This study evaluates whether remotely measured daily activity behavior, captured through a thigh-worn accelerometer, can serve as a reliable and ecologically valid indicator of symptom impact in individuals with Functional Neurologic Disorder (FND). Current clinician-rated assessments capture only a single time point and do not reflect day-to-day symptom variability or functional impact. The study will (1) assess the feasibility of continuous activity monitoring in people with FND, (2) examine associations between activity behavior and established clinician- and patient-reported FND measures, and (3) qualitatively explore participants' lived experiences of daily activity. Findings aim to address a critical gap in understanding real-world function in this heterogeneous population.

Specific Aim 1:

Evaluate the feasibility of remotely assessed activity behavior with thigh-mounted accelerometry in 20 individuals with FND.

The feasibility of remotely assessed activity behavior in participants with FND will be determined based on: 1) enrollment of 20 participants with FND within 10 months, 2) ≥90% adherence to thigh-mounted accelerometer use based on wear time of ≥ 5 days, 3) retaining ≥90% participants with FND at Visit 2, and 4) ≥90% acceptability calculated as the proportion of participants with a response of 'somewhat agree' or better on a 7-point Likert scale asking about acceptability of the study procedures.

Specific Aim 2:

Determine differences in activity behaviors between people with functional neurologic disorder and healthy controls (CTL) over 7-10 days.

Physical activity will be measured by an accelerometer-based activity monitor (activPAL4, PAL Technologies). The thigh-mounted activPAL will be worn continuously for 7 days between visit 1 and visit 2. Primary variables of interest will include mean daily step count, total sedentary time, bouts of sedentary time > 30 min, and number of transitions to standing, and time standing and stepping in order to capture a full picture of free-living mobility and activity.

Specific Aim 3:

Explore the lived experiences of activity behavior in people with FND. Approach: Conduct individual, semi-structured interviews to explore the impact of FND symptoms on activity behavior and integrate these findings with quantitative activity measures to understand the influence on real-world activity.

Aim 3: The lived experience of activity behavior for people with FND will be assessed using a mixed-methods approach. Qualitative data will be analyzed using thematic analysis with deductive and inductive coding to develop qualitative interview themes. Quantitative activity behavior and qualitative interview data will be analyzed together to develop a more comprehensive understanding of the impact of FND on activity behavior.

Inclusion Criteria:

Participants with FND:

•Neurologist-confirmed diagnosis of functional neurologic disorder with motor symptoms, sensory symptoms, dizziness, and/or seizures

Healthy Controls:

• Roughly matched to participants with FND for age and sex
• Free from major disease that affects mobility (e.g., neurologic, movement, cardiac, pulmonary, renal, and psychiatric disorders) by history.

Exclusion Criteria:

Participants with FND

• Physical or cognitive symptoms impairing ability to engage with the protocol (e.g., seizure frequency > 10/day).
• Diagnosis of other major neurologic, cardiovascular, musculoskeletal, or psychiatric disorder that affects mobility as determined by the principal investigator

Participants will be recruited at the University of Colorado Hospital outpatient physical therapy department and the Functional Neurologic Disorder Clinic at the University of Colorado.

There is not an IPD plan for this study.