United Cerebral Palsy Research Foundation (USA)

Fact Sheet - August 2007

Is Lokomat the break-through assisting children with Cerebral Palsy to Walk? 

‘Last month Dr. Paolo Bonato of Spaulding Rehabilitation Hospital reported on study of using robotic assisted body weight supported treadmill training (BWSTT - Lokomat) to improve walking ability in children with Cerebral Palsy.  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 – Lokomat 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 BWSTT².

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 each³.  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 disability⁵.  

Cerebral Palsy 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 children⁶.  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 CP⁷.  

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 ‘- [Part 2 By Mindy Aisen MD].

Could Robotics improve the walking ability of children with Cerebral Palsy? July 2007 Fact Sheet

A decrease in walking proficiency and economy is a major cause of physical disability in children with Cerebral Palsy. High lower limb agonist-antagonist muscle coactivations, increased tone, tightness of Achilles tendon, and knee and hip musculature cause abnormal gait and high energy expenditure while walking. As a result, a high precentage of children with CP have a gait that is characterized by slow speed and disturbed motor control. 

Training interventions to improve gait outcomes in CP usually include strength training, balance control and weight bearing activities. Recent studies have demonstrated beneficial effects of intensive task-specific gait training on motor recovery in children with CP ^1-2 as well as adults with paraparesis and hemiparesis.  

Recent developments in the neuro-rehabilitation field have been stimulated by information on neuronal recovery processes and their modulation by various physical and pharmacological interventions. There is a growing body of evidence demonstrating that the human brain is capable of significant recovery providing that the amount and frequency of treatments are applied appropriately. In addition to quantity, the quality of the intervention is equally important with task specific interventions enhancing neural reorganization and behavioral recovery.^3-5 

Task oriented rehabilitative gait techniques include Lokomat Body Weight Supported Treadmill Training (BWSTT). BWSTT enables severely affected individuals to follow principles of motor learning and to train while walking. Treadmill training has been often cited as task-specific training because it allows for complete gait cycles with multiple repetitions facilitated by the treadmill’s consistent rate of movement. Several studies have shown the potential of this technique in patients after stroke, spinal cord injuries and children with CP.^1,2,6 

Despite the potential benefits of BWSTT, its application is physically demanding and limited by personnel time and labor requirements. At least two therapists are involved in a gait training session. They manually guide the lower extremities of the patient to facilitate movement of the limbs during ambulation. Often a third individual is involved to stabilize the pelvis. Recently, robotic devices referred to as driven gait orthoses (DGOs) have been developed to assist in the delivery of BWSTT. A DGO is a computer-controlled exoskeleton that is secured to a person’s legs while he/she is supported over a motorized treadmill using an unloading system. A DGO replaces the manual assistance provided by therapists with guided lower extremity trajectories that are consistent with physiological gait patterns.  

Led by Paolo Bonato, PhD and Donna Nimec, MD and supported by UCP Research and Educational Foundation, a group of researchers at Spaulding Rehabilitation Hospital in Boston MA (which is home to the Harvard Medical School Department of Physical Medicine and Rehabilitation) is conducting a study on the use of a DGO (Lokomat, Hocoma AG, Switzerland) to enhance gait retraining in children with CP. The robotic components of the device drive the knee and hip joints, which enables movement through symmetric, coordinated trajectories that mimic physiological walking patterns.

Although studies with this robotic-assisted BWSTT have been performed and are underway in the adult spinal cord injured and post-stroke populations, to date there is no published literature on the use a DGO in the pediatric population. There is a great deal of excitement about this ongoing study in children with Cerebral Palsy at the Harvard Medical School. 

The research team anticipates that the use of a Lokomat-DGO will maximize locomotor function in children with CP by increasing the duration, intensity and specificity of training while overcoming the limitations of the labor intensive interventions provided by therapists. The research is a pilot study to investigate the suitability of the DGO for training children with CP, and to develop protocols that will allow clinicians to achieve in children with CP the encouraging results already attained in other adult patient populations.