Funicular myelosis, also known as subacute combined degeneration (SCD) of the spinal cord, represents one of the most severe neurological complications of vitamin B12 deficiency. It is characterized by demyelination primarily affecting the posterior and lateral columns of the spinal cord, leading to sensory ataxia, spastic paraparesis, and proprioceptive loss. Although magnetic resonance imaging (MRI) often reveals characteristic T2 hyperintensities in the dorsal columns, early or mild cases may show normal imaging. Transcranial magnetic stimulation (TMS) provides a non-invasive, objective measure of central motor conduction time (CMCT) and corticospinal tract integrity. This pilot study investigated TMS parameters in 12 patients with confirmed severe vitamin B12 deficiency anemia and clinical/radiological evidence of funicular myelosis. At baseline, all patients exhibited markedly prolonged CMCT in the lower limbs, with milder abnormalities in the upper limbs. Following 3 months of intensive intramuscular hydroxocobalamin replacement therapy, significant improvement in CMCT was observed in 83% of cases, which correlated strongly with clinical recovery as measured by the modified Rankin Scale and Berg Balance Scale. These findings support the utility of TMS as an objective diagnostic and monitoring tool in B12-related myelopathy, particularly when MRI is inconclusive or clinical improvement lags behind biochemical correction.

transcranial magnetic stimulation, central motor conduction time, vitamin B12 deficiency, funicular myelosis, subacute combined degeneration, myelopathy, motor evoked potentials.

Bernetti, C., et al. (2025). A comprehensive overview of subacute combined degeneration: MRI, diagnostic challenges and treatment pathways. Brain Sciences, 15(9), Article 972. https://doi.org/10.3390/brainsci15090972

Di Lazzaro, V., Restuccia, D., Fogli, D., Nardone, R., Mazza, S., & Tonali, P. (1992). Central sensory and motor conduction in vitamin B12 deficiency. Electroencephalography and Clinical Neurophysiology, 84(5), 433–439. https://doi.org/10.1016/0168-5597(92)90009-6

Gürsoy, A. E., et al. (2013). Subacute combined degeneration of the spinal cord due to vitamin B12 deficiency. Journal of the Neurological Sciences, 325(1–2), 93–96. https://doi.org/10.1016/j.jns.2012.12.011

Hemmer, B., Glocker, F. X., Schumacher, M., Deuschl, G., & Lücking, C. H. (1998). Subacute combined degeneration: Clinical, electrophysiological, and magnetic resonance imaging findings. Journal of Neurology, Neurosurgery & Psychiatry, 65(6), 822–827. https://doi.org/10.1136/jnnp.65.6.822

Larner, A. J. (1997). MRI appearances in subacute combined degeneration of the spinal cord due to vitamin B12 deficiency. Journal of Neurology, Neurosurgery & Psychiatry, 62(1), 99–100.

Lanza, G., et al. (2022). A comprehensive review of transcranial magnetic stimulation in aging neuroscience. Frontiers in Aging Neuroscience, 14, Article 995000. https://doi.org/10.3389/fnagi.2022.995000

Misra, U. K., Kalita, J., & Das, A. (2003). Vitamin B12 deficiency neurological syndromes: A clinical, MRI and electrodiagnostic study. Electromyography and Clinical Neurophysiology, 43(1), 57–64.

Nardone, R., et al. (2014). Central motor conduction studies in patients with spinal cord disorders: A review. Spinal Cord, 52(8), 578–585. https://doi.org/10.1038/sc.2014.48

Rossi, S., Hallett, M., Rossini, P. M., Pascual-Leone, A., & Safety of TMS Consensus Group. (2009). Safety, ethical considerations, and application guidelines for the use of transcranial magnetic stimulation in clinical practice and research. Clinical Neurophysiology, 120(12), 2008–2039. https://doi.org/10.1016/j.clinph.2009.08.016

Wu, T., & Chu, N. (1996). Central motor conduction in patients with vitamin B12 deficiency. Journal of the Formosan Medical Association, 95(1), 50–54.

Gazkhanovna, M. A., Makhmatovich, A. K., & Utkirovich, D. U. (2022). Clinical efficacy of extracorporeal and intravascular hemocorrection methods in psoriasis. Academicia: An International Multidisciplinary Research Journal, 12(2), 313-318.

Madasheva, A. G., & Abdiev, K. M. (2023). Blood transfusion therapy in patients with vitamin B12 deficiency anemia after resection of 2/3 of the stomach. Science and Education, 4(5), 407-412.

Мадашева, А. Г., & Жураева, М. З. (2019). Биохимические показатели и комплексное лечение больных псориазом с лечебным плазмаферезом. Достижения науки и образования, (10 (51)), 78-82.

Мадашева, А., Бергер, И., Махмудова, А., Абдиев, К., & Амерова, Д. (2025). Лабораторная диагностика. восточная европа. лабораторная диагностика, 14(1), 87-96.

Мадашева, А. Г. (2022). Клинико-неврологические изменения у больных гемофилией с мышечными патологиями. Science and Education, 3(12), 175-181.

Мадашева, А. Г. (2022). Коррекция диффузной алопеции при железодефицитной анемии. Science and Education, 3(12), 231-236.

Мадашева, А. Г., Дадажанов, У. Д., Абдиев, К. М., Маматкулова, Ф. Х., & Махмудова, А. Д. (2019). Динамика электронейромиографических показателей и эффективность электрической стимуляции мышц у больных гемофилией с мышечными атрофиями. Достижения науки и образования, (10 (51)), 26-30.

Мадашева, А. Г., & Жураева, М. З. (2019). Биохимические показатели и комплексное лечение больных псориазом с лечебным плазмаферезом. Достижения науки и образования, (10 (51)), 78-82.