Postural control - Science topic

Sorry for the late comment. But I was reading the conversation. Does any of you know where to find normalized posturographic values- in some postures? Thank you

Including acquisition of bioelectrical signals (EMG,EEG), in addition to IMUs, could be of help, if the assessment of CNS strategies for balance control is of interest. A recent paper about that:

Best Regards

--

Jorge Airy Mercado

Fundamental of Statistics/Outlines of Statistics (Vols I & II) by Goon, Gupta & Dasgupta & https://bookauthority.org/books/best-anova-books Choice is yours sir ji Ranajay Samanta

Thnak you Dariusz...

and what you thinking on longitudinal monitoring of large group of participates via mobile app and using of data for science?

Dragan

Hi Dragan, E. Jaspers and E. Butler have both created an upper limb model to be applied in Vicon. The protocol developed by E. Jaspers has an open-source software toolbox (with matlab) which can be found online.

Thanks very much, that was very helpful!

Best wishes

Kirsten

Mastication of chewing gum improved the postural stability during upright standing in some studies. Explanation may lay in activation of mastication muscles, condition of temporomandibular joint and trigeminal proprioception. I suggest this study to confirm the opinion:

Dear Hamzeh Baharlouei .

I call you to be cautious in this research.

You are going to analyze a very specific test. It is necessary to take into account the nonstationarity of the observed processes, if you analyze so great standing of the older adults. The standard software of this feature does not take into account this specific character. For example, in this case the spectral analysis is incorrect. I did not see such a test accurately. Sincerely Your

One explanation could be the SAID Principle out of exercise science (specific adaptation to imposed demand), or maybe the intervention did adress only the static part of the nervous system. If I remember correctly, different receptors are used in static balance compared to dynamic balance. Maybe even different pathways? Or maybe even different areas of the Motorcortex? Literature could be: Motor Control by Shumway-Cook and Woollacot.

Careful training depending on patient status, and symptoms such as spasticity and fatigue will help them.

Adding interventions such as cognitive and respiratory training may be more beneficial.  

Thank you very much Servan and McCrum for your helpful tips. I would shoot for short communication in Journal of Biomechanics or Gait and Posture although I don't know whether they will appreciate method oriented study.   

Marcelo,

My project for my Masters dealt with peroneus longus reflex response to sudden ankle inversion under 2 overlapping conditions of cognitive information, anticipation and cognitive loading. We are still waiting for the manuscript to be accepted, but if you send me a message, I would be happy to show you some of the data. I know this is a static task, and not really a dynamic or unstable surface in terms of maintaining stance balance, but hopefully my results can inform you.

I identified a trend suggesting that the later components of the stretch reflex, believed to have more cortical control, were more affected when a more difficult cognitive task was added. While not a strong trend, this may suggest that at minimum our protective strategies for balance recovery stay intact under a cognitive load, but your proposed study will hopefully add to this growing field. 

Additionally, this may help you, J Orthop Sports Phys Ther. 2010 Mar;40(3):180-7 - not healthy participants, but they utilized a biodex stability platform and manipulated surface stability.

Regards,

Susana,

Unfortunately I do not have a reference for you either. I have one suggestion in addition to those of Dr. Müller which may assist you in reporting your data, or at least putting it into context of a clinically meaningful result if you are unable to utilize the distribution-based approach.

Have you collected any measures that do have established MCID values? I have run into a similar issue with my research and population of interest and I haven’t been able to come across established MCIDs for our postural sway (time-to-boundary) and/or SEBT performance (the closest I can find is minimal detectable change). However, I often collect patient reported outcomes such as validated self-assessed disability questionnaires with reported MCIDs in our population.

Based on the reported MDC reported by Munro & Herrington, the SDD in Table 2 for normalized scores or Table 3 for reach distance in cm (http://www.ncbi.nlm.nih.gov/pubmed/21055706), you could identify which participants exceeded both the MDC for SEBT and an established MCID for another measure. Then simply report the proportion of participants that had a meaningful response to your pilates intervention based on a change in SEBT and another measure. The MDC may differ for your postural sway measure if multiple researchers have conducted reliability studies, so I would suggest being conservative and utilizing the higher MDC values that are reported.

