Parkinson’s Disease / 2015 / Article / Tab 2

Research Article

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.

VariablesEffects 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 

Language tests
 NART-R errors11.29 (8.84)20.46 (8.88)ML > BL.83 (0.31, 1.35).003
 British Picture Vocabulary Scale total correct57.31 (2.62)54.08 (5.04)ML > BL.69 (0.18, 1.20).013
 Boston Naming Test English total14.50 (0.80)14.37 (0.77)ML > BL.01 (−0.48, 0.51).95
EF, attention variables
 D-KEFS verbal fluency total correct raw score42.69 (13.73)40.29 (10.74)ML > BL.18 (−0.32, 0.68).50
 D-KEFS category fluency total correct raw score37.36 (11.41)38.71 (9.44)BL > ML.20 (−0.30, 0.80).45
 D-KEFS design fluency filled + empty + switching total correct raw score23.69 (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 correct31.69 (4.24)31.54 (4.24)ML > BL.12 (−0.38, 0.62).64
 Digit Span backwards total6.69 (2.29)6.79 (2.12)BL > ML.17 (−0.33, 0.67).52
 Spatial Span backwards total6.55 (1.96)6.17 (1.60)ML > BL.07 (−0.43, 0.57).77
 TEA Elevator Counting raw score6.90 (.37)6.92 (.28)ML > BL.03 (−0.47, 0.53).89
 TEA Elevator Counting with distraction raw score7.48 (2.49)6.71 (2.86)ML > BL.17 (−0.33, 0.67).51
 Keep Track task total correct7.79 (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).

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