Treating limb apraxia via action semantics: a preliminary study

ABSTRACT

Limb apraxia is evident in approximately 50% of patients after left hemisphere cerebral vascular accident (LCVA) and increases disability and caregiver dependence. Individuals with apraxia exhibit abnormalities in spatio-temporal aspects of gesture production and/or in knowledge of tool-related actions (action semantics). This preliminary study of three LCVA participants aimed to (i) explore the efficacy of a novel Action Network Treatment (ANT) that focused on improving the semantic association between tool actions and other types of tool knowledge, an intervention inspired by successful semantic network treatments in aphasia (e.g., Edmonds et al., 2009), and (ii) explore whether there are individuals with apraxia who benefit from ANT relative to a version of a comparatively well-studied existing apraxia treatment (Smania et al., 2006; Smania et al., 2000) that shapes gesture via focus on practicing the spatio-temporal aspects of gesture production (Tool Use Treatment or TUT). One participant demonstrated treatment benefits from both ANT and TUT, while another only benefited from TUT. These findings indicate that our novel semantic network strengthening approach to gesture training may be efficacious in at least some individuals with apraxia, and provide a foundation for future study of the characteristics of people with apraxia who benefit from each approach.

KEYWORDS:

• Limb apraxia
• Rehabilitation
• stroke
• action
• tool use

Acknowledgements

We would like to thank Cortney Howard, Leyla Tarhan, and Louisa Smith for coding participants’ gestures; and H. Branch Coslett for help with lesion segmentation.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data Availability

In compliance with the guidelines of the Institutional Review Board of Einstein Healthcare Network, all participants gave informed consent and were compensated for travel expenses and participation. The informed consents obtained did not include permission to make data publicly available; as such, the conditions of our ethical approval do not permit anonymized study data to be publicly archived. To obtain access to the data, individuals should contact the corresponding author. Requests for data are assessed and approved by the Institutional Review Board of Einstein Healthcare Network.

Notes

1 The ARTP also included a second symbolic gesture section and a third meaningless imitation section but not all participants were able to complete these sections. Hereafter, we refer to the version completed by all subjects as the ARTP.

2 Following the suggestion of a reviewer, we also performed a post-hoc analysis of arm posture scores using the same analysis approach as described for hand posture scores (section 2.5). The arm posture results are reported in Appendix L, M, and N for P1, P2, and P3 respectively. Significant treatment effects were almost altogether absent in the models of arm posture scores with the exception of two findings for P2, which we examine further in the Discussion section.

Additional information

Funding

This research was supported by NIH grant R01 NS099061 to L.J. Buxbaum and an Albert Einstein Society Award to M.M. de Wit.