Thinning of cervical nerve roots and peripheral nerves in ALS as measured by sonography

•Sonography is a bedside test to visualize morphology of peripheral nerves at various segments including at the nerve root level.•The patients with ALS had smaller nerve diameters or areas in the peripheral nerves or nerve roots in the upper extremity than those of normal subjects.•Sonographic evaluation of cervical nerve roots might be more sensitive to detect nerve atrophy in ALS than peripheral nerves.

ObjectiveProgressive atrophy and loss of motor axons is a hallmark of amyotrophic lateral sclerosis (ALS). Limited sonographic data are available on potential detection of atrophy of peripheral nerves and nerve roots in ALS.MethodsPatients with either definite or probable ALS and control subjects underwent sonographic evaluation of the cervical roots (C5, C6, and C7) and peripheral nerves (median and ulnar nerves) on the right. These diameters and cross-sectional areas (C6, median, and ulnar nerves) were compared.ResultsThe diameters and cross-sectional areas were consistently smaller in ALS than in controls. No correlation was present between the sonographic parameters and the disease severity, disease duration, age, or gender. The overall sensitivity and specificity tended to be greater in the cervical nerve roots than in the peripheral nerves.ConclusionsThis study shows atrophy of cervical nerve roots and peripheral nerves in ALS detected by sonography. Cervical nerve roots might be more appropriate to detect motor axon loss than peripheral nerves.SignificanceSonographic evaluation of nerve roots and peripheral nerves may be a useful disease marker in ALS to confirm the diagnosis and to potentially monitor the disease progression.