Cortical Lesions & Aphasia

Question 1

Major cognitive domains evaluated by MSE

Answer 1

Arousal and attention
Memory
Language
Visuospatial function
Mood and affect
Complex cognition

Question 2

Dysarthria

Answer 2

A disorder of speech due to motor system involvement

Question 3

How is language lateralized?

Answer 3

90% of the population is right handed; 99% of right-handed people are left dominant for language

10% of the population is left handed; 67% of left handed people are left dominant for language

Ambidextrous people may have mixed language lateralization

Question 4

How is aphasia diagnosed?

Answer 4

Assessment of 6 domains:

Spontaneous speech
Auditory comprehension
Repetition
Naming 
Reading
Writing

Question 5

Mini-mental State Examination (MMSE)

Answer 5

AKA “The Folstein”

1-30 point scale

Abnormal score < 24

Question 6

Montreal Cognitive Assessment (MoCA)

Answer 6

1-30 point scale

Abnormal score < 26

Question 7

Alexia

Answer 7

An acquired disorder of reading

Reading is also organized in left perisylvian regions and so most patients with aphasia will also have alexia; reading aloud is more impaired with anterior lesions while reading for comprehension is more impaired with posterior lesions

Question 8

Agraphia

Answer 8

Acquired difficulty with writing (must first rule out mechanical obstacles such as PD, arthritis, etc.)

Writing is organized in the left perisylvian regions and so most aphasias also have agraphia

Sparse, effortful writing is seen with anterior lesions; expansive, paragraphic writing is seen with posterior lesions

Question 9

Broca’s area = Broadman’s area x?

Answer 9

44, 45

Question 10

Broca’s aphasia - Clinical characteristics & Radiographic Findings

Answer 10

Effortful, non-fluent speech
Good auditory comprehension
Poor repetition
Poor naming

CT shows infarct in the left frontal region

Question 11

Wernicke’s Aphasia - Clinical characteristics & Radiographic Findings

Answer 11

Fluent speech, may be paraphasic
Poor auditory comprehension
Poor repetition
Poor naming

CT shows ischemic infarct in the left superior temporal region

Question 12

Wernicke’s Area = Broadman’s area X?

Answer 12

22 - Superior Temporal Gyrus

Question 13

Paraphasias

Answer 13

AKA “paraphasic errors”

Unintended syllables or words of 3 types

1. Literal (phonemic): substitution of phonetically similar words
2. Verbal (semantic): substitution of words with related meanings (i.e. ‘wife’ becomes ‘mother’)
3. Neologism (new and meaningless word insertion)

Question 14

Conduction aphasia - Pathology

Answer 14

damage to the arcuate fasciculus, a white matter tract connecting Wernicke’s and Broca’s areas; may also see supramarginal gyrus damage

T2 MRI shows a focal ischemic region in the left hemisphere extending into the subcortical white matter (arcuate fasciculus)

Question 15

Global Aphasia

Answer 15

The most severe form of aphasia, resulting from destruction of the entire perisylvian zone, usually due to middle cerebral artery infarct

Patients have essentially no language function in addition to right hemiplegia

Question 16

Alexia with agraphia - where is the lesion located?

Answer 16

Left angular gyrus

Question 17

Right hemisphere contributions to language

Answer 17

Automatic speech (expletives, outbursts)
Prosody - infection of speech with emotion
Humor
Metaphor
Recovery

Question 18

Motor aprosody

Answer 18

Inability to inflect speech with emotion

Results form a lesion of the right inferior frontal gyrus (Broca’s area homologue)

Question 19

Sensory aprosody

Answer 19

Diminished ability to comprehend the emotional inflection of speech

Due to a lesion in the right hemispheric analogue of Wernicke’s area in the superior temporal gyrus

Question 20

Hemineglect

Answer 20

Failure to respond or orient to sensory stimuli on one side of the body

More frequently caused by right-sided lesions of the parietal lobe

Question 21

Visual agnosia

Answer 21

Disorders of visual recognition