Language and higher order functions week 7

Question 1

What part of the brain is damaged in conduction aphasia What is the function of this part of the brain?

What is anomic aphasia? Where in the brain does injury cause anomic aphasia?

What part of the brain, when injured, results in mutism?

Answer 1

1. Arcuate fasciculus: connects Broca’s and Wernicke’s areas
2. Anomic aphasia: a disorder which causes problems with recalling words or names. Anomia is a deficit of expressive language. Is a retrieval issue (as opposed to a memory/storage issue). Non-localizing: seen in injuries such as concussion
3. Mutism: supplementary motor cortex. Note that mutism is typically transient and is seen with damage in the dominant hemisphere

Question 2

What is the difference btwn a fluent and non-fluent aphasia?

What kind of aphasia is present with damage to Wernicke’s area? Arcuate fasciculus? Broca’s area?

Answer 2

Fluent aphasia: Phoneme selection and sequencing as well as syntax are preserved in fluent aphasia. Speech is characterized by a facility of articulation and many long runs of words combined using a variety of grammatical constructions.

Non-fluent aphasia: The flow of speech is more or less impaired at the levels of speech initiation, the finding and sequencing of articulatory movements, and the production of grammatical sequences. Speech is choppy, interrupted, and awkwardly articulated.

Fluent aphasias: Wernicke’s area, Arcuate fasciculus

Non-fluent aphasia: Broca’s area

Question 3

What are the acute effects with lesions to speech areas?

Answer 3

acute lesion: decr. speech. acutely lose language which may graduate to other speech issues after time. Is similar to spinal shock in which acutely get hyporeflexia that progresses to hyperreflexia and other UMN signs.

Question 4

What are neighborhood signs? (as it pertains to aphasia)

Answer 4

For example, a person with damage to Broca’s area may have motor deficits due to its proximity to the primary motor cortex. Look for other deficits in people with aphasia.

Question 5

Damage to what part(s) of the brain may cause dysarthria? What is the difference btwn dysarthria and dysphasia?

Answer 5

Primary motor cortex or cerebellar dysfunction may produce dysarthria. Dysarthria is considered a motor problem, not a language problem.

Question 6

Describe the following parameters for Broca’s Wernicke’s, Conduction, and Global aphasias:

speech

comprehension

capacity for repetition

other signs (motor signs, non-motor signs)

region affected

Answer 6

attached is slide 10 of notes, see slide 11 of notes

Question 7

Define the following terms:

alexia

dyslexia

agraphia

Answer 7

Alexia: inability to read (may be a feature of receptive aphasia)

Dyslexia: impaired reading ability with a competence level below that expected on the basis of the individual’s level of intelligence, and in the presence of normal vision and letter recognition and normal recognition of the meaning of pictures and objects – generally no clear neuropathology

Agraphia: inability to write, in the absence of abnormalities of the limb

Question 8

Which hemisphere is the dominant hemisphere for language processing in most people?

What is the contribution of the other hemisphere to language?

Answer 8

Cerebral dominance

• About 70-90% of people are right handed and about 10% left handed, others are mixed
• Almost all right handers depend on the left hemisphere for language processing (about 93-100%). Most left handers also depend on the left hemisphere for language processing.
• It is estimated that 96% of people depend on the left hemisphere for language processing related to grammar, the lexicon (vocabulary), phonemic assembly and phonetic production (Kandel et al, 2000).
• The non-dominant hemisphere has a role in the prosody, the melody, of speech. It contributes to the emotional impact of speech and helps to appreciate the emotion in the speech of others.

Question 9

What is the role of the corpus callosum in language?

Answer 9

Role of corpus callosum

• to carry information from one hemisphere to the other to fully carry out a language function
  
  • to name an object perceived by the nondominant hemisphere
  • to use the non-dominant to carry out a verbal command
  • For example:
    
    • picking up an object in left hand: Information goes to right hemisphere to be processed as an object, go through callosum to Wernicke’s to come up with word for object, then through arcuate fasiculus to Broca’s so one can say what the word is (name of object)

Question 10

What is agnosia? What damage causes agnosia?

Answer 10

Agnosia: Lack of sensory ability to interpret stimuli (e.g. sounds, objects) despite intact elementary sensory function.

The agnosias are seen mostly with bilateral cerebral damage in the sensory association areas, but may also be seen with unilateral damage.

Question 11

Define the following types of agnosias and the area of the brain in which damage produces them:

auditory agnosia

astereogenesis/tactile agnosia

coloar agnosia

proposagnosia

Answer 11

• Auditory agnosia: inability to recognize (the significance of) sounds (e.g. dog bark, telephone ring), despite normal hearing - superior or middle temporal gyrus.
• Astereognosis or tactile agnosia: inability to recognize objects by touch, despite normal two point discrimination - posterior parietal lobe.
• Color agnosia: inability to recognize colors of objectsoccipital cortex (Brodmann area 18, V2) secondary visual cortex responsible for processing info on image detail and color attributes, parvocellular)
• Prosopagnosia: inability to recognize faces (or other familiar visual stimuli) despite intact visual fields- inferior temporal-occipital lobe (Brodmann areas 20, 21)

Question 12

What is neglect syndrome? Damage to what part of the brain causes it? What hemisphere does it typically occur in? (dominant or non-dominant)

What deficit is it typically associated with?

Answer 12

Neglect

▪ Classically attributed to the posterior parietal cortex, but may involve superior temporal cortex (usually the non-dominant hemisphere)

▪ Involves lack of attention to the contralateral sensory field (visual and somatosensory, auditory), typically includes apraxias (dressing, and/or constructional)

Question 13

What is apraxia? Damage to what part(s) of the brain cause apraxia?

What is sympathetic apraxia?

Answer 13

Apraxia

A disorder of voluntary movement. Inability to execute purposeful movements despite the preservation of muscular power, sensibility and coordination in general, eg. comb hair, brush teeth

The apraxias are seen mostly with damage in premotor or parietal cortex.

There are many different named apraxias reflecting the part of the body affected and type of impairment demonstrated.

Sympathetic apraxia: inability to carry out a skilled movement on command using the non-dominant limb. Information cannot travel through the corpus callosum.

Damage to different sites may produce similar symptoms due to interruption in information flow.

A. Lesions to the arcuate fasciculus or the superior longitudinal fasciculus interfere with the flow of information from the temporal, parietal and occipital lobes to the frontal lobe causing apraxias.

B. Apraxias are seen most commonly following frontal or parietal damage, which leaves the primary sensory or motor cortex intact.