Case presentation:

A 72-year-old woman was evaluated at the outpatient EMG clinic, Royal Stoke University Hospital, in December 2025 for a two-year history of progressive neck weakness and marked head drop. Her medical background included hiatus hernia, chronic obstructive pulmonary disease, and vertigo. She was referred to exclude motor neuron disease or myasthenia gravis. Neurological examination revealed severe weakness of neck extension (MRC 2/5) with preserved flexion, normal limb strength, reflexes, and sensation, and no bulbar or ocular involvement. Serum creatine kinase was normal, and both anti-acetylcholine receptor and anti-MuSK antibodies were negative. Cervical spine MRI (December 2024) demonstrated moderate bilateral C5–C6 foraminal stenosis and degenerative changes between C3 and C7 without canal stenosis or myelopathy.
Nerve conduction studies showed absent motor and sensory responses in the lower limbs, attributed to significant peripheral oedema, with normal upper-limb motor and sensory responses. Needle electromyography revealed short-duration, low-amplitude, polyphasic motor unit potentials with early recruitment and mild spontaneous activity confined to the right cervical paraspinal muscles. Electromyography of biceps, extensor digitorum communis, first dorsal interosseous, genioglossus, thoracic paraspinals, trapezius, deltoid, tibialis anterior, and medial gastrocnemius was normal. Repetitive nerve stimulation showed no decremental response, and single-fiber EMG of the right frontalis demonstrated normal jitter, excluding a neuromuscular junction disorder. These findings established the diagnosis of isolated neck extensor myopathy (NEM), with selective myopathic involvement of the cervical extensors and normal bulbar and limb muscles. Management included cervical physiotherapy, postural training, and supportive collar use, leading to partial improvement and functional stabilization.
Dropped head syndrome (DHS) is characterized by weakness of posterior cervical muscles, producing a “chin-on-chest” posture that improves when supine. Its differential diagnosis includes inflammatory myopathies, myasthenia gravis, motor neuron disease, dystrophic and genetic myopathies, Parkinson’s disease, chronic inflammatory polyradiculoneuropathy, and secondary or metabolic causes. Isolated NEM represents a rare, often non-progressive myopathic disorder confined to cervical extensors, possibly reflecting idiopathic or age-related focal muscle degeneration. Recognition of this electrophysiological pattern—myopathic motor unit potentials restricted to neck extensors with sparing of limb and bulbar muscles—is crucial to avoid misdiagnosis as neurogenic or neuromuscular junction disease. This case highlights the pivotal diagnostic role of targeted EMG in differentiating NEM from other causes of DHS and guiding conservative management.