This two-step approach would help frame your results to both clinicians and researchers, however if you did not collect a dependent variable with an established MCID, you could always attempt to establish one on your own (Dr. Müller’s route) or frame your results based on the participants that exceeded the MDC and acknowledging that it may not truly be a clinically significant change.

Best,

Chris

In that case, you could place the subjects on a force plate and use the center of force to quantify their ability to stand as still as possible on one leg, and their distance to the target to quantify their performance in the second pointing task.

However, I would be careful with the instructions you give the participants with respect to task priority, as it has been shown that task performance depends on task priority and that older participants with higher fall risk tend to prioritize not falling over additional tasks. 

Dear Javier,

The different variables comprised traditional linear and non- linear methods as proposed by diverse authors [....]. Duarte & Freitas (2010) subdivided the parameterization methods roughly into two groups: First, the traditional parameters which refer to estimations of the overall size of COP excursions, second, structural posturographic and more sophisticated parameters which describe temporal pattern of the time series in a nonlinear manner [...]. The former ones are used as indicators of postural stability outlining COP displacements as random fluctuations. According to this theory, larger COP deflections are associated with less stable balance and in a next step with aging and disease. Consequently, the assumed random properties are treated as unwanted noise and averaged out. Temporal structures of the displacements are disregarded. In contrast, nonlinear methods determine the time de pendent structure of the time series. Against this back- ground, both analysis techniques create complementary information [...]. In my vision, these two parameters (average and SD of COP) are complementary, they are classified in the first group (traditional paraemters), however I prefer to use the SD of COP because the results are most complet. You will can to show the results of these two variables, but depending of the case it will be unnecessary. 

Look some papers which I sent to you. I believe they can clarify your ideas.

Best regards.

In the early 1980s, I had the opportunity to work with Dr. Anne Shumway-Cook to develop an early postural sway biofeedback device.  In the course of our early clinical testing, one of the PTs on the team became pregnant, which posed the question, what happens to postural sway during pregnancy.  Because our device was an early prototype, we recruited another female therapist to act as a normal, and measured postural sway each day over 6 months.  (Our device measured sway area, and I don't have the absolute numbers any more.)

The really interesting finding was that, in our normal subject, the postural sway varied in a nice sine pattern with a period of 14 days.  We were never able to figure out what biological factor would result in a 14 day cycle.  I'd love to know.

The reason that this is relevant to your question is that the "normal" value varies over time.  If you institute a treatment at the peak of sway, and terminate at the minimum, you will think you have found a significant result, when in fact, it may just be normal variation.  Except for grossly abnormal sway, I'd be very cautious about any single-point measure.

I agree with M.Nachiappan, however It's important to understand that COP is calculated from these ground reaction forces. In reflects the trajectory of the COM and the amount of torque applied at the support surface to control body-mass acceleration. Normally in the gait analysis, its important to measure also the COP amplitude, which to assessment potential modifications in the postural control strategy. In this way, COP velocity or speed, is the measure of the sum of displacements scalars  (ie. The cumulated distance over the sampling period) divided  by the sampling time. It represents the amount of activity required to maintain the stability.

In this way, I found some papers which deal with this subject.

I hope this helps.

Hi Marcelo,

As mentioned in the other responses, there are a number of outcomes which can be used to assess the COP, as a surrogate for COM.  Most of these same outcomes can be applied directly to the movements of the COM as well.  But to your question of how to interpret the movement and speed of the COM, it depends on the lens through which you are looking.  For example, using a more traditional paradigm (i.e. linear measures such as velocity or sway) greater sway and/or greater sway velocity would be interpreted as worse balance due to the individual's inability to control their COM.  However, non-linear paradigms (e.g. time-to-boundary, entropy) view variability as a natural and needed function of a healthy organism.  Having said that, research has suggested that their may be a healthy level of variability while too little or too much may be indicative of a constrained sensorimotor system. 

