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A comparison of modality specific digit span presentations in a group of elderly normals
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Abstracts of 14th Annual Meeting
extremely high interrelationships, well within the range of reliabilities for each test. This suggests that clinicians may use a regression model to predict the summary scores of the opposite scale, but not the summary scores themselves. In addition, each scale has unique subtests and other features that do not allow for alternate-forms comparisons at the subtest level.
Ledbetter, M. F., Kaplan, E., & Marmor, D. A Comparison of Modality Specific Digit Span Presentations in a Group of Elderly Normals. This study examines the relationship between an auditory and visual presentation of Digit Span. Two-hundred ninety-three elderly normals (mean age = 70.5 years, SD = 3.1 years) were administered the Wechsler Memory Scale-Revised (Wechsler, 1987) and MicroCog (Powell et al., 1993), a computer-administered neurocognitive battery. Digit span on the WMS-R was administered in the traditional manner (auditory presentation) but subtest scores were recoded to represent the highest string of forward and backward digits recalled correctly. Similarly, highest level achieved for digits forward and backwards were recorded for the visual presentation of Digit Span on MicroCog. A series of paired t-tests (alpha level adjusted for multiple planned comparisons) examined mean differences between the four study conditions (i.e., auditory-digits forwards, AF; auditory-digits backwards, AB; visual-digits forwards, VF; and visual-digits backwards, VB). The results indicate significant and meaningful differences between the AF-AB, AF-VF, and AF-VB comparisons, with the AF condition recalling a greater number of digits in each case. Differences between AB-VF, AB-VB, and VF-VB were either nonsignificant or not meaningful. These results are discussed with reference to modality specific presentation formats and are generally consistent with the known Digit Span-Visual Memory Span differences on the WMS-R. Several possible reasons for the auditory-visual differences in the Digit Span recall are discussed. Ledbetter, M. E, & Trippel, T. An Evaluation of Speed and Accuracy of Neurocognitive Processing in a Group of Alzheimer Patients and Matched Normal Controls. Measures of processing speed have demonstrated extraordinary sensitivity to cognitive impairment (van Zomeren & Brouwer, 1992). However, many current neurocognitive tests have either ignored information processing speed or interpreted it secondarily to accuracy scores. A recently published computerized cognitive battery, MicroCog (Powell et al., 1993), was used to investigate the relative importance of both processing speed and accuracy in a group of 50 impaired (probable AD) and 50 elderly normal controls. In order to investigate the interaction of speed and accuracy, a combined speed/accuracy variable (proficiency score) was computed by interacting accuracy and an exponential weighting of speed at the item level. Proficiency scores were cal-
Abstracts of 14th Annual Meeting
extremely high interrelationships, well within the range of reliabilities for each test. This suggests that clinicians may use a regression model to predict the summary scores of the opposite scale, but not the summary scores themselves. In addition, each scale has unique subtests and other features that do not allow for alternate-forms comparisons at the subtest level.
Ledbetter, M. F., Kaplan, E., & Marmor, D. A Comparison of Modality Specific Digit Span Presentations in a Group of Elderly Normals. This study examines the relationship between an auditory and visual presentation of Digit Span. Two-hundred ninety-three elderly normals (mean age = 70.5 years, SD = 3.1 years) were administered the Wechsler Memory Scale-Revised (Wechsler, 1987) and MicroCog (Powell et al., 1993), a computer-administered neurocognitive battery. Digit span on the WMS-R was administered in the traditional manner (auditory presentation) but subtest scores were recoded to represent the highest string of forward and backward digits recalled correctly. Similarly, highest level achieved for digits forward and backwards were recorded for the visual presentation of Digit Span on MicroCog. A series of paired t-tests (alpha level adjusted for multiple planned comparisons) examined mean differences between the four study conditions (i.e., auditory-digits forwards, AF; auditory-digits backwards, AB; visual-digits forwards, VF; and visual-digits backwards, VB). The results indicate significant and meaningful differences between the AF-AB, AF-VF, and AF-VB comparisons, with the AF condition recalling a greater number of digits in each case. Differences between AB-VF, AB-VB, and VF-VB were either nonsignificant or not meaningful. These results are discussed with reference to modality specific presentation formats and are generally consistent with the known Digit Span-Visual Memory Span differences on the WMS-R. Several possible reasons for the auditory-visual differences in the Digit Span recall are discussed. Ledbetter, M. E, & Trippel, T. An Evaluation of Speed and Accuracy of Neurocognitive Processing in a Group of Alzheimer Patients and Matched Normal Controls. Measures of processing speed have demonstrated extraordinary sensitivity to cognitive impairment (van Zomeren & Brouwer, 1992). However, many current neurocognitive tests have either ignored information processing speed or interpreted it secondarily to accuracy scores. A recently published computerized cognitive battery, MicroCog (Powell et al., 1993), was used to investigate the relative importance of both processing speed and accuracy in a group of 50 impaired (probable AD) and 50 elderly normal controls. In order to investigate the interaction of speed and accuracy, a combined speed/accuracy variable (proficiency score) was computed by interacting accuracy and an exponential weighting of speed at the item level. Proficiency scores were cal-