Studies using the agilik and its predecessor the p.rex

1 Taylor M. Devine, Katharine E. Alter, Diane L. Damiano, Thomas C. Bulea (2024).

A randomized cross-over study protocol to evaluate long-term gait training with a pediatric robotic exoskeleton outside the clinical setting in children with movement disorders

PLoS ONE 19(7): e0304087.

This randomized crossover study ( NCT05726591) was designed to determine whether 12 weeks of overground gait training with a robotic exoskeleton outside of the clinical setting, following an initial in clinic accommodation period, has a beneficial effect on walking ability, muscle activity and overall motor function. Participants will be randomized to either complete the exoskeleton intervention or continue their standard therapy for 12 weeks first, followed by a crossover to the other study component. The primary outcome measure is change in peak knee extension angle during walking; secondary outcome measures include gait speed, strength, and validated clinical scales of motor function and mobility. Assessments will be completed before and after the intervention and at 6 weeks post-intervention, and safety and compliance will be monitored throughout. We hypothesize that the 12-week exoskeleton intervention outside the clinical setting will show greater improvements in study outcome measures than the standard therapy.

2  Bulea, T. C., Molazadeh, V., Thurston, M., & Damiano, D. L. (2022).

Interleaved Assistance and Resistance for Exoskeleton Mediated Gait Training: Validation, Feasibility and Effects.

2022 9th IEEE RAS/EMBS International Conference for Biomedical Robotics and Biomechatronics (BioRob), Seoul, Korea, Republic of, 2022, pp. 1-8, doi: 10.1109/BioRob52689.2022.9925419

Pathological gait in children with cerebral palsy (CP) is primarily determined by strength and selective motor control. Evidence suggests that a strategy of applying task-specific robotic resistance to functional movements can help children with CP to improve muscle strength and neuromuscular function while walking. A study of a child with CP where the participant walked with a robotic exoskeleton (the Agilik smart orthosis) 9 times, demonstrated that the wearer was able to parse the gait cycle into five discrete phases, with the robotic device providing knee extension assistance during stance and resistance during swing. The findings of this study indicate a need for further investigation through a longitudinal study, particularly in individuals who may be more severely affected such that they would be unable to ambulate using an exoskeleton which only provides resistance to limb motion.

3  Bulea, T. C., Lerner, Z. F., Gravunder, A. J. and Damiano, D.L.

Exergaming with a pediatric exoskeleton: Facilitating rehabilitation and research in children with cerebral palsy

2017 International Conference on Rehabilitation Robotics (ICORR), London, UK, 2017, pp. 1087-1093, doi: 10.1109/ICORR.2017.8009394.

Effective rehabilitation of children with cerebral palsy (CP) requires intensive task-specific exercise but many in this population lack the motor capabilities to complete the desired training tasks. Providing robotic assistance is a potential solution.

Many individuals with cerebral palsy lack the required motor capabilities to complete the desired training tasks in intensive task-specific exercise, an effective rehabilitation measure to treat cerebral palsy. Researchers examined a combination of an exoskeleton, an exercise video game (exergame), and electroencephalography (EEG) to monitor cortical activity to explore the potential of robotic assistance for knee extension as a rehabilitation solution. The game required users to extend their knees while standing to hit targets. Results indicate that children with cerebral palsy maintain or increase knee extensor muscle activity during knee extension with the synergistic assistance of the robotic exoskeleton. The exoskeleton significantly increased knee extension in three out of six study participants. EEG findings demonstrate continued engagement during the exercise with robotic assistance.

4 LERNER, Z. F., DAMIANO, D. L., & BULEA, T. C. (2017)

A lower-extremity exoskeleton improves knee extension in children with crouch gait from Cerebral Palsy


Exoskeletons are effective interventions for gait correction in children with cerebral palsy. In a study of 7 participants, 6 demonstrated considerable improvements in gait with the use of an exoskeleton assisting with knee extension. These improvements are comparable to outcomes from orthopaedic surgery. The exoskeleton works by providing bursts of knee extension assistance during discrete portions of the walking cycle, helping to optimize use of the knee extensor muscles during use. The device was well tolerated by study participants and all were able to walk with it independently.