I hope this helps

Erik

Let’s continue this conversation here so that those who are interested can participate.

 Ankle and hip strategies, as well as stepping strategies are the three strategies that occurs in the sagittal plane.  The ankle strategy is seen at 10 months of age when the child is holding a support and flexing the hips and knees.  The hip strategy begins at 4 approximately 4 year of age and is never seen without the ankle strategy.  The hip strategy controls forward and backwards sway and is often used when standing on a narrow support such as a rope or beam.   Medial lateral stability does occurs at the hip as there is little ankle movement in those directions.  Recently it has been thought that the pelvis is the primary motion of the body as one leg adducts and the other abducts.  Thus they are proximal distal actions where the ankle strategy is distal to proximal.

Best regards, Judy Carmick

Hello, some articles that can help you, kings regards.

1. Arch Phys Med Rehabil. 1994 Aug;75(8):895-9.

Changes in cervicocephalic kinesthesia after a proprioceptive rehabilitation

program in patients with neck pain: a randomized controlled study.

Revel M(1), Minguet M, Gregoy P, Vaillant J, Manuel JL.

Author information:

(1)Laboratoire d'Explorations Fonctionnelles de l'Appareil locomoteur et

d'évaluation du handicap, Hôpital Cochin, Paris, France.

Head repositioning accuracy (HRA) after full range active motion was evaluated in

60 cervicalgic patients. The mean angular error was 7.7 degrees +/- 3.3 (mean +/-

SD) and 82% were outside a threshold value of 4.5 degrees. After randomization 30

patients followed a rehabilitation program based on eye-head coupling (RG) and 30

served as a control group (CG). At 10 week follow-up, a greater gain in HRA was

observed in the RG (2 degrees +/- 2.7, mean +/- SD) than in the CG (0 +/- 2.6,

mean +/- SD) (p = 0.005). Clinical parameters (pain, drug intake, range of

motion, and self assessed functional improvement) were also more improved in the

RG than in the CG. These data emphasize the role of a neck proprioception

alteration in chronic neck pain and suggest that a rehabilitation program based

on eye-head coupling should be included in most medical management of cervicalgic

patients.

PMID: 8053797 [PubMed - indexed for MEDLINE]

2. Arch Phys Med Rehabil. 1991 Apr;72(5):288-91.

Cervicocephalic kinesthetic sensibility in patients with cervical pain.

Revel M(1), Andre-Deshays C, Minguet M.

Author information:

(1)Department de Reeducation, Clinique de Rhumatologie, Hopital COCHIN, Paris,

France.

Head orientation in space makes use of multiple sensory afferents, among which

the cervical proprioceptive cues could play a predominant role. To quantify the

alteration of neck proprioception in patients with cervical pathology, we

proposed a test for the clinical evaluation of the ability to relocate the head

on the trunk after an active head movement, for 30 healthy subjects and 30

patients with cervical pain. The data demonstrated that this ability was

significantly poorer in the patient group, indicating an alteration in neck

proprioception. This test permits a discriminant classification of healthy and

sick subjects, justifies proprioceptive rehabilitation programs, and allows a

quantitative evaluation of their results.

3. Physiother Theory Pract. 2008 Sep-Oct;24(5):380-91. doi:

10.1080/09593980701884824.

Test-retest reliability of cervicocephalic relocation test to neutral head

position.

Pinsault N(1), Fleury A, Virone G, Bouvier B, Vaillant J, Vuillerme N.

Author information:

(1)Laboratoire TIMC-IMAG, UMR UJF CNRS 5525, Grenoble, France.

