Acquired Dyslexias in Kannada-Speaking Adults with Right Hemisphere Damage

In recent times little attention has been given to the acquired disorders of reading. Many authors have proposed different theories such as dual route theory, theory of reading system, and so forth to explain different types of acquired dyslexias. And recently there is some work going on to find out the site of lesions for different types of dyslexias. Previous studies suggest that except for deep dyslexia, all other types of dyslexias have lesions in the left hemisphere. In this study, the authors attempted to identify the types of dyslexias present subsequent to right hemisphere damage. The aim of the present study is to enlighten speech-language pathologists as to the different types of acquired dyslexias and to determine out whether there is any causal relationship between right hemisphere damage and acquired dyslexias. For this study, the subjects were five native Kannada-speaking subjects with age range of 40 to 60 years with a history of right hemisphere damage following ischemic strokes. All subjects were assessed for their reading abilities in Kannada on a tool Analyzing Acquired Disorders of Reading in Kannada by Karanth (1984). The same test was used to diagnose the different types of dyslexias. A variety of reading readdisorders were seen in three patients, including wrong responses, which was semantically related to the stimulus word, visual errors, derivational errors; greater difficulty in reading function words such as prepositions, pronouns, and also reading nonwords. By qualitative analysis of this test and based on their characteristics these three subjects were diagnosed with deep dyslexia. All three subjects had a lesion in the right temporal and frontal lobes. The present study revealed that in all five subjects acquired deep dyslexia and right hemisphere damage may be causally related. Future studies are expected to determine the site of lesions for different types of acquired dyslexias. For speech-language pathologists, it is a challenging task to make an accurate and comprehensive assessment and prioritize steps for intervention based on clients' needs. Normally, speechlanguage pathologists will diagnose a patient with reading and writing difficulties as dyslexic or alexic. But there is a greater need for differential diagnosis of different types of dyslexia and treatment also should be individualized. More clinical research is necessary to aid the SLPs in detailed and comprehensive assessment and rehabilitation, especially in an Indian (non-Western) context

Audiology · Cognitive psychology · Dyslexia · Kannada · Lateralization of brain function · Linguistics · Right hemisphere · Computer Science · EEG and Brain-Computer Interfaces · Medicine · Neurobiology of Language and Bilingualism · Psychology · Reading and Literacy Development · Artificial Intelligence