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The focus of the current study was a comparison of performance on the WAIS-III Digit Symbol-Coding (DS-C) and WAIS-IV Coding (CD) subtests. Two samples of healthy, young adults completed either the DS-C subtest or the CD subtest. Free Recall and Pairing procedures were administered to the second sample. Also, CD performance of the healthy adults was compared to that of a cognitively impaired sample. The older version of the subtest produced higher scores than the newer version. Comparison of transcription patterns across four 30 s intervals indicated different patterns and greater variability on DS-C compared to CD. For this sample, the CD subtest appeared to be more demanding than DS-C. The young adults achieved higher scores on CD than the cognitively impaired sample, suggesting that the CD subtest has retained its clinical sensitivity. Results did not support significant differences between men and women on CD performance. Finally, preliminary norms for CD Free Recall and Pairing are provided.
The Digit Symbol-Coding (DS-C) subtest of the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III; Wechsler, 1997) and the Coding subtest (CD) of the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV; Wechsler, 2008a) are primarily measures of processing speed and clerical efficiency. Both subtests are complex and require attention, concentration, cognitive flexibility, visual scanning, adequate motor coordination, and positive test taking motivation (Joy, Fein, & Kaplan, 2003; Kreiner & Ryan, 2001; Sattler & Ryan, 2009). The DS-C and CD subtests both use keys containing nine numbers, each paired with a different abstract symbol, and a response sheet consisting of boxes with a number in the top part and an empty space in the bottom part. The examinee is required to copy the correct designs under their associated numbers as rapidly as possible within a 120-second time limit. Both editions produce total correct raw scores which are converted into scaled scores with a mean of 10 and a standard deviation of 3.
A validity study reported in the WAIS-IV: Technical and interpretive manual (Wechsler, 2008b) indicates that when both the WAIS-IV and WAIS-III (Wechsler, 1997) were administered to the same individuals, DS-C and CD subtest scores were highly correlated regardless of whether the examinees were healthy controls (n = 240; r = .85), persons with borderline intelligence (n = 24; r...