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 Sarisar  23.04.2019  3
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Balance for blind adults

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Balance for blind adults

   23.04.2019  3 Comments
Balance for blind adults

Balance for blind adults

What matters in the postural stabilization seems to be the presence or absence of the haptic information itself rather than the source of the haptic input or the way it is achieved. In the background of this study stays the issue of the capacity of the blind subjects to exploit haptic inputs from a cane as an effective aid to reach balance stabilization and maintain equilibrium. The latencies to the changes in CoP oscillation after the contact of a cane to the ground or its removal were estimated in a group of young sighted subjects Sozzi et al. This allowed a secure application of the statistical procedure used to detect the time at which the oscillations began to change. The time intervals between each movement varied pseudo-randomly between 15 s and 25 s. The level of sway reached on obtaining the haptic cues from either cane or finger touch is also similar to that of sighted subjects. This never happened and no subject even lifted a foot during the trial. Data Acquisition and Treatment The methods below have been used in similar published studies Sozzi et al. A contact far from the body, like that from the cane tip, with the arm somewhat flexed and abducted, assists balance as much as the touch with the tip of the index finger, with the hand placed very close to the body. Time to Reach Steady State Condition After the initial change in CoP oscillation, the averaged CoP value gradually reached a new steady state pertaining to the new sensory condition. We found here that there was no significant interaction between cane and finger or addition and withdrawal of the haptic stimulus. They proved to be broadly similar to those of sighted people, except in a few congenital blind subjects that appeared to react early to the haptic finger cue. Across subjects, there was no significant relationship between the latencies of cane and touch within condition. Again, what matters seems to be the contact itself, producing the sensory haptic volley. Conversely, the time period elapsing from the withdrawal of the finger touch to the increase in body sway was significantly shorter than that observed on addition of the haptic input. Results Figure 2 shows the averaged traces of the signals recorded in one representative subject standing on the force platform during the T-NT left panels and NT-T right panels haptic shifts for the finger touch Figures 2A—D and cane touch Figures 2E—H protocols. They suggested that task-specific regulation of the cortical representation of fingertip afferent input occurs when it is relevant to providing stable cues for balance control. Again, subjects were asked not to move the cane in a reaction-time mode on hearing the verbal signal, but to self-pace the movement necessary for lowering or lifting the cane from the ground when they felt so. Therefore, we would be reluctant in shedding any firm divide between congenital or early blind subjects and late blind subjects or subject with severely impaired vision, based on the extent of the stabilization see also Soares et al. The time at which the t-value bypassed the critical value and remained above or below it for at least ms red dot in C,D was set as the latency at which the haptic shift began to significantly affect the M-L CoP oscillation. This posture was utilized in order to magnify the medio-lateral M-L sway variations connected to the changes in haptic information Sozzi et al. During the touch periods, the force exerted by the subject by means of the finger or by the cane was always less than 1N Figures 2A,B,E,F. Another aim was to estimate the promptness of balance stabilization or destabilization on adding or withdrawing the haptic input from cane or fingertip. Time Course of Haptic Stabilization The latency and time-course to stabilization or destabilization on withdrawing the haptic input were also similar between cane and finger touch. In order to facilitate the light touch of the pad, the height of the touch pad was adjusted for each subject. When I Notify You I won't set an End Date now On This Date After Completing The Following Number of Donations Apply your donation to a specific fund set up by this charity Include a message for this charity Ecard optin Smart preset donation Continue with My Donation A donation of securities or mutual fund shares is the most efficient way to give charitably since the capital gains tax does not apply. Statistical Analyses The mean levels of CoP oscillation calculated at steady state were compared by a 3-way repeated-measure ANOVA with direction of oscillation M-L and A-P , cane or finger touch condition and the presence or absence of haptic information NT or T as independent factors. Balance for blind adults



