Portable 3D-printed hand orthosis with spatial stiffness distribution personalized for assisting grasping in daily living

Abstract

Stroke survivors having limited finger coordination require an active hand orthosis to assist them with grasping tasks for daily activities. The orthosis should be portable for constant use; however, portability imposes constraints on the number, size, and weight of the actuators, which increase the difficulty of the design process. Therefore, a tradeoff exists between portability and the assistive force. In this study, a personalized spatial stiffness distribution design is presented for a portable and strengthful hand orthosis. The spatial stiffness distribution of the orthosis was optimized based on measurements of individual hand parameters to satisfy the functional requirements of achieving sufficient grip aperture in the pre-grasping phase and minimal assistive force in the grasping phase. Ten stroke survivors were recruited to evaluate the system. Sufficient grip aperture and high grip strength-to-weight ratio were achieved by the orthosis via a single motor. Moreover, the orthosis significantly restored the range of motion and improved the performance of daily activities. The proposed spatial stiffness distribution can suggest a design solution to make strengthful hand orthoses with reduced weight.

The Upper Limb Orthosis in the Rehabilitation of Stroke Patients: The Role of 3D Printing

“…Three trials were RCTs [95,109,110]. Nine trials included chronic stroke patients (onset ≥6 months) [4,11,95,109,[111][112][113][114][115], and one included both post-acute (within 3 months) and chronic stroke patients [110]. Two trials included both ischemic and hemorrhagic stroke [110,111], and nine trials did not report the etiology of the stroke.…”

“…The other authors [4,112,[114][115][116] tested the effectiveness of the devices before and after wearing.…”

A Lightweight Dynamic Hand Orthosis With Sequential Joint Flexion Movement for Postoperative Rehabilitation of Flexor Tendon Repair Surgery

“…While assistance of multiple finger joints can be accomplished by a single motor with exoskeletal links [14,[16][17][18][19]21,22], these links are heavy and require significant space on the dorsal aspect. Alternatively, employing a bendable and lightweight orthosis with a cabledriven mechanism may enable devices to achieve both a wide ROM and lightweightness [39]. Additionally, a TSA mechanism that provides a high contraction force-to-torque ratio can be employed to reduce the weight of an actuation module [40].…”

“…The degree of finger joint stiffness can vary over time after postoperative immobilization [42], and the orthosis should provide the assistive force for passive mobilization against the varying joint stiffness. While the finger joints can be extended by the structure having fixed elasticity [39], the elasticity may not be sufficient to achieve finger extension against the increased joint stiffness. Thus, the varying finger joint stiffness should be accounted for when designing a dynamic hand orthosis that employs an elastic structure for passive assistance.…”

NOHAS: A Novel Orthotic Hand Actuated by Servo Motors and Mobile App for Stroke Rehabilitation

“…The effects of hand therapy and rehabilitation involving orthoses on the independence of individuals in performing ADLs have been examined, underscoring the crucial role of hand function. They emphasize the importance of developing effective and personalized hand orthoses that aid in improving hand function and independence in performing ADLs for individuals with hand impairments [2][3][4][5].…”