The syndrome of combined polar and paramedian thalamic infarction.
BACKGROUND
Occlusion of the polar or the paramedian arteries of the thalamus usually leads to distinct infarcts with specific clinical and imaging correlates. However, vascular variation is such that in up to one third of humans, the polar artery is missing and its territory taken over by the paramedian arteries.


OBJECTIVE
To provide attention to the corresponding stroke syndrome of combined polar and paramedian thalamic infarction.


METHODS
We studied combined polar-paramedian thalamic infarction in 12 patients (6 right-sided lesions, 3 left-sided lesions, and 3 bilateral lesions) who were selected from 208 consecutively registered patients with thalamic strokes in the Lausanne Stroke Registry.


RESULTS
The clinical manifestation included executive dysfunction, apathy, and memory impairment in all patients, with eye movement disturbances in 10 patients (5 with right-sided lesions, 2 with left-sided lesions, 3 with bilateral lesions); acutely impaired consciousness in 11 patients (5 with right-sided lesions, 3 with left-sided lesions, 3 with bilateral lesions); aphasic disturbances in 8 patients (2 with right-sided lesions, 3 with left-sided lesions, 3 with bilateral lesions), including nonfluent aphasia in 1 patient (with left-sided lesions); dysarthria in 5 patients (4 with right-sided lesions, 1 with bilateral lesions); constructional apraxia in 5 patients (with right-sided lesions); mild hemiparesis in 4 patients (2 with right-sided lesions, 2 with left-sided lesions); dyscalculia in 3 patients (1 with left-sided lesions,1 with right-sided lesions, 1 with bilateral lesions); limb dystonia or asterixis in 2 patients (1 with right-sided lesions, 1 with bilateral lesions); mild hemisensory loss in 2 patients (1 with right-sided lesions, 1 with left-sided lesions); hemiataxia in 1 patient (with right-sided lesions); and ideomotor apraxia in 1 patient (with left-sided lesions). Follow-up showed severely disabling, persistent amnesia in 7 patients (4 with right-sided lesions, 3 with bilateral lesions) and persistent eye movement dysfunction in 5 patients (2 with right-sided lesions, 1 with left-sided lesions, 2 with bilateral lesions). The most common etiology appeared to be cardioembolism, followed by artery-to-artery embolism and presumed small-artery disease.


CONCLUSIONS
Key features of this syndrome included amnesia preceded by a period of altered consciousness, and vertical eye movement disturbances. The severe and persistent amnesia may be due to coexisting damage to the anterior and dorsomedial nuclei.
Perren
Fabienne
F
Department of Neurology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland. fabienneperren@yahoo.com
Clarke
Stephanie
S
Bogousslavsky
Julien
J
D000328:Adult; D000368:Aged; D000647:Amnesia / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D020643:Anterior Thalamic Nuclei / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D020520:Brain Infarction / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D002941:Circle of Willis / Q000473:pathology / Q000503:physiopathology; D003244:Consciousness Disorders / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D020645:Mediodorsal Thalamic Nucleus / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D008875:Middle Aged; D015835:Ocular Motility Disorders / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D013786:Thalamic Diseases / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D013788:Thalamus / Q000098:blood supply / Q000473:pathology* / Q000503:physiopathology*; D014057:Tomography, X-Ray Computed