Conceptual- and production-related predictors of pantomimed tool use deficits in apraxia

Abstract

Apraxia following left hemisphere stroke disrupts pantomimed tool use (PTU), a task that requires the integrity of a number of cognitive and motor processes. Although previous studies have identified that apraxics have deficits in (1) the integrity of/access to stored tool-use gesture representations, (2) deficits in intrinsic (body-based) coordinate control, and (3) abnormal reliance on visual feedback, no study to date has simultaneously tested the relative contribution of these three deficits to poor PTU performance. In this study we assessed 38 chronic left hemisphere stroke survivors on tests of PTU and the 3 component processes. We then attempted to predict PTU with the component scores using hierarchical regression to control for overall stroke severity and the possibility of correlated component scores. Results showed that over half of the variability in PTU was predictable, with the strongest independent predictor being a test of intrinsic coordinate control without visual feedback. A test of the integrity of/access to stored representations also predicted PTU. These results confirm and extend previous claims that conceptual- and production-related factors affect PTU, even after considering that deficits in both factors are commonly observed to varying degrees in apraxic patients.

The network underlying human higher-order motor control: Insights from machine learning-based lesion-behaviour mapping in apraxia

“…The finding of a network underlying apraxia is convincing since the ability to pantomime object use is a complex task that requires a wide range of cognitive and motor abilities. Several cognitive models of praxis skills have been proposed in line with findings in apractic patients (e.g., Barbieri & de Renzi, 1988;Cubelli et al, 2000;Bartolo et al, 2003;Johnson-Frey, 2004;Frey, 2008;Jax et al, 2014;Goldenberg, 2017). Although there is no consensus on the cognitive model underlying pantomime (Goldenberg, 2017), the different models generally assume paths along multiple cognitive processes that lie between phonological or visual analysis of the input stimuli (e.g., the word 'tooth brush' or a picture of a tooth brush) and the motor response.…”

“…Although there is no consensus on the cognitive model underlying pantomime (Goldenberg, 2017), the different models generally assume paths along multiple cognitive processes that lie between phonological or visual analysis of the input stimuli (e.g., the word 'tooth brush' or a picture of a tooth brush) and the motor response. For example, a classical cognitive model of apraxia assumes that gestures such as pantomime are conceptualised, converted into a motor programme, and then executed (e.g., Liepmann, 1908;Barbieri & De Renzi, 1988;Jax et al, 2014). More recent models (e.g.…”

Improvement of Apraxia With Augmented Reality: Influencing Pantomime of Tool Use via Holographic Cues

“…Patients show impairments in planning or producing motor actions. Typically, they have problems with gesture imitation, pantomimed tool use, and actual tool use (4,10,11). In the pantomime of tool use task patients are asked to produce an action without holding the object in their hand (12).…”

“…Pantomime of tool use is considered as very sensitive in detecting the presence of limb apraxia; typically the pantomime mode appears more sensitive as compared to actual tool use mode (3,15), however performance measures across these modes correlate and individual patterns appear stable (16,17). While both modes may retrieve similar concepts, differences may be represented by missing visuotactile feedback, i.e., the absence of mechanical interaction and cues from real objects, the heightened demand on imagery and the translation from mental images to motor execution (5,10,11,16,18,19). Contextual information may provide critical cues facilitating the access to an adequate motor concept and may constrain the possibilities for action production (15)(16)(17).…”

“…Contextual information may provide critical cues facilitating the access to an adequate motor concept and may constrain the possibilities for action production (15)(16)(17). While tactile feedback alone, such as a stick that resembles the handle of a tool, seems to be inefficient in evoking the correct motor program of an action (20,21), several studies underlined the role of visual feedback (11,17,22). In this regard, it has been shown that the perception of object affordances (i.e., action possibilities offered by the environment and the object's properties) and its visual attributes is influenced by its visuo-perceptual context, such as thematic and functional properties but also by space (23).…”