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Malešević J, Kostić M, Jure FA, Spaich EG, Došen S, Ilić V, Bijelić G, Štrbac M. Electrotactile Communication via Matrix Electrode Placed on the Torso Using Fast Calibration, and Static vs. Dynamic Encoding. SENSORS (BASEL, SWITZERLAND) 2022; 22:7658. [PMID: 36236758 PMCID: PMC9572222 DOI: 10.3390/s22197658] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/05/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Electrotactile stimulation is a technology that reproducibly elicits tactile sensations and can be used as an alternative channel to communicate information to the user. The presented work is a part of an effort to develop this technology into an unobtrusive communication tool for first responders. In this study, the aim was to compare the success rate (SR) between discriminating stimulation at six spatial locations (static encoding) and recognizing six spatio-temporal patterns where pads are activated sequentially in a predetermined order (dynamic encoding). Additionally, a procedure for a fast amplitude calibration, that includes a semi-automated initialization and an optional manual adjustment, was employed and evaluated. Twenty subjects, including twelve first responders, participated in the study. The electrode comprising the 3 × 2 matrix of pads was placed on the lateral torso. The results showed that high SRs could be achieved for both types of message encoding after a short learning phase; however, the dynamic approach led to a statistically significant improvement in messages recognition (SR of 93.3%), compared to static stimulation (SR of 83.3%). The proposed calibration procedure was also effective since in 83.8% of the cases the subjects did not need to adjust the stimulation amplitude manually.
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Affiliation(s)
| | | | - Fabricio A. Jure
- Neurorehabilitation Systems, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, 9220 Aalborg, Denmark
| | - Erika G. Spaich
- Neurorehabilitation Systems, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, 9220 Aalborg, Denmark
| | - Strahinja Došen
- Neurorehabilitation Systems, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, 9220 Aalborg, Denmark
| | - Vojin Ilić
- Department of Computing and Control Engineering, Faculty of Technical Sciences, University of Novi Sad, 21102 Novi Sad, Serbia
| | - Goran Bijelić
- Tecnalia, Basque Research and Technology Alliance (BRTA), 20009 Donostia-San Sebastian, Spain
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Smith SG, Yokich MK, Beaudette SM, Brown SHM, Bent LR. Cutaneous Sensitivity Across Regions of the Foot Sole and Dorsum are Influenced by Foot Posture. Front Bioeng Biotechnol 2022; 9:744307. [PMID: 35096786 PMCID: PMC8792506 DOI: 10.3389/fbioe.2021.744307] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 11/04/2021] [Indexed: 01/13/2023] Open
Abstract
Understanding the processing of tactile information is crucial for the development of biofeedback interventions that target cutaneous mechanoreceptors. Mechanics of the skin have been shown to influence cutaneous tactile sensitivity. It has been established that foot skin mechanics are altered due to foot posture, but whether these changes affect cutaneous sensitivity are unknown. The purpose of this study was to investigate the potential effect of posture-mediated skin deformation about the ankle joint on perceptual measures of foot skin sensitivity. Participants (N = 20) underwent perceptual skin sensitivity testing on either the foot sole (N = 10) or dorsum (N = 10) with the foot positioned in maximal dorsiflexion/toe extension, maximal plantarflexion/toe flexion, and a neutral foot posture. Perceptual tests included touch sensitivity, stretch sensitivity, and spatial acuity. Regional differences in touch sensitivity were found across the foot sole (p < 0.001) and dorsum (p < 0.001). Touch sensitivity also significantly increased in postures where the skin was compressed (p = 0.001). Regional differences in spatial acuity were found on the foot sole (p = 0.002) but not dorsum (p = 0.666). Spatial acuity was not significantly altered by posture across the foot sole and dorsum, other than an increase in sensitivity at the medial arch in the dorsiflexion posture (p = 0.006). Posture*site interactions were found for stretch sensitivity on the foot sole and dorsum in both the transverse and longitudinal directions (p < 0.005). Stretch sensitivity increased in postures where the skin was pre-stretched on both the foot sole and dorsum. Changes in sensitivity across locations and postures were believed to occur due to concurrent changes in skin mechanics, such as skin hardness and thickness, which follows our previous findings. Future cutaneous biofeedback interventions should be applied with an awareness of these changes in skin sensitivity, to maximize their effectiveness for foot sole and dorsum input.
