The Somatosensory and vestibular interaction in human postural control

Download
2015
Akçay, Mustafa Emre
Human upright posture is essential for people during daily activities. Upright posture is a skill, which is acquired before walking during the human development. Classically defined five senses (as the sense of kinesthesia is not included) are not enough to obtain this difficult and important skill. Thus, the humans need another group of senses; i.e., proprioception, vestibular sensor, joint receptors etc. to achieve the upright posture. In this thesis, two distinct stimulations were given to the subjects to identify the two different kinematic frames of reference. The first perturbation was above the vestibular threshold (high angular velocity) so gravity vertical has been expected to be the reference frame. The second stimulation was below the vestibular threshold thus, the somatosensory system has been proposed to dominate the postural behavior where the reference frame was hypothesized to be the platform normal. A tilt platform was developed and manufactured to check this hypothesis. The experiments were performed in complete darkness. We have shown that the subjects demonstrated a vestibular dominated postural behavior for the high frequency perturbation (kinematics data revealed that postural corrections were performed with respect to gravity vertical) whereas, subjects’ behavior for the low frequency perturbation presented a habitual postural sway-like behavior on the platform. The findings were mathematically modeled by using a 3-DoF inverted pendulum including vestibular and somatosensory dynamics (optimizing the system parameters), where joint control torque compensated for gravity vertical for the high frequency whereas, control strategy used for the low frequency depended on compensation for CoP deviations.

Suggestions

Effect of the vestibular system on search and fall behaviour of human postural sway
Cengiz, Berat Can; Gürses, Senih; Department of Engineering Sciences (2017)
In a person's daily life, upright stance is a very essential postural position for using hands, locomotion, communication, etc. These motivations probably help a baby to solve this complex motor task faster. A healthy individual is thought to maintain his/her upright posture mainly by the help of four senses: vestibular, proprioception, vision, and somatosensory. With a classical view, human upright posture control mechanism is approached as a control system with multi inputs almost single output (CoPx). Ho...
Postural responses of patients with bilateral vestibular loss and healthy subjects to sinusoidal tilts
İmir, Mehmet; Gürses, Senih; Department of Engineering Sciences (2017)
Posture control to maintain the stability of upright posture is a very complex task. It requires sensorimotor integration of all sense organs. If one of these organs loses its functionality, the person may have difficulties in maintaining postural balance. This study examines the difference in postural responses of patients with bilateral vestibular loss and healthy subjects to sinusoidal tilts. It has shown that center of mass(CoM) motions of control and patient groups were similar respect to space coordin...
Investigation of control of human balance-recovery reactions
Bilgin, Nurdan; Özgören, Mustafa Kemal; Department of Mechanical Engineering (2015)
In this study, a natural control law has been conjectured, which is assumed to be applied by the central nervous system of a human being in order to maintain the erect posture after being exposed to a suddenly occurring impulsive disturbance. The control law is conjectured as PD (proportional-derivative) control, because it has to be compatible with the physiological facts. The conjectured control law has been validated by comparing a set of experimental results with the corresponding set of simulation resu...
The Effects of dynamic and static stretching protocols on power, agility and flexibility in elite wrestlers
Çelebi, Murat; Kirazcı, Sadettin; Department of Physical Education and Sports (2014)
The purpose of this study was to investigate the effects of static stretching (SS), dynamic stretching (DS) and no stretching (NS) protocols on power, agility and flexibility in competitive wrestlers. 34 competitive male athletes were recruited for Standing Long Jump, T-Drill and Sit and Reach Test to test power, agility and flexibility of the subjects respectively. The participants performed one of the tests on each day. After the analysis of repeated measures of ANOVA, the results indicated that the measu...
Effect of cognitive task difficulty on postural control
Gürsoy, Zeren Görkem; Kirazcı, Sadettin; Department of Physical Education and Sports (2019)
Human posture control is accompanied usually in daily life with other tasks, such as cognitive tasks. This thesis is on the effects of cognitive task difficulty on postural control, the postural control mechanisms, attention and its relation to posture control and finally the dual task environments for posture control. The experiment’s set an individualized difficulty level for each participant. Results indicate that when motor and challenging cognitive tasks are completed under dual task conditions, dual t...
Citation Formats
M. E. Akçay, “The Somatosensory and vestibular interaction in human postural control,” Ph.D. - Doctoral Program, Middle East Technical University, 2015.