“Motor Band Sign” Seen in Motor Neuron Disease
Authors
Varsha PatilFiles
Key Information
Journal
Published in Vol. 68 No. 1 (2026) of Bombay Hospital Journal.
Bombay Hospital Journal (BHJ) is a peer-reviewed quarterly published Print and Online journal. It is an official Journal of Bombay Hospital institute of medical sciences. The aim of BHJ is to improve medical care by publishing sound scientific articles (both research and practice papers) and focusing on topics that are of great importance to its readership.
Editor-in-Chief- Dr Satish Vasant Khadilkar
About the JournalAbstract
Introduction: The “motor band sign” is an emerging magnetic resonance imaging (MRI) feature of upper motor neuron degeneration
in motor neuron diseases. It appears as a curvilinear hypointensity along the primary motor cortex on iron-sensitive sequences
such as susceptibility-weighted imaging (SWI). Case Report: A 62-year-old male presented with a 3-year history of progressive
gait disturbance, trivial falls, and dysarthria, followed by difficulty rising from a chair over six months. Examination revealed
spastic dysarthria, upper motor neuron signs, and proximal lower-limb weakness. MRI brain demonstrated symmetric curvilinear
hypointensity along the bilateral precentral gyri on SWI and GRE sequences, consistent with the motor band sign. Electrodiagnostic
studies did not show lower motor neuron involvement, supporting a diagnosis of primary lateral sclerosis. Discussion: The motor
band sign represents abnormal iron deposition within the deep cortical layers of the precentral gyrus due to neurodegeneration and
microglial activation. It is best detected using susceptibility-sensitive sequences such as SWI and GRE. Conclusion: Recognition
of the motor band sign on MRI may assist in the identification of motor neuron disease, particularly when conventional imaging is
otherwise unremarkable.
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