Limb apraxia and the left parietal lobe

Abstract

Limb apraxia is a heterogeneous disorder of skilled action and tool use that has long perplexed clinicians and researchers. It occurs after damage to various loci in a densely interconnected network of regions in the left temporal, parietal, and frontal lobes. Historically, a highly classificatory approach to the study of apraxia documented numerous patterns of performance related to two major apraxia subtypes: ideational and ideomotor apraxia. More recently, there have been advances in our understanding of the functional neuroanatomy and connectivity of the left-hemisphere "tool use network," and the patterns of performance that emerge from lesions to different loci within this network. This chapter focuses on the left inferior parietal lobe, and its role in tool and body representation, action prediction, and action selection, and how these functions relate to the deficits seen in patients with apraxia subsequent to parietal lesions. Finally, suggestions are offered for several future directions that will benefit the study of apraxia, including increased attention to research on rehabilitation of this disabling disorder.

Structural Disconnection of the Tool Use Network After Left Hemisphere Stroke Predicts Limb Apraxia Severity

“…Whereas our SVR-VLSM result is consistent with a large body of work demonstrating that apraxia is associated with lesions to the supramarginal gyrus and angular gyrus (for review, see Buxbaum & Randerath, 2018;Goldenberg, 2009;Johnson-Frey, 2004), our SVR-CLSM analysis identified the posterior inferior parietal lobule in the vicinity of the left angular gyrus. This may be driven in part by the use of shortest path tractography, which identifies the optimal path between nodes such that the probability that adjacent voxels form a contiguous, short path between nodes is high.…”

“…These action and object processes, by hypothesis, interface with frontal-motor regions critical for action selection and motor specification. We (and others) refer to the network of brain regions that collectively support the ability to recognize actions and use manipulable objects as the Tool Use Network (see Buxbaum & Randerath, 2018;Garcea & Mahon, 2014). Recent findings suggest that unique variance in apraxia severity may be captured by disruption of functional connectivity among nodes in the Tool Use Network (Watson et al, 2019); however, given the paucity of structural connectivity research in apraxia, the goal of this study was to investigate the extent to which structural disconnection among nodes of the Tool Use Network is predictive of deficits in tool use gesturing.…”

A kinematic examination of dual-route processing for action imitation

“…The dissociation of deficits in meaningful and meaningless action imitation suggests a dual-route for different types of imitation, a model that has seen several developments and adaptations (see Buxbaum & Randerath, 2018or Petreska et al, 2007. Broadly speaking, the dual-route approach to imitation suggests that meaningful actions are normally processed through a semantic, or indirect, route that draws upon stored pre-existing representations of those movements.…”

“…Apraxia, a disorder of complex movement, is one example where this can be the case. Patients with apraxia can show deficits in, among other skills, the ability to imitate meaningful or meaningless actions (Buxbaum & Kalénine, 2010;Buxbaum & Randerath, 2018;Canzano et al, 2016;Petreska et al, 2007;Rumiati et al, 2009).…”

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

“…Goldenberg et al, 2007;Manuel et al, 2013;Hoeren et al, 2014), but also in single cases (Kertesz and Ferro, 1984) and by a fMRI-DTI study (Vry et al, 2015). Thus, damage to a brain network of multiple cortical regions that are connected by white matter fibres likely underlies apraxia (see also Niessen et al, 2014;Vry et al, 2015;Finkel et al, 2018;Buxbaum & Randerath, 2018), which already has been postulated in classical models of praxis skills by Liepmann and Geschwind (see Buxbaum & Randerath, 2018).…”