5 LERNER, Z. F., DAMIANO, D. L., PARK, H. S., GRAVUNDER, A. J., & BULEA, T. C. (2017)

A Robotic Exoskeleton for Treatment of Crouch Gait in Children With Cerebral Palsy: Design and Initial Application


For individuals with cerebral palsy, early interventions to treat crouch gait are critical for maintaining mobility in adulthood. Researchers designed and tested a powered exoskeleton to assist with knee flexion and correct crouch gait. The modular exoskeleton design was called P.REX and was the first prototype of what has become the Agilik. The device was based on a knee-ankle-foot orthosis and weighed 3.2kg. The device improved the gait of a six-year-old male trial participant, with knee extension during stance improving by 18.1° and total knee range of motion improving by 21.0°. During use, the researchers observed no significant decline in knee extensor muscle activity. This indicates that the user was not solely relying on the device to extend his limbs. These results substantiate the need to further study the potential of exoskeleton devices to mitigate crouch and help individuals with cerebral palsy maintain mobility over time.

6 LERNER, Z. F., DAMIANO, D. L., & BULEA, T. C. (2017)

The Effects of Exoskeleton Assisted Knee Extension on Lower-Extremity Gait Kinematics, Kinetics, and Muscle Activity in Children with Cerebral Palsy.


Researchers examined the role of external knee flexion assistance to decrease the burden on knee extensor muscles during walking in cerebral palsy patients. In a multi-week exploratory clinical study, seven individuals (ages 5-19) with mild-moderate crouch from cerebral palsy were observed using a novel pediatric exoskeleton (P.REX) designed to provide aptly timed torque to the knee joint during walking. For six out of seven participants, powered knee extension assistance notably reduced the excessive stance-phase knee extensor moment present during crouch gait by a mean of 35% in early stance and 76% in late stance. Further, peak stance-phase knee and hip extension increased by 12° and 8°, respectively. Support from the exoskeleton slightly decreased knee extensor muscle activity compared to baseline levels. This study found that the P.REX exoskeleton added to the management of crouch gait.

7 BULEA, T. C., STANLEY, C. J., & DAMIANO, D. L. (2017)

Part 2: Adaptation of Gait Kinematics in Unilateral Cerebral Palsy Demonstrates Preserved Independent Neural Control of Each Limb


Cerebral palsy is known to impact locomotor adaptation, an alteration of neural control in response to a perturbation. In response to unilateral leg weighting, children with unilateral brain injuries can adapt their step length. Researchers analyzed the kinematic strategies underlying step adaptation to compare neural control in those with hemiplegic cerebral palsy across legs versus a typically developing control group (10 participants in each group were studied; 20 in total). Study participants were observed using a treadmill. The study examined baseline and task-specific variability and local dynamic stability to assess neuromuscular control across groups and legs. Unlike the controls, children with unilateral cerebral palsy had asymmetries in joint angle variability and local dynamic stability at the baseline level, showing increased variability and reduced stability in the dominant limb. Kinematic variability increased and local stability decreased during weighting of ipsilateral and contralateral limbs in both groups compared to baseline, with each measure returning to baseline after weight removal. Findings demonstrate that children with unilateral brain injury retain separate circuits for each leg during walking and, notably, that those neural networks are adaptable independently from one another to improve gait symmetry in the short term.


Effectiveness of robotic exoskeletons for improving gait in children with cerebral palsy: A systematic review

GAIT & POSTURE, 98, 343–354.

A review of thirteen studies concluded that robotic exoskeletons improve gait given strategic optimisation of exoskeleton torque and that participants had time to practice using the exoskeleton. Studies reported a reduced metabolic cost of walking, increased walking speed, and increased knee and hip extension during stance, all of which improve gait function. Additionally, exoskeletons with an actuated ankle module promoted normal ankle rocker function. The studies analyzed in the review demonstrate the potential of robotic exoskeletons to improve mobility in children with cerebral palsy and, resultantly, to improve quality of life and social participation.

studies supporting the science behind the agilik

1    Hicks, J. L., Schwartz, M. H., Arnold, A. S., & Delp, S. L. (2008, March 4).

Crouched postures reduce the capacity of muscles to extend the hip and knee during the single-limb stance phase of gait.

Retrieved July 12, 2022, from DOI: 10.1016/j.jbiomech.2008.01.002

Crouch gait progressively worsens over time, decreasing walking efficiency and leading to joint degeneration.

Our analysis showed that the capacities of almost all the major hip and knee extensors were markedly reduced in a crouched gait posture, with the exception of the hamstrings muscle group, whose extension capacity was maintained in a crouched posture. Crouch gait also increased the flexion accelerations induced by gravity at the hip and knee throughout single limb stance. These findings help explain the increased energy requirements and progressive nature of crouch gait in patients with cerebral palsy.

