An investigation of the use of co-verbal gestures in oral discourse among Chinese speakers with fluent versus non-fluent aphasia and healthy adults

Abstract

Gesture refers to the arm and hand movements that synchronize with speech (McNeill, 1992). They can facilitate word production among persons with aphasia (PWA) (Rose, Douglas, & Matyas, 2002) and play a communicative role for PWA to convey ideas (Sekine & Rose, 2013). Kong, Law, Kwan, Lai, and Lam (2015) reported a systematic approach to independently analyze gesture forms and functions in spontaneous oral discourse produced by 119 unimpaired speakers. In particular, there were six specific forms of gestures, modified based on McNeill’s (1992) classification, including: (1) iconic gestures (hand movements related to semantic content of the speech), (2) metaphoric gestures (hand movements that show pictorial content but with abstract idea), (3) deictic gestures (pointing movements that indicate objects in conversational space), (4) emblems (gestures with standard of well-formed properties and language-like features in a specific culture, such as the OK sign), (5) beats (hand movements along with rhythmical pulsation of speech), and (6) non-identifiable gestures (uncodable gestures due to ambiguity or visual obstruction). The first four forms were considered as content-carrying gestures, while the latter two were non-content-carrying. Eight functions of gestures, adopted from several previous studies, were also proposed. They included (1) providing additional information to message conveyed (Goldin-Meadow, 2003), (2) enhancing the speech content (Beattie & Shovelton, 2000), (3) providing alternative means of communication (Le May, David, & Thomas, 1988), (4) guiding and controlling the flow of speech (Jacobs & Garnham, 2007), (5) reinforcing the intonation or prosody of speech, (6) assisting lexical retrieval (Krauss & Hadar, 1999), (7) assisting sentence re-construction (Alibali, Kita, & Younhg, 2000), and (8) no specific function. Using the above gesture annotation framework, Kong, Law, Wat, & Lai (2013) compared speech-accompanying gestures used by PWA and unimpaired speakers in oral discourse tasks. It was found that PWA used significantly more gestures per word than controls. There were a higher proportion of content-carrying gestures in PWA, which functioned mainly to enhance speech content. A negative correlation between aphasia quotients and frequency of gesture use was reported, suggesting speakers with more severe aphasia used more co-verbal gestures. Moreover, PWA who produced a higher percentage of complete sentences or simple sentences in their narratives tended to use fewer gestures. Finally, verbal-semantic processing impairment, but not the degree of hemiplegia, was found to affect the employment of gestures in aphasia.