.D

3. The effects of A.D. on language
3.1 Writing Impairments
3.2 Semantic/Vocabulary Impairments
3.3 Comprehension and Production Impairments
3.4 Naming Impairments (Anomia)
3.5 Intrusion Impairments
3.6 Impairments of Grammar and Syntax
3.7 Pragmatic Impairments

4. Conclusion

5. Bibliography

1. Introduction

We are living in the 21st century now and mankind has improved in so many ways. We have travelled to the moon several times, invented the internet, cloned animals and, most importantly, found numerous ways to postpone death. But especially this last point has its perfidies according to Emery (1993:221):

„Persons over 65 years of age have increased more than eight fold since 1900, from approximately 3.1 million persons to 26 million in 1980. This represents a rise from 4.1% to 11.3% of the total population (U.S. Department of Health and Human Services, 1984). The U.S. Bureau of Census (1980) projects that the number of persons over age 65 may reach 36.6 million by the year 2000, accouting for 13% of the total population. Further, the proportion of old people who will survive beyond the age of 75, the 'old-old' age stratum, will account for 43.3% of the total aged population in the year 2000. In 1970 and 1940, the figures were 38.2% and 29.5% respectively (Wang, 1977). […] Given the increasing number of older people in our society, understanding the nature and causes of SDAT^[1] must rank high on research priorities.“

Nowadays it is estimated that in 2045, the number of persons over 60 years will surpass, for the first time in history, the number of persons under 15 years of age. These extended lives have their disadvantages, f.ex. as pointed out by Emery before: Alzheimer's Disease.

Alzheimer's Disease (henceforth „A.D.“) is generally diagnosed in people over the age of 65. So when the world populations becomes older and more persons over the age of 65 populate the world, the disease spreads. By 2006, the number of A.D.-patients had already increased to 26.6 millions. This number is assumed to quadruple by 2050.

But an improved A.D.-research would not only help those persons who suffer from it:

„Alzheimer's Disease offers the challenge not only of delineating the writing disturbance of a common neurodegenerative illness but also the opportunity to discern how widespread neocortical deafferentation affects the neurobehavioral underpinnings of a complex cognitive task such as writing.“ (Glossar et al., 2000:78)

Why especially the examination of language in A.D.-patients can promote the general study of language a great deal is also pointed out by Obler et al. (1999:92):

„The language of dementing patients presents a unique opportunity for examining the relationship between language and cognition. The pattern of dissociation of abilities in dementia can yield information regarding the normal relationship – dependence or independence – between language and more general cognitive abilities. […] To study language production and comprehension abilities in dementing patients is to explore the boundaries between syntax and semantics and among semantics, real world knowledge, and reasoning abilites.“

In this termpaper I will show that A.D. has severe effects on the patients’ language and that it is primarily caused by an impaired memory. During the second chapter, I will give a brief overview of the disease in general, i.e. the history of A.D., the insights and damages of A.D.-patients’ brain and body, and the different stages of this disease. Chapter 3 will present a selection of the most common effects of A.D. on language. The fourth chapter will close with a short summary of the termpaper and a conclusion.

2. The Alzheimer’s Disease – a medical overview

In this chapter, I will outline the history of A.D. and how it was discovered. Then, the impairments of the body and the brain due to A.D. will be explained. Finally, the three stages of A.D. with their particular consequences will be illustrated.

2.1 A short history of Alzheimer’s Disease

Auguste D. was the first person to be diagnosed with A.D, although this name had not been invented at that time. In November of 1901, Auguste D. was observed by Alois Alzheimer, a Bavarian neuropsychiatrist. Until her death five years later, Alois Alzheimer reported and described the changes in the behaviour of this mentally ill patient. He found several changes in the patient’s neuropsychology: deterioration of her memory, disorientation and, occasionally, hallucinations. But, as delineated by Gérard Emilien et al. (2004:3), Alois Alzheimer found out even more:

“He also described the ‘miliary foci’ accumulating extracellularly which are known as senile plaques and the ‘dense bundles of fibrils’ occurring intracellularly which are now known as NFTs. These two pathological lesions that he observed upon postmortem examination remein the key diagnostic features of AD today (Alzheimer, 1907).”

The meticulous description of these two lesions was the reason why Emil Kraepelin named the disorder after Alzheimer in 1910.

The origins of A.D. are unknown. But genetic factors play an important role, especially a defective chromosome 21, which is responsible for the familial form of the disease. Other risk factors are old age, environment and metabolic factors, head trauma and myocardial infarction (Emilien et al. 2004).

A.D. is not necessarily a late-onset disease, although this is the most prominent form. However, there are patients from the fourth decade of life up to the age of 60 or 65 with this disease, called early-onset A.D. Due to the fact that the early-onset A.D. often involves afflicted family member and has therefore a genetic background, I will concentrate on the late-onset A.D in this termpaper .

2.2 Impairments of the body and brain due to A.D.

The general effect and definition of dementia is the disturbance in cognition. A.D. is the most common form of dementia and neuropathological changes, mainly in the hippocampus^[2] and entorhinal cortex^[3], are the general characteristics. A.D. leads to a number of progressive changes in memory, orientation, concentration and calculation ability, language abilities, the ability to draw figures and loss of various functional abilities. The progressive decrease of abilities goes even further and includes losses in executive capacities, in the ability to perform basic life activities, and the ability to perform basic life functions. These progressive changes can be distinguished into two clinical domains: a functional and a cognitive domain.While the disease progresses, cognitive deficits become more striking: consequences are remote memory impairment, time/space disorientation and language disturbances. Moreover, emotional changes or behavioural and psychological symptoms become apparent (Emilien et al. 2004).

While people age, the body and also the brain changes. It is normal to detect slowed thinking and problems rembering things. But severe changes as mentioned above are signs for failing brain cells. These cells, or neurons, communicate inside the brain and form networks. There are networks participating in the process of learning, smelling, rembering, muscle-movement etc. As a consequence of A.D., these networks' functionality decreases. Their communication with different networks and other parts of the body worsens and eventually, the networks die (Alzheimer's Association 2008).

2.3 The different stages of A.D.

A.D. is considered to consist of three different stages. But this fact is not undisputed: There are several theories assuming that there are, for instance, six or seven stages. Due to the fact that the three-stages-theory is the more supported and prestigious one, I will only provide an overview of this theory.

The three-stages-theory starts with the first, or mild, stage. This first stage is supposed to last two to four years. During this stage of the disease, loss of energy and spontaneity, minor memory loss and mood swings can be exhibited, as well as slow reaction and slow learning time. The patients become confused, find it difficult to organize and plan things, get lost easily and exercise poor judgment. Therefore, the patients tend to stick with familiar people and places and withdraw from everything new. Even routine tasks such as communicating and understanding writing material can become troublesome for them.

[...]

^[1] SDAT: Senile Dementia Alzheimer's Type

^[2] Hippocampus: belongs to the forebrain which is located in the medial temporal lobe. It is a part of the limbic system and has a major role in short term memory and spatial navigation.

^[3] Entorhinal Cortex: an important memory center in the brain which is responsible for the pre-processing (familiarity) of input signals formed for the hippocampus. In the entorhinal cortex, the association of impulses from the eye to the ear takes place. It has an important role in memory consolidation and memory optimization during sleep.