Crouched gait postures reduced the capacity of muscles in our model to generate extension accelerations at the hip and knee.

As a consequence, muscles must work harder to maintain a given limb position, which helps to explain the increase in energy expenditure when walking in a crouched posture. The negative impact of this pathological gait pattern increases with worsening crouch severity, which suggests that crouch gait is a downward cycle, a commonly observed clinical phenomenon.

2   Steele, K. M., Shuman, B. R., & Schwartz, M. H. (2017, July 5).

Crouch severity is a poor predictor of elevated oxygen consumption in cerebral palsy.

Retrieved July 12, 2022, from DOI: 10.1016/j.jbiomech.2017.06.036

The average net nondimensional oxygen consumption during gait of the children with CP (0.18 ± 0.06) was 2.9 times that of speed-matched typically developing peers.

Oxygen consumption did increase with crouch severity, with an average increase in oxygen consumption of 8%, 15%, and 23% with a minimum knee flexion angle of 15°, 30°, and 45°, respectively. There was a large degree of variability in oxygen consumptions between individuals with similar crouch severity.

Children who used a walker (N = 34) or crutches (N = 15) also had higher oxygen consumption than children who did not walk with aids

Physical fatigue is prevalent among individuals with CP (Jahnsen et al., 2003), and can hinder activities of daily living.
Crouch gait clearly requires greater energy expenditure compared to unimpaired gait.

3    Armand, S., Decoulon, G., & Bonnefoy-Mazure, A. (2016, December 22).

Gait analysis in children with cerebral palsy.

Retrieved July 12, 2022, from DOI: 10.1302/2058-5241.1.000052

Moreover, even if the brain lesion is static, the chronic neurological impairments affect the development of muscles and bones. Therefore, CP is a progressive musculoskeletal pathology.

The growth of the skeleton associated with spasticity, reduced level of activity and weakness of muscles leads to muscle contractures. Muscle contractures should be evaluated and treated as conservatively as possible to prevent over lengthening and muscle weakness.

4  Winters, T. F., Gage, J. R., & Hicks, R. (1987, March).

Gait patterns in spastic hemiplegia in children and young adults.

Retrieved July 12, 2022, from

17% of their patients had type 4 gait, which is mostly crouch. All of their patients had spastic hemiplegia secondary to cerebral palsy.

5  Lee, M., Ritchie, L., Jackson, K., Acharya, V., Thomas, E., O’Reilly, N., & WikiSysop. (n.d.).

Classification of Gait Patterns in Cerebral Palsy.

Retrieved July 12, 2022, from

Regrettably, the commonest cause of crouch gait in children with spastic diplegia is isolated lengthening of the heel cord in the younger child. Once the heel cord has been lengthened, if the spasticity/contracture of the hamstrings and iliopsoas has not been recognized and is not managed adequately, there will be a rapid increase in hip and knee flexion. The result is an unattractive, energy-expensive gait pattern, followed by anterior knee pain and patellar pathology in adolescence

6  Günef, Y., Birkan, S., Șiehim, K., Süreyya, E., Ankara Üniversitesi Tip Fakültesi, Fiziksel Tip ve Rehabilitasyon Anabilim Dali, & Ankara. (2005).

Use of Gait Analysis in the Treatment

Decision-Making Process of Patients with Spastic Cerebral Palsy. Retrieved July 12, 2022, from ISSN: 1302-0234 / 1308-6316

Ninety-percent of the patients were walking with either toe strike or flat foot contact.

Twenty-five percent of the children with spastic CP had crouch (does not mean this is the norm percentage)

The major neuromuscular problems in CP that may necessitate medical, neurosurgical and/or orthopedic intervention can be divided into four categories: 1) Loss of selective motor control and dependence on primitive reflex patterns for ambulation; 2) Abnormal muscle tone (spasticity or dystonia) that is strongly influenced by body posture, position and /or movement; 3) Relative imbalance between muscle agonists and antagonists which, with time and growth, leads to fixed muscle contracture and bony deformity; 4) Impaired body balance mechanisms.

In this study, 12 patients (28%) had one or more previous operation history. All of the operations had been done on staged, single joint procedures. The most leading pattern after operations was crouch gait which was mainly due to the weakness of gastrocnemius muscle.

