An investigation of semantic similarity judgments about action and non-action verbs in Parkinson's disease: implications for the Embodied Cognition Framework

Abstract

The Embodied Cognition Framework maintains that understanding actions requires motor simulations subserved in part by premotor and primary motor regions. This hypothesis predicts that disturbances to these regions should impair comprehension of action verbs but not non-action verbs. We evaluated the performances of 10 patients with Parkinson's disease (PD) and 10 normal comparison (NC) participants on a semantic similarity judgment task (SSJT) that included four classes of action verbs and two classes of non-action verbs. The patients were tested both ON and OFF medication. The most salient results involved the accuracies and reaction times (RTs) for the action verbs taken as a whole and the non-action verbs taken as a whole. With respect to accuracies, the patients did not perform significantly worse than the NC participants for either the action verbs or the non-action verbs, regardless of whether they were ON or OFF their medication. And with respect to RTs, although the patients' responses were significantly slower than those of the NC participants for the action verbs, comparable processing delays were also observed for the non-action verbs; moreover, there was again no notable influence of medication. The major dissociation was therefore not between action and non-action verbs, but rather between accuracies (relatively intact) and RTs (relatively delayed). Overall, the data suggest that semantic similarity judgments for both action and non-action verbs are correct but slow in individuals with PD. These results provide new insights about language processing in PD, and they raise important questions about the explanatory scope of the Embodied Cognition Framework.

Impaired Comprehension of Speed Verbs in Parkinson’s Disease

“…However, the PD patients in Kemmerer et al (2013) were older than the present group (75.5 vs. 67.4 years) and were diagnosed much earlier (7.6 vs. 4.5 years ago). It is therefore likely that the Kemmerer et al (2013) Table 2), potentially diluting any specific effects. Beyond a general decline, according to some theories, comprehension of abstract words rely on verbal associations, and consequently on executive and control mechanisms more, as they lack a direct referent (Schwanenflugel, 1991).…”

“…MoCA scores did not predict response difference between fast and slow verbs in the present study. However, all of our patients were without mild cognitive impairment and so present an unsuitable population in which to test the role of cognitive impairment, instead comparing groups with and without mild cognitive impairment would be more appropriate (e.g., Bocanegra et al, 2017).One interesting finding from Kemmerer et al (2013) however that supports the present data is that patient's accuracy for cutting verbs correlated with time since diagnosis-with greater disease duration leading to lower accuracy. This is in line with the idea posed above that hand verbs may be more easily affected by motor disorders because they describe actions that require more precision.…”

Are the motor features of verb meanings represented in the precentral motor cortices? Yes, but within the context of a flexible, multilevel architecture for conceptual knowledge

“…Furthermore, in the lesion study by Kemmerer et al (2012) described above, it is possible that the patients who failed the tasks did so not because of their tendency to have damage in left precentral arm/hand-related motor areas, but rather because of their tendency to have damage in one or more of several other left-hemisphere regions that have been associated with action concepts-specifically, the inferior frontal gyrus, the supramarginal gyrus, and the posterior middle temporal gyrus (see also Urgesi et al, 2014). In addition, even though there is, as indicated above, some evidence that Parkinson's disease disrupts the comprehension of action verbs, the impairments in these patients are often mild and may affect non-action verbs as well (Kemmerer et al, 2013; see also Da Silva, Machado, Cravo, Parente, & Carthery-Goulart, 2014).…”

“…But even though the former features most likely facilitate the conceptual comparison process, it is certainly possible that an accurate decision could be reached by relying mostly or even entirely on the latter features. Indeed, this may be part of the explanation for why patients with Parkinson's disease are able to perform the task as accurately as healthy participants (Kemmerer et al, 2013). Likewise, consider the opening lines of the short story by Richard Bausch called Nobody in Hollywood: "I was pummeled as a teenager.…”

Visual and Motor Features of the Meanings of Action Verbs: A Cognitive Neuroscience Perspective

“…Although the studies just described are consistent with the notion that frontal motor areas contribute to the comprehension of action verbs, other studies suggest that those areas are not absolutely necessary for such comprehension (Papeo et al 2010;Arévalo et al 2012;Kemmerer et al 2013;Maieron et al 2013). For example, in Arévalo et al's (2012) study, 27 left-hemisphere stroke patients were given a task that required judging, on every trial, whether a given word correctly described a picture of an action.…”