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Viseu JP, Yiou E, Morin PO, Olivier A. Sport dependent effects on the sensory control of balance during upright posture: a comparison between professional horseback riders, judokas and non-athletes. Front Hum Neurosci 2023; 17:1213385. [PMID: 37584030 PMCID: PMC10423814 DOI: 10.3389/fnhum.2023.1213385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 07/11/2023] [Indexed: 08/17/2023] Open
Abstract
Introduction Compared to judokas (JU) and non-athletes (NA), horseback riders (HR) may develop specific changes in their sensory control of balance. Methods Thirty-four international-level JU, twenty-seven international-level HR and twenty-one NA participated. Participants stood upright on a plateform (static condition) or on a seesaw device with an instability along the mediolateral (ML) or the anteroposterior (AP) direction (dynamic conditions). These conditions were carried out with eyes opened (EO) or closed (EC), and with (wF) or without a foam (nF). Experimental variables included conventional (linear), non-linear center-of-pressure (COP) parameters, Romberg Quotient (RQ) and Plantar Quotient (PQ). Results Group effects. COP Surface (COPS) and standard deviation of COP along AP (SDY) were lower in HR than in JU in Static. SD Y was lower in HR than in JU in Dynamic AP. COP velocity (COPV) was lower in both HR and JU than in NA in Static and Dynamic. Sample entropy along AP and ML (SampEnY and SampEnX) were higher in HR than in JU in Static. SampEnY was higher in HR than in JU in Dynamic ML. Sensory effects. In EC, COPV was lower in JU than in NA in Dynamic AP, and lower in JU than in both HR and NA in Dynamic ML. In EO, COPV was lower in both JU and HR than in NA in Dynamic ML. RQ applied to COPS was lower in JU than in both HR and NA in Dynamic AP, and lower in JU than in HR in Dynamic ML. RQ applied to COPV was lower in JU than in both HR and NA in Static and Dynamic. PQ applied to COPS was higher in JU than in both HR and NA in Dynamic ML. Conclusion Results showed that the effects of sport expertise on postural control could only be revealed with specific COP variables and were directionally oriented and sport-dependant. HR seem to rely more on vision than JU, thus revealing that the contribution of the sensory inputs to balance control is also sport-dependent. Results open up new knowledge on the specificity of sport practice on multisensory balance information during upright posture.
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Affiliation(s)
- Jean-Philippe Viseu
- CIAMS, Université Paris-Saclay, Orsay, France
- CIAMS, Université d’Orléans, Orléans, France
| | - Eric Yiou
- CIAMS, Université Paris-Saclay, Orsay, France
- CIAMS, Université d’Orléans, Orléans, France
| | | | - Agnès Olivier
- CIAMS, Université Paris-Saclay, Orsay, France
- CIAMS, Université d’Orléans, Orléans, France
- Institut Français du Cheval et de l’Equitation, Plateau technique de Saumur, Saumur, France
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Alessandria M, Campisi S, Vieira TM. Can a thin mechanical stimulation on the plantar arch affect the head mobility? A preliminary report. SPORT SCIENCES FOR HEALTH 2023. [DOI: 10.1007/s11332-022-01032-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Alessandria M. Horizontal Heterophoria Modifications by Means of Thin Proprioceptive Stimulations Applied on the Foot Sole: A Randomised Study. J Mot Behav 2022; 54:620-630. [PMID: 35236256 DOI: 10.1080/00222895.2022.2046539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Some authors have demonstrated that proprioceptive stimuli applied on the feet soles can interfere on the ocular muscles. However, these studies do not clarify possible functional differences between the dominant eye and the non-dominant eye. The purpose of this randomised study is to establish if the positioning of an Internal Heel Wedge (IHW) and an External Heel Wedge (EHW) can modify horizontal heterophoria, determine dissimilar behaviours between the dominant eye and the non-dominant eye. Forty-two healthy subjects, with a right dominant eye, were tested. The 1.5 mm-thick proprioceptive stimuli were shaped out of a cork half-moon. The experimental group was divided into two groups: IHW group and EHW group. Both groups performed the "Baseline" (without mechanical stimulation) and "After 15'" (following a fitting period of 15 minutes on a treadmill with mechanical stimulation) trials. The control group performed the same trials without any podalic stimulation. Meaningful changes were observed on the horizontal heterophoria of the non-dominating eye with an IHW. Non-statistically significant variations were observed with an EHW and in the Control group. A thin heel wedge applied on the foot sole was able to generate functional changes in the non-dominant eye and could help health professionals develop increasingly personalised rehabilitation programmes.
