1. Equilibrioception: Sense of balance Presented by: SuhasDeshpande EE 506 Theory & Practice Biomedical Instrumentation Dr. Christopher Druzgalski

2. outline Importance Balance as a sense Vestibular system Sensory factors affecting balance Balance disorders Postural diagnosis Postural balance indicator Research and applications References

3. Importance Dizziness is a common symptom affecting about 30% of people over the age of 65 Difficulty in performing one or more activities of daily living May have serious outcomes even death Falls are the leading cause of fatal and non-fatal injuries for old age person

4. Balance as a sense A complex activity with interaction from various parts of the body. Feedback control system Vestibular system, Nervous system, Eyes, Muscles and tendons www.ebaumsworld.com/pictures/view/80735176

5. Vestibular system Semicircular canals detect the rotation The fluid in the canals moves as our body rotates to produce neurological stimulus

6. Vestibular system Otolith organs: Saccule and Utricle to detect linear acceleration Movement of hair cells in the utricle and sacule innervate the neurons during the motion

7. Vestibular system Nervous system Eyes: VOR (Vestibulo-ocular Reflex) Stabilizes retinal image during rotation Maintains the feedback gain of -1

8. Sensory factors affecting balance Vision Provides necessary information for effective navigation Provides input to the nervous system about the real world

9. Sensory factors affecting balance Vision Vestibular sense Helps in positioning the head VOR helps in maintaining the visual fixation

10. Sensory factors affecting balance Vision Vestibular sense Proprioception Sensory information from muscles, tendons provide feedback of joint position, movement and touch. Lower limbs input contributes to standing balance.

11. Sensory factors affecting balance Vision Vestibular sense Proprioception Central Nervous system Receives feedback from other organs Sends motor response to other organs

12. Balance disorders Related to Ear BPPV (Benign Paroxysmal Positional Vertigo) Meniere’s disease Labyrinthitis (inner ear infection) Related to brain Traumatic Brain Injury Disorders of CNS Diseqillibrium

13. Postural Diagnosis Rotation Tests ENG(Electronystagmography) CDP(Computerized Dynamic Posturography) MRI CT Scan

14. Postural Diagnosis Posturography Non-invasive specialized technique Study the contributions of vestibular inputs, visual inputs, somatosensory inputs, central integrating mechanisms and muscular system outputs for postural and balance control

15. Postural Diagnosis Posturography Patient stands still in a set of conditions with eyes open/closed in fixed and sway referenced surface conditions Three kinds of tests: Sensory Organization Test (SOT), Motor Control Test (MCT) and Adaptation Test (ADT)

16. Postural Diagnosis ENG Electrodes placed around the eye Detects the occurrence of a nystagmus (involuntary eye movement) Ears flushed with warm and then cold water. Amount of nystagmus measured.

17. Postural diagnosis Rotation tests Patient is seated on a rotary chair Chair rotates/moves in specific manner The eye movements are monitored to diagnose the problem

18. Postural balance indicator Two level sensors: fluid filled tubes Photo-resistor and an LED coupled detect the off balance position Signal sent to respective vibrators (left or right or both) The patient senses the vibrations to regain equillibrium (1)

19. Research and application Application of human postural balance mechanism to humanoid robots Study of the zero gravity condition and role of and effect on the human body for astronauts.

20. References P. Ingerson, "Postural balance indicator and associated feedback compensation system," Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings, vol. 26, pp. 2484, 2004. V. Panzer, "Biomechanical changes in postural control concurrent with aging," J. Biomech., vol. 22, pp. 1067, 1989 F.Horak, "Clinical assessment of balance disorders", Gait & Posture, Volume 6, Issue 1, Pages 76-84 L. Kodde, "An application of mathematical models in posturography," J. Biomed. Eng., vol. 4, pp. 44, 1982 Hyon. "Integration of multi-level postural balancing on humanoid robots",2009 IEEE International Conference on Robotics and Automation, pp. 1549, 1556 http://www.physpharm.fmd.uwo.ca/undergrad/sensesweb/L10Balance/L10Balance.pdf http://vestibular.org/index.php http://www.nidcd.nih.gov/health/balance/balance_disorders.asp http://www.dizziness-and-balance.com/index.html http://resourcesonbalance.com http://spaceline.nasaprs.com/pdf/Astronaut_Study.pdf