APHASIA AND RELATED DISORDERS

Question 1

Perisylvian Zone

Answer 1

Perisylvian Zone (in dominant hemisphere—usually
left hemisphere)
* Broca’s area
* Arcuate fasciculus (association fibers)
* Wernicke’s area
* Angular gyrus + supramarginal gyrus = Inferior Parietal
Lobule

Question 2

Aphasia

Answer 2

• Aphasia
• Acquired language disorder
• A dysfunction of the hemisphere dominant for language
• Competency vs performance (access) problem
• Aphasia is an access problem if ….
• Symptoms are sometimes transient
• Co-existing impairments can exacerbate linguistic symptoms
• If a continuum exists from aphasic to typical
• Stimulability of patients with aphasia
• Variability of aphasic behavior

Question 3

Causes of aphasia

Answer 3

• Causes of aphasia:
• Cerebrovascular pathology
• Stroke causes 85% (~20% of all strokes L-CVA 
  aphasia)
• Traumatic brain injury
• Neoplastic conditions ~15%
• Degenerative disease
• Other factors

Question 4

Cerebrovascular Supply
* Two arterial systems
And where do they join?

Answer 4

• Two arterial systems
• CAROTID
• VERTEBRAL BASILAR
  (VERTEBROBASILAR)
• These join at the Circle of
  Willis (base of brain)

Question 5

Carotid System

Answer 5

• Common carotid artery
• Ascends on each side of
  neck
• Posterior to jaw, divides
  into external carotid (EC)
  and internal carotid (IC)
• IC joins Circle of Willis,
  then divides to form two
  cortical arteries
• Anterior cerebral artery
  (ACA)
• Middle cerebral artery
  (MCA)

Question 6

Internal Carotid Arteries divide into ..

Answer 6

Anterior Cerebral
Artery
Medial Surface of__hemisphere___
____________
Middle Cerebral
Artery
__Most of the lateral surface______________
____________

Question 7

Vertebral Basilar System

Answer 7

or “vertebrobasilar”)
* Two vertebral arteries ascend through upper cervical
vertebrae.
* Vertebral arteries merge at pons to form single
basilar artery.
* Single artery joins Circle of Willis.
* Basilar artery bifurcates and forms posterior cerebral
arteries (PCA)

• (Also, cerebellar arteries—blood to pons, cereb; spinal
  arteries—blood to portions of medulla, SC)

Question 8

Cortical Arteries ACA

Answer 8

___Anterior Cerebral artery___________________ (ACA)
* Internal carotid arteries divide into ACA and MCA
* Branches supply medial surface of hemisphere and
superior border of frontal and parietal lobe
* Interruption of bloodflow possibly leads to
* Paralysis of contralateral legs and feet
* Frontal lobe symptoms (inhibition, movement,
judgment, etc.)

Question 9

Cortical Arteries , MCA,

Answer 9

• ______Middle Cerebral Arteries____________________ (MCA)
• Internal carotid arteries divide into ACA and MCA
• Branches supply most of lateral surfaces, superior and
  lateral portions of temporal lobe, lateral surface of
  frontal lobe and deep structures of frontal and parietal
  lobes
• Very important because supplies motor speech areas,
  perisylvian language zones
• Most commonly affected in stroke!

Question 10

Cortical Arteries , PCA

Answer 10

• _____Posterior cerebral artery____________________ (PCA)
• Basilar artery bifurcates into PCA
• Branches supply occipital lobe and medial and inferior portions of temporal lobes
• Penetrating arteries off of posterior; travel deep into
  hemisphere to supply thalamus
• Interruption to bloodflow leads to vision impairment,
  numbness, memory loss, limb weakness, confusion, etc.

Question 11

Circle of Willis

Answer 11

• Connects the posterior and anterior
  cerebral blood system and
  therefore, provides COLLATERAL
  CIRCULATION – important
  function!
• If occlusion to one internal carotid
  artery occurs, the posterior blood
  supply could possibly take over

Question 12

Circle of Willis
* Consists of
Names of arteries that connect the cortical arteries in the circle of Willis

Answer 12

• Consists of:
• Portions of anterior (ACAs), middle (MCAs), and
  posterior cerebral arteries (PCAs)
• Anterior communicating artery
• ACAs are interconnected via anterior communicating
  artery
• Posterior communicating arteries
• Posterior communicating arteries connect internal
  carotids with basilar artery

Question 13

Watershed area
Where is it located ?

Answer 13

• Border zone region located between ACA/MCA
  branches and MCA/PCA branches on lateral
  surface of each hemisphere
• Can be most vulnerable to reductions in perfusion

Question 14

Types of Aphasia

Answer 14

• Aphasia can be broadly classified in different ways
• On the basis of fluency of speech
• Fluent aphasia
• Non-fluent aphasia
• Comprehension vs Production
• Expressive aphasia (e.g., Broca’s aphasia)
• Receptive aphasia (e.g., Wernicke’s aphasia)

Question 15

Classification systems

Answer 15

• Classifying into types of aphasia is helpful but not
  binding.
• Classification controversy of fractionation assumption
• Problematic due to brain damage affecting more than one
  part of the cortical areas
• Reliability issue
• In reality, diagnosing specific aphasia type is difficult and
  reliability is low across and within clinicians

Question 16

Classification systems

Answer 16

• Patients are classified as mild-moderate-severe within
  each aphasia type but more commonly/functionally as
  “expressive” or “receptive” or both.
• Patients may evolve to less severe forms
• E.g., global aphasia  Broca’s