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Introduction 5q Spinal muscular atrophy (SMA) causes progressive, muscle weakness affecting the limbs, trunk, respiratory, and bulbar muscles. Current outcome assessments may be significantly impacted by severe weakness, contractures, pain and injury. Neck movements are relatively unaffected by these processes and not routinely assessed. We studied the feasibility and validity of quantitative neck strength assessment using MicroFET2 handheld dynamometer (HHD) during clinic visits.Methods HHD assessment of neck flexion and extension was performed, alongside baseline function, respiratory and health related quality of life (HRQoL) assessments.Results Forty six SMA patients (Type 2 = 21, Type 3 = 25) underwent HHD assessment. HHD was well tolerated, and took <3 minutes. Neck flexor strength correlated strongly with FVC (r = 0.75), RULM (r = 0.70), EK2 (r = -0.81), and EQ5D Health Utility Value (r = 0.62). Stronger neck flexor strength was associated with greater independence in mobility (WHO stages of mobility) (AUC = 0.94), and independent sitting ability (AUC = 0.85) than RULM or EK2.Conclusion Neck strength assessment with HHD was feasible and well tolerated across SMA type 2 and 3 patients. It correlated strongly with measures of motor function, FVC, and HRQoL.j.street1@nhs.net