既視感（déjà vu）体験評価尺度日本語版の作成とその妥当性の検討

Development of the Japanese Version of the Inventory of Déjà vu Experiences Assessment (IDEA)

【抄録】　既視感は，一般によく認められる精神事象であるが，これまで十分な検討がなされていない。筆者らは，Snoらが開発した既視感および関連精神現象の定量的評価尺度（Inventory for Déjà vu Experiences Assessment）を，原著者の許諾を得て日本語訳し，その信頼性および妥当性を検討した。

　健康正常者73例を対象とし，日本語版を2回実施した。A項目での内的一貫性は良好であった。順位データ項目の級内相関係数は0.49-0.88，二値データ項目のCohenのκ係数は大多数の項目で0.3以上であり，高い信頼性を示した。一般成人における既視感出現頻度は76.7％であり，性差はなく，高齢者では少ない傾向があった。これは，欧米での先行研究とほぼ同等であり，妥当性も十分と考えられた。

　The Japanese version of the Inventory for Déjà vu Experience Assessment (IDEA) has been developed under agreement with Dr. Herman Sno who elaborated the original IDEA. IDEA (Japanese version) was administrated twice for 73 adult volunteers (37 men and 36 women, mean 34.9 yrs) with no history of neuropsychiatric diseases.

　Reliability appeared to be sufficient as the Cronbach's α coefficient of nine items of general (A) section of IDEA was 0.69. With regard to test-retest reliability, intraclass correlation coefficients of the ordinal variables were from 0.49 to 0.88 and most of the kappa scores of the nominal variables were more than 0.30.

　The frequency of déjà vu experiences in Japanese normal subjects was 76.7%. No gender effect was observed in its frequency. Persons of the younger generation tended to show a higher frequency than those in the older generation. As these results were concordant with those in previous studies, the validity of the Japanese version of IDEA was confirmed.

　These findings suggested that the Japanese version of IDEA was quite valid as an evaluation tool for déjà vu experiences.