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Affiliation(s)
- Marco Alessandria
- Department of Life Sciences and Systems Biology, University of Turin, Torino, Italy
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Bousbaïne van de Kerckhove L, Lefaucheur JP, Sorel M. Differences in stabilometric correlates of pain relief after wearing postural insoles for six weeks between chronic nociceptive and neuropathic foot pain. An open-label pilot study. Neurophysiol Clin 2021; 51:267-278. [PMID: 34023188 DOI: 10.1016/j.neucli.2021.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/25/2021] [Accepted: 04/25/2021] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE The aim of this study was to determine if the use of postural insoles could result in a noticeable reduction in the foot pain intensity in patients with a chronic pain condition, either nociceptive (ankylosing spondylitis, AS) or neuropathic (small fiber neuropathy, SFN). METHOD In this open-label pilot study, patients were asked to wear postural insoles for a continuous period of 6 weeks. The primary endpoint was the mean daily pain intensity at foot mobilization measured using a visual analogue scale (VAS). The secondary endpoints included global pain intensity scores (at rest or under mobilization), clinical questionnaires on pain and daily functioning (including the Brief Pain Inventory (BPI), the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), the Neuropathic Pain Symptom Inventory (NPSI) and the DN4 questionnaire), and posturo-podiatric variables assessed on clinical examination or using a baro-stabilometric platform. RESULTS The study was completed by 17 patients with AS and 12 patients with SFN. After wearing postural insoles for 6 weeks, a significant improvement was observed on the primary endpoint (decrease in VAS pain score at the foot during mobilization) in both groups of patients (from 6.4 ± 2.4 to 3.6 ± 2.6 (p = 0.0004) in the AS group and from 5.7 ± 2.2 to 2.4 ± 1.6 (p = 0.0003) in the SFN group). Improvement was also observed for all other pain and activity scores (global pain at rest or during mobilization (VAS), BDI, and BASDAI for the AS group or NPSI and DN4 for the SFN group), as well as for posturo-podiatric clinical variables. However, we did not find any difference in any clinical pain score whether the posturo-podiatric clinical outcomes were positive or not. Regarding the stabilometric measures, the only significant change after the intervention was a reduced mean velocity of center of pressure displacement in the AS group only (mVel in mm/s: from 7.4 ± 2.0 vs. 6.7 ± 1.9, p = 0.017). In addition, the reduction in mVel correlated to that of the BPI score (r = 0.48, p = 0.0496). CONCLUSION In both groups of patients, wearing postural insoles for 6 weeks led to a significant decrease in local pain intensity at foot level and to more global analgesic effects and positive posturo-podiatric changes. However, these latter changes did not appear to be strongly associated with pain relief. Nevertheless, an index of a better postural control, i.e. mVel decrease, was found to be related to a reduction of pain interference in daily life activities in AS patients, but not in SFN patients. Therefore, in the context of neuropathic pain, mechanisms other than postural changes likely contribute to the analgesic effects of wearing postural insoles, in contrast to nociceptive pain due to spinal osteoarthritis.
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Affiliation(s)
- Leïla Bousbaïne van de Kerckhove
- Univ Paris Est Creteil, EA4391, ENT, F-94010 Creteil, France; Osteopathic Office, 123 rue de l'Université, F-75007 Paris, France.
