Chronic cognitive impairment following laterothalamic infarcts: a study of 9 cases.
BACKGROUND
The occlusion of the lateral thalamic arteries leads to infarcts of ventrolateral thalamic nuclei, the ventroposterior nucleus, and the rostrolateral part of pulvinar, and produces hemisensory loss with or without hemiataxia. Cognitive impairment after such strokes has not been systematically studied.


OBJECTIVE
To determine the nature and the extent of long-lasting cognitive deficits following lateral thalamic strokes.


METHODS
Case series.


METHODS
Neurology department, Lausanne University Hospital, Lausanne, Switzerland.


METHODS
Nine patients with hemisensory loss due to an isolated laterothalamic infarct.


METHODS
Three to 6 months after stroke onset, standard neuropsychologic evaluation, including testing of language, ideomotor and constructive praxis, visual gnosis, spatial attention, learning abilities, and executive functions.


RESULTS
Six of 9 patients showed some degree of cognitive impairment. Executive functions tasks, particularly verbal fluency, were impaired in 5 patients (4 with right and 1 with left lesion). Learning and delayed recall in visuospatial and verbal tasks, but not in recognition, were impaired in 3 patients (2 with right and 1 with left lesion). Difficulties in visual gnosia were observed in 1 patient with right lesion while word-finding difficulties were observed in 1 patient with left lesion.


CONCLUSIONS
Our observations show that while learning, naming, and gnosic difficulties fit with the classical verbal/nonverbal dichotomy (left and right hemisphere, respectively), executive dysfunctions, including verbal fluency tasks, were more dominant after right thalamic infarcts. Although the observed deficits appeared to be less severe than those generally found with dorsomedial and polar thalamic strokes, the dominance of executive dysfunction suggests that ventrolateral thalamic lesions may disrupt frontothalamic subcortical loops.
Departments of Neurology, Lausanne University Hospital, Lausanne, Switzerland.
Jean-Marie
JM
Annoni
Asaid
A
Khateb
Sandrine
S
Gramigna
Fabienne
F
Staub
Antonio
A
Carota
Philippe
P
Maeder
Julien
J
Bogousslavsky
D000368:Aged; D000375:Aging / Q000523:psychology; D002544:Cerebral Infarction / Q000150:complications / Q000523:psychology*; D003072:Cognition Disorders / Q000209:etiology* / Q000523:psychology; D004453:Echoencephalography; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D020647:Lateral Thalamic Nuclei / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D020521:Stroke / Q000150:complications / Q000523:psychology; D020651:Ventral Thalamic Nuclei / Q000473:pathology; D014705:Verbal Behavior