Considering the important role of the cervical joint position sense on control of

human posture and locomotion, accurate and reliable evaluation of neck

proprioceptive abilities appears of great importance. Although the

cervicocephalic relocation test (CRT) to the neutral head position (NHP) usually

is used for both research and clinical purposes, its test-retest reliability has

not been clearly established yet. The purpose of the present experiment was to 1)

evaluate the test-retest reliability of the CRT to NHP and 2) to determine the

number of trial recordings required to ensure reliable measurements. To this aim,

40 young healthy adults performed the CRT to NHP on two separate occasions. Ten

trials were performed for each rotation side. Absolute and variable errors,

processed along their horizontal, vertical, and global components, were used to

assess the cervical joint repositioning accuracy and consistency, respectively.

Mean difference between test and retest with 95% confidence interval, intraclass

correlation coefficient, and Bland and Altman graphs with limits of agreement

were used as statistical methods for assessing test-retest reliability. Results

show that the CRT to NHP when executed in its original form (i.e., 10 trials) has

a fair to excellent reliability (ICC ranged from 0.52 to 0.81 and from 0.49 to

0.77, for absolute and variable errors, respectively); the test-retest

reliability of this test increases as the number of trials used to establish

subject's repositioning errors increases; and using the mean of eight trials is

sufficient to ensure fair to excellent reliability of the measurements (ICC

ranged from 0.39 to 0.78 and from 0.44 to 0.78, for absolute and variable errors,

respectively).

PMID: 18821444 [PubMed - indexed for MEDLINE]

4. Ann Readapt Med Phys. 2008 May;51(4):257-62. doi: 10.1016/j.annrmp.2008.02.004.

Epub 2008 Apr 29.

[Impact of nociceptive stimuli on cervical kinesthesia].

[Article in French]

Vaillant J(1), Meunier D, Caillat-Miousse JL, Virone G, Wuyam B, Juvin R.

Author information:

(1)Centre de recherche et d'innovation en kinésiologie, kinésiopathologie et

kinésithérapie, institut universitaire professionnalisé en ingénierie de la

santé, BP 217, 38049 Grenoble cedex 09, France. JVaillant@chu-grenoble.fr

The goal of this study was to evaluate the impact of nociceptive stimuli upon the

cervical proprioception ability.METHOD: Thirty healthy young subjects performed a

cervicocephalic relocation test (CRT) in two random conditions: the first one was

based on a nociceptive electric stimulation called condition "pain", whereas the

second one was targeting a painless electric condition called condition

"control". The CRT consisted of repositioning the head on the trunk, after an

active transversal movement of the head in the transverse field with closed eyes.

The pointing was recorded at the beginning and at the end of each rotation using

a custom video acquisition system.

RESULTS: The average mean of error repositioning was worth 3.98+/-0.99 degrees

(average mean, standard deviation) in the condition "pain", and 1.75+/-0.37

degrees in the condition "control" (p<0.01).

CONCLUSION: Acute pain provokes a disturbance of the cervical proprioception

ability without damaging the anatomic structure. This observation suggests the

interest of an early follow-up of the pain to avoid sensory disturbances, as well

as the establishment of a cervical proprioceptive rehabilitation program after an

algic event.

5. Phys Ther Sport. 2010 May;11(2):66-70. doi: 10.1016/j.ptsp.2010.02.004. Epub 2010

Mar 15.

Cervical joint position sense in rugby players versus non-rugby players.

Pinsault N(1), Anxionnaz M, Vuillerme N.

Author information:

(1)Ecole de kinésithérapie du CHU de Grenoble, France; TIMC-IMAG laboratory AFIRM

and AGIM3 teams, UMR UJF-CNRS 5525, Grenoble, France. npinsault@chu-grenoble.fr

<npinsault@chu-grenoble.fr>

OBJECTIVE: To determine whether cervical joint position sense is modified by

intensive rugby practice.

DESIGN: A group-comparison study.

SETTING: University Medical Bioengineering Laboratory.

PARTICIPANTS: Twenty young elite rugby players (10 forwards and 10 backs) and 10

young non-rugby elite sports players.

