Electrotactile Feedback System Using Psychophysical Mapping Functions

Persistent Link:
http://hdl.handle.net/10150/193947
Title:
Electrotactile Feedback System Using Psychophysical Mapping Functions
Author:
Marcus, Patrick
Issue Date:
2006
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Advancements in movement restoration have accelerated in recent years while the restoration of somatosensation has progressed relatively slowly. This dissertation attempts to partially correct this oversight by developing an electrotactile feedback system that might be used to restore the sense of touch.Initially, the perceptual parameters of the skin regions likely to be used as a source of tactile information (the fingertip) and as a destination for electrotactile feedback (the back of the neck) were evaluated. The perceptual parameters of tactile threshold sensitivity, spatial acuity, and gain scaling were collected from subjects for both regions of skin. These same parameters were also gathered in response to electrotactile stimulation of the neck. The threshold sensitivity and spatial acuity of the fingertip was found to be far superior to that on the back of the neck, yet the mechanical perceptual gain scaling parameters of the neck were similar to that of the finger tip. Yet, the psychometric functions for electrical stimulation on the neck differed markedly in gain sensitivity from that of mechanical stimulation. A mapping function between the two modalities was then calculated based upon the tactile and electrotacile characterization data that was collected.An electrotactile feedback system was then developed based upon the calculated mapping function, allowing conversion of force applied to an artificial sensor on the fingertip to a perceptually equivalent electrical stimulus on the neck. The system proved to be quite effective: Subjects were able to effectively evaluate electrical stimulus that was derived from application of force to the sensor on the fingertip. The perceptual gain scaling for the feedback system matched that of natural mechanical stimulation.A grip force matching task was evaluated in test subjects under three conditions: a) normal tactile sensation, b) anesthesia of the fingers, and c) anesthesia of the fingers with restored tactile information via the electrotactile feedback system. The relative loss in grip-force matching ability when tactile feedback was abolished by local anesthetic was mild, indicating a strong ability for individuals to generate target force levels using other forms of feedback. Electrotactile feedback, therefore, offered only modest improvement when deployed in the anesthetized hand.
Type:
text; Electronic Dissertation
Keywords:
tactile feedback electrotactile somatosensory psychophysics touch
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Biomedical Engineering; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Fuglevand, Andrew J
Committee Chair:
Fuglevand, Andrew J

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleElectrotactile Feedback System Using Psychophysical Mapping Functionsen_US
dc.creatorMarcus, Patricken_US
dc.contributor.authorMarcus, Patricken_US
dc.date.issued2006en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractAdvancements in movement restoration have accelerated in recent years while the restoration of somatosensation has progressed relatively slowly. This dissertation attempts to partially correct this oversight by developing an electrotactile feedback system that might be used to restore the sense of touch.Initially, the perceptual parameters of the skin regions likely to be used as a source of tactile information (the fingertip) and as a destination for electrotactile feedback (the back of the neck) were evaluated. The perceptual parameters of tactile threshold sensitivity, spatial acuity, and gain scaling were collected from subjects for both regions of skin. These same parameters were also gathered in response to electrotactile stimulation of the neck. The threshold sensitivity and spatial acuity of the fingertip was found to be far superior to that on the back of the neck, yet the mechanical perceptual gain scaling parameters of the neck were similar to that of the finger tip. Yet, the psychometric functions for electrical stimulation on the neck differed markedly in gain sensitivity from that of mechanical stimulation. A mapping function between the two modalities was then calculated based upon the tactile and electrotacile characterization data that was collected.An electrotactile feedback system was then developed based upon the calculated mapping function, allowing conversion of force applied to an artificial sensor on the fingertip to a perceptually equivalent electrical stimulus on the neck. The system proved to be quite effective: Subjects were able to effectively evaluate electrical stimulus that was derived from application of force to the sensor on the fingertip. The perceptual gain scaling for the feedback system matched that of natural mechanical stimulation.A grip force matching task was evaluated in test subjects under three conditions: a) normal tactile sensation, b) anesthesia of the fingers, and c) anesthesia of the fingers with restored tactile information via the electrotactile feedback system. The relative loss in grip-force matching ability when tactile feedback was abolished by local anesthetic was mild, indicating a strong ability for individuals to generate target force levels using other forms of feedback. Electrotactile feedback, therefore, offered only modest improvement when deployed in the anesthetized hand.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjecttactile feedback electrotactile somatosensory psychophysics touchen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineBiomedical Engineeringen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorFuglevand, Andrew Jen_US
dc.contributor.chairFuglevand, Andrew Jen_US
dc.contributor.committeememberMcNaughton, Bruceen_US
dc.contributor.committeememberBarton, Jenniferen_US
dc.contributor.committeememberHiggins, Charlesen_US
dc.contributor.committeememberStrickland, Robinen_US
dc.identifier.proquest1891en_US
dc.identifier.oclc659746450en_US
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