To characterize the frequency of respiratory symptoms with spasms (RSwS), to identify if RSwS correlate with other body region involvement, and to assess spirometry patterns in a large stiff person syndrome (SPS) cohort.

SPS-spectrum disorders are characterized by progressive onset of painful spasms and rigidity throughout different body regions, thus reducing mobility and quality of life. Cases of sudden death in SPS have been associated with apnea and acute respiratory failure, however there is limited data on the prevalence of RSwS in SPS and on the spirometry patterns seen in this disorder as part of routine clinical care.

Participants were recruited from the Johns Hopkins SPS Center as part of our ongoing longitudinal observational study. Medical records were retrospectively reviewed to assess patient-reported symptoms and spirometry results. Analyses were performed using descriptive statistics, analysis of variance, and chi-squared tests.

Our SPS cohort of 211 patients were 52.1 + 14.1 years old, had a disease duration of 9.6 + 7.4 years, and 73.5% were female. RSwS were reported in 34% of patients and 12.4% underwent spirometry as part of their routine care. Spirometry patterns included: 32% obstructive, 24% normal, 20% restrictive, 16% unknown, 4% neuromuscular weakness, and 4% abnormal unspecified. RSwS were positively correlated with other symptoms such as torso rigidity/stiffness (p=<0.001), back spasms (p=<0.001), neck stiffness/spasms (p=<0.001), facial spasms (p=<0.001), abdominal stiffness/spasms (p=<0.001), and lower (p=0.003) and upper (p=<0.001) extremity spasms. No associations were found between RSwS and ambulatory status, modified rankin scale score, or timed 25-foot walk.

RSwS are common in SPS and are associated with spasms/stiffness of other body regions. Despite the frequency of these symptoms, spirometry is infrequently obtained as part of SPS routine clinical care. Therefore, spirometry should be considered in patients with RSwS and higher disease burden, since apnea and acute respiratory failure can occur.