Johnson T, Ridgeway G, Luchmee D, Jacob J, Kantak SS. Bimanual coordination during reach-to-grasp actions is sensitive to task goal with distinctions between left- and right-hemispheric stroke. Experimental Brain Research, 2022 Sep;240(9):2359-2373. Epub.

This behavioral study demonstrated that individuals select distinct bimanual grasping strategies dependent on the perceived object properties, thus demonstrating that perceived task goals afford distinct action strategies in both neurotypical individuals and those with stroke. We further observed that individuals with left hemisphere stroke were more impaired in their interlimb coordination compared to controls and those with right-hemisphere damage.

Kantak S, Johnston T, Zarzycki R. Linking Pain and Motor Control: Conceptualization of Movement Deficits in patients with painful conditions. Physical Therapy, 2022, Apr 1, 102(4).

In this perspective paper, we outlined sensory-perceptual, cognitive, and motor processes that contribute to altered movements in the presence of pain. The perspective provides a theory-driven rationale for assessing and treating pain-related movement disorders.

Kantak S, Johnson T, Marsh W.  Differential effects of internal versus external focus of attention on action planning and execution in patients with right and left hemispheric stroke. Human Movement Science- 2020, Aug: 72: 102654.

Therapists often use verbal cues to direct patient attention to either a specific movement of their body (internal) or to an external task-related goal (external). In this study, we demonstrated that individuals with left hemisphere damage who have specific deficits in finger agnosia and right-left discrimination following lesions to left premotor and anterior parietal area attenuate their planning and performance of grasping actions when provided internally-focused instructions

Kantak S and Luchmee D. Contralesional motor cortex is causally engaged during more dexterous actions of the paretic hand after stroke- A preliminary report. Neuroscience Letters, 2020 Feb 16;720:134751. Epub 2020 Jan 10.

Multiple functional imaging studies have reported activation of the contralesional motor cortex during movements of the weaker hand. This activation was distinctively greater when movements required more dexterous actions. In this study, we used transcranial magnetic stimulation to quantify the contralesional motor cortical excitability and probe its causal role during more dexterous actions compared to less dexterous actions. We found that repetitive TMS to the contralesional motor cortex during more dexterous tasks impaired task performance suggesting its causal role in more dexterous tasks. 

Kantak SS, Jax SA, Wittenberg GF. Bimanual coordination: A missing piece of arm rehabilitation after stroke. Restor Neurol Neurosci. 2017, 35(4):347-364.

This perspective paper outlined the state of current research in bimanual coordination after stroke. While most activities engage the two arms in a cooperative manner, much research in stroke rehabilitation is focused on improving the paretic arm alone. This paper challenged the prevalent view and advocated for testing and improving bimanual actions with a focus on bimanual coordination.