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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Clinical Aspect of Language Disorder
Yun-Hee Kim, MD, PhDDepartment of Physical Medicine & Rehabilitation
College of Medicine Sungkyunkwan University Samsung Medical Center
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Facets of Language
Vehicle for communication of information
Medium for artistic expression
Method of expression of emotion
Means for developing thought
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Language Processing
Input AuditionVisionSomesthesis
Output SpeechSignsWritingsBrailleGestures
Interconnecting linguistic processingEmotional coloring
Feedback-looping
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Spoken input Written inputAcoustic phonetic analysis Visual orthographic
analysisPhonetic features phonemes
syllablesAuditory lexicon
Phonological forms of words
Semantic access
Visual Lexicon
Orthographic forms of words
Semantic access
Phonological lexiconOrthographic lexicon
Orthographic forms of words
Orthographic planning
Letter sequences
Written output planning
Manual movements
Phonological forms of wordsPhonological output
planning
Phonetic features
Articulatory planning
Articulatory gestures
Lexical phonology → Orthography
Lexical orthography → Phonology
Sublexical phonology → Orthography
Sublexical orthography → Phonology
Word meaningsComprehension
Production
Caplan’s Diagram for Language Processing: Simple words
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Language Comprehension
Spoken name Wernicke’s area (auditory memory)
Angular gyrus
(visual memory)
Visual image Angular gyrus
(visual memory)
Wernicke’s area (auditory memory)
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Language ProductionBroca’s area :
Program for the control of precentral face area and supplementary motor areaLearned rule for converting auditory pattern into spoken form
Spoken name Wernicke’s area
Transmission of neural pattern through arcuate fasciculus
Broca’s area
Visual image Angular gyrus
Transmission of neural pattern through arcuate fasciculus
Broca’s area
Wernicke’s area
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Cortical Language Areas by Electrical Stimulation of Cortex
Penfield and Roberts, 1958
Left RightBasal temporal language areaLuders et al, Epilepsia, 1988
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Connecting Fibers for Language Processing
Commisural fibers: callosal fiberAssociation fibers:
Superior longitudinal fasciculus (arcuate fasciculus)Superior occipitofrontal fasciculusInferior occipitofrontal fasciculusInferior longitudinal fasciculusShort association fibers
Projection fiber:Corticothalamic fiber
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Fronto-Temporal Connections
Uncinate fasciculus
Arcuate fasciculus
Wise, Br Med Bull, 2003
To ventral and rostralPFC; process word meaning
To dorsolateral PFC; process word sound structure (Phonetics and phonology)
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Language Play-Back Loop
Two sectors in Broca’sarea
posterior -> SMAanterior -> auditory association area
Comparison of language production with language perceptionConnectivity based working memory for language decoding and encoding
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Clinical Language Disorders
Aphasia syndromeDevelopmental language disorderPrimary progressive aphasia
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
22/M with cortical dysplasia: Verb generation vs. rest (Kim, 1998)
LR
Plasticity of Language System
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Mimura et. al. 1998, Brain20 aphasic patients within first year after stroke and 16 aphasic patients 7 years after stroke using SPECTInitial language recovery: primarily by the dominant hemisphereLong term recovery: slow and gradual, increased blood flow in the contralateral hemisphere, especially in the homotopic frontal and thalamic areas
Functional Imaging Studies of Language in Aphasia
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Thulborn et al, Stroke, 1999
•Activation of right hemisphere after stroke in 2 aphasic patients using fMRI, in a Broca homologous area.•Rightward activation appeared early and continued
Broca’s aphasiaWernike’s aphasia
Plasticity of Language-Related Brain Function during Recovery from Stroke
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
6 aphasic patients with left IFG lesionWord stem-completion taskActivation of right IFG for performing language task
Rosen et al, Neurology, 2000
Neural Correlates of Recovery from Aphasia after Damage to Left Inferior Frontal Cortex
L R
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Activation during word generation: Functional correlation of right frontal activity
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
12 aphasic patients using FDG PETWithin 4 wks of stroke, and follow up after I year(7 pts.)
