6 A review of neuropsychological measures of executive functioning in the Japanese and Japanese-American population

Abstract

Objective:There are approximately 1.5 million Japanese and Japanese Americans in the United States, with the Japanese population increasing steadily over the past two decades. Given the growing number of the Japanese population, it is likely that a clinical neuropsychologist may encounter a Japanese patient, particularly for neurocognitive disorder evaluations given the aging population. Literature has reported that cross-cultural bias in neuropsychological testing and cultural factors affect individuals’ test performance. In order to conduct and interpret neuropsychological assessments for this population, it is important to use normative data and consider the impact of various factors such as acculturation, language, and generation in the U.S. Availability of normative cognitive test data for Japanese-Americans is limited. Tests with most extensive use, adaptation, validation, and norming were identified. Many clinically used measures of executive functioning (EF) have been translated into Japanese and studied in multiple clinical populations. We present information on tests in this domain given their appropriateness for use in cross-linguistic and cross-cultural evaluations.Participants and Methods:Available studies of neuropsychological tests measuring EF that have been translated and normed in the Japanese and/or Japanese-American patient population are reported. Review of the literature was conducted by authors of Japanese descent familiar with neuropsychological assessment and Japanese and Japanese-American culture. We prioritized studies published in both English and Japanese and those that included commonly utilized tests in the U.S, allowing for maximum accessibility and utility for Western-based neuropsychologists. Additionally, inclusion priority was given to studies published in English which report the clinical diagnoses, age range, and gender characteristics of the sample population. The Wisconsin card sorting test (WCST) and Trail Making Test (TMT) were reviewed.Results:The WCST and the TMT, with its variant, was the most normed EF cognitive test currently available. The Keio version Japanese-Trail Making Test (J-TMT) and a simplified version of the Trail Making Test (S-TMT) has been utilized in Japan, however norms are still lacking. Of the available studies, the S-TMT and J-TMT were found to be moderately correlated with the TMT. The Keio version WCST (KWCST) (Kao et al., 2012) was correlated to education level (Abe et al., 2004), appropriately differentiating severity of social anxiety disorder (Fujii et al., 2013), patients with schizophrenia (Banno et al., 2012), and cognitive impairment in Parkinson’s disease (Yoshii et al., 2019).Conclusions:Information regarding translated and normed tests are presented to assist clinical neuropsychologists provide competent services to Japanese-Americans. The J-TMT and the S-TMT may be clinically useful as an evaluation of attention for the Japanese population. The KWCST has also been found to be an appropriate tool for this population. However, publicly available norms for these assessments are still sparse, and there is very limited information about administration of these tests by English-speaking neuropsychologists with the use of interpreters. Further work is needed to increase access to and awareness of linguistically and culturally appropriate versions of clinical measures to better serve the Japanese and Japanese-American population.