平板電腦版符號數字轉換測驗應用於思覺失調症病患之隨機測量誤差與練習效應改良

Abstract

背景:訊息處理速度 (information processing speed) 損傷是思覺失調症病患 常見之症狀,影響個案之生活功能甚巨。平板電腦版符號數 轉換測驗(Tablet- based Symbol Digit Modalities Test,T-SDMT)可快速、方便評量思覺失調症病患 之訊息處理速度。然而 T-SDMT 具有中度練習效應與隨機測量誤差,因此本研究 之目的在於探究降低 T-SDMT 練習效應與隨機測量誤差之施測方法,以期提升 T-SDMT 之實用價值。 方法:我們將提出 3 種改良版施測方式,一是多次測量、二是增加練習時 間、三是結合多次測量與增加練習時間,再驗證 3 種改良版施測方式降低隨機誤 差之效能。我們將徵召 120 位慢性思覺失調症病人,這些病人將被隨機分配至 【多次測量】、【增加練習時間】或【多次測量與增加練習時間】組別。三組病 人接受 2 次施測,其時間間隔 2 週。 結果:本研究結果發現三種施測方式都有良好的再測一致性,以【增加練習 時間】組的再測一致性最高。【多次測量與增加練習時間】組較能有效降低隨機 測量誤差與本研究的預期一致,但成效有限。練習效應在三組中都 在,以【多 次測量與增加練習時間】組和【增加練習時間】組比較能降低練習效應。 結論:【多次測量與增加練習時間】組可降低一些隨機測量誤差,與我們的 預期相同,但是還需要繼續改良降低其隨機測量誤差到臨床適用的程度。因練習 效應依舊 在,後續研究宜再增加練習時間與施測次數,以期提升 T-SDMT 之 臨床效能。

Background: Slow information processing speed is a common deficit of patients with schizophrenia, severely affecting their functions of daily life. The Tablet-based Symbol Digit Modalities Test (T-SDMT) is a quick and easy-to use measure assessing processing speed in patients with psychosis. However, the practice effect and substantial random measurement error have limited the utility of the T-SDMT. The purposes of this study were to explore the effect of different measuring methods on reducing the T- SDMT’s practice effect and the random measurement error. Methods: The author proposed three kinds of measuring methods on three groups of patients, respectively. The first group was measured by repeated measurements for 2 formal tests, the second group was to increase practice time for three minutes and then taking one formal testing, and the last group was the combination of increased practice times for three minutes and taking repeated measurements for 2 formal tests. The author recruited 87 patients with chronic schizophrenia. These patients were randomly assigned to 3 groups mentioned above, repeated-measurements group, increasing- practice-time group, combination of repeated measurements and increasing practice time group. Three groups of patients received test and re-test testing. The test and retest were administered 2 weeks apart. Results: The results of this study found that the three methods had good test-retest consistency. The increasing-practice-time group had the highest test-retest consistency. The combination group could effectively reduce random measurement errors. However, practice effect existed in all three groups. The increasing-practice-time group and combination group could reduce the practice effects effectively than the repeated- measurements group. Conclusion: The combination of repeated measurements and increasing practice time can reduce the random measurement errors, which was better than the other 2 groups. However, the random measurement errors needed to be further decreased for clinical utility. In addition to the practice effect, the future studies should further increase practice time and the number of testing (e.g., 3 formal tests), in order to enhance the utility of the T-SDMT.