'Through the Looking-Glass' - Catch a Glimpse of Aphasiology

Aphasia has been in the focus of neurolinguistics, psycholinguistics, sociolinguistics and a great number of other fields of research in the past decades. It is a term used for linguistic disorders caused by damage in a specific area of the brain where language is primarily affected (Crystal, 1980, p. 140). The vast range of research provides valuable information about the role of linguistic and communicative functions in the brain. Moreover, due to the enormous amount of studies new intervention techniques are emerging in order to help patients of dementia (Crystal, 1980, p. 149). Nevertheless, as a result of the remarkably divergent outcomes of different research programs, aphasiology is still a rather controversial field of study (Crystal, 1980, p. 142). The aim of this paper is to give insight to aphasiology by providing general information about the definition, classification and key research issues; in addition, about the importance of assessment and intervention.

            Regarding the definition of the term aphasia, two main approaches can be distinguished: the broad definition encompasses every kind of difficulty with the use of the linguistic functions of the brain, whether it is formulation, expression or association, along with the damage of other cognitive functions; for example, the damage of memory and attention. Although language is in the center, the affected behavioral patterns are considered to be a part of aphasia as well. The other approach is the specified approach: it defines aphasia merely in the field of linguistic pathology (Crystal, 1980, pp. 140-141).

Communication disorder caused by brain damage and characterized by complete or partial impairment of language comprehension, formulation and use…excludes disorders associated with primary sensory deficits, general mental deterioration, or psychiatric disorders (Crystal, 1980, p. 141).

The specified approach allows a solely linguistic analysis with the use of acknowledged categories of language: syntax, morphology, semantics, phonology and so on. Due to the wide range of results in the fieldwork of researchers, it is hard to tell which approach is better. It might be for the best to take linguistic impairments as the primary focus of study but not excluding disturbances of other cognitive functions (Crystal, 1980, pp. 141-142).

            Concerning the classification of aphasia, two main classification systems can be identified. The traditional categorization is based on the neuroanatomical site of the injury that caused the dementia. This model of language pathology differentiates between the places of injury and the movement of the nerve signals. Regarding the place of injury, researchers identify Broca’s aphasia (which is in the anterior part of the left side front vertical brain tissue) and Wernicke’s aphasia (which is in the posterior part of the left side front vertical brain tissue). With reference to the movement of the nerve signals, the traditional medical classification differentiates between motor aphasia and sensor aphasia (Cummings, 2008, p. 344). This is in close relation to the Broca’s and Wernicke’s differentiation, because in the case of the former, the disturbance is in the motor cortex, which is the primary area for all voluntary muscular movement; in the case of the latter, the injury is in the sensory cortex, which is primarily responsible for processing sensations from the body to the brain (Scovel, 2008, pp. 74-75). However, with the recognition of the importance of linguistic features, the traditional classification has been replaced with a new system that uses binary features to create broad categories of aphasia. The categories are the following: nonfluent-fluent, expressive-receptive, executive-evaluative, production-comprehension, motor-sensory and Broca’s-Wernicke’s. The broad system takes into consideration both the neurological and the linguistic point of view. It functions more as a scale, because rarely can a patient be categorized into one clear-cut end of the binary system. It is common to conclude that a patient is ‘predominantly something’, although according to a holistic view, aphasia is a mixed disorder (Crystal, 1980, pp. 142-143). Nevertheless, there are specific syndromes that can be identified in a small number of patients. Examples are pure word deafness and pure word blindness (Crystal, 1980, p. 148). In addition to the classification systems, there is one major diagnostic test that incorporates both the language-based and lesion-based model, which is the Boston Diagnostic Aphasia Examination (Cummings, 2008, p. 345).

            Regarding the fields of research, some aspects are paid special attention by researchers. First of all, concerning all four linguistic modalities – speaking, comprehension, reading, and writing –, the extent to which these are damaged is of main importance (Crystal, 1980, p. 146). There is a major distinction between complete loss of language abilities and partial loss, the former being called aphasia and the latter being called dysphasia. Although the complete loss is extremely rare, aphasia is the generally acknowledged term (Crystal, 1980, p. 141). Moreover, another issue is the extent to which the range of language use is affected. In different cases of aphasia different language use is typical; for example, the use of automatic, fixed phrases or serial sequences. Furthermore, the extent to which the notion of aphasia is applicable to children and adults is also of main concern of aphasiology (Crystal, 1980, p. 147). Surgical evidence from hemispherectomy proves that due to the neuroplasticity of the cerebra, children under ten years old can develop language in the right side of their brain; therefore, complete recovery from dissolution of language can be achieved. Nonetheless, the former finding does not exclude the possibility of dementia in children. The term developmental aphasia/dysphasia is used when children do not develop language ideally, although it is a question whether its use is appropriate, seeing that place aphasia means language loss (Crystal, 2008, p. 148).

            With reference to the assessment and the intervention of aphasia, great developments have taken place in the past decades. Due to the widely different nature of the language disorder, not only narrow linguistic impairments but also communicative troubles are examined. Although the traditional assessment mainly focused on linguistic deficits, by now a wide range of techniques has been developed to facilitate the diagnosis of aphasic patients. It is generally agreed that early diagnosis is an essential basis of later intervention, seeing that the treatment of the aphasic disorders focuses on specific linguistic impairments and put a great emphasis on the communicative effectiveness; therefore, the use of group therapy and conversational partners has emerged (Cummings, 2008, pp. 349-356).

            In conclusion, the aim of this paper was to introduce the general aspects of aphasiology: the definition, the classification, the main research issues, assessment and intervention. It is clear that aphasiology is a lot more complex field of study and it is yet an intensively developing area of research. Despite the large amount of fieldwork, there is still a great need for longitudinal studies. Nonetheless, research in aphasiology proved to be undeniably important for clinical as well as for theoretical reasons (Crystal, 1980, p. 149). The generally evolving study of dementia has a positive effect both in neurological studies, in linguistic pathology and in linguistic therapy.

References

Crystal, D. (1980). Introduction to language pathology. London: Edward Arnold.

Cummings, L. (2008). Clinical Linguistics. Edinburgh: Edinburgh University Press.
Scovel, T. (2008). Psycholinguistics. H. G. Widdowson (Ed.). USA: Oxford University Press.