title: Ataxic hemiparesis: critical appraisal of a lacunar syndrome.
abstract: OBJECTIVE
  Ataxic hemiparesis is a well-recognized lacunar syndrome involving homolateral ataxia with accompanying corticospinal tract impairment. Despite 30 years of clinical experience there continues to be some doubt as to the defining clinical characteristics, precise neuroanatomic localization of the syndrome, and etiologic mechanisms.
  
  
  METHODS
  We now present 45 new cases that have been analyzed for clinico-radiologic correlation and etiology. Also, all published cases from the English literature known to the authors are reviewed.
  
  
  RESULTS
  We found that the clinical syndrome of ataxic hemiparesis accurately predicts a small deep infarction, generally in the pons or internal capsule. Sensory loss is highly associated with a capsular localization. We found that 47% of the cases were attributed to small-vessel disease, 11% to cardioembolism, and only 7% to artery-to-artery embolism (all in the basilar artery); 1 case was attributed to thrombocytosis, 1 to multiple sclerosis, and the rest either had negative or incomplete evaluation. Approximately two thirds of the infarctions occurred in patients with neuroimaging evidence of other ischemic brain lesions.
  
  
  CONCLUSIONS
  Ataxic hemiparesis is a distinct clinical syndrome that accurately predicts a small deep infarction, most commonly in the pons or internal capsule. Only sensory loss accurately predicts a capsular localization. Etiology in nearly half of the cases can be attributed to small-vessel disease. Furthermore, ataxic hemiparesis appears to be a good marker for generalized asymptomatic cerebrovascular disease.
authors.affiliation: Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Gorman
authors.forename: R
authors.initials: R
authors.lastname: Dafer
authors.forename: S R
authors.initials: SR
authors.lastname: Levine
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001259:Ataxia / Q000209:etiology*; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D002544:Cerebral Infarction / Q000150:complications* / Q000175:diagnosis* / Q000188:drug therapy; D005260:Female; D006429:Hemiplegia / Q000209:etiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D013577:Syndrome; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D010975:Platelet Aggregation Inhibitors