title: Recovery of cognitive function after surgery for aneurysmal subarachnoid hemorrhage.
abstract: OBJECTIVE
  Abnormalities in neurocognitive function are common after surgery for aneurysmal subarachnoid hemorrhage, even among patients with good functional outcomes. The time course of neurocognitive recovery, along with the long-term effects of mild intraoperative hypothermia (33 degrees C) and aneurysm location, is unknown. We determined these in a subset of subarachnoid hemorrhage patients enrolled in the Intraoperative Hypothermia for Aneurysm Surgery Trial (IHAST).
  
  
  METHODS
  We performed a longitudinal, multicenter, prospective, blinded study of adult IHAST patients with a Glasgow Outcome Score=1 or 2 (independent function), 3 months postsurgery and a matched control group (n=45). Subjects were tested with a 5-test cognitive function battery and standard neurological evaluations at 3, 9 and 15 months postsurgery. The primary outcome measure was a composite score on cognitive test performance.
  
  
  RESULTS
  There were 303 IHAST patients available for inclusion: 218 eligible, 185 enrolled (89 hypothermic, 96 normothermic). Significant cognitive improvement was noted from 3 to 9 (P<0.001) and 3 to 15 (P<0.001) months in both hypothermic and normothermic groups, even after adjusting for practice effects observed in the control group. No significant change was identified between 9 and 15 months. Neither mild hypothermia nor aneurysm location (anterior communicating artery versus others) had a significant effect on recovery over time or frequency of cognitive impairment. Compared with control group, the frequency of cognitive impairment (Z score <-1.96) in all patients at 3, 9 and 15 months was 36%, 26% and 23%, respectively.
  
  
  CONCLUSIONS
  In this population, cognitive improvement continued beyond 3 months, with a plateau between 9 and 15 months. This was not affected by the use of intraoperative hypothermia or anatomical location of aneurysm.
authors: Department of Anesthesiology, University of Michigan Medical Center, University Hospital, Ann Arbor, MI 48109-0048, USA. satsam@umich.edu
authors: Satwant K
authors: SK
authors: Samra
authors: Bruno
authors: B
authors: Giordani
authors: Angela F
authors: AF
authors: Caveney
authors: William R
authors: WR
authors: Clarke
authors: Phillip A
authors: PA
authors: Scott
authors: Steven
authors: S
authors: Anderson
authors: Byron G
authors: BG
authors: Thompson
authors: Michael M
authors: MM
authors: Todd
mesh_terms: D000328:Adult; D000368:Aged; D003071:Cognition / Q000502:physiology; D003072:Cognition Disorders / Q000209:etiology / Q000503:physiopathology / Q000534:rehabilitation*; D005260:Female; D006801:Humans; D038622:Internationality; D002532:Intracranial Aneurysm / Q000503:physiopathology / Q000534:rehabilitation* / Q000601:surgery; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000503:physiopathology / Q000534:rehabilitation*; D011446:Prospective Studies; D020127:Recovery of Function / Q000502:physiology*; D013345:Subarachnoid Hemorrhage / Q000503:physiopathology / Q000534:rehabilitation* / Q000601:surgery