Objective: Locked-in syndrome is a syndrome that is characterized by the lack of an adequate response of the patient to external, including verbal, stimuli due to tetraplegia and paralysis of the bulbar, facial and masticatory muscles. Stiff-man syndrome, stiff-trunk syndrome – an extremely rare neurological syndrome of unclear etiology, in which the patient has an increase in general muscle stiffness (increased muscle tone, painful spasms. Sleep paralysis is one of the most common forms of parasomnia associated with REM sleep, found in patients by neurologists, and occurs when REM muscle atony extends into the period of awakening or falling asleep.

Background: It is the presence of the autoimmune nature of the rigid person syndrome that determines its difference in differential diagnosis from the other two diseases.

Method: Under our observation there were 2 patients suffering from the locked-in personality syndrome. At the same time, the diagnostic search included a choice between stiff person syndrome, locked-in syndrome, and sleep paralysis. The presence of glutamic acid decarboxylase (GAD) antibodies in both patients confirmed the high probability of having stiff person syndrome. We reproduced this syndrome in 12 white mice by intracerebral injection of anti-GAD antibodies precipitated from the blood of our patients.

Results: In 10 patients with locked-in syndrome and 8 patients with sleep paralysis, these antibodies were not detected. After a 3-fold injection, these animals developed general muscle stiffness, increased muscle tone.

Conclusion: Thus, the presence of anti-GAD antibodies is a diagnostic criterion for stiff-person syndrome, which is confirmed by the reproduction of this syndrome in experimental models.

References: 1. Darras BT, Jones Jr HR, Ryan MM (2014). Neuromuscular Disorders of Infancy, Childhood, and Adolescence. Elsevier Science. p. 188. ISBN 978-0-12-417127-5. The stiff-man syndrome (SMS, also known as stiff-person syndrome) is a rare central nervous system autoimmune disease, but is likely underrecognized.
2. ^ Jump up to:a b “Stiff-Person Syndrome | National Institute of Neurological Disorders and Stroke”. www.ninds.nih.gov. Retrieved 2023-01-18.
3. ^ “Stiff person syndrome – About the Disease – Genetic and Rare Diseases Information Center”. rarediseases.info.nih.gov. Retrieved 2023-01-18.
4. ^ Muranova A, Shanina E (Jul 18, 2022). “Stiff Person Syndrome”. StatPearls. Treasure Island, FL: StatPearls Publishing. PMID 34424651. Retrieved Jan 18, 2023.

« Back to 2023 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/stiff-person-syndrome-diagnosis-and-experimental-models/