The Talking Hands?: The Relation between Gesture and Language in Aphasic Patients

This thesis is composed of two individual but interconnected studies. The first study investigated the gestural ability of aphasic patients in comparison with healthy speakers, by analysing both qualitatively and quantitatively co-speech gestures during a story-retelling task. The objective was to understand the relation between language and gesture ability in the aphasic patient: whether impairments in language production influence gesture production, as suggested by the long existing notion “asymbolia†. If this is not the case, gesture then may play a very potential role in aphasic daily communication and rehabilitation, as suggested by researchers and clinicians (e.g., Marshall, 2006; Rodriguez et al., 2006) who proposed the use of gesture as a compensatory and facilitative means to assist aphasic individuals to communicate. In our first study, four aphasic patients and four age-matched healthy speakers were recruited. They were requested to retell stories after watching eight short films from the cartoon “Tweety and Silvester†. Both verbal and non-verbal production from the participant were video-taped for analyses. Group and individual analyses were performed to examine representational and non-representational gestures in per-100-word and per-minute measures. We found that in aphasic subjects, as a group, gestures were quantitatively indistinguishable from those produced by normal controls. Also, qualitative analyses demonstrated that the aphasic subjects tended to use representational gestures to cue or substitute for difficult-to-name words. This supports the notion that gesture may cue naming and may be a potential treatment approach in aphasia rehabilitation. The second study explored treatment efficacy of three approaches in aphasia rehabilitation – the Gesture-based, the Language-based, and the Combined approach, aiming to understand the effects elicited by these techniques in improving single word naming ability in aphasic patients. Previous research suggested that gesture training can facilitate word naming (see Rose, 2006 for review). Language-based treatment aiming to reconstruct concepts and restore phonological information on difficult-to-name words has been widely studied, but the therapeutic role played by gesture in language recovery has been rarely considered. Our second study recruited four chronic aphasic patients with word-finding difficulty to explore the effects of three types of treatment – Gesture-based, Language-based, and Combined, on the retrieval of nouns and verbs. It was hypothesized that gesture and language-based treatments alone would yield positive effects and that combined treatment would result in the largest improvement of single-word naming. In gesture-based treatment, patients were trained to produce a gesture that can be mapped onto a corresponding word. In language-based treatment, Semantic Feature Analysis and Phonological Component Analysis were used. The combined treatment includes the same materials used in the gesture-based and language-based treatments, but materials were alternated across sessions. Training materials included verbs of hand-related actions and nouns of manipulable objects. We found that all types of treatment, as hypothesized, led to significant item-specific improvement in both verb and noun naming. Three of four subjects showed the largest recovery following combined treatment, especially on verbs. This suggests that gesture, when combined with logopedic treatment, can boost naming skills.