7  O’Sullivan, R., Horgan, F., O’Brien, T., & French, H. (2018, June 27).

The natural history of crouch gait in bilateral cerebral palsy: A systematic review.

Research in Developmental Disabilities 80 (2018) 84–92, Retrieved July 12, 2022, from DOI: 10.1016/j.ridd.2018.06.013

Four of five case studies in the review demonstrate that the evolution of crouch gait in individuals with bilateral CP seems to be towards increased knee flexion over time. According to these findings, there seem to be two patterns of increasing crouch. The first – a gradual increase in knee flexion over time, which may not require surgical treatment. The second – rapid deterioration, which is preventable with well-timed orthopaedic intervention.

Hamstring lengthening is largely supported as an effective surgical intervention against crouch gait. However, there is also evidence suggesting that hamstring tightness is a byproduct and not a cause of knee flexion and subsequently of crouch gait.

To note – the heterogeneity of the studied population makes it difficult to draw strong conclusions.

8    Andersson, C., & Mattsson, E. (2001, February).

Adults with cerebral palsy: a survey describing problems, needs, and resources, with special emphasis on locomotion.

Retrieved July 12, 2022, from DOI: 10.1017/s0012162201

35% reported decreased walking ability

The findings in our study suggest that individuals with CP might benefit from physical training and thus be able to stay ambulatory at an older age, but there is still need to find out the appropriate intensity of training over time.

9  Johnson, D. C., Damiano, D. L., & Abel, M. F. (1997).

The evolution of gait in childhood and adolescent cerebral palsy.

Retrieved July 12, 2022, from PMID: 9150031

A longitudinal study over a mean of 32 months was conducted on 18 subjects with spastic diplegia, ranging in age from 4 to 14 years.

In conclusion, this longitudinal investigation revealed that, in contrast to the gait of children with intact motor function, ambulatory ability tends to worsen over time in spastic cerebral palsy.

10   Lerner, Z. F., Damiano, D. L., & Bulea, T. C. (2017, August 23).

A lower-extremity exoskeleton improves knee extension in children with crouch gait from cerebral palsy.

Retrieved July 14, 2022, from doi: 10.1126/scitranslmed.aam9145

Rather than guiding the lower limbs, the exoskeleton dynamically changed the posture by introducing bursts of knee extension assistance during discrete portions of the walking cycle, a perturbation that resulted in maintained or increased knee extensor muscle activity during exoskeleton use. Six of seven participants exhibited postural improvements equivalent to outcomes reported from invasive orthopedic surgery. We also demonstrate that improvements in crouch increased over the course of our multiweek exploratory trial. Together, these results provide evidence supporting the use of wearable exoskeletons as a treatment strategy to improve walking in children with CP.

“We observed improvements in knee extension in six of seven participants with gains (8° to 37°) similar to or greater than those reported from invasive surgical interventions,”  Kerry Bennet (Office of the VP for Research, Northern Arizona University). (15-20º improvement from surgery).

11   Calderón, C. B. (2018).

Design, Development and Evaluation of a Robotic Platform for Gait Rehabilitation and Training in Patients with Cerebral Palsy (thesis).

Universidad Carlos III de Madrid. Retrieved August 1, 2022 from

Robot- assisted training increases the therapy compliance by proposing goal-directed tasks that encourage the patients. This approach has interesting advantages compared to traditional therapy, because it suggests functional exercises with accurate and assembled movements, instead of repetitive movements without goals. Moreover, robotic trainers reduce the physical load and cost of conventional therapies, integrating at the same time novel systems to objectively measure the progression of the exercise. As a result, the number of sessions, frequency, intensity, and finally the positive impact of the treatment are typically increased.

RAGT has some promising advantages over traditional training, because it is intensive, controlled, repetitive, and provided with goal-oriented tasks, which is known to be related to cortical organization and motor learning processes. This aspect is particularly important for pediatric population, who could obtain better results thanks to their higher neuroplasticity.

12    Opheim, A., Jahnsen, R., Olsson, E., & Stanghelle, J. K. (2008, February 3).

Walking function, pain, and fatigue in adults with cerebral palsy: a 7-year follow-up study.

Retrieved July 14, 2022, from DOI: 10.1111/j.1469-8749.2008.03250.x

The patients from Jahnsen’s study were actually surveyed 7 years later, and the number with deteriorated walking ability had gone up to 52% (71% for those with bilateral spastic CP)

13    Mobility and Changes in Walking Ability for People with Cerebral Palsy. (n.d.).

Retrieved July 14, 2022, from

Walking may become more difficult and less efficient due to developing contractures, diminished muscle strength, joint degeneration and an increase in body weight.

