B – 105 Combined total score for longest digit span forward (LDSF), longest digit span backward (LDSB), and longest digit span sequencing (LDSS) correlates with premorbid functioning and overall neuropsychological test performance

Objective Memory span measures neuropsychological function (Dempster, 1981; Gignac & Weiss, 2015). Performance on the Digit Span subtest (LDSF, LDSB, LDSS) from the WAIS-IV shows linear associations with FSIQ (Gignac & Weiss, 2015). We evaluated combined score of LDSF, LDSB, LDSS (TLDSFBS) and individual test performance to find correlation with premorbid ability and test performance. Method 76 outpatients (M age = 52.75, SD = 17.25; M education = 15.71, SD = 2.35; 56.6% females) at an academic medical center completed cognitive tests including trail making (TMT), premorbid functioning (TOPF), verbal fluency (COWAT), naming (NAB), Stroop, WAIS-IV subtests, and object interference (RIT-OI). Data were analyzed using correlation and linear regression to assess whether age and education predicted TLDSFBS total score. Results TLDSFBS correlated positively with the TOPF, r(73) = .41, p = <.001), FAS, r(39) = .35, p = .03, CFL, r(32) = .38, p = .03, AFV, r(34), p = .03), NAB naming, r(54), p = .02, RIT-OI, r(43) = .55, p = <.001, Stroop Color, r(44) = .33, p = .03, and Stroop Word, r(44) = .56, p = <.001. TLDSFBS correlated negatively with the TMT-A, r(73) = -.34, p = .003, and TMT-B, r(71) = -.46, p = <.001. Education, not age, significantly predicted scores on TLDSFBS, b = .46, t(72) = 3.06, p = .003. Conclusion TLDSFBS appears correlated with test battery performance and is predicted by education. This provides additional evidence that calculating longest digits may be helpful in estimating FSIQ (Gignac & Weiss, 2015), premorbid ability, and overall neuropsychological performance.