Neurological Soft Signs at Presentation in Patients With Pediatric Acute-Onset Neuropsychiatric Syndrome.

Importance: Studies of brain imaging and movements during rapid eye movement sleep indicate basal ganglia involvement in pediatric acute-onset neuropsychiatric syndrome (PANS). Characterizing neurological findings that commonly present among patients with PANS could improve diagnostic accuracy. Objectives: To evaluate the prevalence of neurological soft signs (NSSs) that may be associated with basal ganglia dysfunction among youths presenting with PANS and assess whether clinical characteristics of PANS correlate with NSSs that may be associated with basal ganglia dysfunction. Design, Setting, and Participants: This cohort study included 135 new patients who met strict PANS criteria and were evaluated at the Stanford Children's Immune Behavioral Health Clinic between November 1, 2014, and March 1, 2020. Data on these patients were retrospectively reviewed between December 13, 2020, and September 25, 2023. Sixteen patients were excluded because they had no neurological examination within the first 3 visits and within 3 months of clinical presentation. Statistical analysis was conducted between September 26, 2023, and November 22, 2024. Main Outcomes and Measures: The following NSSs that may be associated with basal ganglia dysfunction were recorded from medical record review: (1) glabellar tap reflex, (2) tongue movements, (3) milkmaid's grip, (4) choreiform movements, (5) spooning, and (6) overflow movements. Data from prospectively collected symptoms and impairment scales (Global Impairment Score [GIS; score range, 1-100, with higher scores indicating greater impairment] and Caregiver Burden Inventory [score range, 0-96, with higher scores indicating greater caregiver burden]) were included. Results: The study included 119 patients; the mean (SD) age at PANS onset was 8.2 (3.6) years, the mean (SD) age at initial presentation was 10.4 (3.6) years, and 66 (55.5%) were boys. At least 1 NSS that may be associated with basal ganglia dysfunction was observed in 95 patients (79.8%); the mean (SD) number of NSSs was 2.1 (1.6). Patients with 4 or more NSSs had higher GISs (mean [SD] score, 56.0 [22.6] vs 40.6 [26.7]; P = .05) and more symptoms (mean [SD] number, 15.1 [4.9] vs 11.5 [4.2]; P = .008) than patients with 0 NSSs. There was no significant difference in age at visit or in Caregiver Burden Inventory score. On Poisson and linear regression, the number of NSSs was associated with global impairment, with 1 more sign increasing the GIS by 2.86 (95% CI, 0.09-5.62; P = .04), and with the number of symptoms, with 1 more sign increasing the number of symptoms by 5% (1.05; 95% CI, 1.02-1.08; P = .002), but not with age or duration of PANS at presentation. Conclusions and Relevance: This cohort study of patients with PANS found a high prevalence of NSSs that may be associated with basal ganglia dysfunction and an association between these NSSs and disease severity that was not associated with younger age. PANS may have a unique profile, suggesting that targeted neurological examinations may support PANS diagnosis.