RESUMEN
OBJECTIVE: To determine the validity and reliability of the Thai version of the Cognitive Impairment or Decline section of WHO Schedules for Clinical Assessment in Neuropsychiatry (SCAN) version 2.1. MATERIAL AND METHOD: The SCAN interview version 2.1 Cognitive Impairment or Decline Section was translated into Thai and its content validity tested by back translation. Psychiatrists competent in the use of the schedules and aware of their underlying objectives tested the linguistic clarity of the psychiatric schedules for Thais from the country's four regions. The reliability of SCAN: Cognitive Impairment or Decline Section was tested between June and November 2005 on 30 participants, including 15 patients with cognitive impairment and 15 normal volunteers. RESULTS: Based on reactions from Thais and consultations from competent psychiatrists, content validity was indeed established. The duration of interviews for the Cognitive Impairment or Decline Section averaged 48.99 min (59.71 for patients with cognitive impairment and 33.77 for normal subjects). The respective mean inter- and intra-rater reliability kappa was 0.72 (SD = 0.31) and 0.78 (SD = 0.23). The reliability of the majority of items reached a substantial to almost perfect level; however, three items (3.66%) had poor and nine (6.67%) only slight inter-rater agreement. Some items needed clarification of the scoring method. The respective inter- and intra-rater reliability of the continuous data was 0.93 and 0.96. CONCLUSION: The Cognitive Impairment or Decline Section of the WHO Schedules for Clinical Assessment in Neuropsychiatry (SCAN Thai Version) is demonstrably an effective tool for diagnosing cognitive impairment disorders among Thais.