Cognitive Reserve in Parkinson’s Disease: The Effects of Welsh-English Bilingualism on Executive Function
Table 2
Comparison of monolinguals and bilinguals on language tests, EF tests.
Variables
Effects of language: monolingual (ML) and bilingual (BL)
After education level as fixed factor in 2-factor ANOVA
Monolingual mean (SD)
Bilingual mean (SD)
Direction (see footnote)
Effect size (95% confidence intervals)
Significance value
Language tests
NART-R errors
11.29 (8.84)
20.46 (8.88)
ML > BL
.83 (0.31, 1.35)
.003
British Picture Vocabulary Scale total correct
57.31 (2.62)
54.08 (5.04)
ML > BL
.69 (0.18, 1.20)
.013
Boston Naming Test English total
14.50 (0.80)
14.37 (0.77)
ML > BL
.01 (−0.48, 0.51)
.95
EF, attention variables
D-KEFS verbal fluency total correct raw score
42.69 (13.73)
40.29 (10.74)
ML > BL
.18 (−0.32, 0.68)
.50
D-KEFS category fluency total correct raw score
37.36 (11.41)
38.71 (9.44)
BL > ML
.20 (−0.30, 0.80)
.45
D-KEFS design fluency filled + empty + switching total correct raw score
23.69 (7.14)
22.63 (8.55)
ML > BL
.02 (−0.44, 0.52)
.93
D-KEFS TMT Part 4 raw score (seconds)
130.86 (58.40)
144.67 (70.74)
ML > BL
.19 (−0.31, 0.69)
.65
RCPM total correct
31.69 (4.24)
31.54 (4.24)
ML > BL
.12 (−0.38, 0.62)
.64
Digit Span backwards total
6.69 (2.29)
6.79 (2.12)
BL > ML
.17 (−0.33, 0.67)
.52
Spatial Span backwards total
6.55 (1.96)
6.17 (1.60)
ML > BL
.07 (−0.43, 0.57)
.77
TEA Elevator Counting raw score
6.90 (.37)
6.92 (.28)
ML > BL
.03 (−0.47, 0.53)
.89
TEA Elevator Counting with distraction raw score
7.48 (2.49)
6.71 (2.86)
ML > BL
.17 (−0.33, 0.67)
.51
Keep Track task total correct
7.79 (2.20)
7.67 (2.12)
ML > BL
.02 (−0.48, 0.52)
.92
Simon task mean reaction time difference (ms)
83 (294)
129 (272)
ML > BL
.13 (−0.37, 0.63)
.61
Stroop reaction time difference (incongruent − congruent reaction time) (ms)
1011 (746)
1311 (699)
ML > BL
.41 (−0.09, 0.91)
.12
Go No-Go commission errors %
5.01 (8.75)
4.60 (7.33)
BL > ML
.03 (−0.47, 0.53)
.90
Go No-Go mean reaction time (ms)
509 (94)
512 (112)
ML > BL
.01 (−0.49, 0.51)
.95
Note: direction indicates which group scored better monolingual (ML) versus bilingual (BL). Effect size (SMD) was calculated as the difference between the estimated marginal means for ML and BL groups divided by the square root of the error mean square term. Significant results in bold after adjustment for multiple comparisons using Holm-Bonferroni method separately for descriptive variables and combined EF/attention/function variables. Delis-Kaplan Executive Function System (D-KEFS), National Adult Reading Test-Revised (NART-R), Raven’s Coloured Progressive Matrices (RCPM), Tests of Everyday Activity (TEA), and Trail Making Test (TMT).
