Posterior Cortical Atrophy

Question 1

What is the pathophysiology of PCA?

Answer 1

Alzheimer’s pathology in most patients
Affects parietal, occipital and occipitotemporal cortices

Can also have Lewy body, corticobasal degeneration and prion

Question 2

Physical exam findings of PCA

Answer 2

Usually unremarkable
Look for visual acuity, fundoscopy, VF assessment
Finger myoclonus

Question 3

Neuroimaging studies and findings for PCA

Answer 3

1. MRI
2. SPECT
3. PET
   Predominant occipito-parietal or occipito-temporal atrophy/hypometabolism/hypoperfusion

Question 4

Diagnostic criteria for PCA

Answer 4

Clinical: insidious onset, gradual progression, prominent early disturbance of visual +/- other posterior cognitive functions

Cognitive
At least 3 of following as early or presenting and must impact ADL: space perception deficit, simultagnosia, object perception deficit, constructional dyspraxia, environmental agnosia, oculomotor apraxia, dressing apraxia, optic ataxia, alexia, L/R disorientation, acalculia, limb apraxia, apperceptive prosopagnosia, agraphia, homonymous visual field defect, finger agnosia

All of: relatively spared anterograde memory function, speech/nonvisual language, executive fun, behaviour/personality

Question 5

What are the exclusion criteria for PCA?

Answer 5

Brain tumour or other mass lesion
Significant vascular disease including focal stroke
Afferent visual cause
Other cause for CI

Question 6

Non pharmacologic management of PCA

Answer 6

Support groups
Resources for visual impairment
OT or sensory team
Ophtho/optometry
Driving is not safe

Question 7

What are pharmacologic management for PCA?

Answer 7

No studies for ACHEI but often used
Antidepressants if persistent low mood
Trial Ldopa if Parkinsonism

Question 8

What two syndromes can PCA have features of?

Answer 8

Balint’s syndrome (simultagnosia, oculomotor apraxia, optic ataxia, environmental agnosia)

Gerstmann’s syndrome (acalculia, agraphia, finger agnosia, L/R disorientation)

Question 9

What is simultagnosia?

Answer 9

Lack of ability to perceive more than one single object at a time

Question 10

What is oculomotor apraxia?

Answer 10

Difficulty with performing voluntary eye movements
Can freely move eyes in all direction but hard time doing it under command

Question 11

What is optic ataxia?

Answer 11

Difficulty completing visually guided reaching tasks in absence of other sensory cues

Question 12

What area of the brain is affected in Balint syndrome?

Answer 12

Posterior parietal cortex
OR
Bilateral occipital-parietal cortex