I just asked both kids and DD (age 8) could do 5 backwards easily and DS (turned 7 a couple months ago) could do 4 but struggled w/ 5. So would that really earn a digit span score of 10-11 for DS? I didn't try forwards but I think for DS it's probably around 6-7 digits. I find it so strange how DD doesn't seem to have any problem with this at all but she looks spaced out if you ask her what's 9+4. DS didn't have nearly as many problems memorizing math facts.
Okay, so here's the scoop. Digits forwards typically is reflective of the auditory short-term memory channel, as well as attention. Digits reversed is often reflective of the visual memory channel. In order to be successful at digits reversed without brute force (i.e., repeating the sequence forwards mentally or subvocally, but saying the last number out loud, and then repeating the whole sequence forwards, but vocalizing the second to last digit, etc.), which is quite laborious, and requires a pretty big auditory loop, one inputs the digit sequence into something like a visual scratch pad in the brain. Those who are most successful then read it off the scratch pad, but backwards. If your visual scratch pad isn't very big, or has a short expiration time, you will have a hard time with digits reversed. This is most likely why a child with DCD might be so much more successful with digits forwards, but tank digits backwards. Both DCD and digits backwards are connected to perceptual deficits.
If DSF and DSB are significantly different, then the combined digit span score does not really capture the working memory profile of the individual.
blackcat, with your children in particular, those spans are actually quite good for their age, and would have suggested higher scaled scores to me for your DS7. On the other hand, in formal testing, we expect them to repeat those spans consistently. If you can do it sometimes, but not every time, you may not receive as high a scaled score as your longest span would suggest. And inconsistency is often what you find when the expected low cognitive load means of completing a task does not come naturally, and children have to enlist a great deal of cognition into working around their deficit areas.