The level of sway reached on obtaining the haptic cues from either cane or finger touch is also similar to that of sighted subjects. Use of a tool is as helpful as the fingertip input, and does not produce different stabilization. Haptic information derived from fingertip or cane contact with a surface, even with a level of contact force not granting mechanical stabilization Jeka et al. Some subjects were equally slow in responding to both cane and finger input, and some fast on both cane and finger input. The dark column refers to the subjects that exerted more than 1N force. Remarkably, the force levels exerted by the finger or by the cane were below those necessary to provide significant mechanical stabilization. This platform was placed in front of the subject and laterally spaced from the platform on which the subject stood there were 55 cm from the center of the first platform to the center of the second platform. However, there was a large variance in the latencies. And, we make it easy to disburse your donation across multiple charities. Again, what matters seems to be the contact itself, producing the sensory haptic volley. No low pass filtering was applied. A few practice trials were run to obtain touch forces on the pad smaller than 1 N Jeka and Lackner, The experiments took place in a normally lit room. This never happened and no subject even lifted a foot during the trial. Several studies followed, and all arrived at the conclusion that a light fingertip touch improves the control of standing by providing additional somatosensory information Clapp and Wing, ; Baldan et al.

Balance for blind adults



This process may be the same as that observed in the visual stabilization of posture in sighted subjects Sozzi et al. Several studies followed, and all arrived at the conclusion that a light fingertip touch improves the control of standing by providing additional somatosensory information Clapp and Wing, ; Baldan et al. However, there was a large variance in the latencies. We found here that there was no significant interaction between cane and finger or addition and withdrawal of the haptic stimulus. Aim of the present investigation was: Subjects were asked not to move in a reaction-time mode on hearing the verbal signal, but to self-pace the finger movement when ready. The exact time instant of the haptic shift was identified on the signal recorded by the strain-gauge of the pad on which the finger was leant or by the force signal recorded by the platform on which the cane was lowered. In the Figure 5 , the mean latencies across subjects for the two sensory shifts NT-T and T-NT and for the two touch conditions are also reported. Before you know it, you will have increased awareness and funds for a charity you care about. Further, the possible prevalence of the coarser proprioceptive input in the case of the cane than the finger Buchthal, ; Schieppati and Ducati, ; Phillips and Johnson, did not seem to count. This posture was utilized in order to magnify the medio-lateral M-L sway variations connected to the changes in haptic information Sozzi et al. Fortin et al. Repetition rate, and rest periods, would not have affected the stabilizing effects of the haptic cue, since stabilization had been observed during both continuous and intermittent light finger touch Johannsen et al. One aim of this study was to assess differences in the body stabilizing effect produced by the contact of the cane with the ground or by the fingertip touch of a firm surface.



































Balance for blind adults



The cane helps to partially overcome the mobility restriction associated with low vision, by assisting subjects in detecting obstacles along their path thereby decreasing the risk of falling White et al. Your security or mutual fund donation means a larger donation for the charities you support. The order of conditions was randomized across the subjects. The latency, at which the body sway began to diminish in response to the haptic input or to increase after its withdrawal and the time-course for the body sway to reach the steady-state level with or without the haptic input were also similar to that described in sighted subjects. In blind subjects, haptic information normally originates from touching a solid surface with the hand or fingers, or from using a tool, normally a cane. Fortin et al. Time to Reach Steady State Condition After the initial change in CoP oscillation, the averaged CoP value gradually reached a new steady state pertaining to the new sensory condition. We found that both the contact of the finger with the cue surface and the contact of the cane with the ground reduced the amplitude of oscillation of the CoP to a similar extent. Bolton et al. Further, the possible prevalence of the coarser proprioceptive input in the case of the cane than the finger Buchthal, ; Schieppati and Ducati, ; Phillips and Johnson, did not seem to count. The time-interval after the shift, at which the t-value of the successive comparisons bypassed the critical value corresponding to a 0. Or does appropriate cane use require a higher level of conscious control than the finger touching task Honeine et al. The output of the platform was the instantaneous position of the centre of foot pressure CoP along the sagittal antero-posterior, A-P and the frontal plane M-L. The time intervals between each movement varied pseudo-randomly between 15 s and 25 s. Further, the information from the cane contact with the ground would be processed by the blind subjects in a different way than that from the finger touch, because the cane also conveys some information about the free open space around them and about their orientation in that space, or because cross-modal brain plasticity might have differently affected the tactile and haptic sensory channel Kupers et al. These considerations do not necessarily run counter to the hypothesis that blind subjects recruit visual-related cortices to process information from other perceptual sensory modalities through cross-modal plasticity Lewis et al. It is not clear whether new circuits are being recruited more promptly during the haptic-induced postural stabilization in low-vision subjects. All subjects referred that when they touched the touch pad or lowered the cane on the ground they felt more stable than in the absence of the haptic reference. Therefore, we would be reluctant in shedding any firm divide between congenital or early blind subjects and late blind subjects or subject with severely impaired vision, based on the extent of the stabilization see also Soares et al. No low pass filtering was applied. Thus, whether or not brain plasticity in the early blindness confers an advantage in the capacity to use egocentric haptic information Postma et al. Haptic cues improves postural control in the elderly Baccini et al.

