Although the majority of Japanese speakers live in Japan, there are also large populations of Japanese speakers in the United States of America and Brazil, with more than a million Japanese speakers across the two countries. Only 53% of foreign-born Japanese individuals in the United States report proficiency in English. Although there has been increasing attention to the neuropsychological assessment of linguistically diverse patients broadly in recent years, there are specific considerations unique to Japanese that clinicians and researchers should be aware of when working with Japanese speakers outside of Japan. The aim of the present study is to present considerations and appropriately normed assessments of verbal abilities for Japanese patients.

A systematic review of cognitive screeners and assessments of verbal fluency, verbal memory, and verbal academic skills that have been translated and normed for use with Japanese speaking populations was conducted. Studies published in both English and Japanese were reviewed. Test content modifications, administration modifications, and relevant cultural and linguistic considerations were synthesized and summarized.

One consideration in translation is the use of words that are linguistically and culturally comparable across the two languages. Multiple cognitive screeners and verbal learning/memory tasks have been translated with cultural equivalency considerations (e.g., for the Montreal Cognitive Assessment, velvet, church, and daisy were changed to silk, shrine, and lily). In Japanese, there is a one-to-one correspondence between sound (syllable) and graphemes (kana script), compared to one-to-many associations in alphabet-based languages like English. This impacts normative expectations on letter fluency tasks. The hiragana letters, A, Ka, and Shi (fc, fr, L) are recommended because there are relatively large number of words that start with these letters and the number of words generated with these letters showed close to normal distributions in previous research. Unlike letter fluency, semantic fluency is believed to be relatively culture-free and independent of language systems. The Japanese writing system utilizes both phonographic systems where written symbols map onto sounds, and logographic systems, where written symbols map onto concepts. This is in contrast to English, which has a solely phonographic written system. These two separate writing systems complicate the assessment of reading among Japanese-speaking individuals, as there may be a dissociation between abilities in reading in the phonographic versus logographic systems. Acculturation has been shown to impact performance on certain verbal task performances, along with demographic variables such as immigration generation status and bilingualism.

Neuropsychologists should be familiar with linguistic differences between English and Japanese such as the one-to-one correspondence between sound and grapheme in Japanese and the use of both phonographic and logographic systems in written Japanese. Neuropsychologists should also be careful to use tests that are translated for cultural equivalence rather than direct translations, and that have been normed for use with Japanese speakers. Finally, general cross-cultural considerations in assessment such as the evaluation of bilingualism, familiarity with the testing environment, and other factors remain essential.