Communication is more than just talking. In a face-to-face conversation, we also use gestures and facial expressions alongside speech to convey information. For example, the concept of waving your hand to greet someone can be expressed by saying the word “waving” or by performing the gesture itself. These concepts stored in long-term memory are thought to be shared across networks of brain areas responsible for speech and gesture. Gestures may also support word-finding: some studies have shown that when people struggle to retrieve words, producing a corresponding gesture also triggers production of the word. Other studies, however, have shown no effect of gesture on word-finding.
For individuals with aphasia, a language disorder that is common after a stroke or brain injury, word-finding difficulties are frequent. Because of this, some types of speech-language therapy encourage individuals with aphasia to rely on gesture to help them retrieve words more easily. However, an alternative approach known as constraint-induced language therapy requires individuals to rely on speech alone and restricts the use of gesture. While some individuals with aphasia benefit from constraint-induced language therapy, others benefit from therapy that allows for the use of gesture. It is unclear why different individuals with aphasia benefit from different types of therapy.
Approximately half of individuals with aphasia following a stroke also suffer from limb apraxia, a disorder which results in the impaired production of gestures and other skilled actions. One possibility is that individuals with limb apraxia will benefit less from the observation and use of gesture during speech-language therapy. To investigate this possibility, researchers from Moss Rehabilitation Research Institute (MRRI) and University College London (UCL) Amy Lebkuecher, PhD, Laurel Buxbaum, PsyD, Isobel Chick, MSc, and Gabriella Vigliocco, PhD, are conducting a study about the effect of gesture on naming ability in individuals with aphasia after stroke. In this experiment, the researchers are using gamified tasks, specifically “Go Fish” and “Heads Up”, to evaluate naming ability in an engaging and naturalistic context. Individuals with aphasia participating in this experiment are asked to complete these gamified tasks in two conditions: one that permits the use of gesture, and one that constrains it. In the condition where use of gesture is permitted, participants also observe the researcher performing gestures that are conceptually related to the objects and actions being named or described. In the condition where the use of gesture is constrained, both participant and researcher are not allowed to use gestures to communicate.
The researchers will compare participants’ performance on the gamified tasks across these conditions to determine whether the ability to name objects and actions improves when individuals with aphasia are allowed to use and observe meaningful, co-speech gestures. Additionally, the researchers will examine whether the benefit of gesture differs for individuals with and without limb apraxia, and explore whether there are other individual differences that affect whether gestures support word retrieval in aphasia. Data collection for this study is currently in progress. This research aims to advance our scientific understanding of the connection between speech and gesture in the brain. From a clinical perspective, the findings of this study may also help identify which individuals with aphasia are likely to benefit from the use of gestures during speech-language therapy, potentially leading to more personalized therapy.