Neuropsychological Test Performance Among Native and Non-Native Swedes: Second Language Effects

OBJECTIVE: We aimed to study second language effects on neuropsychological (NP) test performance. METHOD: We administered an NP test battery in Swedish to 322 healthy community dwelling participants, recruited through the Gothenburg Pilot phase of the Swedish CArdioPulmonary BioImage Study (SCAPIS Pilot). All participants were conversationally fluent Swedish speakers (237 native, 85 non-native, mean age 61.1 years). We compared the NP scores of native and non-native participants. We also investigated the influence of (a) age of arrival to Sweden, (b) majority language family of the birth country, and (c) proficiency in Swedish as assessed with a 30 item Boston naming test (BNT). RESULTS: Native speakers obtained better results on all NP tasks with a verbal component, whereas no significant differences were seen on completely nonverbal tasks (Rey complex figure). For non-native speakers, lower age at arrival to Sweden, arrival from a country where Swedish was also spoken, or arrival from a country with a majority language closer to Swedish, were all linked to better NP scores. Dichotomizing by BNT showed that normally-to-highly proficient non-native speakers obtained better scores. CONCLUSIONS: Second language effects may contribute to misclassification of non-native speakers. Assumptions of fluency based on short conversations may be misleading. A proficiency assessment with BNT may improve NP score interpretation among non-native speakers.