title: A case study of hemispatial neglect using finite element analysis and positron emission tomography.
abstract: BACKGROUND
  The authors present a patient who developed transient hemispatial neglect following surgical drainage of a large right frontotemporal arachnoid cyst. As symptoms evolved in parallel with brain shift over the subsequent months, the authors hypothesized that the disorder was associated with the appearance of mechanical stresses in the cerebral mantle.
  
  
  METHODS
  To map tissue stress at the various stages of deformation, a finite element computer simulation was conducted on the basis of computed tomography scans of the patient.
  
  
  RESULTS
  The authors' results demonstrate substantial shear and compressive stress concentrations in the parietal lobe, a region commonly associated with neglect, and where positron emission tomography confirmed hypoperfusion in this patient. Treatment with combined ventricular-peritoneal and cystoperitoneal shunts was accompanied by clinical recovery and improvement of right parietal lobe cerebral blood flow.
  
  
  CONCLUSIONS
  The authors conclude that brain deformation was a contributing factor in the reversible neglect syndrome by compromising the normal flow of blood and/or the deactivation of subcortical circuits of the parietal lobe.
authors.affiliation: Academic Neurosurgery Unit, Wolfson Brain Imaging Centre, Addenbrooke's Hospital, Department of Engineering, University of Cambridge, United Kingdom. ap10007@wbic.cam.ac.uk
authors.forename: Alonso
authors.initials: A
authors.lastname: Peña
authors.forename: Brian K
authors.initials: BK
authors.lastname: Owler
authors.forename: Tim D
authors.initials: TD
authors.lastname: Fryer
authors.forename: Pawan
authors.initials: P
authors.lastname: Minhas
authors.forename: Marek
authors.initials: M
authors.lastname: Czosnyka
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Crawford
authors.forename: John D
authors.initials: JD
authors.lastname: Pickard
mesh_terms: D000368:Aged; D016080:Arachnoid Cysts / Q000150:complications / Q000601:surgery; D001931:Brain Mapping; D002560:Cerebrovascular Circulation; D020342:Finite Element Analysis; D006801:Humans; D008297:Male; D010468:Perceptual Disorders / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D014055:Tomography, Emission-Computed