title: Prolonged N200 is the early neurophysiologic change in the patient with minimal hepatic encephalopathy.
abstract: BACKGROUND
  In neurophysiological studies, P300, is well known for reflecting early cognitive impairment in minimal hepatic encephalopathy (MHE). Although P300 is investigated extensively, other early event-related potential (ERP) parameters have not been studied in MHE.
  
  
  METHODS
  The subjects were 21 adult cirrhotic patients without clinical encephalopathy and 29 normal controls. For neuropsychological testing, number connection tests, A and B (NCT-A, NCT-B), the line tracing test, the serial dotting test (SDT), and the digit symbol test (DST) were performed. For ERP testing, auditory oddball paradigms were used. The N100, P200, N200, and P300 parameters were measured.
  
  
  RESULTS
  Cirrhosis had longer neuropsychological performance scores on NCT-A, SDT, and DST than the control group. In neurophysiological test, cirrhotic patients showed longer latencies for N100, P200, N200, and P300 than the control group. Although P300 alteration was not seen in patients without MHE compared to the control group (325.4±43.3 vs. 345.21±35.1, p=0.25), N200 latency was significantly prolonged in cirrhotic patients without MHE compared to the healthy group (242.1±30.3 vs. 259.58±33.3, p=0.006). N200 also showed good correlation with psychometric hepatic encephalopathy score and critical flicker frequency.
  
  
  CONCLUSIONS
  N200 is a useful tool for assessing early changes of cognitive dysfunction in cirrhosis. It suggests that slower auditory cortical processing is the first sign of cerebral deterioration in patients with hepatic encephalopathy.
authors.affiliation: Department of Pediatrics, Hanyang University School of Medicine , Seoul , Korea.
authors.forename: Jin-Hwa
authors.initials: JH
authors.lastname: Moon
authors.forename: Dae Won
authors.initials: DW
authors.lastname: Jun
authors.forename: Myung-Kul
authors.initials: MK
authors.lastname: Yum
authors.forename: Kang Nyeong
authors.initials: KN
authors.lastname: Lee
authors.forename: Hang Lak
authors.initials: HL
authors.lastname: Lee
authors.forename: Oh Young
authors.initials: OY
authors.lastname: Lee
authors.forename: Byung Chul
authors.initials: BC
authors.lastname: Yoon
authors.forename: Ho Soon
authors.initials: HS
authors.lastname: Choi
authors.forename: Joon Soo
authors.initials: JS
authors.lastname: Hahm
authors.forename: In Joon
authors.initials: IJ
authors.lastname: Seol
authors.forename: Jae-Won
authors.initials: JW
authors.lastname: Oh
authors.forename: Chang-Ryul
authors.initials: CR
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D016022:Case-Control Studies; D003071:Cognition / Q000502:physiology; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006501:Hepatic Encephalopathy / Q000209:etiology / Q000503:physiopathology* / Q000523:psychology; D006801:Humans; D008103:Liver Cirrhosis / Q000150:complications / Q000503:physiopathology* / Q000523:psychology; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012372:ROC Curve