INTERVENTIONS: Participants were asked to perform the cervicocephalic relocation

test (CRT) to the neutral head position (NHP) that is, to reposition their head

on their trunk, as accurately as possible, after full active left and right

cervical rotation. Rugby players were asked to perform the CRT to NHP before and

after a training session.

MAIN OUTCOME MEASUREMENTS: Absolute and variable errors were used to assess

accuracy and consistency of the repositioning for the three groups of Forwards,

Backs and Non-rugby players, respectively.

RESULTS: The 2 groups of Forwards and Backs exhibited higher absolute and

variable errors than the group of Non-rugby players. No difference was found

between the two groups of Forwards and Backs and no difference was found between

Before and After the training session.

CONCLUSIONS: The cervical joint position sense of young elite rugby players is

altered compared to that of non-rugby players. Furthermore, Forwards and Backs

demonstrated comparable repositioning errors before and after a specific training

session, suggesting that cervical proprioceptive alteration is mainly due to

tackling and not the scrum.

PMID: 20381004 [PubMed - indexed for MEDLINE]

6. Spine (Phila Pa 1976). 2010 Feb 1;35(3):294-7. doi: 10.1097/BRS.0b013e3181b0c889.

Degradation of cervical joint position sense following muscular fatigue in

humans.

Pinsault N(1), Vuillerme N.

Author information:

(1)AFIRM Team, TIMC-IMAG Laboratory, UMR UJF CNRS 5525, La Tronche, France.

STUDY DESIGN: Before and after intervention trials.

OBJECTIVE: To investigate the effect of cervical muscular fatigue on joint

position sense.

SUMMARY OF BACKGROUND DATA: Although fatigue-related degradation of

proprioceptive acuity at lower and upper limbs is well documented, to date no

study has investigated whether muscular fatigue induced at the neck could modify

joint position sense.

METHODS: A total of 9 young healthy adults were asked to perform the

cervicocephalic relocation test to the neutral head position, that is, to

relocate the head on the trunk, as accurately as possible, after full active

cervical rotation to the left and right sides. This experimental task was

executed in 2 conditions of No fatigue and Fatigue of the scapula elevator

muscles. Absolute and variable errors were used to assess the cervical joint

repositioning accuracy and consistency, respectively.

RESULTS: Less accurate and less consistent repositioning performances were

observed in Fatigue relative to No fatigue condition, as indicated by increased

absolute and variable errors, respectively.

CONCLUSION: Results of the present experiment evidence that cervical joint

position sense, assessed through the cervicocephalic relocation test to the

neutral head position, is degraded by muscular fatigue.

PMID: 20075783 [PubMed - indexed for MEDLINE]

7. Arch Phys Med Rehabil. 2008 Dec;89(12):2375-8. doi: 10.1016/j.apmr.2008.06.009.

Cervicocephalic relocation test to the neutral head position: assessment in

bilateral labyrinthine-defective and chronic, nontraumatic neck pain patients.

Pinsault N(1), Vuillerme N, Pavan P.

Author information:

(1)Laboratoire TIMC-IMAG, UMR CNRS 5525, Grenoble, France.

OBJECTIVE: To determine whether vestibular or cervical proprioceptive information

influence the cervicocephalic relocation test to the neutral head position, by

comparing head repositioning errors obtained in asymptomatic, unimpaired control

subjects with those obtained in bilateral labyrinthine-defective patients and

chronic, nontraumatic neck pain patients.

DESIGN: A group-comparison study.

SETTING: University medical bioengineering laboratory.

PARTICIPANTS: Labyrinthine-defective patients (n=7; mean age+/-SD, 67+/-15 y),

nontraumatic neck pain patients (n=7; 56+/-9 y), and asymptomatic, unimpaired

control subjects (n=7; 64+/-12 y).

INTERVENTIONS: Participants were asked to relocate the head on the trunk, as

accurately as possible, after full active cervical rotation to the left and right

sides. Ten trials were performed for each rotation side.

MAIN OUTCOME MEASURES: Absolute and variable errors were used to assess accuracy

and consistency of the repositioning, respectively.

