Nourizadeh M, Juricic M, Begin J, et al. Non-invasive assessment of muscle spasticity in children with cerebral palsy undergoing botulinum toxin treatment using near-infrared spectroscopy. J Neuroeng Rehabil. 2025;22(1):265. Published 2025 Dec 22. doi:10.1186/s12984-025-01853-z
Managing muscle spasticity in children with cerebral palsy (CP) is a lifelong challenge for patients, families, and clinicians. Spasticity, which involves stiff muscles and involuntary spasms, can restrict mobility and limb function. Although botulinum toxin A (BoNT–A, commonly known as Botox) injections are widely used, their effectiveness has traditionally been assessed through subjective clinical examinations. A new study offers a way to generate real-time data that will improve clinical decision-making.
“Botox treatment relaxes spastic muscles, but its effects typically only last four to six months,” said Dr. Babak Shadgan, co-author of the study with Dr. Kishore Mulpuri and the Hippy Lab team. “The duration varies between individuals, so clinicians need to evaluate treatment effectiveness and determine the optimal timing for the next injection.”
“We used near-infrared spectroscopy (NIRS) as an objective, non-invasive method to measure muscle oxygenation level, which is altered in spastic muscle,” said Shadgan.
A pilot study recently published in the Journal of NeuroEngineering and Rehabilitation, led by Dr. Shadgan and Dr. Mulpuri, along with a multidisciplinary team from ICORD and the Division of Pediatric Orthopaedics, explored a non-invasive method for evaluating spasticity and muscle oxygenation using NIRS, which measures muscle oxygen levels beneath the skin.
Children with CP often experience reduced blood flow and abnormal oxygen levels in affected spastic muscles due to sustained low-level contractions and increased pressure. When treatments such as BoNT–A reduce spasticity, these muscles relax, decrease intramuscular pressure, and, consequently, improve perfusion and oxygen supply, which NIRS can detect in real time.
Eight children aged 2 to 17 participated in the study at BC Children’s Hospital. Researchers used a portable NIRS device to measure muscle oxygenation at multiple points over six months following BoNT–A injection. Clinicians also assessed spasticity using the Modified Ashworth Scale (MAS).
Researchers found that muscle oxygenation (TOI%) increased significantly after treatment, peaking at 6-10 weeks, after which it began to decline again. Spasticity levels, measured by MAS, improved in parallel, confirming the treatment’s strongest effects during these periods.
What is most exciting about this study and the new technique is not only the promising data, but also the potential for a more objective and child-friendly way to assess treatment progress.
“In the future, orthopaedic surgeons may use a wireless, handheld device smaller than a standard smartphone to determine the optimal treatment window for each patient, which could make monitoring spasticity easier for clinicians and families,” said Shadgan.
Although this was a small pilot study, the implications are significant. While the researchers recommend larger studies to further validate NIRS as a clinical biomarker, their results suggest a future in which treatment decisions are guided by measurable data, enabling children with CP to receive more individualized and
precise care.