A picture naming test for Dutch adults: DNT-II

A picture naming test for Dutch adults: DNT-II ABSTRACT Background: A picture naming test can be useful in identifying anomia (naming difficulties). For Dutch adults suspected to have anomia, such as patients with acquired brain injury or neurodegenerative diseases, there is no reliable and valid tool to diagnose anomia properly. Therefore, a new picture naming test is developed: DNT-II. In selecting test items, Age of Acquisition of words (AoA) and word frequency taken into account because of their influence in the process of naming. Aim: To demonstrate effects of AoA and word frequency on latency of correctly named pictures in younger and older healthy Dutch adults. Methods and procedures: This study has an experimental psycholinguistic quantitative design. Thirty healthy Dutch adult native speakers in two age groups named 99 coloured pictures of words with AoA (early/late) and word frequencies (high-/mid-/low word frequency) in all possible combinations: early/high frequency, early/mid frequency, early/low frequency, late/high frequency, late/mid frequency and late/low frequency. Latencies of correctly given answers were statistically analysed with a Kruskal Wallis Test. In case of significance, pairwise comparisons between word subgroups were conducted using the Mann-Whitney U Test. Age-effect on latency was analysed with the Mann-Whitney U Test. Results: Latencies were significantly influenced by AoA and to a lesser extent by word frequencies. Early AoA and high frequency words were named faster than late AoA and low frequency words. Explained variance in latencies had highest values when AoA and word frequency were combined. Young participants named pictures of early and late acquired high frequency words significantly faster than the older participants. Conclusion: With the inclusion of both variables AoA and word frequency the DNT-II not only has the potential to be a sensitive diagnostic tool to diagnose naming disorders in Dutch adults but also the ability to determine which step/steps of the word retrieval process is/are impaired. Keywords: Picture naming test, Adults, Age of Acquisition, Word frequency