持續性注意力(sustained attention)損傷影響中風個案之功能性預後甚鉅。電腦化數字警醒度測驗(Computerized Digit Vigilance Test, C-DVT)可有效且快速評量個案之持續性注意力。然而，C-DVT之再測信度與隨機測量誤差仍待改善。昔日研究發現：二次施測取平均值較有助於再測信度與隨機測量誤差，然該研究因樣本數過低，研究結果仍不肯定。本研究目的為比較三種施測C-DVT方式（「增加施測次數再取平均（二次測量組）」、「增加練習時間（增加練習組）」、與「綜合增加施測次數與練習時間（綜合組）」）之於改良C-DVT再測信度與隨機測量誤差的效果。共62位中風個案參與本研究，個案被隨機分配到上述三組之一（「二次測量組」及「綜合組」21人；「增加練習組」20人）。再測信度結果顯示：「增加練習組」之組內相關係數(intraclass correlation coefficient = 0.94)高於「綜合組」(0.84)與「二次測量組」(0.74)；隨機測量誤差（以最小可偵測差異值百分率[percentage of minimal detectable change]）之結果顯示：「增加練習組」(10.9%)最佳，「綜合組」次之(18.1%)，「二次測量組」最差(21.3%)。上述結果顯示：正式施測C-DVT前多增加練習時間，最具潛力可改善C-DVT之再測信度與隨機測量誤差。本研究結果有助於後續使用者如何使用C-DVT以提升測量效能。

Deficits of sustained attention substantially affect functional outcomes of patients with stroke. The Computerized Digit Vigilance Test (C-DVT) is an efficient and valid measure of sustained attention. However, the test-retest reliability and random measurement error of the C-DVT remain to be improved. A previous study showed that the average score of two C-DVT assessments appears useful for improving the test- retest reliability and random measurement error of the C-DVT. However, the sample size of the study was small so the results were not conclusive. The purpose of this study was to investigate the effect of three methods of administrations (i.e., "increasing times of assessments and averaging the scores of assessments [increasing assessments]", "increasing practice time", and “combination of the two methods”) on improving test-retest reliability and random measurement errors of the C-DVT in patients with stroke. Sixty-two patients with stroke were randomly assigned to three groups. The results of the test-retest reliability showed that the increasing practice time group had highest intraclass correlation coefficient (ICC) of 0.94, the combination group had modest ICC of 0.84, and the increasing assessments group had the lowest ICC of 0.74. Regarding the random measurement error, the increasing practice time group had smallest percentages of minimal detectable change (MDC%) of 10.9%, the combination group had modest value of 18.1%, and the increasing assessments group had the highest value of 21.3%. Our findings suggest that increased practice time has great potential to improve the test-retest reliability and random measurement errors of the C-DVT. These findings are helpful for prospective users of the C-DVT to improve the efficiency of assessments.