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    Device Technologies and Biomedical Robotics

    (J-389) Sex-Based Differences in Goal-Directed Reaching Before and After Training with Supplemental Kinesthetic Vibrotactile Feedback

    Saturday, October 14, 2023
    9:30 AM – 10:30 AM PDT
    Location: Exhibit Hall - Row J - Poster # 389

      Presenting Author(s)

    • MG

      Mariana E. Guerrero

      Undergraduate Research Assistant
      Marquette University
      Wisconsin, Wisconsin, United States

      • Co-Author(s)

    • RM

      Rachel N. Mazorow (she/her/hers)

      Graduate Researcher
      Marquette University & Medical College of Wisconsin
      Milwaukee, Wisconsin, United States

    • KB

      Kimberly D. Bassindale, DPT

      Assistant Lab Director, Physical Therapist
      Marquette University & Medical College of Wisconsin
      Milwaukee, Wisconsin, United States

      • Primary Investigator(s)

    • RS

      Robert A. Scheidt, PhD

      Lab Director, Professor
      Marquette University & Medical College of Wisconsin
      Milwaukee, Wisconsin, United States

    Introduction::

    Preferred Sub-Track: Interventional Devices and Robotics


    Prior research has revealed that healthy individuals and some stroke survivors can utilize 2-dimensional supplemental vibrotactile feedback (VTF) to enhance the accuracy of reaching without relying on visual feedback1-4. Previous analysis of this study’s data has shown efficacy for 3-dimensional feedback as well among healthy individuals. Other studies have found sex-based differences in strategies navigating peripersonal space (PPS)5,6. PPS is the space surrounding the body where we physically interact with objects or other individuals7. There is a lack of systematic study analyzing how body shape contributes to navigation in PPS. We examined how sex differences and body shape influence the spatial accuracy of goal-directed reaching in the absence of concurrent visual feedback. We hypothesized that reaching movements exhibit sex-based differences such that women exhibit greater spatial awareness than men in PPS surrounding the upper versus lower body. We additionally hypothesized that training with VTF would decrease sex-related differences in the accuracy of goal-directed reaching.  

    Materials and Methods:: Thirteen healthy individuals (7 female; 19-29 years old; 10 right-handed) sat in a chair with their dominant arm supported against gravity. They also held a squeeze bulb in their dominant hand as they made reach-to-grasp movements toward visual targets presented on a computer display screen. An OPTOTRAK 3020 system tracked the motions of the squeeze bulb in real-time and sometimes projected them onto cursor motions displayed on-screen. The display presented a 5x5 grid of targets (±x, ±y) where each target location had 5 concentric rings representing motion in depth (±z). The stationary arm had 6 eccentric rotating mass motors placed in different locations, thereby implementing a "vibrotactile display". Each motor vibrated in proportion to the cursor's deviation from the middle of the workspace along one direction (±x, ±y, ±z). Participants completed two blocks of 25 reaches each using intrinsic somatosensory feedback (no vision or vibration) separated by three 1-hour sessions of VTF training (with intertrial corrections performed with both visual and vibrotactile feedback). We tested our hypotheses by analyzing the z-axis (proximal/distal) components of reach errors within the upper and lower regions of the reachable workspace (i.e., the upper region of PPS defined by the y+ hemispace above the participant's midline, and the lower region defined by the y- hemispace below the midline). 

    Results, Conclusions, and Discussions::

    Mixed model repeated measures ANOVA revealed that proximal/distal target capture errors demonstrated main effects of hemispace (upper and lower workspace; F(2,33)=44.5 p< 0.01), block (before and after VTF training; F(3,99)=6.4, p< 0.01), and interaction effects between hemispace and sex (F(6,99)=5.3, p< 0.01), and hemispace and block (F(2,33)=5.5, p< 0.01). Post-hoc t-tests revealed a significant difference between sexes in the upper hemispace for the baseline intrinsic block (p=0.008) whereby men, but not women, biased their reach endpoints closer to the upper body before but not after VTF training. No significant differences were seen in the lower hemispace.    




    During baseline assessments of reaching, we observed a difference in how accurately women and men reached for targets in regions of PPS surrounding the upper body: women reached more accurately in that region of the workspace whereas men exhibited bias in reach endpoints towards the upper body. The absence of this after VTF training suggests VTF can counteract proximal/distal biases that arise in the absence of vision for healthy individuals. This analysis lays the foundation for future studies investigating sex-based differences in goal-directing reaching. 




    Acknowledgements (Optional): : This work was supported by the National Institute of Child Health and Human Development grant 2R15HD093086.

    References (Optional): : 1Risi N., et al. Journal of Neurophysiology. 2019.; 2Ballardini G., et al. Sensors. 2021; 3Shah V., et al. Experimental Brain Research. 2022.; 4Mazorow R., et al. Sensors. 2023; 5Simon-Dack et al. Neuroreport. 2009; 6Hugdahl et al. Neuropsychologia. 2006; 7Rabellino et al. Front Neurosci. 2020.