Higher Cortical Functions Cerebral Asymmetry Cerebral Dominance Fall 2012

Association Fibers

Corpus Callosum

Lateral Fissure Asymmetries

Planum Temporale Larger Left hemisphere = 65% Right hemisphere = 11%

Cerebral Dominance Dominant Non-dominant Language/Speech Math skills Problem solving Processing sign language Non-dominant Spatial relationships Music and poetry Artistic ability Emotion

Cerebral Dominance 90-95% right handed people = left hemisphere dominance 65-75% left handed people = left hemisphere dominance True ambidextrous people 60% left dominance 30% right dominance 10% equal dominance Handedness is not a 100% accurate assessment of cerebral dominance Wada testing

Language Areas Central Sulcus Precentral Gyrus Postcentral Gyrus Arcuate Fasciculus Angular Gyrus Broca’s Area 44 & 45 Wernicke’s Area 22 Lateral Fissure Superior Temporal Gyrus

Broca’s Aphasia NON-FLUENT, MOTOR OR EXPRESSIVE APHASIA SPONTANEOUS SPEECH Non-fluent, telegraphic, often dysarthric Greatly reduced - 10 wpm COMPREHENSION Intact, mild difficulty with complex grammatical phrases REPETITION Impaired

Broca’s Aphasia NAMING READING WRITING Impaired Prompting helps significantly READING Often impaired WRITING Impaired, dysmorphic, dysgrammatic

Broca’s Aphasia Anterior distribution of left middle cerebral artery

Wernicke’s Aphasia FLUENT, SENSORY OR RECEPTIVE APHASIA SPONTANEOUS SPEECH Fluent, often increased, paraphasias common, usually not dysarthric Often meaningless - Neologisms COMPREHENSION Impaired REPETITION

Wernicke’s Aphasia NAMING READING WRITING Impaired Impaired for both comprehension and reading out loud WRITING Well-formed letters in meaningless combinations

Wernicke’s Aphasia Posterior distribution of left middle cerebral artery

Conduction Aphasia SPONTANEOUS SPEECH COMPREHENSION REPETITION Fluent, some hesitancy May be paraphasic - meaningless COMPREHENSION Intact REPETITION Severely impaired Lesion involves arcuate fasciculus in dominant hemisphere

Conduction Aphasia NAMING May be moderately impaired READING Reading out loud severely impaired Reading comprehension usually good WRITING Variable deficits

Aphasia Square Good Comprehension Poor Comprehension Fluent Speech Wernicke’s Aphasia Fluent Speech Conduction Aphasia Transcortical Sensory Aphasia Broca’s Aphasia Mixed Transcortical Aphasia Non-Fluent Speech Transcortical Motor Aphasia POOR REPETITION GOOD

Anomic Aphasia (Anomia) SPONTANEOUS SPEECH Fluent, some pauses, circumlocution COMPREHENSION Intact REPETITION NAMING Impaired, but prompting helps READING WRITING Intact, except for anomia