Design Inputs

Requirement
Specification(s)
Verification Activity
Validation Activity
1. The device must measure hand and wrist positions. 1. The device must have ≤ 8 mm3 1. Using a silicone hand model, compare device acquired position to a known distance using a ruler.  1. User survey if position data is representative and present after the hand is moved.
1. Accurate position measurements is essential for deriving secondary kinematic data, such as joint angles and velocity.
2. The device must measure hand and wrists joints range of motion (ROM)
 2.1 Angular accuracy < ±5° per joint
2. Compare device measured angles to known angles (0° to 180°) set by a precision goniometer

2. Joint exercise and ROM tests for human subjects
2.2 Angular resolution ≤ 1° for fingers, ≤ 2° for wrist joints
2. Accurate ROM measurements is essential for therapists to track progress and adjust rehabilitation programs.
3. The device must calculate velocity of joint movement.
 3.1 Linear velocity of 0-50 cm/s ± 1 cm/s 3. Compare device calculated linear and angular velocities against linear actuator and motorized goniometer reference values
3. User performing tendon gliding exercises, testing if velocities are reported
3.2 Angular velocity calculation of 0-20 deg/s ± 1 deg/s
3. To detect abnormal timing/rhythm, ensure safe exercise intensity, and aid in providing corrective feedback
4. The device must have an adjustable resistance mechanism to increase difficulty for finger movement.
 4.1 Must have finger flexion resistance force range 0 to 40 N
4. Tensile testing to measure max resistance force, compared to specification with a safety factor.

4. Confirming that human subjects can independently adjust the resistance mechanism during supervised testing
4.2 Must have finger extension resistance force range 0 to 22 N
4.3 Have resistive element adjustable by user
4. To personalize therapy intensity to patient needs, recovery stages, and therapeutic goals.
5. The device must provide feedback during exercises performed by user.
 5.1 Visual, auditory, or tactile message sent to user if cadence or ROM exceeds therapeutic thresholds or to continue exercises 5.1 Use of a hand model or user’s hand within and beyond exercise thresholds to record if appropriate feedback signals are generated

5. Confirming that the device provides real-time corrective or reinforcing feedback while subjects perform exercises
5.2 Feedback latency ≤ 250 ms (near real time) 5.2 Measure the time delay between when the threshold was reached and the feedback response
5. Feedback has been shown to reduce errors and support motor learning during rehabilitation.
6. The device must fit adult arthritis/hand injury patient
 6.1 Accommodates hand circumference 15cm – 25cm
6. N/A

6. Fit testing across a range of hand sizes will confirm the device can accommodate different hand sizes without discomfort or restriction
6.2 Accommodates hand breadth 6cm – 11cm
6.3 Accommodates hand length 15cm-24cm
6. To accommodate natural variations in hand dimensions as well as patients with hand swelling, arthritis deformations, or anatomical changes.
7. The device must allow users to independently don and doff the glove quickly.
 7.1 Unassisted donning system
7. N/A

7. Usability testing will validate that participants can independently don and doff the device within 60 seconds
7.2 Donning time ≤ 60 seconds
7. Ease of donning and doffing is consistently identified as a major barrier to use in rehab gloves.
8. The hand component of device must be lightweight.
 8.1 The device must have a mass of ≤500g on the hand
8. Weigh the complete hand-worn device using a precision digital scale. Determine and compare the CoM of the device attached to hand to the CoM of a hand.
8. N/A
8.2 The device must alter the natural center of mass of the hand by ≤ 10% of hand length
8. Avoids adding excess mass that would restrict natural hand motion and/or increase strain on the user.
9. The device must meet IEC 60601-1 standards and limit electrical leakage for safe skin contact 9. The device must have ≤0.1 mA of leakage current1 9. Measure device leakage currents connected to simulated human conditions under normal and single fault conditions 9. No validation activity is performed for this input
 9. Addresses safety concerns regarding potential body contact with electrical components
10. The device must meet ANSI/AAMI ST98 standards to withstand routine disinfection ¹ 10. Must maintain integrity after ≥ 70% isopropyl alcohol wipes 10. Apply artificial soil and perform standardized ST98 cleaning cycles to confirm that visible residue is removed and materials do not degrade 10. Confirming that device function and appearance remain unchanged after at least 15 sanitation cycles
10. Addresses safety concerns and performance concerns regarding contact with water/sweat