Two strategies to recover from post-stroke aphasiaStructural repair of primarily speech-relevant regionsActivation of compensatory areasSMA: most prominent compensatory activation in the subacute stageRestitution of the left STC determine the long-term prognosisRight hemisphere compensation was less effective than the repair of original speech network
Karbe et al, Brain and Language, 1998
Brain Plasticity in Poststroke Aphasia: What is the Contribution of the Right Hemisphere?
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Relation between Accuracy of Token Test and Regional Activation
One year follow up
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Frontal Laterality Index in Aphasic Patients
Cortical
Cortical
Cortical
Subcortical
Cortical
Cortical
Cortical
Cortical
Subcortical
Subcortical
Cortical
Cortical
Cortical
Subcortical
Subcortical
Cortical
Subcortical
Aphasia Type
0.20 93.5%8.5F/15Lt. MCA infarction13
0.12 66.6%37M/64HICH on Lt. B.G.14
0.08 68.5%8M/41Lt. MCA infarction15
-0.10 63.3%3.5M/36Lt. T-P infarction16
49.5M/48
F/54
M/65
F/44
F/58
M/35
M/41
M/62
M/65
M/62
M/53
M/49
M/48
Sex/Age
-1.00 10.4%5.5Cbr. Infarction17-0.2062.0%17.1Mean
24
2.5
4.5
3
29
72.5
8
8
2.5
32
29.5
13
POD (months)
0.01 55.7%Lt. MCA infarction12
-1.00 53.3%Multi-infarct, Lt F, Rt. T 11
-0.41 27.1%Lt. MCA infarction10
-0.64 93.0%HICH on Lt. B.G.9
0.27 95.7%HICH on Lt. B.G.8
0.18 42.9%Lt. MCA infarction7
-0.12 75.4%ICH on Lt. P-O6
-0.21 19.9%Lt. MCA infarction5
-0.34 72.0%ICH on Lt. B.G.4
-0.41 52.0%HICH on Lt. B.G.3
-0.35 85.8%Lt. MCA infarction2
0.25 78.1%HICH on Lt. B.G.1
Laterality In.PerformanceLesionPatient
Kim et al, 2002
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Comparison by Postonset Duration
-0.01
65.1%
4
6 months ~1 year
0.01*-0. 58 Laterality Index
68.1%53.2%Language Performance
76Number of Patient
Above 1 yearWithin 6 msPostonset Duration
* p < .05
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Aphasia Treatment: Changes of Laterality Index in Chronic Aphasics after Rehabilitation
41.8 months24.3 monthsPOD (mean)
0.17*-0.09Laterality Index
74.3%*65.2%Lang. Performance
8Number of Patient
F/U fMRI1st fMRIComparison of Pre and Post Study
* p < .05
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Differential Capacity of Left and Right Hemispheric Areas for Compensation of Poststroke Aphasia
23 right-handed aphasic patients, 7 frontal, 9 subcortical, 7 temporalH215O PETWord repetition task2 and 8 weeks after strokePoorest outcome in temporal group
Heiss et al, Ann Neurol, 1999
Frontal lesionFrontal lesion
Subcortical lesionSubcortical lesion
Temporal lesionTemporal lesion
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Hierarchy within the Language-Related Network
Effectiveness of improvement of aphasiaRight hemispheric area contribute if left hemispheric lesions destroyedEfficient restoration of language is usually only achieved if left temporal areas are preserved and can be integrated into the functional network
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
20 patients with Wernick’s aphasia (42-70 yrs.)Language comprehension training4 patients (55-60 yrs.) – PETLanguage comprehension task
Training-Induced Brain Plasticity in Aphasia
Musso et al, 2002
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Neural Correlates of Aphasia Treatment
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Leger et al, Neuroimage, 2002
Neural Substrates of Spoken Language Rehabilitation
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Effect of Combined Medication and Speech Therapy:Use of Amphetamine in the Treatment of Aphasia
Walker-Batson et. al., Stroke, 2001
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
24 stroke patients12 piracetam, 12 placebo6-wk intensive speech therapyH215O PET before and after therapyWord repetition taskImproved language performance and blood flow in language relevant areas
Kessler et al, Stroke, 2000
Effect of Combined Medication and Speech Therapy:iracetam Improves Activated Blood Flow and Facilitates