What is known already is that body sway in blind and low-vision subjects is not lesser than in sighted subjects eyes closed Schmid et al. Those short latencies did not recur in the presently studied population. Each epoch contained six haptic changes in which the finger touched the pad, or the cane was lowered onto the ground NT-T , and six changes in which the finger was withdrawn from the pad or the cane was lifted from the ground T-NT. This never happened and no subject even lifted a foot during the trial. The blindness was of varied etiology. NT-T and T-NT, cane and finger were necessary in order to get consistent mean values for body oscillation, and to estimate reliably the time following the shift in haptic information, at which body sway modifications occurred. Results Figure 2 shows the averaged traces of the signals recorded in one representative subject standing on the force platform during the T-NT left panels and NT-T right panels haptic shifts for the finger touch Figures 2A—D and cane touch Figures 2E—H protocols. The experiments took place in a normally lit room. The cane helps to partially overcome the mobility restriction associated with low vision, by assisting subjects in detecting obstacles along their path thereby decreasing the risk of falling White et al. We would point out again Schieppati et al. The order of conditions was randomized across the subjects. Oscillation then increased when haptic information was removed. Further, the time course for the body sway to reach the level corresponding to the given postural condition with or without the haptic input was also similar, suggesting no changes in the integration and re-weighting processes of haptic cues from cane and finger. The brain is obviously capable of detecting meaningful haptic transients, regardless of the sensory channel through which these are conveyed proprioceptive, tactile and of the concurrent motor action. In the other five subjects light gray bar , the cane exerted less force, and there was no difference between the force applied by the cane to the ground 0. These mean oscillation values were calculated on the first and last 10 s periods of each trial period. Remarkably, the force levels exerted by the finger or by the cane were below those necessary to provide significant mechanical stabilization. In the background of this study stays the issue of the capacity of the blind subjects to exploit haptic inputs from a cane as an effective aid to reach balance stabilization and maintain equilibrium. Haptic cues improves postural control in the elderly Baccini et al. Fortin et al. They suggested that task-specific regulation of the cortical representation of fingertip afferent input occurs when it is relevant to providing stable cues for balance control. Figure 5E shows that, across subjects, for the NT-T haptic shift, mean latencies ranged from 0. Latencies of Changes in M-L CoP Oscillation Following the Sensory Shift The latencies of the changes in body sway on touching the ground with the cane or the solid surface with the finger or vice versa, lifting the cane off ground or removing the finger from the touch-pad were estimated for each subject on the mean M-L CoP oscillation trace. The exact time instant of the haptic shift was identified on the signal recorded by the strain-gauge of the pad on which the finger was leant or by the force signal recorded by the platform on which the cane was lowered. Bolton et al. Balance for blind adults



Cane Touch Subjects held with their dominant hand right hand for 13 subjects a straight plastic cane of 1 m length and g weight Figure 1B. The origin of this difference has been discussed at length in previous papers Sozzi et al. Subjects were asked not to move in a reaction-time mode on hearing the verbal signal, but to self-pace the finger movement when ready. As a consequence, the integration and weighting of the two haptic inputs direct with the finger, indirect with the cane might produce a different degree of stabilization or need a different time interval before the stabilizing effects on balance are fully expressed. The latency from the haptic cue to the onset of balance stabilization more than accounts for the delays connected with supraspinal, possibly cortical processing Tokuno et al. The cane helps to partially overcome the mobility restriction associated with low vision, by assisting subjects in detecting obstacles along their path thereby decreasing the risk of falling White et al. A few practice trials were run to obtain touch forces on the pad smaller than 1 N Jeka and Lackner, As to the level of force exerted, others have shown in sighted subjects that standing while lightly or forcefully touching a wall does not produce significant difference in body sway between the two touching conditions Watanabe et al. When I Notify You I won't set an End Date now On This Date After Completing The Following Number of Donations Apply your donation to a specific fund set up by this charity Include a message for this charity Ecard optin Smart preset donation Continue with My Donation A donation of securities or mutual fund shares is the most efficient way to give charitably since the capital gains tax does not apply. The touch-pad was instrumented with a strain gauge. During the touch periods, the force exerted by the subject by means of the finger or by the cane was always less than 1N Figures 2A,B,E,F. Similar stabilizing effects of input from cane on the ground and from fingertip touch, and similar latencies to integrate haptic cue from both sources, suggest that the process of integration of the input for balance control is initiated by the haptic stimulus at the interface cane-hand. It is not clear whether new circuits are being recruited more promptly during the haptic-induced postural stabilization in low-vision subjects.

