Table 1.

Overall patients’ characteristics.

Age at symptom onset, years, mean (SD)	44.1 (14.5)
Time from symptom onset to diagnosis, months, mean (SD)	53.3 (59.2)
Female, n (%)	154 (75.1)
Race, n (%) White Black Asian Other	135 (65.9) 51 (24.9) 5 (2.4) 8 (3.9)
Ethnicity, n (%) Hispanic	10 (4.9)
GAD-65 antibody status Serum positive, n (%) Titer IU/mL, mean (SD) CSF positive, n (% of tested)	175 (86) 171094 (583353) 52 (59.8)
Other SPSD antibody status Glycine serum positive, n (% of tested) Amphiphysin serum positive, n (%)	11 (5.4) 7 (3.4)
SPSD phenotype, n (%) Classic SPS SPS-plus Partial SPS Pure CA PERM Possible SPS	135 (66) 36 (18) 8 (4) 6 (3) 12 (6) 8 (4)

SD = standard deviation; GAD-65 = glutamic acid decarboxylase-65; IU/mL, international units/milliliter; SPSD, stiff person spectrum disorder; SPS, stiff person syndrome; CA, cerebellar ataxia; PERM, progressive encephalomyelitis with rigidity and myoclonus.