Table 2.
Descriptive statistics and linear regression results for association between diabetes and performance on individual neuropsychological measures at baseline and final follow-up
| Baseline | Follow-up | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Variable | Possible Range | Non-diabetes mean (± SD) |
Diabetes mean (± SD) |
B | SE | Cohen’s d | p | Non-diabetes mean (± SD) |
Diabetes mean (± SD) |
B | SE | Cohen’s d | p |
| N | 1115 | 378 | 1115 | 378 | |||||||||
| Memory | |||||||||||||
| SRT-total recall | 0–72 | 38.24 (±10.45) | 36.87 (±9.83) | −1.36 | 0.62 | 0.13 | .028 | 34.28 (±11.55) | 32.87 (±11.27) | −1.42 | 0.76 | 0.12 | .061 |
| SRT-delayed recall | 0–12 | 5.56 (±2.63) | 5.38 (±2.42) | −0.17 | 0.16 | 0.07 | .275 | 4.46 (±2.89) | 4.25 (±2.62) | −.023 | 0.19 | 0.07 | .255 |
| SRT-delayed recognition | 0–12 | 11.14 (±1.44) | 11.06 (±1.37) | −0.07 | 0.09 | 0.06 | .390 | 10.16 (±2.37) | 10.17 (±2.11) | <.001 | 0.15 | 0.01 | .998 |
| Language | |||||||||||||
| Naming total | 0–15 | 13.66 (±1.73) | 13.37 (±1.78) | −0.29 | 0.11 | 0.17 | .007 | 13.47 (±1.94) | 13.39 (±1.98) | −0.09 | 0.13 | 0.04 | .504 |
| Letter fluency mean (# of words) | 0+* | 10.07 (±4.42) | 8.66 (±4.02) | −1.41 | 0.26 | 0.33 | <.001 | 9.77 (±6.13) | 8.67 (±6.19) | −1.11 | 0.41 | 0.18 | .007 |
| Category fluency mean (# of words) | 0+* | 14.78 (±4.29) | 13.77 (±4.05) | −1.01 | 0.26 | 0.24 | <.001 | 13.03 (±4.43) | 12.25 (±4.10) | −0.77 | 0.29 | 0.18 | .007 |
| Similarities | 0–28 | 11.98 (±7.32) | 9.53 (±7.08) | −2.48 | 0.43 | 0.34 | <.001 | 11.81 (±7.63) | 9.58 (±7.18) | −2.25 | 0.49 | 0.30 | <.001 |
| Repetition | 0–8 | 7.68 (±0.69) | 7.59 (±0.76) | −0.09 | 0.04 | 0.13 | .031 | 7.37 (±1.11) | 7.33 (±1.11) | −0.04 | 0.07 | 0.04 | .560 |
| Comprehension | 0–6 | 5.28 (±1.07) | 5.07 (±1.20) | −0.21 | 0.07 | 0.19 | .002 | 5.05 (±1.25) | 4.75 (±1.39) | −0.30 | 0.09 | 0.23 | <.001 |
| Visual-spatial | |||||||||||||
| BVRT recognition | 0–10 | 7.04 (±2.17) | 6.60 (±2.23) | −0.45 | 0.13 | 0.20 | .001 | 6.80 (±2.26) | 6.29 (±2.31) | −0.52 | 0.16 | 0.22 | .001 |
| BVRT matching | 0–10 | 8.69 (±1.81) | 8.35 (±1.99) | −0.35 | 0.11 | 0.18 | .002 | 8.51 (±1.84) | 8.04 (±1.99) | −0.47 | 0.13 | 0.25 | <.001 |
| Rosen | 0–5 | 2.66 (±0.95) | 2.38 (±1.09) | −0.27 | 0.06 | 0.28 | <.001 | 2.41 (±1.11) | 2.25 (±1.15) | −0.16 | 0.08 | 0.14 | .032 |
| Identities/Oddities | 0–16 | 14.52 (±1.75) | 14.15 (±1.91) | −0.38 | 0.11 | 0.21 | .001 | 14.54 (±1.83) | 14.23 (±2.00) | −0.30 | 0.13 | 0.17 | .020 |
| Processing speed | |||||||||||||
| CTT 1 (seconds) | <360┼ | 94.60 (±46.85) | 105.38 (±52.94) | 10.67 | 3.57 | 0.22 | .003 | 108.85 (±62.54) | 123.17 (±67.10) | 14.30 | 4.69 | 0.22 | .002 |
| CTT 2 (seconds) | <360┼ | 158.18 (±52.00) | 169.19 (±54.82) | 10.87 | 4.04 | 0.21 | .007 | 182.85 (±73.94) | 209.17 (±80.19) | 26.21 | 6.03 | 0.35 | <.001 |
SRT = Selective Reminding Test; BVRT = Benton Visual Retention Test
B, standard error, and p values are from linear regressions with diabetes as the predictor variable and cognitive score as the dependent variable. B (unstandardized coefficient) is equal to the difference in mean scores between those with and without diabetes. Cohen’s d of 0.2, 0.5, and 0.8 are considered small, moderate, and large effect sizes, respectively35. Hierarchical linear regression models demonstrated that, after adjusting for age and education, diabetes was associated with significantly poorer baseline performance on measures of language (Letter Fluency: B ± SE = −.89 ± .22, p < .001; Category Fluency: B ± SE = −.61± .22, p = .007; Similarities: B ± SE = −1.26 ± .33, p < .001) and visuospatial abilities (Rosen: B ± SE = −.19 ± .06, p = .001; Identities/Oddities: B ± SE = −.22 ± .10, p = .029) with trends toward poorer performance on executive functioning/processing speed (Color Trails 1: B ± SE = 5.74 ± 3.12, p = .066; Color Trails 2: B ± SE = 6.34 ± 3.57, p = .076). After adjusting for age and education, diabetes was associated with poorer follow-up performance on measures of language (Similarities: B ± SE = −1.02 ± .39, p = .009) and executive functioning/processing speed (Color Trails 1: B ± SE = 9.30 ± 4.41, p = .035; Color Trails 2: B ± SE = 20.55 ± 5.69, p < .001) with trends toward poorer performance on additional measures of language (Category Fluency mean: B ± SE = −.44 ± .26, p = .082; Comprehension: B ± SE = −.15 ± .08, p = .052); and visuospatial abilities (Benton Matching: B ± SE = −.20 ± .12, p = .089).
Participants are asked to generate as many words as they can that begin with each letter or category (e.g., animals) in 60 seconds (within specific guidelines). Mean number of correct words named across the three letters or categories are displayed.
The Color Trails test (CTT) requires participants to connect numbers (CTT 1) or numbers alternating in the same color (CTT 2) in the correct order as quickly as possible. Higher scores indicate slower speeds (i.e., worse performance).