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Toronto Notes 2019 Behavioural Neurology Creutzfeldt-Jakob Disease
• raredegenerativefatalbraindisordercausedbyprionproteinscausingspongiformchanges, astrocytosis, and neuronal loss
• mostcommonformsaresporadic(85%),hereditary(5-10%),andacquired(<1%)
• investigations:CSFanalysis,MRIbrain(corticaland/orsubcorticalFLAIRchanges),EEG(periodic
complexes)
• definitive diagnosis is by brain biopsy
• notreatmentscurrentlyexist
Aphasia
Definition
• anacquireddisturbanceoflanguagecharacterizedbyerrorsinlanguageproduction,writing, comprehension, or reading
Neuroanatomy of Aphasia
• Broca’s area (posterior inferior frontal lobe) involved in language production (expressive)
• Wernicke’s area (posterior superior temporal lobe) involved in comprehension of language (receptive) • angulargyrusisresponsibleforrelayingwrittenvisualstimulitoWernicke’sareaforreading
comprehension
• arcuatefasciculusassociationbundleconnectsWernicke’sandBroca’sareas
Assessment of Language
• assessmentofcontext
■ handedness (writing, drawing, toothbrush, scissors), education level, native language, learning
difficulties
• assessmentofaphasia
■ spontaneous speech (fluency, paraphasias, repetition, naming, comprehension – auditory and reading, writing, neologisms)
Neurology N27
Prion proteins have a normal form and an infectious form, which results from conversion of the protein from α-helix (normal) to β-pleated sheet (abnormal); these abnormally folded proteins aggregate leading to neuronal loss
>99% of right-handed people have left hemisphere language representation
70% of left-handed people have left hemisphere language representation, 15% have right hemisphere representation, and 15% have bilateral representation
Types of Paraphasias
Semantic (“chair” for “table”) Phonemic (“clable” for “table”)
Aphasia localizes the lesion to the dominant cerebral hemisphere
APHASIA
FLUENCY
REPETITION
Poor
Global
LESION LOCALIZATION
Good
Mixed TCA*
NON-FLUENT
Poor Good
Broca’s Motor TCA*
FLUENT
Poor
Wernicke’s
Good Poor Good
COMPREHENSION
Poor Good Poor Good
NAMING
Relatively Relatively
Poor Poor Poor Poor spared spared Poor Poor
Sensory TCA* Conduction
Anomic
Posterior inferior frontal lobe and posterior superior temporal lobe
Sensory and motor transcortical regions
Posterior inferior frontal lobe
Frontal lobe watershed between MCA and ACA territories
Posterior superior temporal lobe
Temporoparietal Arcuate fasciculus Numerous possible watershed between locations for lesion MCA and PCA territories
TCA=transcortical aphasia
*Transcortical aphasias are typically associated wtih cerebral anoxia (e.g. post-MI, CO poisoning, hypotension)
Figure 19. Aphasia classification
© Ashley Hui 2015