Table 1.

Clinical and laboratory features of patients with stiff person syndrome spectrum disorders who received formal cognitive testing as part of routine clinical care for patient-reported cognitive changes.

Patient number	Baseline characteristics							Cognitive testing results
	Age at testing	Years with SPSf	SPS phenotypes	Anti GAD-65 titer	Relevant medical comorbidities	Psychiatric comorbiditiesa	Psychoactive and immune-based medications	Areas of impairment	Psychiatric symptoms g
1	59	2	GAD+SPS Cerebellar predominant	63,525 IU/mL	Vitiligo B12 deficiency Remote Intestinal Ca Remote Testicular Ca	None	Clonazepam	Processing speed Verbal phonemic fluency	GDS-15: 8/15 NPI-Q: agitation, depression, apathy, irritability, nighttime behaviors, appetitive changes
2	39	<1	GAD -SPS	39 U/mL e	T2DM B12 deficiency Vit D deficiency Narcolepsy Small fiber neuropathy Mild OSA	Depression Anxiety PTSD ADHD	Oxymorphone Oxycodone Pregabalin Metaxalone Baclofen Clonazepam Alprazolam Armodafinil Certirizine	No areas of impairment	PHQ-9 = 15 (moderately severe depressive symptoms)
3	74	8	GAD+SPS Cerebellar predominant	6.3 U/mL	Coronary artery disease	Depression	IVIG Duloxetine	Verbal learning and recall Motor speed Executive function (Set-shifting) Processing speed Verbal phonemic fluency	BAI 8 (minimal anxiety) PHQ-9 = 0 (no symptoms)
4	22	2	GAD+SPS	30 U/mL	Hypothyroidism Sickle cell anemia Asthma CVA partial seizures	Generalized anxiety disorder b Major depressive disorder, recurrent, moderate b Adjustment disorder due to medical condition b	Baclofen Diazepam Benzonatate Diphenhydramine	Executive functioning (inhibition) Attention Verbal phonemic fluency Verbal recall Motor speed	PAI: severe depressive symptoms
5	60	8	GAD-Possible SPS	Not available	B12 deficiency Vit D deficiency Ankylosing spondylitis Hypertension OSA	None	Clonazepam Methotrexate Bupropion Tramadol	Verbal recall	Not assessed
6	29	17	GAD+SPS	250 IU/mL	Hypothyroidism Primary Immune deficiency Orthostatic hypotension Crohn's disease Chiari Malformation	None	Adalimumab Tacrolimus Clonidine Duloxetine Modafinil Prednisone Topriamate	Verbal learning and recall Executive functioning (set shifting) Attention Verbal phonemic fluency Verbal semantic fluency Working memory	Not assessed
7	54	12	GAD+SPS	21,888 U/mL	SLE	Depression Anxiety	Baclofen Diazepam Clonazepam IVIG Duloxetine Buspirone Doxylamine Melatonin	Verbal phonemic fluency Visual recall Executive function (set shifting) Attention Processing speed	BDI: 29 (moderate depression) PAI: significant depression and anxiety
8	43	6	GAD+SPS Plus	25,000 U/mL	Insulin dependent diabetes Epilepsy, sickle cell trait, migraines	None	Clonazepam Cyclobenzaprine Lacosamide Levitracetam Oxycodone	Language (verbal and reading comprehension, naming, spelling) Visual learning and recall	PAI: significant anxiety
9	36	4	GAD+SPS	320 IU/mL	Neuropathy Migraine	Anxiety Depression PTSD	Baclofen IVIG Clonazepam Diazepam Gabapentin Paroxetine	Verbal phonemic fluency Verbal semantic fluency Verbal recall Motor speed	PAI: significant anxiety, depression, anxiety related to past trauma and stress
10	59	20	GAD-Possible SPS	Not available	Cervical stenosis Migraines	None	Carbamazepine Tizanidine	Verbal recallc	Not assessed
11	49	12	GAD+SPS	117 IU/mL	None	Major Depressive Disorder, recurrent b	Baclofen Bupropion Buspirone Clonazepam Diazepam IVIG Rituximab	Processing speed Attention Verbal recall Visuospatial judgement	Not assessed
12	59	3	GAD+SPS	615 nmol/L	None	Paranoid schizophreniab	Fluoxetine Levitracitam Diazepam Olanzapine Memantine	Verbal learning and recall c Visual learning and recall Language (expression) Verbal phonemic fluency Motor speed Executive function (inhibition) Processing speed	BDI and BAI within normal limits (score not reported)
13	49	24	GAD+SPS	207,650 U/mL	Diabetes Mellitus Epilepsy (s/p temporal lobectomy) Hypothyroidism Pernicious anemia SLE	None	Baclofen Diazepam Lacosamide Levetiracetam Pregabalin	Processing speed Executive function (Set shifting) Verbal learning and recall Language (naming) Verbal phonemic fluency	PHQ-9 = 7 (mild depression) GAD-7 = 12 (moderate anxiety)
14	54	22	GAD+SPS	6.6 U/mL	Insomnia Postural orthostatic tachycardia syndrome Migraines	Generalized anxiety disorderb Major depressive disorderb	Doxepin SCIG Pregabalin	Processing speedc Verbal semantic fluency	PHQ-9 = 27 (severe depression) GAD-7 = 19 (severe anxiety)
15	45	9	GAD+SPS	213 IU/mL	Tublerculosis (1 yo) Coronary artery disease Dyslipidemia HTN Hypothyroidism	None	Clonazepam Diazepam Hydralazine IVIG	Verbal recall Verbal semantic fluency Executive functioning (Set-shifting) Processing speed Motor speed	Not assessed
16	45	23	GAD+SPS	174.2 U/mL	Anemia Anticardiolipin antibody positive T1DM Hepatitis Rheumatoid arthritis SLE	Major depressive disorder Anxiety	IVIG Baclofen Clonazepam Escitalopram Prednisone	Attentiond Verbal learning and recall Visual learning and recall	Not assessed
17	41	9	GAD+SPS	174.2 U/mL	Dysautonomia Idiopathic small fiber sensory neuropathy T1DM	None	Baclofen Clonazepam Diazepam Pregabalin Modafinil Oxycodone Roxicodone Paroxetine IVIG Tizanidine	Verbal phonemic fluency Motor speed	GAD-7 = 1 PHQ-9 = 19
18	41	3	GAD+SPS	53,650 U/mL	Anemia (iron deficiency) Eczema Asthma Seizures	Anxiety	Baclofen Diazepam Mirtazapine	Attentiond Visuospatial skills Verbal phonemic fluency Verbal learning and recall	Not assessed
19	33	7	GAD+SPS	34 IU/mL	Seizures Ataxia Nystagmus	None	Baclofen Escitalopram IVIG Levetiracetam Rituximab	Attentiond Verbal phonemic fluency Verbal recall Visual recall Visuospatial skills	Not assessed
20	56	1	GAD+SPS	Not available	SLE Psoriatic arthritis T1DM B12 deficiency Autoimmune thyroiditis Hypertension Sjogren's syndrome	Depression	Amlodipine Apremilast Diazepam Escitalopram Estradiol Clonazepam	Attention Verbal phonemic fluency Verbal recall Motor speed	Not assessed

