13) Language, Aphasia, Frontal Lobe

Question 1

What is aphasia?

Answer 1

= aquired disturbance of comprehension and production of language caused by dysfunction in specific brain regions

• (only) language faculty is impaired, other cognitive faculties are not impaired
• supramodal dysfunction = all modalities of communication are impaired (different degree of severity possible)
• mostly left hemisphere, around the parasylvian area
  –> bc language is mostly left lateralised, but can be right or bilaterlised
• can result from a huge variety of CNS diseases
• primary progressive forms may be precursors of dementia
• severely impairs communication, social functioning and ADL
• most common cause = stroke (80%)

• before language loss (aphasia) a language needs to be acquired (infants are not aphasic but prelinguistic)

Question 2

What is language?

Answer 2

= a formal system of signs governed by grammatical rules to communicate meaning

involves phonology (sign), syntax (combination rules (sentence level) + morphology (combination rules word level), semantics (formal meaning)

many interaction between phonology, syntax and semantics
- lexicon (= all phonetic word forms, meaning (potentially orthography and morphology)
- phonotactics (= phonological rules of syllable structures)
- pragmatics (= meaning in context)

Question 3

Diseases underlying language disorders

Answer 3

developmental disorders (eg dyslexia)
genetic disorders (eg KE-family FoxP2-gene)

cerebro-vascular disease (eg stroke, ICH)
traumatic brain injury (often with executive dysfunction)
operations (intraoperative mapping)

infectious disease (eg herpes-encephalitis)
tumors (eg astrocytoma)
degenerative disease (eg AD, Pick, FTLD, primary progressive aphasias)

green = infectious diseases, tumors, degenerative disease
pink = cerebro-vascular disease, traumatic brain injury, operations

light blue = neurotypical development

Question 4

What is NOT aphasia?

Answer 4

• aphasia can be differentiated from other/general cognitive impairment
• not deficits in attention, memory, executive functions, hearing …

–> dissociation between linguistic and other cognitive abilities is central

Question 5

Different types of aphasia

Answer 5

• Broca’s aphasia
• Wernicke’s aphasia
• amnestic
• global
• overlap, more differentiated, no two aphasias are the same

Question 6

What type of errors occur in aphasia?

Answer 6

Phonological
- neologism
- distortion of pronunciation

Semantic
- co-activation of related words
- right meaning cannot be accessed but related meaning
- description of targeted meaning

Syntactic
- agrammatic = loss of function words till complete reduction to content words (includes loss of morphology)
- paragrammatic = addition of words (interaction with morphology and pragmatics)

Question 7

What is Broca’s aphasia?

Symptoms

Answer 7

• non-fluent, effortful speech
• agrammatism, phonematic paraphasias
• combination with AOS/Dysarthria

Question 8

What is Wernicke’s aphasia?

Answer 8

• fluent speech (logorrhoic)
• paragrammatism, semantic/phonematic paraphasias
• neologisms
• repetitions
• comprehension impaired

Question 9

Different aphasia types: comprehension, fluency, repetition, reading, writing

Answer 9

1. Fluent or non-fluent?
2. Good comprehension or impaired?
3. Repetition or no repetition?
   (4. Reading?)
   (5. Writing?)

Broca’s area = speech production
Wernicke’s area = speech processing, comprehension
Arcuate fasiculus = connection between Broca’s area and Wernicke’s area
Angular gyrus = important for semantic integration/retrieval between Wernicke’s and (sensory) cortex
Primary auditory and visual cortices provide input to Wernicke’s
Motor area = connected to Broca’s area, sends motor signal to produce speech

Question 10

What is apraxia?

Answer 10

= neurological disorder of learnt directed motor control, which cannot be explained by deficits of the basic sensorimotor system

• left-hemispheric
• movement/motorics need to be learnt first to then be lost –> not acquired means it is not apraxia

• abnormal use of tools but carrying tool is normal

Question 11

What types of apraxia exist?

Answer 11

Ideatoric apraxia = plan of action is abnormal –> apraxia of action consequences

Ideomotoric apraxia = realisation of plan is abnormal

Limb-kinetic apraxia = differential movements of the hand and fingers is disturbed, increases with complexity

One can be apraxic for speech

Question 12

How to test for apraxia?

Answer 12

• have patients imitate (meaningless) movements
  –> patients often look like they search for movement
  –> imitate the movement incorrectly
• daily movements (like brushing teeth): misconception of orientation of things to execute plan

Question 13

Classification of apraxias according to Goldenberg

Answer 13

Bilateral apraxia after left hemispheric lesion
abnormal:
- imitation of gestures
- execution of meaningful gestures
- use of objects and tools

Question 14

Lesions in a network for object use (brain regions and deficits)

Answer 14

Parietal lobe
- integration of knowledge about the object and movement
–> meaningless gestures

Frontal lobe
- action planning
–> pantomime

Temporal lobe
- semantic knowledge
–> military salutation, lighting of cigarette

Question 15

Aphasia and Apraxia

Answer 15

• often combined
• lesions mostly left-hemispheric –> bilateral maifestation (apraxia) (language mostly left lateralised)

rare: unilateral apraxia after lesion of comissural fibres

10/699 Apraxia without aphasia
149/699 Aphasia without apraxia