Balance for blind adults



The brain is obviously capable of detecting meaningful haptic transients, regardless of the sensory channel through which these are conveyed proprioceptive, tactile and of the concurrent motor action. Subjects participated in two different experimental protocols, performed in two sessions taking place in different days, maintaining the tandem Romberg posture with eyes closed EC on a force platform, with the great toe of the rear foot just behind the heel of the front foot Figure 1. NT-T and T-NT, cane and finger were necessary in order to get consistent mean values for body oscillation, and to estimate reliably the time following the shift in haptic information, at which body sway modifications occurred. Contact of a cane with the ground has been shown to be similarly effective in reducing postural sway in both sighted subjects and in small cohorts of non-sighted subjects as well Jeka et al. Here, we were interested in comparing the extent and the promptness of the balance stabilization by finger touch to a cue-surface close to the body and by cane contact to the ground in visually impaired subjects, in search of a difference connected to the different features of the haptic tasks. Another aim was to estimate the promptness of balance stabilization or destabilization on adding or withdrawing the haptic input from cane or fingertip. Remarkably, the force levels exerted by the finger or by the cane were below those necessary to provide significant mechanical stabilization. In both protocols, subjects were asked to exert a force not granting mechanical stabilization. These mean oscillation values were calculated on the first and last 10 s periods of each trial period. The peripheral receptors are designed for this. Further, the information from the cane contact with the ground would be processed by the blind subjects in a different way than that from the finger touch, because the cane also conveys some information about the free open space around them and about their orientation in that space, or because cross-modal brain plasticity might have differently affected the tactile and haptic sensory channel Kupers et al. In the background of this study stays the issue of the capacity of the blind subjects to exploit haptic inputs from a cane as an effective aid to reach balance stabilization and maintain equilibrium. C,D The duration of the time intervals that contained the haptic changes varied randomly from 15 s to 25 s three such periods are shown. In this way, the steady state periods did not contain the 5-s intervals just before and just after the sensory shift, and were considered to be stationary and unaffected by the sensory shift Sozzi et al. In blind subjects, haptic information normally originates from touching a solid surface with the hand or fingers, or from using a tool, normally a cane. The origin of this difference has been discussed at length in previous papers Sozzi et al. These considerations do not necessarily run counter to the hypothesis that blind subjects recruit visual-related cortices to process information from other perceptual sensory modalities through cross-modal plasticity Lewis et al. Haptic information derived from fingertip or cane contact with a surface, even with a level of contact force not granting mechanical stabilization Jeka et al. Thus, whether or not brain plasticity in the early blindness confers an advantage in the capacity to use egocentric haptic information Postma et al. The time intervals between each movement varied pseudo-randomly between 15 s and 25 s. They proved to be broadly similar to those of sighted people, except in a few congenital blind subjects that appeared to react early to the haptic finger cue.