^aPsychiatric diagnoses are based only on patient report unless noted otherwise;

^bpsychiatric diagnoses confirmed by psychiatric or psychologist notes;

^cno raw score or percentiles from neuropsychological batteries were reported for these patients. Domains of impairment were only based on testing interpretation summary;

^donly results of Repeatable Battery for Assessment of Neuropsychological Status (RBANS) completed by a Speech and Language Pathologist available;

^eWhile this patient had one positive anti-GAD65 antibody test, at the time closest to neuropsychological testing, prior and subsequent tests have been negative, thus categorization of phenotype is GAD-;

^fduration of illness calculated from time of symptom onset to time of cognitive testing;

^gPsychiatric symptoms were considered clinically significant based on previously established cut-offs of >9 for the Generalized Anxiety Disorder Assessment (GAD-7) (14) and >4 for the Patient Health Questionnaire-9 (PHQ-9) (15), >9 for Beck Depression Inventory (BDI) (16), >7 for the Beck Anxiety Inventory (BAI) (17). For individuals whose psychiatric symptoms were only assessed using the PAI, clinically significant symptoms were identified based on interpretation in the neuropsychiatric report. GAD -, anti-glutamic acid decarboxylase antibody negative; GAD +, anti-glutamic acid decarboxylase antibody positive; SLE, systemic lupus erythematosus; T1DM, type 1 diabetes; OSA, Obstructive Sleep Apnea; PTSD, Post-traumatic stress disorder; ADHD, Attention Deficit Hyperactivity Disorder; CVA, Cerebrovascular accident; Ca, Cancer; s/p, status-post; IVIG= Intravenous immunoglobulin; SCIG= Subcutaneous immunoglobulin; NPI-Q, Neuropsychiatric Inventory – Questionnaire (18); PHQ-9, Patient health questionnaire-9 (15); GAD-7, Generalized anxiety disorder-7 (14); PAI, Personality assessment inventory (19); BDI, Beck depression inventory (16); BAI, Beck anxiety inventory (17).