Preoperative Functional Imaging Predicts Deep Brain Stimulation Outcome in Craniocervical Dystonia

Deep brain stimulation (DBS) is an established treatment for craniocervical dystonia (CCD), yet postoperative benefit varies widely and cannot be estimated before surgery. Resting-state functional MRI (rs-fMRI) has shown prognostic value across DBS indications. The objective of this study was to develop and externally validate preoperative rs-fMRI models estimating DBS response in CCD.

Forty-two patients from two independent centers underwent preoperative 3 T rs-fMRI (discovery, n = 26; validation, n = 16). Using 12 literature-informed, symptom-relevant regions of interest, we quantified the amplitude of low-frequency fluctuation as a measure of intrinsic regional neural activity. We applied regularized modeling to classify super-responders, distinguish responders from non-responders, and estimate improvement in Burke-Fahn-Marsden Dystonia Rating Scale motor subscore.

When applied to the validation cohort, the imaging models achieved a three-category classification accuracy of 75.0% (50.5%-89.8%) using a sequential two-step procedure (P_perm = 0.002). Predicted continuous improvement was also correlated with empirical improvement (R_ext = 0.65, Q² = 0.34, P_perm = 0.004). Within the discovery cohort, nested leave-one-out-cross-validation, in which feature selection and decision-threshold derivation were repeated independently within each training fold, yielded areas under the curve (AUCs) of 0.73 (0.50-0.96) and 0.77 (0.51-1.00). Across models, baseline primary motor cortex activity was consistently associated with diminished postoperative benefit.

Preoperative rs-fMRI captures clinically relevant variation in baseline brain state in CCD, with predictive performance supported in an external validation. These findings provide preliminary support for rs-fMRI as a potential source of information to aid patient counseling and clinical decision-making, pending prospective validation. © 2026 International Parkinson and Movement Disorder Society.