Naming Images in Aphasia: Effects of Graphic Representations and Photographs on Naming Performance in Persons With and Without Aphasia

Abstract

Background: Picture naming is a common tool in aphasia diagnosis and therapy. However, opinions differ as to which type of image (e.g., photographs, drawings) is most suitable for naming tasks and whether there is a difference on naming correctness and latencies based on image type. Moreover, recent studies have mainly analysed colour photographs and black-and-white line drawings leaving out image types like graphic representations that apply image features that can facilitate naming such as colour, controlled size, or texture. Aims: To shed more light on appropriate image types for persons with aphasia, we created graphic representations depicting nouns and verbs and compared them to photographic stimuli in a naming task including persons with aphasia (PWA) and a control group (CG). Methods & Procedures: 33 PWA and 33 age matched persons (CG) participated in the study. Naming correctness and latencies were measured in two different conditions: concepts depicted as coloured photographs vs. as graphic representations. 128 pictures of linguistically controlled German-language concepts (64 nouns, 64 verbs) had to be named. The designed graphic stimuli were developed by professional designers based on photographs. The photographs were selected from stock image databases according to a defined image concept. This image concept was based on empirical findings regarding image features that facilitate naming (e.g., colour, texture, shading) and was applied to the selection of the photographs as well as to the creation of the graphic representations. The images were presented in pseudo-randomized sequences on a tablet and all reactions of the participants were videotaped. The data from the main study was analysed using generalized linear mixed models (GLMM) and linear mixed models (LMM). Outcomes & Results: Our analysis showed no significant difference in naming correctness and latencies between photographic and graphic stimuli. On average, PWA named terms presented as graphical representations more correctly than the photographs. But this difference was below the significance level. Conclusions: In our study we showed that graphic representations, when including image features that facilitate naming like colour, texture, and shading, can evoke the same naming performance as photographs. Graphic representations can thus be used in combination with photographs in an image set, especially when depicting concepts that benefit from reduced representation, e.g., verbs. We therefore advocate the transparent and methodologically stringent implementation of image features that facilitate naming when creating image stimuli.