Instrumenting and Validating a Vibrotactile Device to Assess and Rehabilitate Dynamic Seated Balance

• Author / Creator

  Williams, Andrew D

• Tools that effectively assess and train dynamic seated balance are critical for enhancing functional independence and reducing risk of secondary health complications in the elderly and individuals with neuromuscular impairments. On the one hand, current assessment tools quantify changes in the integrity of the postural control system by measuring biomechanical characteristics of balance during postural perturbations. On the other hand, current training tools augment inherent sensory systems with encoded sensory cues that pertain to balance performance. However, these methods are complex or costly and, thus, have limited potential to serve as clinical assessment or training tools. The objective of this thesis research was to devise and validate a portable tool for assessing and training dynamic sitting balance. An instrumented wobble board was designed and constructed that can: (1) elicit multidirectional perturbations in seated individuals; (2) quantify seated balance proficiency; and (3) provide kinematics-based vibrotactile feedback. Interchangeable, curved bases were designed to elicit modular levels of seated instability in all tilt directions. An embedded, inertial measurement unit was used to estimate the tilt angle and direction, whereas eight vibrating tactors displayed feedback cues on the sitting surface. A microprocessor encoded the vibrotactile stimulation based on the wobble board’s tilt angle and speed, similar to sensory augmentation devices that improve balance-impaired standing. After performing a technical validation study to compare kinematic wobble board measurements against a gold-standard motion capture system, twelve non-disabled participants performed a dynamic sitting task using the wobble board. Posturographic analyses in time and frequency domain as well as stabilogram diffusion analyses were used to characterize sitting balance for three different conditions: (1) with eyes open and closed; (2) with two different levels of seated instability; and (3) with vibrotactile feedback on and off. Our results demonstrate that the tilt angle measurements were highly accurate throughout the range of wobble board dynamics. Furthermore, the posturographic analyses for the dynamic sitting task revealed that the wobble board can effectively discriminate between the three conditions of perturbed balance, demonstrating the potential for the wobble board to serve as a clinical tool for the assessment and training of seated balance. Unlike similar instrumented tools, the wobble board is portable, requires no laboratory equipment, and can be adjusted to meet the user’s balance abilities. While future work is warranted, this thesis contributes to the knowledge of assessment and training techniques for seated balance. Obtained findings will aid in effective translation of such techniques to a clinical setting, which has the potential to enhance diagnosis and prognosis for individuals with seated balance impairments.

• Subjects / Keywords

  • Device
  • Assessement
  • Sitting
  • Sensory feedback
  • Perturbation
  • Training
  • Posture
  • Balance

• Graduation date

  Fall 2017

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3HD7P63Q

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.