Table 1.

Clinical Characteristics of Patients With Low-Titer and High-Titer GAD65 Antibodies

Clinical characteristic	Low-titer GAD65 Antibodies (n = 6)	High-titer GAD65 Antibodies (n = 24)	p Value
Female (%)	3 (50)	20 (83)	0.12
Age at onset, y, median (range)	43.5 (26 to 83)	52.5 (23 to 71)	0.42
Time from symptom onset to diagnosis, mo, median (range)	2.5 (2 to 48)	13 (1 to 96)	0.01
Clinical phenotype (%)			1.00
Classic SPS	4 (67)	17 (71)
SLS	2 (33)	7 (29)
PERM	0 (0)	0 (0)
Type 1 DM (%)	3 (50)	10 (42)	0.53
Other autoimmune diseases (%)	1 (17)	10 (42)	0.26
Malignancy (%)	2 (33)	2 (8)	0.17
Lack of antagonist inhibition on EMGa	5/5 (100)	8/10 (80)	0.43
CSF pleocytosis	0/6 (0)	2/16 (13)	0.52
Elevated CSF protein	2/5 (29)	3/15 (20)	0.37
mRS at baseline, median (range)	3.5 (2 to 4)	4 (1 to 5)	0.15
Follow-up period, m, median (range)	47 (2 to 120)	44 (15 to 192)	0.98
mRS at the last follow-up, median (range)	2.5 (0 to 6)	2 (0 to 4)	0.56
Change in mRS, median (range)	0.5 (−2 to 2)	2 (0 to 5)	0.09

Abbreviations: DM = diabetes mellitus; GAD65 = glutamic acid decarboxylase 65; mRS = modified Rankin Scale; PERM = progressive encephalomyelitis with rigidity and myoclonus; SLS = stiff-limb syndrome.

^aLack of antagonist inhibition on EMG is defined by the continuous co-contraction of agonist and antagonist muscles (with inability to relax) as confirmed by EMG.