APHASIA

'Aphasia' (or 'aphemia') is a loss of the ability to produce and/or comprehend language, due to injury to brain areas specialized for these functions. It is not a result of deafness or muscle paralysis, and it does not necessarily affect intelligence. Aphasia can be distinguished from dysphasia, the prefix ''a-'' indicating a complete loss, which is a condition usually only seen in adult brain damage, when it is too late in life for the nervous system to make gross adjustments. In contrast, the prefix ''dys-'' indicates a partial loss, which is more common when the dysfunction occurs in children.Robert Graham: ''Reading guide for Kolb & Whishaw,'' East Carolina University, revised 2006, found on: http://core.ecu.edu/psyc/grahamr/DW_3311Site/ReadingGuidesF/KW_19_RG.html
Depending on the area and extent of the damage, someone suffering from aphasia may be able to speak but not write, or vice versa, or display any of a wide variety of other deficiencies in language comprehension and production, such as being able to sing but not speak. Aphasia may co-occur with speech disorders such as dysarthria or apraxia of speech, which also result from brain damage.

Contents

Causes

Prognosis

Diagnosis

Symptoms

Types of aphasia

Classification of aphasia

The locationist model

Fluent, non-fluent and "pure" aphasias

The cognitive neuropsychological model

Primary and secondary aphasia

Famous individuals who suffered from aphasia

See also

Sources

Academic references

Personal experiences of aphasia

References

External links

Causes

Usually, aphasias are a result of damage to the language centres of the brain (like Broca's area). These areas are almost always located in the left hemisphere, and in most people this is where the ability to produce and comprehend language is found. However, in a very small number of people language ability is found in the right hemisphere. In either case, damage to these language areas can be caused by a stroke, traumatic brain injury, or other head injury. Aphasia may also develop slowly, as in the case of a brain tumor or progressive neurological disease.

Prognosis

The brains of young children with brain damage sometimes restructure themselves to use different areas for speech processing, and regain lost function; adult brains are less adaptable and lack this ability.

Diagnosis

Aphasia can be assessed in a variety of ways, from quick clinical screening at the bedside to several-hour-long batteries of tasks that examine the key components of language and communication.

Symptoms

Any of the following can be considered symptoms of aphasia:

★ inability to comprehend language

★ inability to pronounce, not due to muscle paralysis or weakness

★ inability to speak spontaneously

★ inability to form words

★ inability to name objects

★ poor enunciation

★ excessive creation and use of personal neologisms

★ inability to repeat a phrase

★ persistent repetition of phrases

★ paraphasia (substituting letters, syllables or words)

★ agrammatism (inability to speak in a grammatically correct fashion)

★ dysprosody (alterations in inflexion, stress, and rhythm)

★ uncompleted sentences

★ inability to read

★ inability to write

Types of aphasia

The following table summarizes some major characteristics of different types of aphasia:

Type of aphasia	Repetition	Naming	Auditory comprehension	Fluency	Presentation
Wernicke's aphasia	mild–mod	mild–severe	defective	fluent paraphasic	Individuals with Wernicke's aphasia may speak in long sentences that have no meaning, add unnecessary words, and even create new "words" (neologisms). For example, someone with Wernicke's aphasia may say, "You know that smoodle pinkered and that I want to get him round and take care of him like you want before", meaning "The dog needs to go out so I will take him for a walk". Individuals with Wernicke's aphasia usually have great difficulty understanding the speech of both themselves and others and are therefore often unaware of their mistakes.
Transcortical sensory aphasia	good	mod–severe	poor	fluent	Impaired comprehension of speech and writing, but writing, reading aloud and speech spared.
Conduction aphasia	poor	poor	relatively good	fluent	Speech, writing and silent reading intact, but repetition, reading aloud and dictation impaired.
Anomic aphasia	mild	mod–severe	mild	fluent	Anomic aphasia, also called anomia, is essentially a difficulty with naming. The patient may have difficulties naming certain words, linked by their grammatical type (e.g. difficulty naming verbs and not nouns) or by their semantic category (e.g. difficulty naming words relating to photography but nothing else) or a more general naming difficulty. Patients are usually aware and it is comparable to a 'tip of the tongue' sensation experienced by most people.
Broca's aphasia	mod–severe	mod–severe	mild difficulty	non-fluent, effortful, slow	Individuals with Broca's aphasia frequently speak short, meaningful phrases that are produced with great effort. Broca's aphasia is thus characterized as a nonfluent aphasia. Affected people often omit small words such as "is", "and", and "the". For example, a person with Broca's aphasia may say, "Walk dog" meaning, "I will take the dog for a walk". The same sentence could also mean "You take the dog for a walk", or "The dog walked out of the yard", depending on the circumstances. Individuals with Broca's aphasia are able to understand the speech of others to varying degrees. Because of this, they are often aware of their difficulties and can become easily frustrated by their speaking problems.
Transcortical motor aphasia	good	mild–severe	mild	non-fluent	Understanding of speech, writing, repetition and reading intact, but impaired voluntary speech and writing.
Global aphasia	poor	poor	poor	non-fluent	Individuals with global aphasia have severe communication difficulties and will be extremely limited in their ability to speak or comprehend language.
Mixed transcortical aphasia	moderate	poor	poor	non-fluent	-
Mixed	non-fluent	moderate	moderate	mild (worse than Broca’s non-fluent)	-
Alexia	-	-	-	-	Alexia is a severe reading impairment.
Agraphia	-	-	-	-	Agraphia is a severe writing impairment
Pure word deafness	-	-	-	-	Expressive channels intact, but all understanding impaired. Patients can hear the sounds of the words, but they don't understand that these sounds are words and they can't repeat them.Robert Graham: ''Reading guide for Kolb & Whishaw'', East Carolina University, revised 2006, found on: http://core.ecu.edu/psyc/grahamr/DW_3311Site/ReadingGuidesF/KW_19_RG.html Note that pure word deafness is techinally classified as an agnosia rather than as an aphasia per se.

