Reliability of Peg Restrained Intrinsic Muscle Evaluator for Measurement of Intrinsic Hand Muscle Strength in Adults with Tetraplegia

Background: The manual muscle test (MMT) is the traditional method to assess the intrinsic hand muscle test. However, this test is qualitative and subjective. A device capable of rapidly measuring motor output along a linear scale may be of value in the evaluation of hand recovery from any neurological impairment. Objective: To demonstrate inter-rater reliability of the Peg Restrained Intrinsic Muscle Evaluator (PRIME) device for measuring intrinsic hand muscle strength in adults with impaired hand functions. Methods: 16 subjects (2 female, 14 male, mean age=47±15 years) with cervical spinal cord injury were enrolled. Intrinsic hand muscle strength of adults were performed by two-tester with use of PRIME device and manual muscle testing, within the same session. Inter-tester correlation was tested by Pearson's correlation and Intraclass correlation coefficient (ICC). Results: Intraclass correlation coefficients for hypothenar, first dorsal interosseous, abductor pollicis brevis and opponence pollicis muscles ranged from 0.7 to 0.8 with hypothenar muscle test being lowest ICC=0.7 and thumb opposition highest, ICC=0.81. Conclusion: Results from this study suggest that PRIME device demonstrates good reliability within testers for quantified measuring of intrinsic hand muscle strength. Further use of PRIME in clinic will aid in diagnostics, medical decision making and evaluation of rehabilitation progress in patients with cervical spinal cord injury.