This study aims to bring the importance of paroxysmal stereotypic sub-axial cervical spinal movement disorder in diagnosing Neuromyelitis Optica Spectrum Disorder

Neuromyelitis Optica spectrum disorder (NMOSD) is a demyelinating disease that has classic symptoms of optic neuritis, myelitis, and autoantibody to aquaporin-4 (AQP4) water channel, though broad variety of manifestations have been recognized.

This is a case series of seven patients presented with sub axial cervical long segment demyelination between October 2025 to January 2026 enrolled after informed consent. Morbidity by Modified Rankin Scale (mRS) was noted at admission and discharge.

Among the 7 patients of demyelination, 2 (28.5%) were multiple sclerosis, 3 (42.8%) were NMOSD, and 2 (28.5%) were seronegative immune-mediated.

Clinical features of motor weakness are present in all cases. Optic neuritis only in 1 case of NMOSD. Among NMOSD, all 3 (100%) had painful tonic spasm at a mean duration of 18 days

Mean CSF protein among NMOSD was the least, with 79, for MS was 126, and for seronegative it was 135.5.

Serum aquaporin 4 was positive in all 3 NMOSD, and OCB was positive among 2 multiple sclerosis patients. 

Imaging showed all 3 of NMOSD (100%) had sub axial cervical involvement. 2 of MS (100%) showed short-segment sub axial involvement. Optic neuritis and brain involvement are present in 1 among both the MS and NMOSD groups.

Mean MRS at admission was 4, and at discharge was 3 among NMOSD, whereas mean MRS was 4.5 among MS at admission and at discharge was 3.5.

All 3 seropositive NMOSD patients had both long-segment cervical demyelination as well as tonic spasms at a mean period of 18 days. The other 4, who have cervical demyelination, did not have spasms or Aquaporin 4 positive. Hence combination of sub axial cervical demyelination with tonic spasms had high diagnostic significance