A. 6 - Types and localisation of aphasia Flashcards

1
Q

what is aphasia?

A

speech disorder with an inability to comprehend and/or formulate language. It is caused by lesions of cortical speech centers and their connections.

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2
Q

where are the Brain regions related to speech located ?

A

in most people in the dominant (left)
hemisphere

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3
Q

what are the 2 Brain regions related to speech located?

A

Wernicke’s speech center

Broca’s motor speech
center

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4
Q

where is Wernicke’s speech center?

A

(Br22 + small part of Br39 and Br40) → comprehension of speech

○ Lies adjacent to the primary auditory cortex (in
the posterior 2/3 of the superior temporal gyrus

○ Connection with angular gyrus ensures coupling of perceptual and
learned memories with speech

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5
Q

Where is Broca’s motor speech
center?

A

In the middle and inferior frontal gyrus + the lower part of the precentral gyrus (Br44)

○ Connected to the arcuate bundle with the angular and the supramarginal gyri + the Wernicke area

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6
Q

what are the Basic types of aphasia?

A

Motor:
(Broca’s, expressive, non-fluent, anterior type)

Sensory
(Wernicke’s, receptive, fluent, posterior type)
* Undercategories: conduction, transcortical sensory and amnestic aphasias

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7
Q

what are the Lesions of cortical speech centers?

A

Global aphasia
Motor (Broca’s) aphasia
Sensory (Wernicke’s) aphasia

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8
Q

what is global aphasia?

A

The entire distribution of the middle cerebral artery is affected, including both Broca’s and Wernicke’s areas and arcuate fasiculus (which connects both areas)

-no fluency, no comprehension, no repetition
Severe impairment of speech production and comprehension
Patient may be mute or only utter sounds

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9
Q

what is affected in global aphasia?

A

all aspects of language and severely impairs spoken communication.
Patient is unable to speak and understand language.

● Language automatism (repetition of gibberish) is a characteristic feature.

● Associated with severe hemiparesis – simultaneously destroy the motor and sensory speech centers

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10
Q

what is Motor (Broca’s) aphasia?

A

Disorder of coordination of the muscles of speech and the verbal elements of language.

no fluency
no repetition
only comprehends

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11
Q

what is the etiology behind motor aphasia?

A

May be due to an infarction of a branch of the middle cerebral artery

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12
Q

what imotor (broca’s) aphasia is characterised by?

A

severe impairment of spontaneous speech, while comprehension is not affected

● The patient can only speak with great effort (knows what he wishes to say, but unable to say it)

● Paraphasia: Substitutes one word for another

● Agrammatism: Grammatical errors in speech

● Telegraphic type: Gives responses with one word or simple sentences

● Agraphia: Writing is affected

● Patient is aware of disorder, and will be quiet

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13
Q

what is Sensory (Wernicke’s) aphasia?

A

Severe impairment of comprehension, while spontaneous speech remains fluent with a normal rhythm.

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14
Q

what is Sensory (Wernicke’s) aphasia caused by?

A

May be due to infarction of posterior temporal artery
(branch of middle cerebral artery).

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15
Q

what Sensory (Wernicke’s) aphasia is characterised by?

A

● Use of inappropriate words, generated nonsensical sentences and tends to speak too much with repetition of certain words.

● Paraphasia

● Agrammatism

● Neologism: Forming new and non-existent words, making speech incomprehensible

● The patient is typically unaware of his disorder

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16
Q

what are the Dissociation syndromes?

A

disruption of pathways between language areas

ex:
Conduction aphasia
Alexia without agraphia
Auditory agnosia
Transcortical motor aphasia
Amnestic aphasia

17
Q

what is Conduction aphasia?

A

Lesion of the arcuate fasciculus. Characterized by normal speech, but impaired repetition. Patient is aware and frustrated by this.

18
Q

Alexia without agraphia?

A

Lesion in left occipital lobe usually due to infarct of the posterior cerebral artery.

The visual information cannot reach the language areas, and the patient is unable to read, but are able to write (pure word blindness).

19
Q

what is Auditory agnosia?

A

Bilateral lesion of superior temporal gyri. The patient is unable to understand spoken words, and thus unable to repeat them (pure word deafness).

20
Q

what is Transcortical motor aphasia?

A

Lesion in the frontal lobe bordering on Broca’s area – disrupts connection
between Broca area and premotor and supplementary motor areas.

Heard words can be repeated
(echolalia), but other linguistic functions are impaired.

21
Q

what is Amnestic aphasia ?

A

Diffuse lesion of temporoparietal cortex, or in metabolic encephalopathies. Word finding difficulty.

22
Q

what is Subcortical aphasia?

A

Damage to subcortical areas of the dominant hemisphere (mainly in cerebrovascular disorders) leads to
aphasia, which is often difficult to categorize.

Lesions of the basal ganglia, internal capsule and corona radiata.

23
Q

how do you do Examination of aphasia?

A
  1. Fluent or not
  2. Comprehensive or not
  3. Repeats or not
  4. Check reading, writing and object naming