title: Preliminary report of the Hepatic Encephalopathy Assessment Driving Simulator (HEADS) score.
abstract: BACKGROUND
  Audiovisual simulations of real-life driving (ie, driving simulators) have been used to assess neurologic dysfunction in a variety of medical applications. However, the use of simulated driving to assess neurologic impairment in the setting of liver disease (ie, hepatic encephalopathy) is limited.
  
  
  OBJECTIVE
  The aim of this analysis was to develop a scoring system based on simulated driving performance to assess mild cognitive impairment in cirrhotic patients with hepatic encephalopathy.
  
  
  METHODS
  This preliminary analysis was conducted as part of the Hepatic Encephalopathy Assessment Driving Simulator (HEADS) pilot study. Cirrhotic volunteers initially underwent a battery of neuropsychological tests to identify those cirrhotic patients with mild cognitive impairment. Performance during an audiovisually simulated course of on-road driving was then compared between mildly impaired cirrhotic patients and healthy volunteers. A scoring system was developed to quantify the likelihood of cognitive impairment on the basis of data from the simulated on-road driving.
  
  
  RESULTS
  Mildly impaired cirrhotic patients performed below the level of healthy volunteers on the driving simulator. Univariate logistic regression and correlation models indicated that several driving simulator variables were significant predictors of cognitive impairment. Five variables (run time, total map performance, number of collisions, visual divided attention response, and average lane position) were incorporated into a quantitative model, the HEADS scoring system. The HEADS score (0-9 points) showed a strong correlation with cognitive impairment as measured by area under the receiver-operator curve (.89).
  
  
  CONCLUSIONS
  The HEADS system appears to be a promising new tool for the assessment of mild hepatic encephalopathy.
authors.affiliation: Department of Transplantation Surgery, Mayo Clinic College of Medicine, Rochester, Minnesota, USA.
authors.forename: Edwina S
authors.initials: ES
authors.lastname: Baskin-Bey
authors.forename: Charmaine A
authors.initials: CA
authors.lastname: Stewart
authors.forename: Mary M
authors.initials: MM
authors.lastname: Mitchell
authors.forename: John P
authors.initials: JP
authors.lastname: Bida
authors.forename: Theodore J
authors.initials: TJ
authors.lastname: Rosenthal
authors.forename: Scott L
authors.initials: SL
authors.lastname: Nyberg
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D000368:Aged; D001333:Automobile Driver Examination; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D005260:Female; D006501:Hepatic Encephalopathy / Q000150:complications / Q000503:physiopathology / Q000523:psychology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D012720:Severity of Illness Index; D013647:Task Performance and Analysis; D014584:User-Computer Interface