Towards the development of a dynamic device for the evaluation of hypertonia of the upper extremity

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Towards the development of a dynamic device for the evaluation of hypertonia of the upper extremity

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Proxenos, Matthew

Includes bibliographical references. ; Traditional evaluation techniques for spastic hypertonia, such as the Modified Ashworth Scale (MAS), are prone to subjectivity and have been shown to have poor inter- and intra-rater reliability. Automated objective electromechanical devices for upper-limb evaluation do exist, such as the commercially available NeuroFlexor device. These assess combined wrist and finger flexor tone by monitoring wrist joint torque during passive wrist extension. Wrist flexor tone evaluations made by manipulation of the wrist joint alone, however, could be affected by possible hypertonia of the finger flexors due to the moment arm that these muscles‟ tendons have at the wrist joint. As such, robotic wrist flexor evaluation devices that measure only the wrist joint torque cannot distinguish between wrist and finger flexor hypertonia. A robotic device measuring involuntary resistance at the wrist and finger joints separately during wrist manipulation can be used to provide wrist flexor tone assessments that compensate for the influence of hypertonia of the finger flexor muscles, and therefore provide more accurate tone assessments of the wrist flexor muscles. To design, construct and evaluate a patient-safe device for the independent measurement of wrist and finger joint torque during wrist extension, and to use the device to accurately evaluate wrist flexor tone, in isolation from possible effects of finger flexor tone. Evaluations were made using the device in a clinical setting with volunteers (n=6) with varying levels of hypertonia in the hands and wrists. Volunteers’ wrist flexor tone was also assessed by three clinicians using the MAS score.