Aphasia Research: Unraveling the Mysteries of Language and Brain Function - Paper Example

Over the years, several cases of impaired language and speech disorders have been witnessed. Some an individual might not be able to express themselves verbally hence using signs to convey information while others could not express themselves at all (Grossman 3). Causes of paralysis and stroke have not been established since there are many theories related to these locomotive malfunctions, which in most if not all cases would eventually cause death. The question that has drawn phrenologists' attention in present times has been the fact that there exist aphasia patients who are not able to express their needs using speech but intelligent enough to express them using other methods.

Is your time best spent reading someone else’s essay? Get a 100% original essay FROM A CERTIFIED WRITER!

Order now

Before Broca’s study, there had been an ongoing debate on the localization of higher-order functions in the human brain, as part of the scientific study of acquired language disorders (Grossman 4). Gall, Sperzheim, and other phrenologists argued that the normal moral, intellectual, and spiritual capabilities of an individual relied on functions of particular portions of the brain and that the size of the head would be palpated to determine the size of the underlying brain and hence their intellectual capacity. “The phrenologists argued that the size of portions of the skull reflected the size of the underlying brain...” (Grossman 4). They also asserted that the analysis of lesions in terms of absolute distances from major anatomical functions would be a base of higher-order function localization. These arguments caused mixed reactions in the Scientific community and were refuted by 1861.

Broca’s first attention was, Lebourgne, an aphasia patient in Bicetre hospital. Lebourgne had speech impairment syndrome and could only say the syllable “tan” but was seen as independent in that he used other methods to communicate his needs (Grossman 6). Broca studied the history of his patient’s illness and noticed that it progressed in three stages. In the first stage, he found that he went mute but functioned independently and responded duly, which made him seem like a difficult character. Secondly, he lost the use of his arm and face, and finally paralysis of the right leg and development of an infection, which later caused a stroke and eventually death.

An autopsy report done by Broca revealed the existence of a lesion in the frontal lobe. He further ascertained that the lesion contained a cyst which was located at the third front convolution (Grossman 8). Puncturing the cyst, he found fluid and later observed that the underlying part of the brain appeared softer, compared to a healthy brain, as he moved posteriorly. Broca’s analysis of language abnormality was based on two major lines: linguistic and non-linguistic communication as well as receptive and expressive capabilities. Based on Lebourgne’s behavior, he determined that his deformity was only based on the “faculty of articulate language” since his linguistic and non-linguistic capability was excellently characterized by his ability to respond and express his needs (Grossman 9). This caught Wernickle’s attention.

Broca’s contribution to the theory of the brain relied on detailed historical cases, autopsy, and anatomical findings. His theory on the location of language in the brain was confirmed by Aubertin after observing his (Broca’s) patient. Contrary to the arguments of other phrenologists, Broca presented the insights that convolutions of the brain were relatively constant and that neuroanatomical features were related to psychological function (Grossman 10). He concluded, from the findings from Lebourgne's history, that aphasia followed lesions of the left hemisphere and not the right, as Dax stated earlier in his paper. Broca pointed out that the eight consecutive cases of aphasia he had observed had left hemisphere lesions (Grossman 11). However, this exhibited contradiction to the biological law of symmetry on identical functions of organs. Objections and re-interpretation of the location of speech apparatus as being related to a small area of the cortex became an approximation that has since been believed.

In his study of language and brain, Carl Wernicke classified aphasic syndromes, which led him to the discovery that there are two distinct classifications of these syndromes (Grossman 13). One is that these disorders cause lesions in the brain, and the other is that these areas have various tasks regarding language representation and processing.

Wernicke highlighted nine causes of language disorders as a result of acquired disease of the brain. He examined two patients and realized that both manifested a deficit in understanding, and one was thought to be deaf. "The second patient was originally thought to be deaf..." (Grossman 16). Unlike Broca's finding of depicting a patient as partially mute, Wernicke found that his patients would recognize gestures and patterns. He found out that errors in language and speech were, as a result, of omission and choice of sounds evidenced by his patients' ability to speak fluently but not being able to make sense.

Wernicke, together with other scientists, did not understand words thought to be non-existent in the German language. “Wernicke and other examiners were at a loss to understand what the patients were trying to say” (Grossman 17). This led him to conclude that the reasons for this patient’s failure to convey information verbally were due to difficulties in performing semantic relationships. The death of one of his patients caused him to perform further studies on the autopsy of the brain (Grossman 27). He predicted that the deficit of expressive language was due to the same lesion causing a reduction in language processing capability and not as argued by Broca, although he agreed with findings that the location of defective tissues was the left hemisphere of the brain (Grossman 47). Wernicke also described the primary auditory cortex to be responsible for speech recognition, which he argued that it is responsible for the modification of sensory and motor information.

In his model, Wernicke adopted the notion that various components of the brain are connected. He added that psycholinguistic elements had been considered to constitute psychological entities that legitimately represented the center of brain functions (Grossman 48). He further proposed that concerning the posterior language area, simple psychological functions had been perceived to be located in the first temporal gyrus. His proposal was named “connectionist” since he stated that many simple functions were being connected to form complex functions (Grossman 51). This approach immediately received appreciation and became the method that was adopted by scientists as the dominant method of classifying aphasia.

Conclusion

In conclusion, aphasia has been depicted to be a disorder that progresses gradually and eventually causes death as characterized by both Broca's and Wernicke's patients, who followed the same pattern. The findings from their autopsy results have been observed to confirm the position of language in the brain as being related to the left lower convolution of the brain. This, therefore, illustrated that the loss of speech occurred as a result of lesions in the anterior part of the brain before any paralysis or intellectual ability. The atomic descriptions made by Broca are not enough to conclude; however, tests on various patients depicted a psychological understanding of how speech and language are output rather than processed in the human brain.

Work Cited

Grossman, Murray. "Neurolinguistics And Linguistic Aphasiology: An Introduction. By David Caplan Cambridge, Cambridge University Press, 1987 498 Pp, Illustrated, $49.50". Annals of Neurology, vol 24, no. 6, 1988, pp. 3-55. Wiley, https://doi:10.1002/ana.410240625. Accessed 12 Aug 2020.