Aphasia

Definitions of aphasia

There are many definitions about aphasia. • Darley, Aronson & Brown (1975) assert that ‘aphasia is a multi-

modality reduction in the capacity to decode and encode meaningful linguistic elements’.

• Kertesz (1985) defined ‘aphasia as an acquired loss of language due to cerebral damage, characterized by errors in speech, impaired comprehension, and word-finding difficulties’.(Benson & Ardila, 1996)

• Finally, aphasia has arisen by brain damage which causes language disorders. It is associated with an amount of deficits in language comprehension and production. (Gazzaniga et al, 1998)

• The term aphasia can be called sometimes dysphasia. (Smyth et al, 1996)

Characteristics

Some of the general characteristics of aphasia are the following:

• Lack of understanding• Lack of producing spoken language (e.g.

conversations)• Reading & writing problemsFinally, aphasia seems to has direct impact on

personal relationships, employment, and social rehabilitation. (Townend et al, 2007)

Etiology

• Seizure disorders (Landav-Kleffner syndrome)• Vascular disorders (ischemic stroke/hemorrhagic

stroke)• Traumatic disorders (head injury)• Brain tumors• Cancer treatments (radiotherapy/chemotherapy)• Infectious conditions (viral, bacterial microorganisms)• Hypoxic disorders (anoxia)• Metabolic disorders (Farah & Feinberg, 2000).

Types of aphasia

• Broca• Wernicke• Conduction• Global• Transcortical motor• Transcortical sensory• Mixed transcortical• Anomic striatocapsular• Thalamic (Biller, 2008)

Diagnosis of aphasia

Many tools can be used for diagnosis of aphasia :• Boston Diagnostic aphasia examination• Western Aphasia battery• Aphasia Diagnostic profiles• Examining of aphasia• Aphasia language Performance Scale• Sklar Aphasia Scale• Bedside Evaluation & Screening test of aphasia• Minnesota test for the differentical diagnosis of

aphasia (Johnson, 2007)

Study on aphasia

• Miceli et al (2004) in order to understand the association between phonological & morphological procedure, they investigated in depth the continual performance of 26 members.

• They appeared morphological errors in a specific screening battery of aphasia.

• The relation between morphological & phonological errors is incoherent.

• The members who made morphological errors also made phonological, whereas some aphasics who made phonological errors did not produce morphological.

Broca’s aphasia

During 19th century phrenologists found out that specific brain injuries are possible to cause specific functional damages (Gazzaniga et al, 1998).

A main separation has been done between Broca’s and Wernicke’s aphasia.

Broca’s aphasia

• Broca’s aphasia is also known as expressive aphasia.• It was found out by the French surgeon Paul Broca in

1861.• Broca examined patients after a stroke, who were not

often capable to express themselves by more than a word at a time.

• Although, nouns & verbs were usually pronounced, they had difficulty in articles, conjunctions & agrammatical inflections. (Canoll, 1999)

Broca’s aphasia• Broca’s area in the left frontal region is

very near to that part of the motor strip that controls the tongue & lips and damage to Broca’s area cause the aphasic syndrome, called Broca’s aphasia. (Gleason, 1997)

• It has been known that Broca’s aphasia is caused by damage in Broca’s area, while Mohr has indicated that damage constrained to the Broca’s area produce only transient language disorders. Broca’s aphasia follows larger damages involving Broca’s area (Gianfranco, 1998).

• However the question whether there is a correlation between Broca’s aphasia & Broca’s area is still ambiguous (Gazzaniga et al, 1998).

Broca’s aphasia

Some distinctive characteristics of Broca’s aphasia are:

i. Broca’s aphasics encounter speaking problems such as pauses & slips of the tongue.

ii. They have difficulty in words, such as “a, the , of”’.iii. They make ungrammatical sentences.iv. They have difficulty in using syntactic informationv. Good comprehension (Hunt & Ellis, 1999,

Gleason, 1997).

Studies on broca’s aphasia• Braber et al (2005) based on previous research of Bird et al, examined

10 non-fluent aphasic patients.• The main purpose was to use a large framework of errors caused by

the aphasics in skills such as reading, repetition & sentence completions for regular & irregular verbs.

• The aim was to expand their comprehension of the association between morphological & phonological impairments.

• The patients were administered with 3 different tasks related to speech: single world reading, immediate repetition & sentence completion.