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Affiliation(s)
- Simone G.V.S. Smith
- Department of Human Health and Nutritional Science, University of Guelph, Guelph, ON, Canada
| | - Maiya K. Yokich
- Department of Human Health and Nutritional Science, University of Guelph, Guelph, ON, Canada
| | - Shawn M. Beaudette
- Department of Human Health and Nutritional Science, University of Guelph, Guelph, ON, Canada
- Department of Kinesiology, Brock University, St. Catharines, ON, Canada
| | - Stephen H. M. Brown
- Department of Human Health and Nutritional Science, University of Guelph, Guelph, ON, Canada
| | - Leah R. Bent
- Department of Human Health and Nutritional Science, University of Guelph, Guelph, ON, Canada
- *Correspondence: Leah R. Bent,
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Oppici L, Grütters K, Garofolini A, Rosenkranz R, Narciss S. Deliberate Practice and Motor Learning Principles to Underpin the Design of Training Interventions for Improving Lifting Movement in the Occupational Sector: A Perspective and a Pilot Study on the Role of Augmented Feedback. Front Sports Act Living 2021; 3:746142. [PMID: 34796319 PMCID: PMC8593185 DOI: 10.3389/fspor.2021.746142] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 10/12/2021] [Indexed: 11/18/2022] Open
Abstract
Spine posture during repetitive lifting is one of the main risk factors for low-back injuries in the occupational sector. It is thus critical to design appropriate intervention strategies for training workers to improve their posture, reducing load on the spine during lifting. The main approach to train safe lifting to workers has been educational; however, systematic reviews and meta-analyses have shown that this approach does not improve lifting movement nor reduces the risk of low back injury. One of the main limitations of this approach lies in the amount, quality and context of practice of the lifting movement. In this article, first we argue for integrating psychologically-grounded perspectives of practice design in the development of training interventions for safe lifting. Principles from deliberate practice and motor learning are combined and integrated. Given the complexity of lifting, a training intervention should occur in the workplace and invite workers to repeatedly practice/perform the lifting movement with the clear goal of improving their lifting-related body posture. Augmented feedback has a central role in creating the suitable condition for achieving such intervention. Second, we focus on spine bending as risk factor and present a pilot study examining the benefits and boundary conditions of different feedback modalities for reducing bending during lifting. The results showed how feedback modalities meet differently key requirements of deliberate practice conditions, i.e., feedback has to be informative, individualized and actionable. Following the proposed approach, psychology will gain an active role in the development of training interventions, contributing to finding solutions for a reduction of risk factors for workers.
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Affiliation(s)
- Luca Oppici
- Psychology of Learning and Instruction, Department of Psychology, School of Science, Technische Universität Dresden, Dresden, Germany.,Centre for Tactile Internet With Human-in-the-Loop (CeTI), Technische Universität Dresden, Dresden, Germany
| | - Kim Grütters
- Psychology of Learning and Instruction, Department of Psychology, School of Science, Technische Universität Dresden, Dresden, Germany
| | - Alessandro Garofolini
- Institute for Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia
| | - Robert Rosenkranz
- Centre for Tactile Internet With Human-in-the-Loop (CeTI), Technische Universität Dresden, Dresden, Germany.,Acoustic and Haptic Engineering, Faculty of Electrical and Computer Engineering, Technische Universität Dresden, Dresden, Germany
| | - Susanne Narciss
- Psychology of Learning and Instruction, Department of Psychology, School of Science, Technische Universität Dresden, Dresden, Germany.,Centre for Tactile Internet With Human-in-the-Loop (CeTI), Technische Universität Dresden, Dresden, Germany
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Smith SGVS, Power GA, Bent LR. Foot sole cutaneous stimulation mitigates neuromuscular fatigue during a sustained plantar flexor isometric task. J Appl Physiol (1985) 2020; 129:325-334. [PMID: 32584665 DOI: 10.1152/japplphysiol.00157.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Neuromuscular fatigue impairs motor coordination, movement stability, and proprioception, which further decreases performance. A neuromechanical coupling exists between foot sole cutaneous mechanoreceptors and motoneurons of the lower limb, however, the contribution of skin sensory input on muscle fatigue remains unclear. The purpose of this study was to determine if the presence of cutaneous stimulation could mitigate the effect of fatigue of the plantar flexor muscles during a sustained isometric task at 30% maximal voluntary contraction (MVC). Participants (N = 16, age 24.1 ± 2.6 yr) underwent a 30% isometric plantar flexor fatiguing task in a seated position with hip, knee, and ankle angle at 80°, 100°, and 90°, respectively, with intermittent MVCs until task failure. Failure was defined as when the participant could no longer maintain 30% MVC for a minimum of two seconds. Throughout the protocol, electrical stimulation was applied to either the right heel, right metatarsals, or no stimulation. A subset of participants (N = 6) underwent an additional condition with electrical stimulation applied to the left arm. MVCs were also conducted intermittently throughout recovery for 30 min. Foot sole cutaneous stimulation mitigated fatigue, as demonstrated by an ~15% increased time to task failure (TTF) compared with the control condition. When normalized to TTF, MVC torque amplitude was not different at each time epoch, which indicated that each %MVC was maintained longer into the fatigue task during the heel and metatarsal stimulation conditions However, there was no significant effect of cutaneous stimulation on recovery. The results indicate that cutaneous stimulation may serve as a feasible means to mitigate fatigue.NEW & NOTEWORTHY Cutaneous coupling with lower limb motor neurons has long been known. We set out to establish whether this pathway could serve a purpose other than muscular modulation during standing and walking. We found that during a submaximal contraction of the plantar flexor muscles, the addition of intermittent cutaneous stimulation to the skin of the foot sole resulted in an increase in time to task failure by 15%, which was over a minute longer in duration. We conclude that skin stimulation may serve as a mechanism to mitigate fatigue.
