Language, Speech & Aphasias

Language: refers to vocabulary & syntax independent of mode of production or comprehension Speech: actual production Vocalization: production of sound without linguistic content

Language areas of brain Broca’s area: anterior speech area Location- 3rd frontal gyrus Detailed and co-ordinated pattern of vocalization

Wernicke’s area: posterior speech area/ sensory area of speech Location: Temporal lobe Comprehension of speech Dejerine’s area: area 39 Location: angular gyrus Exner’s area: Motor writing centre Location: Middle frontal gyrus of categorical hemisphere

Types of speech 1. Spoken speech: understanding spoken words & expressing ideas in speech 3. Written speech: understanding written words and expressing ideas in writing

Mechanism of speech Primary auditory cortex/primary visual area Auditory/visual association areas Dejerine’s area Wernicke’s area

Arcuate fasciculus Broca’s area Exner’s area Motor area Vocalization/Writing

Comprehension of written speech and vocalization

Speech/Language Disorders Aphasias: Abnormalities of language functions not due to defects of vision, hearing or motor system Classification: 3. Fluent aphasia 4. Non-fluent aphasia 5. Anomic aphasia

Fluent aphasia (sensory aphasia): Injury to wernicke’s area Conduction aphasia- lesions in & around auditory cortex Talks excessively without sense Neologism Phonemic paraphasias “I went to the…..they brought me to the place where….it wasn’t the one that”

Nonfluent aphasia (Motor aphasia): Slow & effortful No grammar Telegraphic speech Incorrect writing Good comprehension

Anomic aphasia: Injury to angular gyrus Difficulty in understanding written language and pictures Global aphasia: Injury to both broca’s & wernicke’s area

Dyslexia: Impaired ability to read Phonemic deficit Artists, musicians, mathematicians Dysarthria: Imperfect vocalization Defect in motor areas & their connections

Recognition of face • Right inferior temporal lobe • Prosopagnosia • Autonomic changes

Cerebral Dominance • Categorical hemisphere- analytic processes • Representational hemisphere- visuospatial relations • 90% left hemisphere is categorical • 70% of left handed have left hemisphere dominance

Lesions of categorical hemisphere: Language disorders Disturbed and depressed Lesions of representational hemisphere: Astereognosis & other agnosias Hemineglect Unconcerned and euphoric