Posterior versus anterior circulation infarction: how different are the neurological deficits?

BACKGROUND AND
PURPOSE: Distinguishing between symptoms of posterior circulation infarction (PCI) and anterior circulation infarction (ACI) can be challenging. This study evaluated the frequency of symptoms/signs in the 2 vascular territories to determine the diagnostic value of particular symptoms/signs for PCI.
METHODS: Neurological deficits were reviewed and compared from 1174 consecutive patients with a diagnosis of PCI or ACI confirmed by magnetic resonance imaging in the Chengdu Stroke Registry. The diagnostic value of specific symptoms/signs for PCI was determined by measuring their sensitivity, specificity, positive predictive value (PPV), and the OR.
RESULTS: Homolateral hemiplegia (PCI, 53.6% versus ACI, 74.9%; P<0.001), central facial/lingual palsy (PCI, 40.7% versus ACI, 62.2%; P<0.001), and hemisensory deficits (PCI, 36.4% versus ACI, 34.2%; P=0.479) were the 3 most common symptoms/signs in PCI and ACI. The signs with the highest predictive values favoring a diagnosis of PCI were Horner's syndrome (4.0% versus 0%; P<0.001; PPV=100.0%; OR=4.00), crossed sensory deficits (3.0% versus 0%; P<0.001; PPV=100.0%; OR=3.98), quadrantanopia (1.3% versus 0%; P<0.001; PPV=100.0%; OR=3.93), oculomotor nerve palsy (4.0% versus 0%; P<0.001; PPV=100.0%; OR=4.00), and crossed motor deficits (4.0% versus 0.1%; P<0.001; PPV=92.3%; OR=36.04); however, all had a very low sensitivity, ranging from 1.3% to 4.0%.
CONCLUSIONS: This study indicates that the symptoms/signs considered typical of PCI occur far less often than was expected. Inaccurate localization would occur commonly if clinicians relied on the clinical neurological deficits alone to differentiate PCI from ACI. Neuroimaging is vital to ensure accurate localization of cerebral infarction.