The first age group is around 20 to 25 years. The mobility decline in individuals with spastic diplegia has been attributed to an increase in crouch gait which results in inefficient walking. Increasing difficulty in keeping up with peers in the community, workplace or academic setting has also been reported.

The second age group is around 40 to 45 years of age, where a decrease in functional ability because of increasing fatigue and pain is reported. This is often due to joint degeneration as a result of excessive stresses on the joints. Progressive pain and fatigue are the two most commonly reported reasons for gait deterioration in walking ability. A lack of adapted physical activity is also a self-reported cause of deterioration in walking.

Patella alta is also a condition that is common in ambulatory adults with spastic diplegia. This is caused by the constant loading of the quadriceps muscles in a flexed gait pattern.

Other factors that can influence the ability to continue walking and transfer include fatigue, weight gain, physical activity, decreasing balance, falls, increased spasticity, contractures, a decrease in muscle strength and physiological burn-out syndrome.

Physical activities such as strengthening, balance exercises and walking training have been linked to improved balance, walking capacity and speed. Physical activities have also been shown to have a positive psychosocial benefit.

Physiological burn out is a condition where the body’s systems are placed under stress over an extended period of time, resulting in eventual exhaustion of the system. This leads to a decline in functional abilities such as walking and transfers. It is important to prevent physiological burnout before it occurs, as it cannot be reversed.

14    Kedem, P., & Scher, D. M. (2016, February).

Evaluation and management of crouch gait.

Current Opinion in Pediatrics 28(1):p 55-59, February 2016. | DOI: 10.1097/MOP.0000000000000316

Crouch gait is a common gait deviation, often seen among ambulatory diplegic and quadriplegic patients, once they reach the pubertal spurt, when weak muscles can no longer support a toe walking pattern because of rapidly increased weight. This form of gait is highly ineffective and might compromise walking ability over time. The anterior knee is overloaded; pain, extensor mechanism failure, and arthritis might develop. Its progressive nature often requires surgical intervention. The cause of crouch gait is multifactorial, and surgery should be tailored to meet the individual’s specific anatomic and physiologic abnormalities.

15    Murphy, K. P., Molnar, G. E., & Lankasky, K. (1995, December).


Retrieved July 14, 2022, from

One hundred and one adults (19 to 74 years of age) with cerebral palsy were interviewed and examined. Several had multiple musculoskeletal problems. In 63 per cent, these occurred under 50 years of age, suggesting that abnormal biomechanical forces and immobility had led to excessive physical stress and strain, overuse syndromes, and possibly early joint degeneration. Treatment for the musculoskeletal system and availability of adaptive devices were less adequate than for children with cerebral palsy.

16   Amen, J., ElGebeily, M., El-Mikkawy, D. M., Yousry, A. H., & El-Sobky, T. A. (2018).

Single-event multilevel surgery for crouching cerebral palsy children: Correlations with quality of life and functional mobility.

Retrieved July 14, 2022, from doi: 10.4103/jmsr.jmsr_48_18

Because lack of adherence by patients to the hospital-centered rehabilitation protocols might impact the outcomes of surgery, the role of family-centered care should be expanded.

17  Meyer-Heim, A., Ammann-Reiffer, C., Schmartz, A., Schäfer, J., Sennhauser, F. H., Heinen, F., Knecht, B., Dabrowski, E., & Borggraefe, I. (2009, August).

Improvement of walking abilities after robotic-assisted locomotion training in children with cerebral palsy.

Retrieved July 14, 2022, from DOI: 10.1136/adc.2008.145458

RAGT has some promising advantages over traditional training, because it is intensive, controlled, repetitive, and provided with goal-oriented tasks, which is known to be related to cortical organization and motor learning processes.

18 Fasoli, S. E., Ladenheim, B., Mast, J., & Krebs, H. I. (2012, November).

New horizons for robot-assisted therapy in pediatrics.

Retrieved July 14, 2022, from DOI: 10.1097/PHM.0b013e31826bcff4

Clinical experience of gait rehabilitation suggests that gait training in children could be conducted even more effectively using robot-based therapy rather than conventional strategies.

19   Jahnsen, R., Villien, L., Stanghelle, J. K., & Holm, I. (2003, May 1).

Fatigue in adults with cerebral palsy in Norway compared with the general population.

