Related Experiment Video
Updated: Jul 4, 2025
Home-Based Monitor for Gait and Activity Analysis
Published on: August 8, 2019
Standardizing Continuous Physical Activity Monitoring in Patients with Cervical Spondylosis
Nicolai Maldaner1,2, Aneysis D Gonzalez-Suarez1, Megan Tang1
1Department of Neurosurgery, Stanford University Hospital and Clinics, Stanford, CA.
Study Design/Setting:
Prospective cohort study.
Objective:
To use a commercial wearable device to measure real-life, continuous physical activity in patients with CS and to establish age-adjusted and sex-adjusted standardized scores.
Summary Of Background Data:
Patients with cervical spondylosis (CS) often present with pain or neurologic deficits that result in functional limitations and inactivity. However, little is known regarding the influence of CS on the patient's real-life physical activity.
Methods:
This study included 100 English-speaking adult patients with cervical degenerative diseases undergoing elective spine surgery at Stanford University who owned iPhones. Patients undergoing surgery for spine infections, trauma, tumors, or lumbar degenerative disease were excluded. Activity two weeks before surgery was expressed as raw daily step counts. Standardized z-scores were calculated based on age-specific and sex-specific values of a control population. Responses to patient-reported outcome measures (PROMs) surveys assessed convergent validity. Functional impairment was categorized based on predetermined z-score cut-off values.
Results:
Thirty CS with a mean (±SD) age of 56.0 (±13.4) y wore an Apple Watch for ≥8 hours/day in 87.1% of the days. The mean watch wear time was 15.7 (±4.2) hours/day, and the mean daily step count was 6400 (±3792). There was no significant difference in activity between 13 patients (43%) with myelopathy and 17 (57%) without myelopathy. Test-retest reliability between wearable step count measurements was excellent (ICC β=0.95). Physical activity showed a moderate positive correlation with 36-Item Short Form Survey Physical Component Summary, EuroQol-5-dimension visual analog scale, and Patient-Reported Outcomes Measurement Information System Physical Function Subscale. Activity performance was classified into categories of "no impairment" [step count=9640 (±2,412)], "mild impairment" [6054(±816)], "moderate impairment" [3,481 (±752)], and "severe impairment" [1,619 (±240)].
Conclusion:
CS patients' physical activity is significantly lower than the general population or the frequently stated goals of 7000 to 10,000 steps/day. Standardized, continuous wearable physical activity monitoring in CS is a reliable, valid, and normalized outcome tool that may help characterize functional impairment before and after spinal interventions.
