Duration of symptoms in the quantification of upper limb disability and impairment for individuals with mild degenerative cervical myelopathy (DCM)

Abstract

Objectives Degenerative cervical myelopathy (DCM) involves spinal cord compression, which causes neurological decline. Neurological impairment in DCM is variable and can involve complex upper limb dysfunction including loss of manual dexterity, hyper-reflexia, focal weakness, and sensory impairment. DCM can cause progressive loss of manual dexterity, reduced upper limb (UL) function and disability. The purpose of this study was to define relationships between impairment and disability of the UL and determine the impact of duration of symptoms on disease severity. Design An observational cross-sectional study quantifying disease severity, UL impairment and disability at time of diagnosis was conducted. A second observational longitudinal cohort was studied at the time of diagnosis and 1 year later. Setting Toronto Western Hospital, Spine Program. Subjects The cross sectional study included 140 study subjects diagnosed with mild, moderate or severe DCM. For the longitudinal study, 61 study subjects with mild DCM were enrolled and split into two groups, one group with less than 12 months of symptom duration and more than 12 months. Main measures Modified Japanese Orthopaedic Assessment (mJOA); Graded Redefined Assessment of Sensation, Strength and Prehension (GRASSP); Quick Disability of the Arm, Shoulder and Hand (QuickDASH). Results Pearson correlation coefficients between GRASSP and QuickDASH revealed significant relationships between strength, sensation and dexterity for all patients to varying degrees. The covariate (mJOA) was significantly related to QuickDASH, indicating duration of symptoms has an important effect on UL disability in the mild severity group. Conclusions Strength, sensation and dexterity play a defining role in disability of the UL across all severities of DCM and are discriminant measures. Duration of symptoms has a significant impact on self-perceived disability, where a longer duration in mild patients results in diminished disability, suggesting adaptation. Duration of symptoms is an important factor to consider in the treatment plan for patients with mild disease.