# Efficacy of Madopar and trihexyphenidyl combination therapy for dystonia in children with cerebral palsy

## TL;DR

Combining Madopar and trihexyphenidyl improves dystonia and quality of life in children with cerebral palsy more than using trihexyphenidyl alone.

## Contribution

Demonstrates that combining Madopar and trihexyphenidyl overcomes the plateau effect of monotherapy in treating dystonia in cerebral palsy.

## Key findings

- Combination therapy reduced dystonia severity more than trihexyphenidyl alone at 16 weeks.
- Combination therapy improved motor function, upper limb skills, and quality of life significantly more.
- Parents reported higher improvements in daily activities and ease of care with combination therapy.

## Abstract

Dystonia is a predominant and debilitating movement disorder associated with dyskinetic cerebral palsy (DCP). Although trihexyphenidyl (THP) is commonly used as a treatment, its efficacy often exhibits a plateau effect. The combination of dopaminergic and anticholinergic agents represents a rational therapeutic strategy; however, robust evidence for the combination of Madopar (levodopa/benserazide) and THP is lacking.

This retrospective cohort study compared THP monotherapy (n = 25) with combined Madopar + THP therapy (n = 24) in children with DCP and dystonia. Propensity score matching was used to balance the baseline characteristics. Various outcomes were analyzed at baseline and at both 8 and 16 weeks, including the Barry-Albright Dystonia Scale (BADS), Gross Motor Function Measure-88 (GMFM-88), Quality of Upper Extremity Skills Test (QUEST), and Cerebral Palsy Quality of Life Questionnaire (CP-QOL) measures. Parent-reported improvements in daily activities, drooling, speech, and sleep were also analyzed.

Compared with the THP group, the Madopar + THP group demonstrated significantly greater reductions in dystonia severity at both 8 and 16 weeks (mean BADS change: −5.25 ± 1.45 vs. −2.52 ± 1.36 at 16 weeks, p < 0.001). Superior improvements were also observed in gross motor function (GMFM-88: 14.29 ± 3.39 vs. 8.56 ± 2.29), upper limb function (QUEST: 6.33 ± 1.43 vs. 3.24 ± 1.05), and quality of life (CP-QOL: 6.17 ± 2.12 vs. 3.24 ± 0.66, all p < 0.001). Notably, the combination therapy yielded markedly higher rates of parent-reported improvements in daily life (88% vs. 24%, p < 0.001) and easy of care (71% vs. 20%, p = 0.001) at 16 weeks. No serious adverse events were reported in either group.

Compared with THP monotherapy, the combination of Madopar and THP is significantly more effective at alleviating dystonia and improving both motor function and quality of life in children with DCP. By leveraging low-dose synergy, this strategy effectively overcomes the efficacy ceiling of first-line monotherapy and translates into meaningful, patient-centered functional gains (including improvements in sleep and communication) without increasing the burden of adverse events.