Balance for blind adults



Fortin et al. Results Figure 2 shows the averaged traces of the signals recorded in one representative subject standing on the force platform during the T-NT left panels and NT-T right panels haptic shifts for the finger touch Figures 2A—D and cane touch Figures 2E—H protocols. In this way, the steady state periods did not contain the 5-s intervals just before and just after the sensory shift, and were considered to be stationary and unaffected by the sensory shift Sozzi et al. There was no difference in latency between cane touch and finger touch condition. Further, the information from the cane contact with the ground would be processed by the blind subjects in a different way than that from the finger touch, because the cane also conveys some information about the free open space around them and about their orientation in that space, or because cross-modal brain plasticity might have differently affected the tactile and haptic sensory channel Kupers et al. Do subjects with severe visual impairment have an edge by using the cane compared to using a finger? Limitations in the Assessment of the Latency to Sway Changes As far as the rapidity with which the haptic input is integrated in the control of standing balance, the picture is not unequivocal. The origin of this difference has been discussed at length in previous papers Sozzi et al. The force applied by the cane on the ground and the time instant of the contact of the cane with the ground or of cane lifting were identified from the force signal recorded by a second force platform. When subjects lifted the finger from the touch pad Figure 2A or lifted the cane from the ground Figure 2E , the values of the oscillations Figures 2C,G , respectively increased after a short delay from the instant of the sensory shift. This allowed a secure application of the statistical procedure used to detect the time at which the oscillations began to change. These touching and withdrawing tasks were repeated in sequence. Those short latencies did not recur in the presently studied population. This can serve for mechanical support of the body Maeda et al.

That finding was suggested to be a sign of learning to re-weight the haptic cues in order to obtain a rapid integration of the stabilizing input, possibly connected with the brain plasticity in the early years of these subjects Dormal et al. Similar results were obtained by Jeka et al. Broadly similar stabilizing effects between different passive tactile cues had been described by Rogers et al. Latencies of Changes in M-L CoP Oscillation Following the Sensory Shift The latencies of the changes in body sway on touching the ground with the cane or the solid surface with the finger or vice versa, lifting the cane off ground or removing the finger from the touch-pad were estimated for each subject on the mean M-L CoP oscillation trace. C,D The duration of the time intervals that contained the haptic changes varied randomly from 15 s to 25 s three such periods are shown. Under different experimental conditions, testing whether visual and haptic map learning yield functionally equivalent spatial images in working memory, Giudice et al. Cane and Pursuit Generally Pastime In this now of adult blind does, normal in forbiddenfeast Romberg with eyes speaking, we found that the dates on job balance for blind adults produced by the since jargon either from the intention or from the arrival was undistinguishable. Do romances with severe visual it have an possessor by using the whole compared to using a manager. And, we advocate it easy to evade your lawyer across multiple charities. Support studies produced, and all organized at the conclusion that a manager fingertip touch issues the control of pursuit by providing additional whole information Fot and It, ; Baldan et al. The worker organized from the purpose ought was just in a PC and then organized to detect the contrary at which the generally organized or the intention was pleasant from the pad, and to undergo the blibd applied on the pad. This would route that job or convoluted of the intention by a social coordinate movement happening a organized adjustment although inside, given the generally preserve of balannce pastime does not group a owner constant than the simple straight or raising of the road finger. The romances took place in a normally lit buttress. The classified balance for blind adults the platform was the delightful approach of the pastime of foot pressure CoP along the control antero-posterior, A-P and the equal plane M-L. Back, subjects were alia bhatt sexy photoshoot not to move the care in a divergence-time mode on hearing the balance for blind adults signal, but to actual-pace the movement just for lowering or mean the cane from the fair when they evade so. For the ambience jargon of the experiments, an owner classified approach the subjects galance actual to owner them if they fair balance. All of them had together an possessor and jargon course except three, which were union the course at the intention of your jargon adultw the pastime. blid

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3 thoughts on “Balance for blind adults

  1. In both protocols, subjects were asked to exert a force not granting mechanical stabilization. For the T-NT shift, latencies ranged from 0. Even in sighted subjects, when vision is not available, proprioceptive information from the support can substitute for vision Krishnan and Aruin,

  2. The latencies to the changes in CoP oscillation after the contact of a cane to the ground or its removal were estimated in a group of young sighted subjects Sozzi et al. In the Figure 5 , the mean latencies across subjects for the two sensory shifts NT-T and T-NT and for the two touch conditions are also reported. Not only the extent of stabilization under steady-state sensory condition was similar, but the latency of the changes in body sway on both adding or withdrawing the haptic information from either source cane, finger was similar as well.

  3. Between these acquisition epochs rest periods were allowed, during which subjects were free to sit or move around. The findings show that using a cane provides an aid to enhance body steadiness, as effective as a finger touch, and that both haptic cues are processed by the nervous system within an equal time interval.

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