Effect of Intensive Segmental Trunk Training on Upper Extremity Function and Seated Postural Stability in Children With Spastic Diplegic Cerebral Palsy

This single-blind randomized controlled trial investigated the efficacy of intensive segmental trunk training (ISTT) as a targeted intervention for improving seated postural control and upper limb function in children with spastic diplegic cerebral palsy (CP). Trunk control deficits are a hallmark impairment in this population, contributing to compromised upper extremity function, reduced seated stability, and limitations in activities of daily living. While conventional physical therapy often addresses trunk control indirectly, this study evaluated whether a structured, segment-specific approach yields superior outcomes.

Thirty children aged 4-12 years with spastic diplegic CP and Gross Motor Function Classification System (GMFCS) levels II-IV were recruited from outpatient neurorehabilitation center. Inclusion required moderate trunk control impairment, defined as a score of ≤ 3 on the Trunk Control Test (TCT) item assessing sitting without arm support. Children with uncontrolled seizures, Botulinum toxin injections within the preceding six months, orthopedic surgery within the past year, or cognitive impairment that would preclude task comprehension were excluded.

Participants were randomly assigned to either the ISTT group (n = 15) or the control group (n = 15) using a computer-generated sequence (www.randomization.com) produced by an independent researcher, uninvolved in recruitment, intervention, or assessment. Allocation was concealed in sequentially numbered, opaque, sealed envelopes opened only after baseline measures were complete. The ISTT group received specialized training targeting segmental trunk control at the thoracic, lumbar, and pelvic levels. Training sessions, conducted five times weekly for eight weeks (40 sessions total, 60 minutes each), incorporated graded exercises progressing from static to dynamic sitting balance. Key ISTT components included pelvic tilt facilitation, isolated thoracic and lumbar segmental mobilization during weight shifting, trunk rotation with reaching tasks, and perturbation-based reactive balance training using a tilt board. Exercises were progressively advanced based on individual tolerance and performance.

The control group received standard physical therapy of equal duration and frequency, emphasizing neurodevelopmental treatment (NDT) principles, passive stretching of lower extremity muscles, strengthening of the lower limbs, and gait training.

Outcome measures were assessed at baseline and immediately post-intervention (week 8). The primary outcomes were seated postural stability, measured by the Segmental Assessment of Trunk Control (SATCo). Secondary outcomes included the Trunk Control Test (TCT), upper extremity function, assessed via the Quality of Upper Extremity Skills Test (QUEST) and the Box and Block Test (BBT), and gross motor function, measured by the Gross Motor Function Measure (GMFM-88); Dimensions D (Standing) and E (Walking, Running, Jumping) monitored for unintended change in gross motor function. All assessments were performed by a blinded pediatric physical therapist.

Sample size was calculated a priori using G*Power (version 3.1.9.7). A pilot study of 8 participants (4 per group) yielded a partial eta-squared of 0.14 for the group × time interaction on the Box and Block Test, the primary outcome. With alpha 0.05, power 0.80, two groups, and two measurement points, 22 participants (11 per group) were required; accounting for an anticipated 25% dropout, 30 participants (15 per group) were recruited. The primary analysis used a 2 × 2 mixed-model ANOVA with group (ISTT, control) as the between-subjects factor and time (baseline, post-intervention) as the within-subjects factor; the group × time interaction was the effect of primary interest, with partial eta-squared (η²p) as the effect-size measure (small ≥ 0.01, moderate ≥ 0.06, large ≥ 0.14). Significant interactions were followed by paired t-tests within group and independent t-tests at each time point, with Bonferroni correction for multiple comparisons.

The study was approved by the institutional ethics committee. Written informed consent was obtained from parents or legal guardians.