Cognitive reappraisal training as an intervention in patients with functional movement disorders: a placebo-controlled EEG pilot study.

Functional movement disorders (FMD) are common and disabling neurological conditions characterized by impaired voluntary motor control in the absence of structural disease. Accumulating evidence suggests that emotion regulation deficits contribute to the pathophysiology of FMD. This randomized, placebo-controlled pilot study investigated the clinical and neural effects of a digital cognitive reappraisal training program in patients with FMD, targeting emotion regulation as a potential therapeutic mechanism. Twenty adult patients diagnosed with clinically definite FMD (mean age = 50.7 years, 11 females) were randomly assigned in a 1:1 ratio to either an intervention group practicing cognitive reappraisal (n = 11) or an active control group completing reflection exercises (n = 9). Both groups underwent 14 brief, app-based training sessions over four weeks. Clinical outcomes were assessed before and after the intervention using standardized measures of mood, motor function, and overall illness severity. Simultaneously, brain activity at rest and during a standardized reappraisal task was recorded via electroencephalography, focusing on prefrontal alpha asymmetry as a neural marker of reappraisal engagement. Compared to the control group, the intervention group showed significantly greater improvements in mood (Mdiff = 0.542, p = .010), motor function (Mdiff = 0.542, p = .033), and overall illness severity (Mdiff = 0.528, p = .040). Both groups improved over time in mood (p = .030), tremor severity (p = .014), and subjectively rated motor function (p = .022), suggesting non-specific benefits of structured emotional self-reflection. Crucially, electroencephalography data revealed a significant post-training increase in right-lateralized frontopolar resting-state activity in the intervention group (Mdiff = 13.29, p = .026), aligning with prior evidence linking right prefrontal activity to successful reappraisal. Although task-related EEG activity did not differ significantly between groups, a statistical trend (p = .115, d = 1.14) suggests increased right frontal activity during reappraisal generation in the intervention group. Reappraisal training performance correlated with EEG changes and with the frequent use of the distancing strategy "relativizing," implicating right prefrontal involvement in specific cognitive control processes. These findings provide preliminary evidence that cognitive reappraisal training delivered via mobile app is feasible and may enhance both clinical outcomes and prefrontal brain function in FMD. Future studies with larger samples are needed to confirm these effects and better understand the neural mechanisms of digital interventions for emotion regulation in functional neurological disorders.