Cerebral Palsy

Summary — The best-known stem cell study in cerebral palsy is a randomised, placebo-controlled study of autologous cord blood by a team at Duke University in the United States (2017, 63 children). Children who received at least a certain dose per body weight showed greater improvement in gross motor function scores, together with changes in imaging measures of brain connectivity. A 2016 systematic review also observed a small improvement in motor function in stem cell groups, while noting that the number and quality of studies were limited.

What is cerebral palsy?

Cerebral palsy refers to disorders of movement and posture caused by damage to the developing brain before birth, around birth or in early infancy. Causes include preterm birth, lack of oxygen at birth, brain haemorrhage, infection and malformations of the brain, and sometimes the cause cannot be identified. The brain injury itself does not progress, but as a child grows, muscle tone, joint movement and bone growth can change how movement problems appear.

Cerebral palsy is classified by the area of damage and symptoms — spastic, dyskinetic, ataxic and so on — and by which limbs are affected. Severity ranges from children who walk with little difficulty to those who need help with most daily activities. Problems with speech, vision, hearing, learning and epilepsy may also occur.

Current standard treatment and support

Rehabilitation is central. Physiotherapy, occupational therapy and speech therapy help maximise function, together with orthoses and walking aids. Muscle spasticity is treated with botulinum toxin injections, medication and neurosurgical procedures such as selective dorsal rhizotomy, and joint deformities with orthopaedic surgery. These treatments continue long term as the child grows. Stem cell research aims to test whether recovery of already-damaged brain function can be further supported.

Why stem cells are studied

Researchers hypothesised that the various cells in cord blood might modulate inflammation, secrete neuroprotective factors and support the brain's re-formation of connections (neuroplasticity). Because young children's brains are more plastic than adults', some hoped that support given early might have a larger effect. There is, however, no evidence that infused cells become brain cells and replace damaged areas, and the mechanism remains a hypothesis.

Cells used and how they were given

The leading approach gives a single intravenous infusion of the child's own cord blood, banked by the family at birth. Small studies in several countries have also given donor cord blood, bone marrow mononuclear cells or mesenchymal stem cells intravenously or intrathecally.

Reported research findings

① Randomised, placebo-controlled autologous cord blood study (Duke University, 2017) — 63 children aged 1–6 with cerebral palsy took part. In a crossover design, children first received cord blood or placebo and switched a year later, so every child eventually received their own cord blood. At one year, a simple comparison of the whole group did not show a clear difference, but children who received at least a certain number of cells per kilogram showed greater improvement in gross motor function scores (GMFM-66) than during their placebo period. Brain connectivity measures on diffusion tensor imaging (DTI) were also reported to increase in these children. The investigators concluded that dose may be an important factor and that larger studies are needed.

② Systematic review and meta-analysis (2016) — pooling randomised and non-randomised stem cell studies in cerebral palsy, the review found that stem cell groups improved slightly but statistically significantly more in gross motor function than groups receiving rehabilitation alone. However, the included studies differed in cell type, administration and assessment, and their quality was uneven, so the authors rated the certainty of evidence as low.

What has been reported about safety

In the Duke study, autologous cord blood infusion was reported to be generally well tolerated, with infusion-related reactions mostly transient. The systematic review also found that serious adverse events were uncommon during study periods. Risks may differ, however, with invasive methods such as intrathecal injection or with cells whose quality control has not been verified. The U.S. FDA urges caution about the risks of unapproved stem cell interventions.

What the results mean and open questions

Because children with cerebral palsy often gain function over time with rehabilitation alone, placebo control and precise assessment are essential to confirm any stem cell effect. The Duke study is significant in showing dose-related differences in a study with such a design, but it was small. Follow-up studies are needed to determine the appropriate age, type of cerebral palsy, cell dose and number of infusions. The ISSCR guidelines also emphasise this stepwise confirmation.

How results are measured in cerebral palsy research

Motor function in children with cerebral palsy is classified with the Gross Motor Function Classification System (GMFCS) into levels 1–5, where level 1 means walking without limitation and level 5 means needing full assistance to move. Treatment studies use changes in the Gross Motor Function Measure (GMFM-66), which assesses activities such as lying, sitting, crawling, standing and walking, as the main measure; the Duke University study also used this score.

The above summarises results reported in published papers and public-agency materials. University and institute names are given to identify research sources, not to introduce or recommend any medical institution. Reported results do not mean the same effect for everyone, and the suitability of any treatment is decided by the medical team.

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