Long-term stability of visual processing abnormalities in cervical dystonia: A 5-year follow-up study

Cervical dystonia (CD) is a network disorder with non-motor manifestations, including visuocognitive and oculomotor deficits that remain underexplored.

To characterize the longitudinal stability of motor, cognitive, oculomotor, and visuocognitive performance in patients with isolated CD over long-term follow-up during botulinum toxin type A (BoNT-A) treatment.

Twenty-one patients were assessed at baseline (E1) and after 5.84 ± 1.93 years (E2), outside the BoNT-A effect period, using TWSTRS, MMSE, Trail Making Test (TMT), Useful Field of View (UFOV®), and oculomotor testing. Effect sizes, confidence intervals, and false discovery rate (FDR) corrections were computed.

Motor severity (TWSTRS total, raw p = 0.69, adjusted p = 0.81), global cognition, executive function, processing speed, divided attention, and oculomotor measures remained unchanged. Selective attention (UFOV®-3) showed improvement in raw analysis (p = 0.016), but did not remain significant after FDR correction (adjusted p = 0.160). Changes in motor severity were not associated with visuocognitive changes.

Visuocognitive function in isolated CD showed no substantial longitudinal decline, supporting the concept that visuocognitive abnormalities represent stable non-motor features. Given the small sample size, these findings should be regarded as preliminary.