Case studies in neuroscience: a dissociation of balance and posture demonstrated by camptocormia

R. J. St George, V. S. Gurfinkel, Jeff Kraakevik, John Nutt, Fay Horak

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Up-right stance in humans requires an intricate exchange between the neural mechanisms that control balance and those that control posture; however, the distinction between these control systems is hard to discern in healthy subjects. By studying balance and postural control of a participant with camptocormia — an involuntary flexion of the trunk during standing that resolves when supine — a divergence between balance and postural control was revealed. A kinematic and kinetic investigation of standing and walking showed a stereotyped flexion of the upper body by almost 80° over a few minutes, and yet the participant’s ability to control center of mass within the base of support and to compensate for external perturbations remained intact. This unique case also revealed the involvement of automatic, tonic control of the paraspinal muscles during standing and the effects of attention. Although strength was reduced and MRI showed a reduction in muscle mass, there was sufficient strength to maintain an upright posture under voluntary control and when using geste antago-niste maneuvers or “sensory tricks” from visual, auditory, and haptic biofeedback. Dual tasks that either increased or decreased the attention given to postural alignment would decrease or increase the postural flexion, respectively. The custom-made “twister” device that measured axial resistance to slow passive rotation revealed abnormalities in axial muscle tone distribution during standing. The results suggest that the disorder in this case was due to a disruption in the automatic, tonic drive to the postural muscles and that myogenic changes were secondary. NEW & NOTEWORTHY By studying an idiopathic camptocormia case with a detailed biomechanical and sensorimotor approach, we have demonstrated unique insights into the neural control of human bipedalism 1) balance and postural control cannot be considered the same neural process, as there is a stereotyped abnormal flexed posture, without balance deficits, associated with camptocormia, and 2) posture during standing is controlled by automatic axial tone but “sensory tricks” involving sensory biofeedback to direct voluntary attention to postural alignment can override, when required.

Original languageEnglish (US)
Pages (from-to)33-38
Number of pages6
JournalJournal of Neurophysiology
Volume119
Issue number1
DOIs
StatePublished - Jan 1 2018

Fingerprint

Postural Balance
Neurosciences
Posture
Muscles
Paraspinal Muscles
Biomechanical Phenomena
Walking
Healthy Volunteers
Equipment and Supplies
Camptocormia

Keywords

  • Axial tone
  • Balance
  • Camptocormia
  • Posture
  • Standing

ASJC Scopus subject areas

  • Neuroscience(all)
  • Physiology

Cite this

Case studies in neuroscience : a dissociation of balance and posture demonstrated by camptocormia. / St George, R. J.; Gurfinkel, V. S.; Kraakevik, Jeff; Nutt, John; Horak, Fay.

In: Journal of Neurophysiology, Vol. 119, No. 1, 01.01.2018, p. 33-38.

Research output: Contribution to journalArticle

@article{f56d07518d1b4d108e906b5fb8b2e6ec,
title = "Case studies in neuroscience: a dissociation of balance and posture demonstrated by camptocormia",
abstract = "Up-right stance in humans requires an intricate exchange between the neural mechanisms that control balance and those that control posture; however, the distinction between these control systems is hard to discern in healthy subjects. By studying balance and postural control of a participant with camptocormia — an involuntary flexion of the trunk during standing that resolves when supine — a divergence between balance and postural control was revealed. A kinematic and kinetic investigation of standing and walking showed a stereotyped flexion of the upper body by almost 80° over a few minutes, and yet the participant’s ability to control center of mass within the base of support and to compensate for external perturbations remained intact. This unique case also revealed the involvement of automatic, tonic control of the paraspinal muscles during standing and the effects of attention. Although strength was reduced and MRI showed a reduction in muscle mass, there was sufficient strength to maintain an upright posture under voluntary control and when using geste antago-niste maneuvers or “sensory tricks” from visual, auditory, and haptic biofeedback. Dual tasks that either increased or decreased the attention given to postural alignment would decrease or increase the postural flexion, respectively. The custom-made “twister” device that measured axial resistance to slow passive rotation revealed abnormalities in axial muscle tone distribution during standing. The results suggest that the disorder in this case was due to a disruption in the automatic, tonic drive to the postural muscles and that myogenic changes were secondary. NEW & NOTEWORTHY By studying an idiopathic camptocormia case with a detailed biomechanical and sensorimotor approach, we have demonstrated unique insights into the neural control of human bipedalism 1) balance and postural control cannot be considered the same neural process, as there is a stereotyped abnormal flexed posture, without balance deficits, associated with camptocormia, and 2) posture during standing is controlled by automatic axial tone but “sensory tricks” involving sensory biofeedback to direct voluntary attention to postural alignment can override, when required.",
keywords = "Axial tone, Balance, Camptocormia, Posture, Standing",
author = "{St George}, {R. J.} and Gurfinkel, {V. S.} and Jeff Kraakevik and John Nutt and Fay Horak",
year = "2018",
month = "1",
day = "1",
doi = "10.1152/jn.00582.2017",
language = "English (US)",
volume = "119",
pages = "33--38",
journal = "Journal of Neurophysiology",
issn = "0022-3077",
publisher = "American Physiological Society",
number = "1",

}

TY - JOUR

T1 - Case studies in neuroscience

T2 - a dissociation of balance and posture demonstrated by camptocormia

AU - St George, R. J.

