Higher Cortical Function: Language

Question 1

Which hemisphere of the cortex is responsible for speech?

Answer 1

The dominant hemisphere (i.e. the left hemisphere in right handed people).

Question 2

List the areas of the brain that are responsible for the generation of speech.

Answer 2

1 - Broca’s area of the inferior frontal gyrus.

2 - Wernicke’s area of the superior temporal gyrus.

3 - Arcuate fasciculus.

Question 3

What is the arcuate fasciculus?

Answer 3

A bundle of axons that connects the Broca’s area of the inferior frontal gyrus to the Wernicke’s area of the superior temporal gyrus.

Question 4

List the areas of the brain that are responsible for the modulation of motor output to the muscles controlling speech.

Answer 4

1 - Corticobulbar pathway.

2 - Cerebellum.

3 - Basal ganglia.

Question 5

List 2 cranial nerves and 1 spinal nerve that convey the motor output to the muscles controlling speech.

List the structures that each nerve supplies.

Answer 5

Cranial nerves:

1 - CN X - supplies the larynx.

2 - CN XII - supplies the tongue.

Spinal nerves:

1 - Phrenic nerve - supplies the intercostals.

Question 6

List 4 mechanical structures that produce and control speech.

Answer 6

1 - Larynx (generates the voice).

2 - Oropharynx (modulate the voice).

3 - Sinuses (modulate the voice).

4 - Intercostals (act as bellows).

Question 7

Define aphonia.

Answer 7

Complete loss of phonation.

Question 8

Define dysphonia.

Answer 8

Partial impairment of phonation.

Question 9

Define anarthria.

Answer 9

Complete impairment of articulation of speech.

Question 10

Define dysarthria.

Answer 10

Partial impairment of articulation of speech.

Question 11

Define aphasia.

Answer 11

Complete loss of language comprehension and production.

Question 12

Define dysphasia.

Answer 12

Partial loss of language comprehension and production.

Question 13

List 4 characteristics of aphonia and dysphonia.

Answer 13

1 - Low volume of speech.

2 - Muscle weakness.

3 - Vocal cord paralysis.

4 - Can still write and gesture accurately.

5 - Pathology is lower than the brainstem, e.g. damage to the nerves supplying the vocal cords or mechanical damage to the vocal cords.

Question 14

List 5 characteristics of anarthria and dysarthria.

Answer 14

1 - Slurring but content is normal.

2 - Muscle weakness.

3 - Partial vocal cord paralysis.

4 - Can still write and gesture accurately.

5 - Pathology is non-cortical, i.e. cerebellar or brainstem.

Question 15

List 2 types of aphasia.

Answer 15

1 - Expressive.

2 - Receptive.

Question 16

What causes expressive aphasia?

List 2 characteristics of expressive aphasia.

Answer 16

• Expressive aphasia is caused by a lesion in the the Broca’s area of the inferior frontal gyrus of the dominant hemisphere.

1 - Speech is not fluent.

2 - Comprehension of speech is preserved.

3 - Motor pathways are impaired.

4 - Patients can understand their own speech (frustrated).

Question 17

What causes receptive aphasia?

List 2 characteristics of receptive aphasia.

Answer 17

• Receptive aphasia is caused by a lesion in the Wernicke’s area of the superior temporal gyrus of the dominant hemisphere.

1 - Speech is fluent but is unintelligible.

2 - Comprehension of speech is impaired.

3 - Sensory pathways are impaired.

4 - Patients cannot understand their own speech (not frustrated as they are unaware of their limitation).

Question 18

What is global aphasia?

Answer 18

A combination of both receptive and expressive aphasia.

Question 19

Give an example of a shared feature between expressive and receptive aphasia.

Answer 19

Both expressive and receptive aphasia impair naming.

Question 20

Which disorder is characterised by an impairment of repetition of speech?

What causes this disorder?

Answer 20

• Conductive aphasia is characterised by an impairment of repetition of speech.
• It is caused by a lesion in the arcuate fasciculus.

Question 21

List 2 causes of aphasia.

Answer 21

1 - Stroke.

2 - Brain tumours.