Using EMG spectral analysis to predict modified Japanese Orthopaedic Association score in patients with cervical myelopathy

![CDATA[Rationale/Objectives: Modified Japanese Orthopaedic Association (mJOA) score is a widely used tool to assess the severity of cervical myelopathy. However, evaluation of mJOA score can be subjective and time consuming. The present study aimed to develop a robust and simple method to predict the mJOA score. Methods: Nine patients with cervical myelopathy (6 males and 3 females, age=64.8±14.8 years) were examined from a local hospital before and one week after decompression surgery. During each time point, two wireless EMG sensors sampling at 1,000 Hz were placed onto bilateral wrist extensor muscles. The patients were asked to perform 10-second grip-and-release test (10GRT). We conducted spectral analyses on the raw EMG data by computing the power in four preset bandwidths (1-10, 11-20, 21-30, and 31-100 Hz). A multiple regression model was used to predict the mJOA scores, which were charted by a single research nurse, with the EMG power parameters. Results: We found significant correlations between mJOA score with EMG power of higher-functioned hand and lower-functioned hand at preset bandwidths (p<0.05) A prediction equation was established with R2=0.742 and RMSE was 1.215 unit of mJOA score. Conclusions: Our findings suggest that spectral analyses of wrist extensor muscles activity can be a potential non-invasive clinical tool to predict mJOA score for patients with cervical myelopathy.]]