RESULTS: No significant difference in repositioning errors was observed between

labyrinthine-defective patients and control subjects, whereas nontraumatic neck

pain patients demonstrated significantly increased absolute errors in horizontal

and global components and higher variable errors in horizontal component.

CONCLUSIONS: These findings suggest that the vestibular system is not involved in

the performance of the cervicocephalic relocation test to neutral head position,

and further support this test as a measure of cervical proprioceptive acuity.

PMID: 19061750 [PubMed - indexed for MEDLINE]

Thank you dear Ellie

as you know, cerebellar control of posture is mainly based on the coordinated activity of the cerebellum, brainstem reticular formation and vestibular systems, providing the control of  posture and body balance.Cerebellar damage in humans results in increased standing postural sway, hypermetric postural responses and prolonged muscle activity.

Previously, we assessed the postural control of patients with low back pain and healthy controls by altering the systems involved in balance control (eyes open vs closed , vestibular and properiocetion manipulation) before and after the 3 months balance training and therapeutic exercise.

In recent researches, perturbation-based balance training for preventing falls, movement strategies for maintaining standing balance during arm tracking in people with multiple sclerosis, effects of a predefined mini-trampoline training program on balance, mobility and activities of daily living after stroke, and so etc.... were done.

You may want to use structural equation modeling to test the effects. SEM is more flexible than standard regression in terms of treating a given variable as both dependent and independent variable. For instance, perhaps you would seek to treat attention as a mediating variable between caffeine consumption and postural control.

Best wishes,

Damian

Hi,

i basically agree with what Graham Pulford reported.

I have no experience in EMG signals processing but i use HMM for electrical characterization. I enclose two links to publications in which we use HMM to characterize random telegraph signals in emerging memories, if you want to compare. 

HMM is very useful if your system can be described as a memoryless process with a given number of states. Even more than two, of course. The HMM tries to find the best description of the system, so how and when the system switches from one state to another, based on the experimental observation. So it will work also with more than two levels. As a drawback you should estimate the number of levels beforehand as this is a required input for the algorithm.

There is a great guide to HMM by Rabiner. It shows application to speech recognition but if you have a look at it you may find it useful to understand whether HMM is a suitable solution for you or not.

Hope this is helpful.

Regards.

For the Kinect you just have to plug it in the computer with USB. Currently it is only possible with the old Kinect (360) not the new one (Kinect One).

Then you have two options: if you use the Kinect for Xbox you have to install Kinect SDK and Windows Developper Toolkit (http://www.microsoft.com/en-us/kinectforwindowsdev/Downloads.aspx). If you use the Kinect for Windows you don't have to install anything.

For the Balance Board you simply have to connect it to the computer with Bluetooth connection.

Then it is up to you to create software to collect informations from these devices (C++, Matlab...)

Hi,

I am not sure whether I properly understand your problem, but if you want to correlate configurations (or so said a list of coordinates) you should use the bidimensional regression analysis approach (not to be mixed up with biVARIATE regression analysis!).

What is the big advantage over other approaches? With the bidim-approach the coordinates are still entangled and are not used independently from each other (which would not make sense).

I have written and published an open-source project on this topic. You can retrieve it from

Carbon, C. C. (2013). BiDimRegression: Bidimensional regression modeling using R. Journal of Statistical Software, Code Snippets, 52(1), 1-11.

Within the routine you can use Euclidean as w ell as Affine geometry.

You can also directly download it here:

All the best, hope this helps,

CCC

Ability appropriate balance training interventions have been shown to improve postural control scores and reduce falls risk in the elderly across a number of investigations. There is also a very limited body of evidence that suggests that sensory-targeted interventions (e.g. Massage or joint mobs) have a positive effect on postural control in the elderly. There is a growing body of evidence to support this theory in individuals with ankle joint pathologies.

While not familiar with the literature, sensory reweighting studies will help connect somatosensory function with the postural control system.