The present study aimed to assess and compare semantic processing of spoken words in adolescents with cerebral palsy and healthy adolescents. For this purpose, 30 adolescents with cerebral palsy aged 10 to 15 years were selected by convenience sampling method, all of whom were spastic. Surveillance of Cerebral Palsy in Europe (SCPE) network was used to classify adolescents with cerebral palsy. For the control group, 30 healthy adolescents were selected according to gender, age and education of adolescents with cerebral palsy. To assess the subjects, spoken word-picture matching test (47) was used. The results showed that adolescents with cerebral palsy had significantly weaker spoken word skill than healthy adolescents. Furthermore, the developing spoken words pattern in adolescents with cerebral palsy is delayed compared to healthy adolescents. In addition, data analysis revealed that adolescents with cerebral palsy have vocabulary network and perceptual impairment in spoken word processing. However, their perceptual impairment is far greater.
1. Introduction
Language disorders can disrupt different components of the language system such as vocabulary, syntax, and semantics at different levels. One of the diseases that can cause language disorders is cerebral palsy. Children with cerebral palsy have more communication difficulties due to defects in language skills that are often affected by motor speech disorders. The present study aims to evaluate the semantic processing of spoken words in adolescents with cerebral palsy. Research has shown that children with cerebral palsy have delays in language processing during development. Most of these research have identified physical features and problems as the most influential factors in the language defects of these people. The present study seeks to clarify the issue that after passing the growth period, during adolescence, the language processing of these people, especially their lexical processing, still faces problems or not. In this regard, in this research, we intend to evaluate the semantic processing of spoken words in adolescents with cerebral palsy by using the test (47) of spoken word-picture matching (from the series of Palpa tests) and compare their performance results with their healthy peers.
Research Question(s)
The research questions of this study can be formulated as follows:
1. What is the difference between the performance of adolescents with cerebral palsy and their healthy peers in terms of matching spoken words with pictures?
2. What is the development pattern of spoken words in adolescents with cerebral palsy and healthy peers?
3. What is the cause of the defect in lexical processing of adolescents with cerebral palsy?
2. Literature Review
The theoretical framework of this study follows the model of single-word processing (Kay et al., 1992) deals with how people act to distinguish a word from a non-word. By integrating the parts of object recognition, written and auditory word recognition, a general model for understanding and producing language vocabulary has been formed and the core of the model is the semantic system. Based on this model, if imageability/word objectivity has a semantic nature, then by examining the effect of these variables on the performance of participants in the tasks in question, information can be obtained for aspects of their semantic processing abilities.
3. Methodology
The statistical population of the present study includes adolescents with spastic cerebral palsy and their healthy counterparts. In this research, the experimental group consisted of 48 adolescents with cerebral palsy who were selected through available sampling. After the investigations and the application of background variables and entry and exit criteria, the subjects were reduced to 30 people. They included 17 girls and 13 boys. The average age of adolescents with cerebral palsy was 12 years and 4 months, and their maximum and minimum ages were between 10.3 and 15.7 years. These people were all Farsi speakers and lived in Tehran. The control group consisted of 30 healthy Persian-speaking adolescents who lived in Tehran. In the control group, healthy adolescents were selected according to the characteristics of gender, age, and education of adolescents with cerebral palsy. The average age of these adolescents was 12 years and 7 months and the range of maximum and minimum age for them was 10.2 to 15.3. In this study, the classification system provided by the Surveillance of Cerebral Palsy in Europe (SCPE) network was used to classify adolescents with cerebral palsy. According to this classification system, the brain injury types of all sick adolescents are bilateral spasticity, unilateral spasticity, and spasticity with ataxia or dyskinesia.
In this research, the tool required for data collection included the localized version of the test (47) from the Palpa test set (Danai Tos, 2016). The test (47) is used to evaluate the ability to understand the meaning of words. In the data analysis, the descriptive statistics involved mean, standard deviation, minimum, and maximum. In the inferential statistical analysis, the non-parametric Mann–Whitney test was used to compare the performance of the control group and the experimental group in the test (47).
4. Results
In the descriptive analysis, the spoken word-picture matching test results showed that the adolescents’ ability with cerebral palsy is weaker than the ability of healthy adolescents to process the spoken word meaning. Similarly, the inferential analysis showed that the difference in the performance of healthy adolescents and adolescents with cerebral palsy in the spoken word-picture matching test is significant. The investigation of the research results also showed that adolescents with cerebral palsy have defects in the semantic processing of words and perceptual disorders in the processing of spoken words. However, the type and number of errors they had in the test (47) show that their disorder is more related to the perceptual component. In addition, in the semantic processing of words, adolescents with cerebral palsy had more defects in the lexical network.
The analysis of the vocabulary development process of children with language development disorder shows that although these people are significantly delayed in vocabulary processing, their development pattern is similar to healthy children (Drljan & Vukovic, 2020). In line with the results of previous research, the findings of the present research also showed that with increasing age, the development pattern of spoken words in healthy adolescents and adolescents with cerebral palsy increases with a similar trend but not to the same extent. However, by comparing the development patterns of spoken words, it was found that the development pattern of spoken words in adolescents with cerebral palsy is delayed compared to healthy adolescents. By studying the results of previous research and comparing them to the findings of the current research, the following conclusions can be presented:
1. The cerebral palsy leads to language disorder in affected patients.
2. Vocabulary (speech) development is delayed in adolescents with cerebral palsy.
3. In the processing of spoken words, adolescents with cerebral palsy, in addition to have defects in the vocabulary network, are more likely to have perceptual disorders..