Creating a Patient-Based Diagnostic Checklist for Functional Tics During the COVID-19 Pandemic

Background and Objectives: Since the onset of the COVID-19 pandemic, there has been a dramatic change in the presentation of patients with tics. The explosive presentation of atypical tics has been noted worldwide and thought to be the manifestation of a pandemic-associated functional neurological disorder following social media exposure to tics. Nevertheless, despite the frequent diagnosis of functional tics, there is no existing formal diagnostic criteria. The primary aim of this study was to create a patient-based diagnostic checklist for making the diagnosis of a functional tic disorder during the COVID-19 pandemic.

Methods: A retrospective chart review at a single institution during the pandemic was performed. Based on available literature, diagnostic criteria were created for typical tics, functional tics, and patients with dramatically evolving symptoms (i.e., ‘mixed’ with prior history of mild tics with later fulminant functional worsening). Patient demographics, comorbidities, and tic characteristics of these groups were then compared. Following initial assessments, new diagnostic criteria were established and statistically reanalyzed.

Results: 198 patients underwent investigation. Significant differences in age, sex, psychological comorbidities, tic characteristics, and tic severity were found between patients with typical tics when compared to either of the two the functional groups. Only the presence of rostrocaudal progression and increased obsessive-compulsive behaviors were significantly different between patients with new onset functional tics and those with functional worsening of a previous tic disorder. Results also showed that age of tic onset was not a contributing factor for group differentiation. Many patients with functional tics were not exposed to videos depicting tics on social media.

Discussion: This study confirms the presence of a distinct presentation of atypical tics during the pandemic period. It further establishes the validity of specific criteria useful in dividing patients with tics into three formal diagnostic criteria: 1) primary tic disorders; 2) a strictly functional tic disorder; and 3) a mixed tic disorder consisting of patients with an initial history of a primary tic disorder and the later development of functional tics. Explicit diagnostic criteria should enable clinicians and researchers to make a definitive identification and assist patients and families become more knowledgeable and accepting of the diagnosis of functional tics.