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Affiliation(s)
- Simone G V S Smith
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Geoffrey A Power
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Leah R Bent
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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Smith SGVS, Yokich MK, Beaudette SM, Brown SHM, Bent LR. Effects of foot position on skin structural deformation. J Mech Behav Biomed Mater 2019; 95:240-248. [PMID: 31054375 DOI: 10.1016/j.jmbbm.2019.04.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 02/12/2019] [Accepted: 04/11/2019] [Indexed: 11/29/2022]
Abstract
As the largest and most superficial organ, the skin is well positioned for receiving sensory information from the environment. It is conceivable that changes in posture could result in deformations of the skin and subsequent changes in skin material properties. Specifically, the ankle and metatarsophalangeal joints have the capability to undergo large postural alterations with the potential to induce large structural deformations in the skin of the foot. The purpose of this study was to determine the extent to which alterations in foot posture may influence measures of foot sole and dorsum skin stretch, hardness, and thickness in vivo. Ten young and healthy individuals were tested while three static foot postures (plantar flexion, neutral and dorsiflexion) were maintained passively. Skin stretch deformation was quantified across each posture using an 11 × 4 point matrix of 3D kinematic markers affixed to the skin of the foot sole and dorsum. Skin hardness was assessed across each posture at specific locations of the foot sole (1st metatarsal, 5th metatarsal, medial arch, lateral arch and heel) and foot dorsum (proximal, middle and distal) using a handheld Shore durometer. Skin (epidermal + dermal) thickness was measured in each posture from the same test locations using ultrasound images obtained for the foot sole and dorsum. In the plantar flexion ankle posture, the foot sole skin was observed to relax/retract on average (± standard errorr of the mean (SEM) by 9 ± 2% to become both 20 ± 6% softer and 10 ± 6% thicker. In this posture, the foot dorsum skin stretched on average by 7 ± 2% resulting in 84 ± 8% harder and 5 ± 4% thinner skin. In the dorsiflexion ankle posture, the skin of the foot sole was observed to stretch on average by 5 ± 1% to become both 20 ± 8% harder and 4 ± 7% thinner. In this posture, the skin of the foot dorsum relaxed/retracted on average by 9 ± 1% resulting in the skin becoming 27 ± 12% softer and 7 ± 5% thicker. Notably, all of the sites responded with movement in a similar direction, but each site responded to a variable extent. Importantly, it was clear that the majority of skin structural deformation of the foot sole occurred within the 1st metatarsal, 5th metatarsal, and medial arch regions, while deformation was more evenly distributed across regions of the foot dorsum. The results suggest there is location specificity in the retraction and stretch characteristics of the foot skin. While not tested directly, this may suggest that local stretch distributions could be in part due to the underlying dermal and hypodermal structures in these foot regions. With these observed changes in the mechanical structure of the foot sole and dorsum skin tissue matrix, it is possible that corresponding posture-dependent changes in cutaneous mechanoreceptor activation may be present.
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Affiliation(s)
- Simone G V S Smith
- University of Guelph, Department of Human Health and Nutritional Science, Guelph, ON, Canada
| | - Maiya K Yokich
- University of Guelph, Department of Human Health and Nutritional Science, Guelph, ON, Canada
| | - Shawn M Beaudette
- University of Ottawa, School of Human Kinetics, Faculty of Health Sciences, Ottawa, ON, Canada
| | - Stephen H M Brown
- University of Guelph, Department of Human Health and Nutritional Science, Guelph, ON, Canada
| | - Leah R Bent
- University of Guelph, Department of Human Health and Nutritional Science, Guelph, ON, Canada.
