Do you mean you would do all three tests and use the two scores of the three that are closest to each other? With DD, she decided ahead of time that she would do arithmetic instead of digit span. Possibly because DD told her she likes math in school, or because of what the NAGC says. I thought that testers had to decide ahead of time which tests would be used in scoring.
Do you have any thoughts as to why there would be a big gap between Digit Span and Letter-Number Sequence for DS? It seems like practically the same test. I think after the skull fractures/brain injury his scores were 10 and 14, and then 6 months later 11 and 15 (or something along those lines), so there was the same gap both times he did it.
Not exactly. (You are correct that examiners are supposed to select subtests before administration, based on perceived need. Sometimes you can't, though, such as when one is spoiled during testing.) I would do the original two: ds and lns, and then if they were widely divergent, I would add ar, and then use the two that were most consistent for the Index score, and also include a discussion of the diversity (and thus lowered reliability of Index score) among the subtest scores, with my hypotheses about the explanation. I justify the selection after testing with the same reasoning that says that excessive scatter among the subtests in a cluster makes the Index score invalid. I suppose this is my way of minimizing the impact of a questionable Index score on the IQ, and of creating a better fit between the numbers people see and the clinical interpretation.
WRT your DS, was there any mention of differences between digit forwards and digits reversed in the Digit Span subtest? Forwards is more closely related to short-term rote memory and attention, while Backwards usually tracks better with LNS, as the mental manipulation aspect of it is more similar.
Also, six months out from a TBI, the brain is still healing. Actually, we continue to see improvements in cognitive functions for a couple of years after the trauma.
