The impact of impaired semantic knowledge on spontaneous iconic gesture production

Abstract

BackgroundPrevious research has found that people with aphasia produce more spontaneous iconic gesture than control participants, especially during word-finding difficulties. There is some evidence that impaired semantic knowledge impacts on the diversity of gestural handshapes, as well as the frequency of gesture production. However, no previous research has explored how impaired semantic knowledge impacts on the frequency and type of iconic gestures produced during fluent speech compared with those produced during word-finding difficulties.AimsTo explore the impact of impaired semantic knowledge on the frequency and type of iconic gestures produced during fluent speech and those produced during word-finding difficulties.Methods & ProceduresA group of 29 participants with aphasia and 29 control participants were video recorded describing a cartoon they had just watched. All iconic gestures were tagged and coded as either “manner,” “path only,” “shape outline” or “other”. These gestures were then separated into either those occurring during fluent speech or those occurring during a word-finding difficulty. The relationships between semantic knowledge and gesture frequency and form were then investigated in the two different conditions.Outcomes & ResultsAs expected, the participants with aphasia produced a higher frequency of iconic gestures than the control participants, but when the iconic gestures produced during word-finding difficulties were removed from the analysis, the frequency of iconic gesture was not significantly different between the groups. While there was not a significant relationship between the frequency of iconic gestures produced during fluent speech and semantic knowledge, there was a significant positive correlation between semantic knowledge and the proportion of word-finding difficulties that contained gesture. There was also a significant positive correlation between the speakers' semantic knowledge and the proportion of gestures that were produced during fluent speech that were classified as “manner”. Finally while not significant, there was a positive trend between semantic knowledge of objects and the production of “shape outline” gestures during word-finding difficulties for objects.ConclusionsThe results indicate that impaired semantic knowledge in aphasia impacts on both the iconic gestures produced during fluent speech and those produced during word-finding difficulties but in different ways. These results shed new light on the relationship between impaired language and iconic co-speech gesture production and also suggest that analysis of iconic gesture may be a useful addition to clinical assessment.

A Comparison of Coverbal Gesture Use in Oral Discourse Among Speakers With Fluent and Nonfluent Aphasia

“…It is more important to note that the fact that our nonfluent PWA had a tendency to produce fewer words and complete sentences than their counterparts with fluent aphasia and that they were more impaired in oral naming abilities than fluent PWA echoed this claim by de Ruiter and de Beer. However, we acknowledge that this finding regarding a different gesture rate by fluency groups of PWA could have been confounded by aphasia severity because the fluent PWA in the present study were generally Cocks et al (2013), in which information in speakers' gestures produced during fluent speech as well as during word-finding difficulties were linked to a speaker's semantic knowledge.…”

“…This finding suggested concomitant impairment between gestural and linguistic skills in PWA. In contrast, it has also been reported that a significantly greater proportion of PWA used gestures, including iconic gestures (Cocks, Dipper, Pritchard, & Morgan, 2013), than their unimpaired counterparts, and many of the PWA produced iconic gestures that served communicative and/or facilitative functions . This observation supported the sketch model (de Ruiter, 2000) and provided evidence for independent deficits of gesture and verbal production.…”

“…Cocks et al (2013) reported a significant correlation between semantic knowledge among PWA and their proportion of anomic behaviors that involved gestures. The potential impact of semantic impairment among PWA on gesture use is further illustrated in the present study.…”

The relationship between co-speech gesture production and macrolinguistic discourse abilities in people with focal brain injury

“…The study of individuals with aphasia forms an important part of our understanding of the relationship between gesture and speech (e g Ahlsén, 1991; Cicone et al, 1979; Cocks, Dipper, Pritchard, & Morgan, 2013; Dipper, Cocks, Rowe, & Morgan, 2011; Hadar et al, 1998; Pritchard, Cocks, & Dipper, 2013; Wilkinson, 2013). If co-speech gestures and speech are produced by a common system of processing, then one would expect impairments in one system to be reflected in the other (see Eling & Whitaker, 2009; McNeill, 1985, 1992; McNeill et al, 2008).…”

“…As to the possibility of compensation, there is evidence that while individuals with severe deficits in nonverbal semantic processing (Hogrefe et al, 2012) and semantic knowledge (Cocks et al, 2013) cannot use nonverbal tools efficiently for interpersonal communication, patients with intact semantic processing can use gesture as a compensatory strategy for communication (Göksun et al, 2015; Hogrefe et al, 2012). Thus, we expected that people with damage to language-related areas of the brain (the left temporal lobe and left inferior frontal cortex) to produce more gestures to compensate for their verbal impairment, provided that they do not have semantic deficiencies.…”