By Mindy Aisen, MD
Last month Dr. Paolo Bonato of Spaulding Rehabilitation Hospital reported on his study of using robotic assisted body weight supported treadmill training (BWSTT) to improve walking ability in children with CP. I want to expand on this topic by reporting on the recently published results of three different groups of investigators who are also evaluating the effectiveness of this treatment modality in CP kids. In addition, I want to discuss the use of neuromuscular stimulation used in combination with BWSTT as a potential rehabilitation technique for impaired gait, and finally, I want to re-emphasize the great need for more rigorous, well-controlled clinical trials to provide definitive scientific evidence for the widespread use of this promising intervention for the improvement of gait and ambulatory skills in children with CP.
As Dr. Bonato previously stated, there is growing evidence that the human central nervous system is capable of significant recovery after insult or injury when prescribed an effective treatment modality at the proper dose. In particular, the use of task-specific training such as BWSTT, has shown great promise in helping stroke and motor incomplete spinal cord injured patients regain some walking ability. In addition, BWSTT has shown promise in helping to correct the gait and improve functional ambulation in children with CP. In a non-randomized study of 10 children with CP, some of who were non ambulatory, Schindl et al reported significant improvement in functional ambulation of all 10 children after 3 months of BWSTT 1. In 2004, Day et al reported a case study in which a 9 year old child with spastic tetraplegic CP who could not support his own weight and had never experienced walking began to walk short distances with a rolling walker after 44 sessions of locomotor training that included BWSTT 2.
More recently, Provost et al reported improvement in four out of six ambulatory children with CP after only 2 weeks of BWSTT in twice daily therapy sessions lasting 30 minutes each 3. Four of these children showed improvement in endurance and a functional gait measure. Begnoche et al combined intensive physical therapy with BWSTT in a study of 5 children with spastic CP. The training sessions consisted of 4 weeks of training, three to four sessions per week for 2 hours each. All five children showed significant improvements in motor and ambulatory skills 4. Finally, Dodd and Foley conducted a small, controlled clinical trial of 14 children who were matched according to type of CP (spastic, athetoid), age, sex and gross motor functional classification system level. The experimental group underwent BWSTT twice a week for 6 weeks in a school-based program. The experimental group showed significant improvements over the control group in walking speed and a trend towards increased endurance over the range of moderate to severe disability 5.
CP may lead to profound muscle weakness in the affected extremities. Stackhouse et al demonstrated that children with CP have large deficits in voluntary muscle activation as compared to a group of age-matched unaffected children 6. This inability to produce sufficient force using voluntary contractions may not induce muscle growth during training exercises prescribed for CP kids. Recently, this same group conducted a study using neuromuscular electrical stimulation (NMES) in conjunction with a 12 week isometric strength training program in a group of children with spastic diplegic CP 7. The control group participated in the strength training program without the NMES. The investigators found that the NMES group had greater normalized force production for the quadriceps (muscle strength) and greater walking speed post training than did the control group. While to date, NMES in conjunction with BWSTT has not been reported in CP children, it has been shown to be more effective in restoring gait in stroke patients than BWSTT alone 8. NMES may enhance the benefits of BWSTT already demonstrated in CP children by recruiting and strengthening muscles that are needed to complete normal gait cycles.
There is limited scientific evidence that supports the use of BWSTT, NMES and many other treatment modalities to improve strength, endurance and functional mobility in children with CP. Unfortunately, none of these modalities have been clearly established as effective in scientifically rigorous, well-controlled clinical trials. Until there is well-established evidence for the use of these interventions they will never come into widespread use for the treatment of gait abnormalities in children with CP because of third-party reimbursement issues. I urge investigators interested in the neurorehabilitation of CP to begin to collaborate on issues of dose, frequency of therapy and different combinations of treatment modalities so that the much needed large clinical trials can begin to take place. Without these studies, treatment advances that are taking place in the treatment of stroke, spinal cord injury and other nervous system disorders will not be realized in the treatment of CP.
1. Schindl MR. Forstner, C, Kern H, and Hesse S. Treadmill training with partial body weight support in nonambulatory patients with cerebral palsy. Arch Phys Med Rehabil. 2000:81(3) 301-6
2. Day JA, Fox EJ, Lowe J, Swales HB and Behrman AL. Locomotor training with Partial Body Weight Support on a Treadmill in a non-ambulatory Child with Spastic Tetraplegia Cerebral Palsy: A Case Report. Pediatr Phys Ther 2004: 16(2):106-113.
3. Provost B, Dieruf K, Burtner PA, Phillips JP, Bernitsky-Beddingfield A, Sullivan KJ, Bowen CA, Toser L. Endurance and gait in children with cerebral palsy after intensive body weight-supported treadmill training. Pediatr. Phys Ther 2007: 19(1)2-10.
4. Begnoche DM and Pitetti KH. Effects of traditional treatment and partial body weight treadmill training on the motor skills of children with spastic cerebral palsy. A pilot study. Pediatr Phys Ther. 2007 19(1): 11-19.
5. Dodd KJ and Foley S. Partial body-weight supported treadmill training can improve walking in children with cerebral palsy: a clinical controlled trial. Dev Med Child Neurol. 2007 49(2):101-105.
6. Stackhouse SK, Binder-Macleod SA, and Lee SC. Voluntary muscle activation, contractile properties and fatigability in children with and without cerebral palsy. Muscle Nerve 2005 31(5):594-601.
7. Stackhouse SK, Binder-Macleod SA, Stackhouse CA, McCarthy JJ, Prosser LA and Lee SC. Neuromuscular Electrical Stimulation versus Volitional Isometric Strength Training in Children with Spastic Diplegic Cerebral Palsy: A Preliminary Study. Neurorehabil Neural Repair. 2007. Mar 16
8. Daly JJ, Roenigk KL, Rogers JM, Butler K, Gansen J, McCabe J, Fredrickson E, Holcomb J, Ruff RL: A Randomized Controlled Trial of FNS in Chronic Stroke Subjects. Stroke 2006, 37:172-178.