New Method for the Quantitative Assessment of Sensory Disturbances in Cervical Myelopathy: Application for Neurological Level Diagnosis

INTRODUCTION: Cervical myelopathy frequently manifests as sensory disturbances, including numbness, and their distribution pattern aids in neurological level diagnosis. However, the objective assessment of sensory disturbances is challenging. In this study, we attempted to quantitatively evaluate sensory symptoms in patients with cervical myelopathy according to lesion level using PainVision(Ⓡ). METHODS: Dermal sensations were evaluated in patients (n = 158) and healthy volunteers (n = 100) using PainVision(Ⓡ) PS-2100, which measured the current perception threshold (CPT). The results were analyzed for their correlation with magnetic resonance imaging (MRI) data, visual analog scale (VAS) scores, and patient functional status assessed by the Japanese Orthopaedic Association (JOA) and JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) scores. RESULTS: Forearm and palm CPT values were significantly higher in patients with cervical myelopathy (both sites, P < 0.001) and were negatively correlated with the JOA score (forearm, r = −0.33; palm, r = −0.35; P < 0.001) and the JOACMEQ scores for upper extremity function (forearm, r = −0.37; palm, r = −0.39; P < 0.001), lower extremity function (forearm, r = −0.39; palm, r = −0.40; P < 0.001), and quality of life (forearm r = −0.27, P = 0.0025); however, no correlation was observed with the VAS score. Stratification of patients according to their lesion levels determined by MRI revealed that the C3/C4 subgroup had significantly higher forearm CPT values than the C4/C5 (P = 0.024) and C5/C6 (P = 0.0013) subgroups and higher palm CPT values than the C5/C6 subgroup (P = 0.009). CONCLUSIONS: Quantitative measurements of sensory disturbances using the PainVision(Ⓡ) device correspond to the degree of patient functional disability and the lesion level. This indicates that both the distribution and intensity of sensory abnormalities are important for neurological level diagnosis in patients with cervical myelopathy.