| | - Jean-Pascal Lefaucheur
- Univ Paris Est Creteil, EA4391, ENT, F-94010 Creteil, France; AP-HP, Henri Mondor University Hospital, Clinical Neurophysiology Unit, F-94010 Creteil, France
| | - Marc Sorel
- Univ Paris Est Creteil, EA4391, ENT, F-94010 Creteil, France; CH Sud-Seine-et-Marne, Pain Clinic (Centre d'Evaluation et Traitement de la Douleur), F-77140 Nemours, France
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Marco A, Massimiliano G. Proprioceptive effects on gait and postural stability through mechanical stimulation with an Internal and External Heel Wedge: An interventional single-arm study. J Bodyw Mov Ther 2020; 24:195-201. [PMID: 32825988 DOI: 10.1016/j.jbmt.2020.03.007] [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] [Received: 06/05/2019] [Revised: 12/20/2019] [Accepted: 03/07/2020] [Indexed: 01/12/2023]
Abstract
BACKGROUND Previous studies have shown that the stimulation of the foot sole can provide important information about the body's position and locomotion. However, these studies do not clarify how the position of the mechanical stimulation on the foot sole affects the gait cycle. AIMS This interventional single-arm study aims to verify if the insertion of an Internal Heel Wedge (IHW) and External Heel Wedge (EHW) can modify the stabilometric and podobarometric variables, the functional changes during the gait cycle, the different responses between the dominating lower limb and the non-dominating lower limb, and the potential temporal summations of the proprioceptive stimulation. METHOD Twenty-three healthy subjects (age 31 ± 5 years; weight 62 ± 1 kg; height 168±6 cm), with a right dominating lower limb, were recruited. The IHW and EHW were created out of half-moon-shaped cork pieces having a 1.5 mm thickness, 6 cm length and 3 cm height. The sequence of tests foresaw trials without IHW or EHW (Baseline), trials with IHW or EHW (Acute), trials after an adaptation period of 15 min on a treadmill with IHW or EHW (after 15'). RESULTS Data showed statistically significant variations in the Step Rate, Duration of the cycle of the left step and Single Right Support phase for the IHW, Duration Single Right support and Single Left Support phase for the EHW. CONCLUSION Data showed that a thin proprioceptive stimulation of the plantar arch was enough to induce changes in the gait cycle and that, upon changing the position of the proprioceptive stimulation, the functional response of the feet was inverted. These results can help health professionals provide a correct interpretation of the clinical data during follow-ups, avoiding undesirable and harmful effects on the patients' recovery.
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Affiliation(s)
- Alessandria Marco
- Experimental Medicine and Therapy, Laboratory of Adapted Training and Performance Research Group, University of Turin, Italy.
| | - Gollin Massimiliano
- Department of Clinical and Biological Sciences, S.U.I.S.M, Laboratory of Adapted Training and Performance Research Group, University of Turin, Italy
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Souza MV, Souza AVD, Almeida MRD, Santos POD. Análise do equilíbrio postural estático e da intensidade das dores musculoesqueléticas após o uso de palmilhas proprioceptivas por militares do serviço ostensivo. FISIOTERAPIA E PESQUISA 2020. [DOI: 10.1590/1809-2950/18011827012020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
RESUMO Para a manutenção do equilíbrio, o organismo utiliza os sistemas visuais, vestibulares e proprioceptivos, que enviam informações para o sistema nervoso central acerca das condições do corpo com o objetivo de estabilizá-lo. Este estudo avaliou o efeito das palmilhas proprioceptivas sobre o equilíbrio postural estático e as dores musculoesqueléticas após dois meses de uso, por meio de uma pesquisa analítica longitudinal com 15 militares saudáveis do sexo masculino com média de idade de 34±7,5 anos. Eles foram submetidos à avaliação do equilíbrio por meio da plataforma Medicapteurs® e pelo protocolo CNT. Não houve diferença estatística para os desvios do corpo e velocidade do centro de pressão. A pressão plantar teve mudança estatisticamente significante para o pé esquerdo e o pé direito correspondendo a p=0,0001 e p=0,0007, respectivamente. Houve redução das médias de dores nos joelhos, pés e calcanhares e diminuição significativa da dor lombar, com p=0,0180. O equilíbrio estático não foi alterado significativamente com o uso das palmilhas proprioceptivas pelos militares, contudo elas proporcionaram melhor redistribuição das pressões plantares e parecem atenuar as dores musculoesqueléticas das extremidades inferiores. Por isso as palmilhas podem ser consideradas para esse grupo uma terapêutica de prevenção contra lesões relacionadas à sua atividade laboral.
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Tramontano M, Piermaria J, Morone G, Reali A, Vergara M, Tamburella F. Postural Changes During Exteroceptive Thin Plantar Stimulation: The Effect of Prolonged Use and Different Plantar Localizations. Front Syst Neurosci 2019; 13:49. [PMID: 31572134 PMCID: PMC6753192 DOI: 10.3389/fnsys.2019.00049] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Accepted: 08/30/2019] [Indexed: 01/01/2023] Open
Abstract
Somatosensory information arising from the foot has an important role in posture as well as visual and vestibular cues. Our hypothesis is that the effects of prolonged stimulation are greater than those of short stimulation and that varying the plantar location can affect postural control. Forty healthy participants were recruited and randomly assigned to four different plantar location groups: Lateral Insert (LI), Medial Insert (MI), Disharmonious Insert (DI), and Central Insert (CI). An instrumental assessment was performed before the plantar stimulation (T0), immediately after the positioning of the inserts (T1), and after 7 days of daily stimulation (T7). A follow-up was performed 15 days after (T15). The following stabilometric parameters were considered for both open eyes (OE) and closed eyes (CE) conditions: length of the sway (L) of the Center of Pressure (CoP); CoP maximum movements in the medio-lateral (X), and antero-posterior directions (Y). Comparing the effects of different plantar insert locations, the MI and CI groups were significantly different in the follow-up measures at T15, specifically for closed eyes measures. When we compared measures across time within each location group, CI group increased measures of X and Y data at T7 compared to other assessment times (T0, T1, and T15). In both MI and LI groups, L was significantly reduced, and X significantly increased at the T7 assessment compared to the T0, T1, and T15 assessments. The prolonged use of exteroceptive plantar stimulation and the location of plantar inserts may have a role to reshape postural control.
