Cognitive Reserve in Parkinson’s Disease: The Effects of Welsh-English Bilingualism on Executive Function
Table 3
The effects of different degrees of language use in bilinguals.
Variables
Degree of bilingualism-cluster analysis ANOVA Cluster 1: less frequent Welsh speakers Cluster 2: more frequent Welsh speakers
Bilingualism index Nonparametric correlations
df
Significance P value
Spearman’s rho
Significance value
Language tests
NART-R errors
40
7.31
.010
0.001
.99
British Picture Vocabulary Scale total correct
43
5.12
.029
−0.07
.60
Boston Naming Test English total
43
2.77
.10
0.02
.85
EF, attention variables
D-KEFS verbal fluency total correct raw score
42
3.36
.07
0.03
.76
D-KEFS category fluency total correct raw score
41
0.48
.48
0.01
.93
D-KEFS design fluency filled + empty + switching total correct raw score
40
0.24
.62
0.06
.66
D-KEFS TMT Part 4 raw score (seconds)
33
0.01
.91
−0.23
.15
RCPM total correct
40
1.4
.24
0.38
.01
Digit Span backwards total
42
0.35
.55
0.19
.20
Spatial Span backwards total
41
0.64
0.42
0.03
.81
TEA Elevator Counting raw score
37
0.002
0.96
0.17
.26
TEA Elevator Counting with distraction raw score
36
0.02
0.87
0.12
.46
Keep Track task total correct
36
0.09
0.75
0.34
.02
Simon task mean reaction time difference (ms)
41
0.75
0.38
−0.11
.45
Stroop reaction time difference (incongruent − congruent reaction time) (ms)
35
0.83
0.36
−0.10
.54
Go No-Go commission errors %
39
3.66
0.06
−0.06
.69
Go No-Go mean reaction time (ms)
39
0.53
0.46
−0.18
.24
Significant results in bold after adjustment for multiple comparisons using Holm-Bonferroni method separately for descriptive variables and combined EF/attention/function variables in ANOVA. 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).
