Synonyms:
(1) syndrome of the basilar communicating artery of Percheron
(2) syndrome of the mesencephalic artery
(3) thalamosubthalamic infarction syndrome
(4) syndrome of the thalamoperforating pedicle of Foix and Hillemand
Main features:
(1) abrupt onset
(2) dramatic fluctuations in sensorium/symptoms
(3) hypersomnolent apathy
(4) persistent amnesic syndrome resembling Korsakoff's syndrome
(5) abnormal vertical gaze, most often with dysfunction of downward gaze
Additional findings:
(1) "subcortical" dementia with preservation of verbal IQ and a relative absence of aphasia, agnosia and verbal apraxia.
(2) dysorthographia (disturbed writing without oral language difficulties)
(3) language difficulties (confabulatory and perseveratory responses, hypophonia, hypokinetic dysarthria, aprosodia)
(4) convergence insufficiency causing difficulty reading
(5) poor learning and recall
(6) impaired comprehension of complex auditory commands
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Symptom
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Anatomic Correlate
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amnesia
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dorsomedial nucleus
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vertical gaze abnormalities
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prerubral region
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hypokinetic dysarthria
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basal ganglia afferents
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obtundation
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intralaminar nuclei
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fluctuating deficits
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intralaminar nuclei
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Figure 5, page 384
Differential diagnosis:
(1) Korsakoff's syndrome
(2) cortical syndrome (these tend to be stable while PDS shows dramatic fluctuations in symptoms)