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Viseux F, Lemaire A, Barbier F, Charpentier P, Leteneur S, Villeneuve P. How can the stimulation of plantar cutaneous receptors improve postural control? Review and clinical commentary. Neurophysiol Clin 2019; 49:263-268. [PMID: 30639034 DOI: 10.1016/j.neucli.2018.12.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 12/19/2018] [Accepted: 12/22/2018] [Indexed: 12/13/2022] Open
Abstract
Postural control requires constant and subconscious postural sway to manage balance and achieve postural stability. These movements of regulation are based in particular on cutaneous plantar information. The foot constitutes a functional whole that participates in the mechanisms of postural control and regulation. It represents the direct interface between the body and the ground during quiet standing, and plantar cutaneous information contributes to postural control. Upright balance mechanically depends on the gravitational torque produced by the forces of gravity and reaction of the ground. In this context, the foot behaves like a sensory system for postural regulation whose objective is to maintain a state of stability within a changing and constraining environment. There is a relation between balance improvement and the facilitation of sensory feedback related to the activation of the plantar cutaneous mechanoreceptors. From a clinical point of view, the application of additional tactile cues may have therapeutic benefits in relation to fall prevention, or to improve specific types of chronic pain.
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Affiliation(s)
- Frederic Viseux
- Laboratoire d'automatique, de mécanique et d'informatique industrielles et humaines (LAMIH), UMR CNRS 8201, université de Valenciennes et du Hainaut-Cambrésis (UVHC), 59313 Valenciennes, France; Centre d'évaluation et de traitement de la douleur (CETD), centre hospitalier de Valenciennes (CHV), 59322 Valenciennes, France; Posture Lab, 75012 Paris, France.
| | - Antoine Lemaire
- Centre d'évaluation et de traitement de la douleur (CETD), centre hospitalier de Valenciennes (CHV), 59322 Valenciennes, France
| | - Franck Barbier
- Laboratoire d'automatique, de mécanique et d'informatique industrielles et humaines (LAMIH), UMR CNRS 8201, université de Valenciennes et du Hainaut-Cambrésis (UVHC), 59313 Valenciennes, France
| | - Pascal Charpentier
- Centre d'évaluation et de traitement de la douleur (CETD), centre hospitalier de Valenciennes (CHV), 59322 Valenciennes, France
| | - Sebastien Leteneur
- Laboratoire d'automatique, de mécanique et d'informatique industrielles et humaines (LAMIH), UMR CNRS 8201, université de Valenciennes et du Hainaut-Cambrésis (UVHC), 59313 Valenciennes, France
| | - Philippe Villeneuve
- Laboratoire d'automatique, de mécanique et d'informatique industrielles et humaines (LAMIH), UMR CNRS 8201, université de Valenciennes et du Hainaut-Cambrésis (UVHC), 59313 Valenciennes, France; Posture Lab, 75012 Paris, France
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Foisy A, Kapoula Z. Plantar cutaneous afferents influence the perception of Subjective Visual Vertical in quiet stance. Sci Rep 2018; 8:14939. [PMID: 30297709 PMCID: PMC6175839 DOI: 10.1038/s41598-018-33268-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 09/13/2018] [Indexed: 12/12/2022] Open
Abstract
The estimation of Subjective Visual Vertical (SVV) involves the allocentric, gravitational and egocentric references, which are built by visual, vestibular and somatosensory afferents. Our goals were to assess the influence of plantar cutaneous afferents on the perception of SVV, and to see if there is a difference according to the efficiency of plantar cutaneous afferents. We recruited 48 young and healthy subjects and assessed their SVV and postural performances in quiet stance with a force platform, at 40 or 200 cm, in four ground conditions: on firm ground, on foam, with a bilateral, or with a unilateral 3 mm arch support. We also assessed the efficiency of our subjects' plantar afferents with the plantar quotient method and divided them in two groups: subjects with a normal use of plantar afferents and subjects with Plantar Exteroceptive Inefficiency (PEI). The results showed significant decreases in the counter clockwise SVV deviation only with the unilateral arch support, at near distance, and among the typically behaving subjects. We conclude that asymmetric foot cutaneous afferents are able to bias the egocentric vertical reference and hence influence the perception of SVV. This influence disappears among subjects with PEI, probably because of a distortion of the plantar signal.
