Balint’s Syndrome

• Triad of:

o Simultanagnosia

o Ocular apraxia

o Optic Ataxia

• Individual elements:

o Simultanagnosia

- Inability to grasp entire meaning of a picture despite the capacity to recognise individual elements (Cant see the forest for the trees)

- Deficit/narrowing of attention

o Ocular apraxia

- Unable to generate voluntary saccades despite normal involuntary, reflexive saccades

- Disconnection of occipital lobe from frontal eye fields

- Also referred to as “psychic gaze paralysis” or “spasm of fixation”

o Optic ataxia (visuomotor ataxia)

- A defect in reaching under visual guidance

- Disconnection between occipital lobe and anterior frontal motor control centres

• Other symptoms/signs:

o Will not fixate on novel stimuli in visual field

o Lack of blink to threat

o Become visually fixated on single objects

• Bilateral parietal lesions

• Specific causes:

o Hypotensive stroke

o Dementia’s (Posterior cortical atrophy)

o PRES

o CJD

o PML

o Other: CNS vasculitis, adrenoleukodystrophy, perinatal hypoxic injury, RCVS, acute haemorrhagic leukoencephalitis

Gerstmann Syndrome

Clinical features

• Alexia +/- agraphia

• Acalculia

• Left-right disorientation

• Finger agnosia

Localisation:

• Dominant Parietal lobe

o If in isolation may be Inferior parietal lobule, particularly angular gyrus and surroundwhite matter

Examination:

• Finger agnosia – ask patient to name or point to a finger (of their own or examiner)

• Left right disorientation – ask patient to raise left/right hand

• Combine above:

o by asking patient to put left thumb or little finger on right ear.

o Examiner crosses their arms and asks patient to touch a specific digit (with a specific hand) – e.g. touch my left ring finger with your right hand

Posterior Cortical Atrophy Syndrome

Consensus classification of posterior cortical atrophy. 2017

Clinical Features

• Insidious onset

• Gradual progression

• Prominent early disturbance of visual ± other posterior cognitive functions

Cognitive Features

(At least three of the following must be present as early or presenting features):

• Space perception deficit

• Balint’s syndrome:

o Simultanagnosia

o Oculomotor apraxia

o Optic ataxia

• Object perception deficit

• Constructional dyspraxia

• Environmental agnosia

• Dressing apraxia

• Gerstmann syndrome:

o Alexia

o Agraphia

o Acalculia

o Left/right disorientation

o Finger agnosia

• Limb apraxia (not limb-kinetic)

• Apperceptive prosopagnosia (

• Homonymous visual field defect

All of the following must be evident:

• Relatively spared anterograde memory function

• Relatively spared speech and nonvisual language functions

• Relatively spared executive functions

• Relatively spared behaviour and personality

Neuroimaging:

• Predominant occipito-parietal or occipito-temporal atrophy on magnetic resonance imaging/hypometabolism on positron emission tomography/hypoperfusion single-photon emission computed tomography

Title

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Visual agnosia (inc. prosopagnosia)

• Loss of ability to recognise despite normal visual and naming function

• Apperceptive agnosia

o Perceptual defect distorts the visual image so that the object is unrecognisable

o May be able to see parts but not the whole (e.g. simultanagnosia)

o Apperceptive prosopagnosia – able to recognise parts of face, but not put it all together

o Lesions of bilateral parieto-occipital regions

• Associative agnosia

o Inability to associate object with past experience and memory

o Object can be recognised using other sensory modalities

o Associative prosopagnosia - Can describe face but unable to associate it with particular person

o Lesions of bilateral occipitotemporal region