Classifying Hand Dexterity Impairment in Degenerative Cervical Myelopathy with 10-Second Grip and Release Test

Study design. Diagnostic accuracy study with prospectively collected data. Objective. This study aimed to establish optimal cutoff values for the 10-second Grip and Release (10s-G&R) Test to distinguish between mild, moderate, and severe levels of hand dexterity impairment in patients with Degenerative Cervical Myelopathy (DCM). Background. The 10s-G&R test is widely utilized to assess hand function in DCM patients. However, whether this test can effectively distinguish between varying severities of hand dexterity impairment, along with the relevant cut-off values, remains unknown. Methods. We analyzed hand motion data from 551 consecutively enrolled DCM patients using an AI system. Additionally, we conducted evaluations of functional status, quality of life, and outcome measures. Receiver operating curve analysis was performed to determine cutoff values that differentiate mild, moderate, and severe hand dexterity impairments based on the ability to fasten buttons, as assessed by the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) Q2-1. The validity of these cutoffs was assessed by comparing G&R parameters, upper limb disability, overall disease severity, and quality of life among patients in different severity groups. Results. We identified 16 G&R cycles as the cutoff for moderate hand dexterity impairment and 13 G&R cycles as the cutoff for severe impairment. Patients with severe impairment exhibited significantly worse G&R parameters, more severe upper limb symptoms, greater overall disease severity, and reduced quality of life. Patients completing fewer than 13 G&R cycles within 10 seconds were more likely to have moderate-to-severe DCM, indicating the need for potential surgical intervention. Conclusion. We propose classifying mild hand dexterity impairment as 17-20 cycles on the 10s-G&R test, moderate as 14-16 cycles, and severe as 13 cycles or less. Our study underscores that the 10s-G&R test can serve as an effective supplementary tool within the context of other currently available measurement tools.