Retrieved July 14, 2022, from DOI: 10.1017/s0012162203000562

A study of 406 respondents between the ages of 18 and 72 with different types of CP (Hemiplegia, Diplegia, Quadriplegia, Dyskinesia, unknown/other [in descending order of # of respondents]) found that fatigue is a significant issue amongst adults with CP. The most prevalent predictors of fatigue were bodily pain, deterioration of functional skills, limitations in physical and emotional role function, and low life satisfaction. While deterioration of functional skills was shown to be associated with fatigue, level of physical function was not found to be a significant factor, indicating that the onset of novel functional problems in adults with CP is a higher driver of fatigue than baseline physical function level. Fatigue needs to be addressed on both a physical and psychological level.

20   Jahnsen, R., Villien, L., Egeland, T., Stanghelle, J. K., & Holm, I. (2004, May).

Locomotion skills in adults with cerebral palsy.

Retrieved July 14, 2022, from DOI: 10.1191/0269215504cr735oa

There were 97 persons (27%) who reported improvement of walking skills, mainly before 25 years, 102 (28%) reported no change, and 160 (44%) reported deterioration, mainly before 35 years of age.

21  Murphy, K. P. (2010, October).

The adult with cerebral palsy.

Retrieved July 14, 2022, from The adult with cerebral palsy

Early identification and intervention for symptoms during childhood and early adulthood is the ideal approach to optimizing musculoskeletal function and lifestyle into the adult years. Often, secondary and associated conditions are overlooked in people with P because the primary focus is usually the condition itself only.  These symptoms are treatable both surgically and non surgically.

In adults, there are two peaks of age at which loss of ambulatory skills occur. The first occurs between the ages of 20-25 and is most associated with progressive crouch gait and young adults’ challenges keeping up with peers in their community, workplace, and in school. The second peak occurs at 40-45 years, at which point progressive fatigue, pain, and potentially accelerated joint degeneration make further functional ambulation impossible. Anecdotal evidence supports accelerated arthritis and joint degeneration in adults with CP, but this has not been formally studied.

22   O’Shea, T. M. (2008, December).

Diagnosis, treatment, and prevention of cerebral palsy.

Retrieved July 14, 2022, from DOI: 10.1097/GRF.0b013e3181870ba7,_Treatment,_and_Prevention_of_Cerebral.19.aspx

In a large population-based study of very low birth weight children with cerebral palsy, 25% of children with spastic CP had hemiplegia, 37.5% had quadriplegia, and 37.5% had diplegia.

23    Mulligan H., Fjellman-Wiklund A., Hale L., Thomas D., Häger-Ross C.

Promoting physical activity for people with neurological disability: perspectives and experiences of physiotherapists.

Physiother Theory Pract. 2011;27(6):399-410. doi:10.3109/09593985.2010.519015

Despite New Zealand and Sweden having policies to promote recreational exercise in the disability community, people with disabilities in both countries do not report engaging in physical activity at the desired levels. A qualitative study of nine physiotherapists found that they feel unable to fully support and implement these policies for patients with chronic neurological conditions. This gap between policy and actual outcomes was found to be correlated with a perceived lack of support for the physiotherapists’ work within the health system as well as insufficient knowledge of disability within the sphere of recreation. If these issues were better managed, the physiotherapists could be more effective in their role as advocates for physical activity for people with neurological conditions.

24   Rethlefsen SA, Blumstein G, Kay RM, Dorey F, Wren TA

Prevalence of specific gait abnormalities in children with cerebral palsy revisited: Influence of age, prior surgery, and gross motor function classification system level.

Dev Med Child Neurol 2017;59:79-88.

In addition, crouch gait may occur as a part of the natural history of gait progression in CP children, especially around puberty. This is usually attributed to the imbalance between body mass and muscle strength

25  Stout, J. L., Gage, J. R., Schwartz, M. H., & Novacheck, T. F. (2008, November).

Distal femoral extension osteotomy and patellar tendon advancement to treat persistent crouch gait in cerebral palsy.

Retrieved July 14, 2022, from DOI: 10.2106/JBJS.G.00327

*Note: The study covered surgery, not orthopedic interventions, but still outlined which treatments specifically are effective for crouch gait.

