#BAKWARD DIGIT SPAN TEST PDF TRIAL#
For example, a subject with variable performance who misses one trial in FS testing at lengths of 3, 4, 5, 6, 7 and 8 will have the same total correct score as another subject who accurately reports all trials at lengths 3, 4, and 5, but who fails twice at list length 6. First, it conflates inconsistent performance with limits in maximal DS. In addition, the standard Wechsler total correct metric of DS performance is problematic for two reasons. However, it may seriously underestimate the ML of subjects who are distracted or who encounter idiosyncratically difficult digit strings (e.g., permutations of their telephone area code) at a particular length. This procedure assumes that the subject’s “true” maximum length (ML) span can be assessed by only four list presentations: two at the ML and two above. A second, more serious problem relates to the suboptimal sampling of list lengths that bound the subjects’ maximal DS: testing ceases as soon as the subject misses two lists of the same length. This procedure is relatively inefficient for subjects with normal memory spans (e.g., 7 digits in FS) because eight trials are delivered before the subject reaches list lengths that challenge memory capacity. First, WMS-III testing involves the presentation of two digit lists at each span length, beginning with three digits in FS testing and two digits in BS testing. There are also two problems in the methods used by the Wechsler Memory Scale-III (WMS-III) ( Wechsler, 1997b) to sample digit list lengths.
#BAKWARD DIGIT SPAN TEST PDF CODE#
Certain digit sequences (e.g., the local telephone area code) may inflate digit span in geographic regions where particular digit sequences are overlearned and underestimate span where digit sequences conflict with previously overlearned strings (e.g., the digit sequence “415” in a region where the local telephone area code is “451”). In addition, the digits in each list are not selected randomly. First, because each list is read aloud by an examiner there are variations in the rate, intensity, emphasis and clarity of digit enunciations on each presentation as well as variations in clarity between different examiners ( Reeves, Schmauder, & Morris, 2000 Silverman, 2007). In traditional DS testing digit salience is influenced by two factors. The total number of lists reported correctly is combined across forward span (FS) and backward span (BS) to produce a Wechsler total correct score. Testing ceases when the subject fails to accurately report either trial at one sequence length or when the maximal list length is reached (9 digits forward, 8 backward). Digit sequences are presented beginning with a length of two digits and two trials are presented at each increasing list length. In each case, digit span is measured for forward and reverse-order (backward) recall of digit sequences. For decades they have been a component of the widely used Wechsler memory scales (WMS) and Wechsler intelligence scales for adults and children ( Wechsler, 1997a, 1997b). Results supported measurement invariance and it was concluded that forward and backward digit span scores should be interpreted as measures of the same cognitive ability.Measures of forward and backward digit span (DS) are among the oldest and most widely used neuropsychological tests of short-term verbal memory ( Richardson, 2007). Measurement invariance tests of the precise numerical generalization of trait estimation across groups. The model for Digit Span was then cross-validated in a seizure disorders sample (n = 223) by replication of the CFA and by examination of measurement invariance. Results suggested that four correlated factors underlie Digit Span, reflecting easy and hard items in both forward and backward presentation orders. The present study explored the dimensionality of the Wechsler Memory Scale-III Digit Span (forward and backward) items in a sample of heterogeneous neuroscience patients (n = 267) using confirmatory factor analysis (CFA) for dichotomous items. Some published research suggests that Digit Span forward should be interpreted differently from Digit Span backward. The Digit Span subtest from the Wechsler Scales is used to measure Freedom from Distractibility or Working Memory.
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