Association of joint hypermobility with range of cervical motion and its impact on the motor unit loss in patients with Hirayama disease

Abstract

Introduction/Aims: Some patients with Hirayama disease (HD) may have generalized joint hypermobility (GJH), which may excessively increase cervical range of motion (ROM) and then worsen the HD. The purpose of this study was to identify the frequency of GJH in HD patients and to analyze the effect of GJH on cervical ROM and the severity of HD. Methods: The Beighton scoring system (≥4) was used to diagnose GJH in 84 HD patients. All patients underwent assessments of cervical-flexion/extension ROM; motor unit number estimation in bilateral abductor pollicis brevis (APB) muscles; handgrip strength; and the disabilities of the arm, shoulder, and hand assessments. Results: Concomitant GJH was identified in 20 (23.8%) HD patients. The HD patients with GJH exhibited greater cervical-flexion (P