Cognitive testing of elderly Chinese people in Singapore: influence of education and age on normative scores

Age and Ageing, Nov, 1997 by Suresh Sahadevan, Noellyn J.L. Tan, Tahchew Tan, Shirley Tan

Table 1. Number of subjects by education, age and gender

                      No. of subjects, by gender and age (years)

                      Male
Education level
(years)               60-64   65-74   75-84   All
0                       1       0        3     4
1-6                     7      13        9    29
[is greater than] 6    16      18        9    43
Total                  24      31       21    76

                      Female
Education level
(years)               60-64   65-74   75-84   All
0                      11      10       8     29
1-6                     8       9       4     21
[is greater than] 6    11      11       7     29
Total                  30      30      19     79

Influence of variables

Four demographic variables (age, education, gender and language tested) were assessed to analyse their influence on the mean scores of the neuropsychological assessment battery. We anticipated that education would have a marked effect; the associations between education and the remaining demographic variables were thus looked at by the [chi square] method. It was then found that gender and language were strongly associated with education (P [is less than] [10.sup.-5]) while age was not (P = 0.63). Hence age and education remained as the independent variables requiring further analysis of their effects on the test performances and this was accomplished by the GLM procedure.

Despite our original intentions to age- and sex-match the subjects, the observational design of this study could not totally avoid discrepancies in the various stratified cells (see Table 1). There were no male subjects between 65 and 74 who were uneducated, but gender was not independently exerting any influence on the psychological tests scores so we pooled the numbers from both genders for the GLM analysis and the results are shown Table 2.

Table 2. General linear model results education by
age--statistically significant effects

                                      Main effect (P
                                      [is less than])

                                                         Interaction
                                                            effect
                                                         (P [is less
Test                                  Education   Age      than])

Abbreviated Mental Test                 0.001      --     0.013
Chinese Mini-Mental Status              0.001     0.004     --
Set test (animal category)              0.001     0.026     --
Word list memory (immediate recall)     0.001     0.009     --
Word list memory (delayed recall)       0.008     0.004    0.003
Word list (recognition)                 0.010     0.001     --
Modified Boston naming test             0.001     0.034     --
WAIS-R block design                     0.001      --       --
WAIS-R object assembly                  0.001      --       --
Constructional praxis                   0.001      --       --

WAIS-R, Wechsler Adult Intelligence Scale-Revised.