Research Digest – November 2019

Author: Gabriel Qi

For our November ANA Listserv Research Digest, I would like to introduce
neuropsychological research studies involving the Vietnamese-speaking populations.

I did a quick literature search, but found very few studies focused on
neuropsychology with Vietnamese-speaking populations. The two articles I reviewed
this time were both published two decades ago. It looks like there’s much that can
be done there.

Kempler and colleagues (1998) compared the performances on animal fluency by
participants speaking different languages: Chinese, Spanish, Vietnamese and English.
Besides expected findings of impact of age and education on number of words
generated in the expected directions, there were significant differences between
ethnicities (i.e., languages spoken). It was found that the Vietnamese-speaking
participants were able to generate significantly more words than the other three,
and the Spanish-speaking ones significantly fewer than the other three.

The authors explored possible explanations for the differences, and one of them is
response length in each language. Close to 80% of responses in Vietnamese were
monosyllabic, whereas close to half in Spanish were words with 3 or more syllables.
The pattern of number of syllables in responses was quite consistent with number of
animals the participants were able to name. I found that an interesting linguistic
characteristic, informative to neuropsychologists working with patients who speak
these languages. In addition, the authors provided an education-stratified norm for
animal fluency among older adults speaking English, Chinese, Spanish and
Vietnamese, respectively.

For the second article, I found a preliminary examination of a Vietnamese version of
Stroop test (Doan & Swerdlow, 1999). The authors compared 30 ethnically diverse
US-born adults (aged 19–57 yrs) and 30 Vietnamese adults (aged 19–68 yrs) residing
in the US. They found no significant differences in their performances on all tasks of
the Stroop Test. Interestingly, to accommodate for language differences, where the
Vietnamese words for green and blue were the same (“xanh”), the authors used the
word and color “brown” (“nau”) in the Vietnamese version of the task. Whereas the
results among the English-speaking participants were all in the expected directions
compared to the reference group, there was not any significant impacts of age on
Vietnamese-speaking subjects’ Stroop test performance. Several possible
explanations were provided, but I think bilingualism may the most probable one.
Although duration in the U.S. and frequency of Vietnamese/English speaking were
not correlated with Stroop scores, the total number of years speaking English was
significantly correlated with Vietnamese-language interference scores. Yet still, it
warrants further research to examine these findings.

Food for thought this month:

How may the native languages of your patients impact their verbal fluency
performances? For example, it was hard to test phonemic verbal fluency in Chinese,
as Chinese is a logographic language and it is either very common for people to
generate words by (often) the starting consonant.

Here are the links to access the articles this month:

  1. https://www.ncbi.nlm.nih.gov/pubmed/10050357
  2. https://www.ncbi.nlm.nih.gov/pubmed/10544412

References:

• Doan, Q. T., & Swerdlow, N. R. (1999). Preliminary findings with a new Vietnamese
Stroop test. Perceptual and Motor Skills, 89(1), 173-182.
doi:10.2466/PMS.89.5.173-182
• Kempler, D., Teng, E. L., Dick, M., Taussig, I. M., & Davis, D. S. (1998). The effects of
age, education, and ethnicity on verbal fluency. Journal of the International
Neuropsychological Society, 4, 531-538.