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Michael Palladino Natalie Pebbles Spenser Mitchell Summary of: Ketteler, D., & Ketteler, S. (2010). Is schizophrenia “the price that Homo sapiens pays for language”? Sub cortical language processing as the missing link between evolution and language disorder in psychosis—A neurolinguistic approach. Journal of Neurolinguistics, 23(4), 342-353. doi:10.1016/j.jneuroling.2010.04.003 Ketteler and Ketteler(2010) emphasize the importance of language impairment as one of the core symptoms of Schizophrenia. Research has postulated that, according to the ICD-10 diagnostic criteria for Schizophrenia, “language symptoms like semantic/phonemic paraphasias or poverty of speech were superior to nuclear symptoms[e.g. delusions](343). It has been proposed that the delusions are in fact a manifestation of language impairment (343). Ketteler and Ketteler propose that there are two approaches to understanding the neurological basis of schizophrenia . First, they propose that hemispheric imbalances aid in the development of schizophrenia (350). This notion is supported by research in the article that showed that, “decreased lateralization was significantly correlated to the severity of hallucinations.”(344). Hallucinations and delusions, characteristic symptoms of Schizophrenia, may be caused by a breakdown in lateralsation. Thoughts what is perceived as coming from within by a normally functioning brain may be perceived as coming from an external source. Similarly, auditory hallucinations can be perceived as coming from another person as a running commentary on the action being performed by the Schizophrenic patient (344). Recent studies have found that persons at high risk for Schizophrenia, i.e. children of a Schizophrenic patient, an identical or fraternal twin of a Schizophrenic, have structural abnormalities that exist in regions of the brain associated with language processing (345). Furthermore, research supports the importance of the Foxp2 gene’s role in patients suffering from Schizophrenia characterized by auditory hallucinations. A case study of a third generation Schizophrenia sufferer highlights the role of the Foxp2 gene in producing language disorder (specifically verbal dyspraxia) and its link to auditory hallucinations. It has been proposed that, “auditory hallucinations represent a disorder of speech rather than a unique group of psychotic symptoms.”(346). Evolutionarily, the hemispheric segregation of the brain aided in our ability to stand upright (345-6), therefore this research would support the notion that Schizophrenia is the price we pay. The second approach to understanding Schizophrenia posed by the authors is the role specific brain structures play in higher order language functioning. The article suggests that these language impairments may be genetically inherent in patients with Schizophrenia. Evidence of this can be seen in the negative reaction that is elicited when Schizophrenic patients are asked to interpret ambiguous terms. This has been hypothesized as a, “pathogonomical marker for psychotic language processing… and for the lack of a Theory of Mind”(347) in patients suffering from Schizophrenia. The suggested variable of difficulty interpreting ambiguous stimuli has been tested using Lexical Decision Tasks(LDT). Patients with Schizophrenia have shown consistent impairment in their ability to select the appropriate context from an ambiguous stimuli (347). In an experiment comparing the results of an LDT between Schizophrenic patients and controls, it was found that, “the right hemisphere exhaustively activates the various meanings with a word, while the left hemisphere’s initial access is selectively restricted to the dominant meaning.”(348). This supports the hypothesis that hemispheric interaction problems are a major contributor to Schizophrenia. Another important brain region that is postulated to be effected by Schizophrenia is the caudate nuclei, a region of the Basal Ganglia involved in learning and memory amongst other things. It has been found that stimulation of this brain area brings about irrelevant language, a major symptom of Schizophrenia. This result has been found in the extended use of antipsychotic drugs. The prolonged use of these drugs has been associated with increases in caudate volume. Another brain region that has been found to be associated with Schizophrenia are the Thalamas. There is strong evidence that suggests that, “ basal ganglia and thalamus changes in schizophrenic patients cause cortical dysfunction in several language related cortical areas (e.g. superior frontal gyrus)”(350). Though much future research needs to be done on the importance of language impairment as a distinctive or casual feature of Schizophrenia it is an new and exciting approach to a disorder that has gone misunderstood for many years. Test Questions 1. Which is NOT an approach to understanding the neurological basis of schizophrenia that is proposed by Ketteler and Ketteler? a. Hemispheric Imbalances b. Overactive Limbic System c. Specific roles of brain structures in higher order language functioning and their effect on the disorder 2. The article suggests that major symptoms of schizophrenia such as delusions may be a manifestation of language impairment. a. True b. False 3. Evolutionary, the hemispheric segregation of the brain (lateralization) aided in our ability to: a. Think Creatively b. Stand Upright c. Memorize Information d. Make Tools 4. Research has shown that decreased lateralization significantly correlates with a. Severity of hallucinations b. Ability to speak c. Reading comprehension d. Ability to hear 5. The article suggests that the negative reactions elicited in patients with schizophrenia when asked to interpret ambiguous terms is evidence that that certain language impairments may be genetically inherent in patients with schizophrenia a. True b. False 6. In the article, it is suggested that young children who grow up with speech impediments have an increased risk of schizophrenia a. True b. False Answer Key 1. 2. 3. 4. 5. 6. B A B A A B