• The central phonological deficits of patient were direct affected by the big amount of errors in repetition, reading & sentence completion, it could be ranked as either similar or non similar phonological errors.

• The majority of errors is connected with regular past-tenses forms due to a hidden phonological rather than a morphological deficit.

Studies on broca’s aphasia• Researchers tested the understanding of complementizers such as

that & if and verb inflections by English agrammatic broca’s aphasics speakers.

• The study involved 2 experiments. In the 1st experiment members heard clause sentences, while in the 2nd experiment they heard sentences with finite auxiliaries & sentences with finite verbs & control sentences with uninflected verbs.

• According to the results there is a separation in the classes of functional morphology. Grammaticality assessment for complementizers is relatively spared.

• The perception of verbal inflection is more influenced. • The specific results confirm previous surveys & show that the

patients with agrammatic broca’s aphasia incline to some but not all kinds of syntactic structure. (Dickey et al 2005)

Wernicke’s aphasia

• Another type of aphasia is Wernicke’s aphasia which is a result from injury to an area in the temporal lobe in the left hemisphere (Best, 1999).

• Another name of Wernicke’s aphasia is receptive aphasia (Canoll, 1999).

Wernicke’s aphasia

Some of characteristics are the below:i. Fluent , rapid speechii. Well-structured syntaxiii. Function wordsiv. Articulatory problemsv. Prosodic difficultiesvi. Repetition problemsvii. Comprehension is poorviii. Word-finding problemsix. Paragrammatic errors (Field, 2003, Yudofsky & Hales,

2004, Harley, 1996, Gleason, 1997)

Study• A study conducted by Nakano & Blumstein (2004) examined how normal people

& broca’s & wernicke’s aphasics unite thematic information increasingly using syntax, lexical-semantics & pragmatics in an active declarative sentence.

• 3 experiments were carried out with the use of an auditory lexical decision task in which members made a lexical decision on a “target” prefaced by a prime.

• Normal participants appeared evidence for connective thematics important & larger percentage of thematic priming.

• Also, they appeared inclination to both syntactic structures & pragmatics.• Although, broca’s aphasics didn’t appear important priming for any situation nor

did they appear similarity in the magnitude of priming among the conditions, nonetheless they showed sensitivity to pragmatics.

• Wernicke’s patients tend to show substantial priming for all conditions, but did not appear differences in the magnitude of priming among the conditions.

• Also, they showed tendency to sentence grammaticality & pragmatics.

Conduction aphasia

• Conduction aphasia is caused by lesions in either the superior temporal or inferior parietal areas (Bradley, 2003).

Conduction aphasia

Patients with conduction aphasia disorder have:

1. Inability to repeat

2. Normal speech comprehension & production

Aphasics people have the aknowledgement that they have language problems & will try to correct their errors (Emilier et al, 2004, Martin, 2006)

Studies on conduction aphasia• Balasubramanian (2005) examines the word level writing in 2

conduction aphasics and tries to explore the parallel association between speech production deficits and deficits in written expression.

• They were a 66-year-old female with left posterior parietal lobe lesion & a 65-year-old female with a left posterior temporo-parietal lobe lesion.

• Both cases were examined by Boston Naming Test (BNT) & written naming task (JHDB).

• Both patients have appeared phonological & semantic paraphasias on BNT,although a 65-year-old woman had better performance than that of 66-year-old woman.

• 66-year-old female appeared many reactions to stimuli compared to 65-year-old female.

• 65-year-old woman’s performance on the written naming task was worst to that of 66-year-old woman.

Studies on conduction aphasia

• Hickok et al (2000) tested the hypothesis that at least 1 form of conduction aphasia is caused from damage to cortical fields in the left posterior superior temporal gyrus, which is involved not only in speech perception, but also in phonemic aspects of speech production.

• The researchers conducted 4T fMRI in which members named visually presented objects sub-vocally.

• The results indicate that the majority of participants appeared activation in 2 regions on the dorsal portion of the left posterior superior temporal gyrus.

ReferencesBalasubramanian. V. (2005). Dysgraphia in two forms of conduction aphasia. Brain and

cognition, 57, 8-15.Benso. D. F. & Ardila. A. (1996). Aphasia: A clinical perspective. UK: Oxford University

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in Broca’s aphasia: Further evidence from errors in verb inflection. Brain and language, 92, 278-287

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aphasia. Brain and Language, 95, 82-83Emilier. G.et al. (2004). Memory: neuropsychological, imaging and psychopharmacological

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