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Affiliation(s)
- A Foisy
- IRIS team, Physiopathologie de la Vision et Motricité Binoculaire, FR3636 Neurosciences CNRS, Université Paris Descartes, 45 rue des Saints-Pères, 75006, Paris, France.
| | - Z Kapoula
- IRIS team, Physiopathologie de la Vision et Motricité Binoculaire, FR3636 Neurosciences CNRS, Université Paris Descartes, 45 rue des Saints-Pères, 75006, Paris, France
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Daniel F, Foisy A, Morize A, Kapoula Z. Inefficience podale, dysfonctionnement des vergences et nouvelles technologies : la vergence au carrefour de la cognition et du contrôle postural. Neurophysiol Clin 2017. [DOI: 10.1016/j.neucli.2017.10.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Morize A, Kapoula Z. Reeducation of vergence dynamics improves postural control. Neurosci Lett 2017; 656:22-30. [PMID: 28729073 DOI: 10.1016/j.neulet.2017.07.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 07/14/2017] [Accepted: 07/14/2017] [Indexed: 10/19/2022]
Abstract
INTRODUCTION The purpose was to investigate the effect of vergence reeducation on postural control, in subjects with isolated vergence disorders. MATERIAL AND METHODS We studied the dynamics of vergence in 19 subjects (20-44 years old) using video-oculography (Eye See Cam). On the basis of orthoptic and symptomatology assessments, ten of the subjects were diagnosed for vergence disorders then vergence eye movements were reeducated with the REMOBI method (US8851669, 5 weekly sessions lasting for 35min). Postural control was measured before and after reeducation, postural recording was done in upright stance (Dynaport), with both eyes closed or open and looking a visual target located at 2m distance. RESULTS After reeducation with REMOBI, the visual symptomatology faded away and the stereoacuity improved at least for some subjects; the vergence latency decreased significantly and the vergence accuracy increased significantly. In terms of posture, the Mean Power Frequency (MPF) of the body sway decreased significantly in both eyes open and eyes closed conditions. Considering all subjects together (i.e. healthy subjects and subjects with vergence disorders before the reeducation), the antero-posterior body sway (Root Mean Square A/P) was positively correlated with the visual symptomatology: the higher the visual symptomatology, the higher was the body sway. CONCLUSION The results bring evidence for synergy between the quality of vergence and the quality of postural control. They open a new research line that bridges the gap between neuroscience, ophthalmology-orthoptics and posturology.
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Affiliation(s)
- Aurélien Morize
- CNRS, FR3636, IRIS, University Paris Descartes, Paris, France.
| | - Zoï Kapoula
- CNRS, FR3636, IRIS, University Paris Descartes, Paris, France.
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Foisy A, Kapoula Z. Plantar Exteroceptive Inefficiency causes an asynergic use of plantar and visual afferents for postural control: Best means of remediation. Brain Behav 2017. [PMID: 28638699 PMCID: PMC5474697 DOI: 10.1002/brb3.658] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
INTRODUCTION Some subjects have difficulty to integrate both visual and plantar inputs, showing at the same time a "postural blindness" and a Plantar Exteroceptive Inefficiency (PEI). The former corresponds to a better stability eyes closed (EC) than eyes open (EO), while the latter is defined as a better stability on foam than on firm ground. Clinical studies reported that a manipulation of either plantar or visual input could affect the weight of both cues in postural control, suggesting interdependence in their use. The purpose of the experiment is to characterize the PEI phenomenon better and see if such synergy can be objectified. METHODS We recruited 48 subjects (25 ± 3.3 years) and assessed their balance with a force platform, EO, EC, at 40 or 200 cm, on firm ground, Dépron® foam, Dynachoc® foam, or on a 3 mm-thick Anterior Bar AB®. We assessed their sensorial preferences through their PQ and RQ. RESULTS The main results are that there normally exists a synergy in the use of plantar and visual afferents, but only at 40 cm and in the absence of PEI. CONCLUSIONS Plantar Exteroceptive Inefficiency interferes with the role of vision in postural control, its effects are distance specific, are better revealed by Dépron® foam and the AB® improves posture but does not solve visual-podal asynergy. These results also have clinical interests as they indicate the best way in terms of distance and choice of foam to diagnostic PEI. Finally, they suggest restricting the use of the AB®, commonly employed. These findings can be useful for clinicians concerned with foot, eye, and posture.