Classification of aphasia

Classifying the different subtypes of aphasia is difficult and has led to disagreements among experts. The locationist model is the original model, but modern anatomical techniques and analyses have shown that precise connections between brain regions and symptom classification don't exist. The neural organization of language is complicated; language is a comprehensive and complex behavior and it makes sense that it isn't the product of some small, circumscribed region of the brain.

No classification of patients in subtypes and groups of subtypes is adequate. Only about 60% of patients will fit in a classification scheme such as fluent/nonfluent/pure aphasias. There is a huge variation among patients with the same diagnosis, and aphasias can be highly selective. For instance, patients with naming deficits (anomic aphasia) might show an inability only for naming buildings, or people, or colors. ^[1]

The locationist model

The locationist model attempts to classify the aphasia by major characteristics and then link these to areas of the brain in which the damage has been caused. The initial two categories here were devised by early neurologists working in the field, namely Paul Broca and Carl Wernicke. Other researchers have added to the model, resulting in it often being referred to as the "Boston-Neoclassical Model". The most prominent writers on this topic have been Howard Goodglass and Edith Kaplan.

★ Individuals with Broca's aphasia (also termed expressive aphasia) were once thought to have ventral temporal damage though more recent work by Nina Dronker using imaging and 'lesion analysis' has revealed that patients with Broca's Aphasia have lesions to the medial insular cortex. Broca missed these lesions because his studies did not disect the brains of diseased patients so only the more temporal damage was visible. Individuals with Broca's aphasia often have right-sided weakness or paralysis of the arm and leg because the frontal lobe is also important for body movement.

★ In contrast to Broca's aphasia, damage to the temporal lobe may result in a fluent aphasia that is called Wernicke's aphasia (also termed sensory aphasia). These individuals usually have no body weakness because their brain injury is not near the parts of the brain that control movement.

★ Working from Wernicke's model of aphasia, Ludwig Lichtheim proposed five other types of aphasia but these were not tested against real patients until modern imaging made more indepth studies available. The other five types of aphasia in the locationist model are:
#Pure word deafness
#Conduction aphasia
#Apraxia of speech, which is now considered a separate disorder in itself.
#Transcortical motor aphasia
#Transcortical sensory aphasia

★ Anomia is another type of aphasia proposed under what is commonly known as the Boston-Neoclassical model, which is essentially a difficulty with naming. A final type of aphasia, global aphasia, results from damage to extensive portions of the language areas of the brain.

