Multimodal rehabilitation in PLP1-associated spastic paraparesis: a case report with clinical and biomechanical outcomes

Background PLP1-related disorders, including the Pelizaeus–Merzbacher disease spectrum and X-linked spastic paraplegia type 2, are rare hypomyelinating conditions characterized by progressive gait impairment, lower limb spasticity, and motor disability. Evidence supporting rehabilitation strategies in these disorders remains limited, particularly for technology-assisted interventions. Case presentation We report the case of a 29-year-old man with progressive PLP1-related spastic paraparesis, prominent gait impairment, recurrent falls, lower limb spasticity, and preserved independence in activities of daily living. Genetic testing identified a hemizygous PLP1 variant, classified as likely pathogenic. The patient underwent a 20-session outpatient rehabilitation program organized into two sequential blocks: 10 sessions of anti-gravity treadmill training (Alter-G), followed by 10 sessions combining Alter-G and EXOPULSE Mollii Suit stimulation. Methods and outcomes Clinical, gait analysis, and posturographic outcomes were collected at baseline (T0), after the first block (T1), and after completion of the full intervention (T2). Across the intervention period, balance, lower limb strength, and spasticity showed overall improvement, whereas timed mobility and endurance displayed an initial worsening at T1 followed by partial recovery at T2. Instrumental gait analysis revealed marked step-length reduction after the first block, with substantial recovery by T2, alongside side-specific changes in gait quality indices. Static posturography showed progressive normalization of foot load distribution under eyes-open conditions, while residual asymmetry persisted with eyes closed. Fatigue scores, assessed during the second block only, improved over time. Conclusion This case suggests that sequential technology-assisted rehabilitation combining body weight-supported treadmill training and wearable electrical stimulation is feasible in PLP1-related spastic paraparesis and may be associated with improvements in selected domains, including balance, strength, spasticity, and selected gait parameters. Given the single-case design, multimodal treatment structure, and potential confounding factors, these findings should be considered exploratory and hypothesis-generating.