A study evaluating the management of crouch gait using surgical techniques addressing knee contracture (distal femoral extension osteotomy) and knee extensor insufficiency (patellar tendon advancement) found that the patellar tendon advancement is key to achieving optimal results. When implemented at the stage where the individual has stopped growing, it is reasonable to assume that the adolescent who received the procedure(s) will maintain walking ability into adulthood.

26 Chen, J., Hochstein, J., Kim, C., Tucker, L., Hammel, L. E., Damiano, D. L., & Bulea, T. C. (2021, June)

A Pediatric Knee Exoskeleton With Real-Time Adaptive Control for Overground Walking in Ambulatory Individuals With Cerebral Palsy.

Retrieved July 14, 2022, from

The study addressed two modes of exoskeleton assistance (Constant and Adaptive) and found that the Adaptive mode showed the best improvement in peak knee angle with the least impact on gait speed and no undesirable EMG effects (ie no increased spastic response to assistance with extension). The Adaptive mode reached the highest statistical significance in peak knee extension of the modes tested (Constant, Zero, and Adaptive). The Adaptive mode provided a large burst of assistance in both the left and right limbs during early stance of the individual being tested and little assistance in other phases of gait. The Adaptive mode also addressed the asymmetric gait pathology in the individual, with the assistance provided during the knee extensor moment being greater in the left knee than in the right, per the individual’s needs.




The study identifies three primary measures of walking ability: performance, capability, and capacity. These not only provide a framework to analyze walking function and ability, but also to monitor how ambulation changes throughout the lifespan – as it often does in individuals with cerebral palsy. Many previously ambulant adults with CP report completely stopping walking relatively early in their adulthood, often in their early 20s and 30s). Individuals with poorer gait function requiring the use of gait aids during childhood (GMFCS level III) are more likely to report a deterioration in walking ability or stop walking entirely (Jahnsen et al. 2003; Opheim, Jahnsen, Olsson and Stangelle 2009). Performance refers to what the individual actually does within their daily environment, whereas capability refers to what the individual is able to do. Capacity refers to what the individual can do in a standardized, controlled environment. It is difficult for both researchers and individuals to assess long-term changes in walking ability or track walking decline accurately because of these three distinct and non-interchangeable measures. For example, an individual may opt to use a wheelchair or other mobility device to achieve vocational and recreational demands more easily (modify performance), but not perceive a change in walking ability (no change detected in capability). A change in environment may be misconstrued as a change in walking ability depending on which measure of walking ability is used and which factors are considered. Conducting accurate longitudinal studies on changes in walking ability and gait are made difficult due to these complex metrics and frameworks to evaluate ability.‌

28 PIMM, P. (1992).



There is a common assertion that cerebral palsy (CP) is a nonprogressive disorder, in the sense that the lesion of the brain responsible for CP remains unaltered with time. However, Ss with CP often experience a decline in performance for no apparent reason early in adult life. Three case studies of Ss with CP are presented, all of whom experienced, as adults, a decline in physical functioning that could not be attributed to any other medical condition. In the 3rd case, stress played a likely role in the decline. While it is possible that Ss with CP experience a form of physiological burnout, another explanation relates to the psychological stress that Ss face in trying to maintain performance at the optimum level. (PsycINFO Database Record (c) 2016 APA, all rights reserved)




Clinical experience of gait rehabilitation suggests that gait training in children could be conducted even more effectively using robot-based therapy rather than conventional strategies. The intensity and frequency of task-specific training in gait rehabilitation is related to cortical reorganization. This is why a driven gait orthosis (DGO) provides nearly ideal conditions for specific gait training, as it has the capability to increase frequency and intensity while maintaining a physiological gait pattern. In a study of 67 children and adolescents with cerebral palsy, the use of a DGO yielded a gait speed increase of 15%.




A study of 40 participants who experienced perinatal stroke (22 with arterial, 18 with venous, with 60 healthy controls) has demonstrated that position sense deficits are common in children with perinatal stroke and cerebral palsy. Using a robotic measurement tool, researchers were able to observe that arterial strokes typically cause greater impairments than venous strokes. These findings suggest that traditional clinical tests may not be sensitive enough to detect position sense deficits and that more accurate robotic measurements may be required to evaluate the effects of rehabilitation strategies. Evaluations with the most common available devices for rehabilitation have been mostly carried out following position control mode instead of training with “assist as needed” strategy. Moreover, they avoid correcting the posture during walking and do not allow free movement in real environment. A new device with the goal of including all the advantages of current treatments in only one equipment is necessary, as outcome studies are only as effective as the tools which measure them.