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Affiliation(s)
- Arnaud Foisy
- IRIS Team, Physiopathologie de la Vision et Motricité Binoculaire FR3636 Neurosciences CNRS, University Paris Descartes Paris France
| | - Zoï Kapoula
- IRIS Team, Physiopathologie de la Vision et Motricité Binoculaire FR3636 Neurosciences CNRS, University Paris Descartes Paris France
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Foisy A, Kapoula Z. How Plantar Exteroceptive Efficiency Modulates Postural and Oculomotor Control: Inter-Individual Variability. Front Hum Neurosci 2016; 10:228. [PMID: 27242490 PMCID: PMC4866577 DOI: 10.3389/fnhum.2016.00228] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 04/29/2016] [Indexed: 11/13/2022] Open
Abstract
In a previous experiment, we showed that among young and healthy subjects, thin plantar inserts improve postural control and modify vergence amplitudes. In this experiment, however, significant inter-individual variability was observed. We hypothesize that its origin could be attributed to a different reliance upon feet cutaneous afferents. In order to test this hypothesis, we re-analyzed the data relative to 31 young (age 25.7 ± 3.8) and healthy subjects who participated in the first experiment after having classified them into two groups depending on their Plantar Quotient (PQ = Surface area of CoPfoam/Surface area of CoPfirm ground × 100). Foam decreases the information arising from the feet, normally resulting in a PQ > 100. Hence, the PQ provides information on the weight of plantar cutaneous afferents used in postural control. Twelve people were Plantar-Independent Subjects, as indicated by a PQ < 100. These individuals did not behave like the Normal Plantar Quotient Subjects: they were almost insensitive to the plantar stimulations in terms of postural control and totally insensitive in terms of oculomotor control. We conclude that the inter-individual variability observed in our first experiment is explained by the subjects' degree of plantar reliance. We propose that plantar independence is a dysfunctional situation revealing inefficiency in plantar cutaneous afferents. The latter could be due to a latent somatosensory dysfunction generating a noise which prevents the CNS from correctly processing and using feet somatosensory afferents both for balance and vergence control: Plantar Irritating Stimulus. Considering the non-noxious nature and prevalence of this phenomenon, these results can be of great interest to researchers and clinicians who attempt to trigger postural or oculomotor responses through mechanical stimulation of the foot sole.
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Affiliation(s)
- Arnaud Foisy
- IRIS Team, Physiopathologie de la Vision et Motricité Binoculaire, FR3636 Neurosciences Centre National de la Recherche Scientifique University Paris Descartes Paris, France
| | - Zoï Kapoula
- IRIS Team, Physiopathologie de la Vision et Motricité Binoculaire, FR3636 Neurosciences Centre National de la Recherche Scientifique University Paris Descartes Paris, France
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Namazi H, Kulish VV, Akrami A. The analysis of the influence of fractal structure of stimuli on fractal dynamics in fixational eye movements and EEG signal. Sci Rep 2016; 6:26639. [PMID: 27217194 PMCID: PMC4877595 DOI: 10.1038/srep26639] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 05/06/2016] [Indexed: 12/18/2022] Open
Abstract
One of the major challenges in vision research is to analyze the effect of visual stimuli on human vision. However, no relationship has been yet discovered between the structure of the visual stimulus, and the structure of fixational eye movements. This study reveals the plasticity of human fixational eye movements in relation to the ‘complex’ visual stimulus. We demonstrated that the fractal temporal structure of visual dynamics shifts towards the fractal dynamics of the visual stimulus (image). The results showed that images with higher complexity (higher fractality) cause fixational eye movements with lower fractality. Considering the brain, as the main part of nervous system that is engaged in eye movements, we analyzed the governed Electroencephalogram (EEG) signal during fixation. We have found out that there is a coupling between fractality of image, EEG and fixational eye movements. The capability observed in this research can be further investigated and applied for treatment of different vision disorders.
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Affiliation(s)
- Hamidreza Namazi
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
| | - Vladimir V Kulish
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
| | - Amin Akrami
- School of Mechanical engineering, University of Tehran, Iran
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