Conduction aphasia, what are its main characteristics?

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Sherman Hoover

Aphasias are pathological states in which language is altered as a result of brain injury. It is one of the most studied pathologies at the brain level. However, with regard to driving aphasia there is still much to discover.

Broca's aphasia and Wernicke's aphasia are among the most popular and common, and perhaps for this reason the most investigated. Throughout the article we will address the characteristics of conduction aphasia and it will be possible to see how there is still debate about the areas affected at the brain level.

Contents

  • Introduction to conduction aphasia
  • Table of conduction aphasia alterations
    • Expressive language
    • Receptive language
    • Sensory system
    • Motor system
  • Neuroanatomy of conduction aphasia
  • Evaluation and Intervention
    • Evaluation
    • Intervention
      • Substitution techniques
      • Restoration techniques
        • Language comprehension
        • Language expression
        • Other types of expression
    • Final reflection
    • Bibliography

Introduction to conduction aphasia

Conduction aphasia is one of the less common aphasias. According to Pedersen (2004), it affects 6-7% of the population with respect to the rest of aphasias. In this type of aphasia, understanding is preserved but the ability to repeat is impaired. A fluent language is also appreciated but with frequent presence of phonetic paraphasias. A paraphasia consists of the substitution of syllables or words behind in an unintentional way. For example, instead of saying "scissors," the patient might say "iseras.".

"Aphasia is a language disorder acquired as a result of brain damage, which generally compromises all its modalities: expression and comprehension of oral language, writing and reading comprehension". -González and Hornauer-Hughes-

Patients are aware of these phonetic paraphasias and they attempt to correct themselves, known as approach behavior or aiming behavior. Following the previous example: "bise ... tise ... tiselas ... scissors! (Arnedo, Bembibre and Triviño, 2013).

González and Hornauer-Hughes (2014), state that "aphasia can be produced by one of the following causes: cerebrovascular accident (CVA), brain injury (TEC), tumor (TU), infections and neurodegenerative diseases".

Table of conduction aphasia alterations

Below is a summary table of the main conduction aphasia disorders (Arnedo, Bembibre & Triviño, 2013):

Expressive language

  • Conversational language - Fluent but with the presence of paraphasias.
  • Denomination - Altered
  • Repetition- Very altered
  • Reading aloud - Altered
  • Writing - Altered

Receptive language

  • Listening Comprehension - Preserved
  • Reading Comprehension - Preserved

Sensory system

  • Sensitivity - Altered
  • Hemianopia - Absent
  • Agnosia - Absent

Motor system

  • Hemiparesis - Absent or mild
  • Dysarthria - Absent
  • Dysphagia - Absent
  • Apraxia - Ideomotor

Neuroanatomy of conduction aphasia

Scientific research is still looking for the specific injury that causes conduction aphasia. The strongest theory is a disconnection between Broca's area and Wernicke's area due to an arcuate fasciculus injury. However, it is still in full development.

"The role of the arcuate fasciculus can be remarkably more complex than the simple transmission of information between the Wernicke and Broca areas." -Matsumoto-

The main controversy about this theory is that cases of conduction aphasia with damage only to the arch fasciculus have not yet been published, but cases have been described with said lesion without the symptoms of aphasia.

However, Catani and Mesulam (2008) state that there is more and more data on the belonging of the arcuate fascicle to the superior longitudinal fascicle. In this way, it would involve not only the arched fascicle but the surrounding structures. The superior longitudinal fascicle is composed of three perisylvian segments:

  • Inferior beam or direct segment. This is the arched fascicle. Joins the posterior area of ​​the superior temporal gyrus (Wernicke's area) with the inner frontal gyrus (Broca's area).
  • Superior horizontal beam or indirect anterior segment. Joins the inferior parietal cortex with the frontal operculum, with the inferior precrental and frontal gyri.
  • Posterior bundle or posterior indirect segment. Joins the superior temporal gyrus (Wernicke's area) with the inferior parietal cortex.

Another later study by Bernal and Ardila (2009) seems to indicate that the arcuate fascicle connects directly with premotor areas but indirectly with Broca's area through the premotor cortex (involved in language programming).

Despite all the investigations underway to clarify which specific areas are involved in conduction aphasia, there is no doubt that the arcuate fasciculus is an important structure in this pathology.

Evaluation and Intervention

Evaluation

After conducting the initial interview, Aguilar's team (2010) highlights the use of "an evaluation protocol made up of the orientation, language, verbal memory, praxis and gnosia subtests of the Barcelona Integrated Neuropsychological Exploration Program".

Intervention

The main objective is to try to reestablish functional speech. In this case, replacement and restoration techniques are used.

Substitution techniques

The objective of these techniques is to enhance the preserved linguistic abilities. At the same time, any form of communication that may be present is also worked on. The therapist must also teach the patient's environment to communicate correctly and appropriately with him. One of the most important goals is to involve the family in therapy. In this way, the patient is helped to improve communication.

Family stimuli (information with which the patient has been in contact throughout his life) and functional stimuli that are useful to communicate the most basic needs are also used..

Restoration techniques

Among the restoration techniques you can find those that correspond to the compression and expression of language as well as other types of expression. Both in the understanding and expression of language, work is done at the phonological, lexical-semantic and syntactic level.

Language comprehension
  • Phonological level. Phoneme discrimination tasks and minimum pairs of words are worked on.
  • Lexical-semantic level. Word discrimination is worked.
  • Syntactic level. Word-function and word-content discrimination. Order tracking, as well as tasks to answer yes or no.
Language expression
  • Phonological level. Combination of syllables and phonemes, reproduction of phonemes with and without visual support, and phonological dictation.
  • Lexical-semantic level. Reproduction of automatisms and naming by visual and auditory confrontation.
  • Syntactic level. Use of "wildcard" words and circumlocutions.
Other types of expression

Use of gestures and onomatopoeia. For example, the patient chooses an image and must describe it through gestures while emitting an onomatopoeia for the therapist to guess..

Final reflection

Little by little, scientific research provides more data on brain disorders. Data that will serve to improve the quality of life of people affected by these types of pathologies. What is now a challenge, perhaps in a few years will lead to a simpler solution. It is therefore so important to promote research so that it can have an impact on the benefit of all.

Bibliography

  • Aguilar, O., Ramírez, B., Acevedo, J. and Berbeo, M. (2010). Conduction aphasia as a consequence of a left parieto-temporooccipital anaplastic astrocytoma: a case study. Universitas Psychologica, 10 (1), 163-173.
  • Arnedo, M., Bebibre, J. and Triviño, M. (2013). Neuropsychology: Through clinical cases. Madrid: Editorial Médica Panamericana. 
  • Bernal, B, and Ardila, A. (2009). The role of the arcuate fasciculus in conduction aphasia. Brain, 132, 2309-2316.
  • Catani, M, and Mesulam, M. (2008). The arcuate fasciculus and the disconnection theme in language and aphasia: history and current state. Cortex, 44, (8), 953-961.
  • González, V. and Hornauer-Hughes, A. (2014). Aphasia: a clinical perspective. Revista Hospital Clínico Universitario de Chile, 25, 291-308.

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