AU - Gurfinkel, V. S.

AU - Kraakevik, Jeff

AU - Nutt, John

AU - Horak, Fay

PY - 2018/1/1

Y1 - 2018/1/1

N2 - Up-right stance in humans requires an intricate exchange between the neural mechanisms that control balance and those that control posture; however, the distinction between these control systems is hard to discern in healthy subjects. By studying balance and postural control of a participant with camptocormia — an involuntary flexion of the trunk during standing that resolves when supine — a divergence between balance and postural control was revealed. A kinematic and kinetic investigation of standing and walking showed a stereotyped flexion of the upper body by almost 80° over a few minutes, and yet the participant’s ability to control center of mass within the base of support and to compensate for external perturbations remained intact. This unique case also revealed the involvement of automatic, tonic control of the paraspinal muscles during standing and the effects of attention. Although strength was reduced and MRI showed a reduction in muscle mass, there was sufficient strength to maintain an upright posture under voluntary control and when using geste antago-niste maneuvers or “sensory tricks” from visual, auditory, and haptic biofeedback. Dual tasks that either increased or decreased the attention given to postural alignment would decrease or increase the postural flexion, respectively. The custom-made “twister” device that measured axial resistance to slow passive rotation revealed abnormalities in axial muscle tone distribution during standing. The results suggest that the disorder in this case was due to a disruption in the automatic, tonic drive to the postural muscles and that myogenic changes were secondary. NEW & NOTEWORTHY By studying an idiopathic camptocormia case with a detailed biomechanical and sensorimotor approach, we have demonstrated unique insights into the neural control of human bipedalism 1) balance and postural control cannot be considered the same neural process, as there is a stereotyped abnormal flexed posture, without balance deficits, associated with camptocormia, and 2) posture during standing is controlled by automatic axial tone but “sensory tricks” involving sensory biofeedback to direct voluntary attention to postural alignment can override, when required.

AB - Up-right stance in humans requires an intricate exchange between the neural mechanisms that control balance and those that control posture; however, the distinction between these control systems is hard to discern in healthy subjects. By studying balance and postural control of a participant with camptocormia — an involuntary flexion of the trunk during standing that resolves when supine — a divergence between balance and postural control was revealed. A kinematic and kinetic investigation of standing and walking showed a stereotyped flexion of the upper body by almost 80° over a few minutes, and yet the participant’s ability to control center of mass within the base of support and to compensate for external perturbations remained intact. This unique case also revealed the involvement of automatic, tonic control of the paraspinal muscles during standing and the effects of attention. Although strength was reduced and MRI showed a reduction in muscle mass, there was sufficient strength to maintain an upright posture under voluntary control and when using geste antago-niste maneuvers or “sensory tricks” from visual, auditory, and haptic biofeedback. Dual tasks that either increased or decreased the attention given to postural alignment would decrease or increase the postural flexion, respectively. The custom-made “twister” device that measured axial resistance to slow passive rotation revealed abnormalities in axial muscle tone distribution during standing. The results suggest that the disorder in this case was due to a disruption in the automatic, tonic drive to the postural muscles and that myogenic changes were secondary. NEW & NOTEWORTHY By studying an idiopathic camptocormia case with a detailed biomechanical and sensorimotor approach, we have demonstrated unique insights into the neural control of human bipedalism 1) balance and postural control cannot be considered the same neural process, as there is a stereotyped abnormal flexed posture, without balance deficits, associated with camptocormia, and 2) posture during standing is controlled by automatic axial tone but “sensory tricks” involving sensory biofeedback to direct voluntary attention to postural alignment can override, when required.

KW - Axial tone

KW - Balance

KW - Camptocormia

KW - Posture

KW - Standing

UR - http://www.scopus.com/inward/record.url?scp=85043478304&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85043478304&partnerID=8YFLogxK

U2 - 10.1152/jn.00582.2017

DO - 10.1152/jn.00582.2017

M3 - Article

C2 - 28978769

AN - SCOPUS:85043478304

VL - 119

SP - 33

EP - 38

JO - Journal of Neurophysiology

JF - Journal of Neurophysiology

SN - 0022-3077

IS - 1

ER -