Rehabilitation of Poststroke Aphasic Patients
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Factors Influencing on Reorganization and Language Recovery
Severity of language area damageLesion locationTiming and type of rehabilitationMedications
DopaminergicCholinergic
Further development of various rehabilitation methodologies to maximize brain plasticityshould be encouraged
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
~ 7 % of childrenAbsence of mental retardetion, deafness, neurological deficit or social deprevationGenetic or familial predispositionNeuroanatomical correlation:
Planum temporaleBroca’s area and adjacent sulcal morphologyCaudate neucleusCorpus callosum
c.f. Language regression in childhoodAutistic regressionAcquired epileptic aphasia (Landau-Kleffner syndrome)
Developmental Disorders of Speech and Language
Watkins et al, Brain, 2002Fabbro et al, Neuropsychologia, 2002
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Persistent Developmental Stuttering
Developmental stutteringCompromised complex system interacting between speech and languageInvoluntary repetition, lengthened sounds, or arrest of sounds4-5% of 3-5 y-o childrenImpairments persists after puberty in 1% of people (men> women)Genetic basis
PathophysiologyAbnormal patterns of cerebral hemispheric dominanceShift of activation to the right hemisphereImpaired oral motor controlImpaired auditory self-monitoring of speechSynchronization deficit in speech preparation and execution
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Disconnection of Speech Relevant Areas in Persistent Developmental Stuttering
Cortical disconnection immediately below the laryngeal and tongue representation in the left sensorimotor cortex (Rolandicoperculum)
Relative FA reduction (32.8%, p=0.014 corrected) in stutter group than controls Sommer et al, Lancet, 2002
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Primary Progressive Aphasia (PPA)A Language-Based Dementia
Inciduous onset, gradual but progressive impairment of word finding, object naming, syntax, or word comprehensionAll major limitation of ADL can be attributed to the language impairment for at least two years after onsetPremorbid language function is known to be intactProminent apathy, disinhibition, loss of memory, visuospatialimpairment, visual-recognition deficit, sensorimotorimpairment are absent during the initial 2 years of illnessAcalculia and idiomotor apraxia can be present even in the first 2 years of illness but neither visuospatial deficit nor behavioral dysinhibition substantially limits ADLOther cognitive functions may be affected after the first two years of illness, but language remains the most impaired function throughout the course of illnessSpecific causes of aphasia, such as stroke or tumor, as ascertained by neuroimaging, are absent
Mesulam, N Engl J Med, 2003
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Pathologic Changes of Left Perisylvian Area in PPA
Atrophy in the parietal operculum, the insula, middle, and inferior temporal gyri of the left hemisphere
Decreased blood flow in the early stage of disease
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Axonal Injury within Language Network in PPA
Catani et al., Ann Neurol, 2003
Asymmetrical N-acetylaspartate/creatine ratio reduction in the PPA group (L>R) compared with Alzheimer’s disease and controls in the central portion of the SLF
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KOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUPKOREAN BRAIN MAPPING & PLASTICITY RESEARCH GROUP
Conclusions
Language is a unique channel of exploring the human brain function.Brain-language network has remarkable plasticity, however, classical left hemispheric language system is the most efficient one. Functional imaging is a powerful technology of investigating pathogenesis of and recovery from various language disorders.
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