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Pinto BL, Beaudette SM, Brown SHM. Tactile cues can change movement: An example using tape to redistribute flexion from the lumbar spine to the hips and knees during lifting. Hum Mov Sci 2018; 60:32-39. [PMID: 29772412 DOI: 10.1016/j.humov.2018.05.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 05/10/2018] [Accepted: 05/10/2018] [Indexed: 10/16/2022]
Abstract
Given the appropriate cues, kinematic factors associated with low back injury risk and pain, such as spine flexion, can be avoided. Recent research has demonstrated the potential for tactile sensory information to change movement. In this study an athletic strapping tape was applied bilaterally along the lumbar extensor muscles to provide continuous tactile feedback information during a repeated lifting and lowering task. The presence of the tape resulted in a statistically significant reduction in lumbar spine flexion when compared to a baseline condition in which no tape was present. This reduction was further increased with the explicit instruction to pay attention to the sensations elicited by the tape. In both cases, the reduction in lumbar spine flexion was compensated for by increases in hip and knee flexion. When the tape was then removed and participants were instructed to continue lifting as if it was still present, the reduction in lumbar flexion and increases in hip and knee flexion were retained. Thus this study provides evidence that tactile cues can provide vital feedback information that can cue human lumbar spine movement to reduce kinematic factors associated with injury risk and pain.
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Affiliation(s)
- Brendan L Pinto
- Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Shawn M Beaudette
- Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Stephen H M Brown
- Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada.
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Beaudette SM, Pinto BL, Brown SHM. Tactile Feedback can be Used to Redistribute Flexion Motion Across Spine Motion Segments. Ann Biomed Eng 2018; 46:789-800. [PMID: 29464461 DOI: 10.1007/s10439-018-1998-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 02/12/2018] [Indexed: 12/01/2022]
Abstract
This experiment investigates the efficacy of tactile feedback in affecting changes to dynamic spine movements. A sample of (n = 24) young, healthy males were assessed while completing targeted spine flexion movements with instruction to minimize stretching of the skin beneath an applied tactile stimulus (liquid bandage). Localized tactile stimuli were placed bilaterally at either lumbar (L4), lower thoracic (T10) or upper thoracic (T4) levels. Results demonstrate that localized tactile feedback elicited a re-distribution of spine flexion movement across spine sub-sections (e.g. lumbar vs. thoracic) and intervertebral segments (e.g. C7/T1 through L5/S1). Further, tactile feedback successfully limited the magnitude of end-range flexion, but did not limit functional mid-range spine flexion. Finally, tactile feedback located in the lower thoracic region (T10) increased thoracic flexion variability; however, tactile feedback located at the T4 and L4 regions had no significant effect on movement variability. These findings provide evidence that spine neuromuscular control patterns can be altered using simple tactile stimuli. In terms of low back injury prevention and/or rehabilitation, the tactile feedback investigated here has apparent utility in limiting recognized mechanical risk factors for low back injury; specifically, the local incidence of flexion at specific spine levels, and the incidence of end-range flexion.
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Affiliation(s)
- Shawn M Beaudette
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Brendan L Pinto
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Stephen H M Brown
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada.
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Cimino SR, Beaudette SM, Brown SHM. Kinesio taping influences the mechanical behaviour of the skin of the low back: A possible pathway for functionally relevant effects. J Biomech 2017; 67:150-156. [PMID: 29276069 DOI: 10.1016/j.jbiomech.2017.12.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 11/24/2017] [Accepted: 12/04/2017] [Indexed: 10/18/2022]
Abstract
Despite claims of functional benefits of kinesio tape application, little mechanistic evidence exists to support physiological pathways to achieve these benefits. As kinesio tape is adhered directly to the skin, it can be supposed that any pathway needs to first achieve effects at this level. To address this, two layers of the skin, the combined epidermis and dermis, as well as the hypodermis were studied. Specifically, -kinematic measures of skin surface stretch and retraction, as well as ultrasound measures of skin thickness, were made along all edges of kinesio tape applied over the low back. Results demonstrated that the more superficial skin layer (combined epidermis and dermis), but not the deeper hypodermis, was significantly stretched (p = .0001) and thinner (p = .0016) at either end of the tape, and significantly retracted (p < .0001) and thicker (p = .0001) along the lateral edges of the tape. These results were partly dependent upon spine posture; skin retraction along the tape edges was only apparent in neutral and flexed (but not extended) spine postures, while skin thinning at the tape ends was only apparent in neutral and extended (but not flexed) spine postures. Hypodermal thickness was not affected by kinesio tape application at any location or in any posture. In summary, measured deformations at the skin surface and within the epidermal and dermal regions provide plausible pathways through which kinesio tape could achieve its claimed benefits.
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Affiliation(s)
- Stephanie R Cimino
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Shawn M Beaudette
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Stephen H M Brown
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada.
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