Fluent, non-fluent and "pure" aphasias

The different types of aphasia can be divided into three categories: fluent, non-fluent and "pure" aphasias.^[2]

★ 'Fluent aphasias', also called 'receptive aphasias', are impairments related mostly to the input or reception of language, with difficulties either in auditory verbal comprehension or in the repetition of words, phrases, or sentences spoken by others. Speech is easy and fluent, but there are difficulties related to the output of language as well, such as paraphasia. Examples of fluent aphasias are: Wernicke's aphasia, Transcortical sensory aphasia, Conduction aphasia, Anomic aphasia

★ 'Nonfluent aphasias', also called 'expressive aphasias' are difficulties in articulating, but in most cases there is relatively good auditory verbal comprehension. Examples of nonfluent aphasias are: Broca's aphasia, Transcortical motor aphasia, Global aphasia

★ '"Pure" aphasias' are selective impairments in reading, writing, or the recognition of words. These disorders may be quite selective. For example, a person is able to read but not write, or is able to write but not read. Examples of pure aphasias are: Alexia, Agraphia, Pure word deafness

The cognitive neuropsychological model

The cognitive neuropsychological model builds on cognitive neuropsychology. It assumes that language processing can be broken down into a number of modules, each of which has a specific function. Hence there is a module which recognises phonemes as they are spoken and a module which stores formulated phonemes before they are spoken. Use of this model clinically involves conducting a battery of assessments (usually from the PALPA), each of which tests one or a number of these modules. Once a diagnosis is reached as to where the impairment lies, therapy can proceed to treat the individual module.
A few less common subtypes include:

★ Subcortical motor aphasia

★ Subcortical sensory aphasia

★ Mixed transcortical aphasia

★ Acquired eleptiform aphasia (Landau Kleffner Syndrome)
A combination of subtypes is possible.

Primary and secondary aphasia

Aphasia can be divided into primary and secondary aphasia.^[3]

★ ''Primary aphasia'' is due to problems with language-processing mechanisms.

★ ''Secondary aphasia'' is the result of other problems, like memory impairments, attention disorders, or perceptual problems.

Famous individuals who suffered from aphasia

★ Maurice Ravel

★ Jan Berry of Jan and Dean

★ Sven Nykvist

★ Ralph Waldo Emerson

★ Robert E. Lee

★ Joseph Chaikin

★ Sir John Hale

See also

★ Speech disorder

★ Dysnomia disorder

Sources

Academic references

★ R. Chapey (Ed.) (2001). ''Language Intervention Strategies in Aphasia and Related Neurogenic Communication Disorders'' (Fourth Edition). Philadelphia: Lippincott, Williams & Wilkins.

★ Goodglass, H. & Kaplan, E. (1972). ''Assessment of Aphasia and Related Disorders''. Philadelphia: Lea and Febinger.

★ Kay, J., Lesser, R., & Coltheart, M. (1992). ''Psycholinguistic Assessments of Language Processing in Aphasia (PALPA)''. Hove: Erlbaum.

★ Spreen, O. & Risser, A.H. (2003). ''Assessment of Aphasia''. New York: Oxford University Press.

Personal experiences of aphasia

★ Hale, S (2003), ''The Man Who Lost His Language'', Penguin.

★ Paul E. Berger and Stephanie Mensh, ''How to Conquer the World With One Hand...And an Attitude'', 2nd Ed., ISBN 0-9668378-7-8

★ Cindy Greatrex (2005) ''Aphasia in the Deaf Community''.

★ Dardick, Geeta (1991), Prisoner of Silence, ''Reader's Digest'', June issue

References

1. Kolb & Whishaw: ''Fundamentals of Human Neuropsychology'' (2003), page 502, 505, 511.
2. Kolb & Whishaw: ''Fundamentals of Human Neuropsychology'' (2003), pages 502-504. The whole paragraph "fluent, non-fluent and pure aphasias" is written with help of this reference.
3. http://christofflab.psych.ubc.ca/psych260/docs/L12-Language.pdf

External links

★ American Speech-Language-Hearing Association Description of aphasia and the role of the speech-language pathologist in assessment and treatment.

★ Aphasia Center of California in Oakland, CA, U.S.

★ The Aphasia Institute Pat Arato Aphasia Center

★ NIDCD health information: Aphasia (public domain source)

★ "In So Many Words" Radio documentary broadcast on the Canadian Broadcasting Corporation's "The Sunday Edition" program on Sunday, December 15, 2002

★ "Picturing Aphasia" Documentary film about aphasia that uses drawings to help bridge the gap between hearing, seeing, and comprehending. Directed by Mores McWreath.

★ "Lingraphica" Laptop based speech-generating software designed for adults with aphasia.

★ Description of four types of aphasia: auditory, afferent, efferent, and semantic at University of Washington

★ National Aphasia Association (U.S.)

★ Aphasia Project: Research into assistive devices for people with aphasia (Princeton University)

★ UK Based advice on aphasia and a forum for aphasics