What is the role of the AlterG in neuro-rehab? The team at PhysioFunction tell us more about the space-inspired piece of technology which is inspiring the progress of so many patients
What is the AlterG?
The AlterG is an antigravity treadmill that uses NASA differential air pressure technology to de-weight the user to a comfortable bodyweight so they can safely stand, walk or run as part of their rehabilitation or training. The AlterG was initially developed for astronauts to enable them to exercise in space to combat bone mass and muscle loss and has since been adapted for use on land for different forms of exercise and rehabilitation.
What does it do?
The AlterG treadmill is fitted with a sensitive bodyweight measurement system and once the user is secured in the air-locked bag, the Alter G calibrates to their weight. This allows precise bodyweight support provision up to 80 per cent of the user’s bodyweight, providing a supported and fall-safe environment for the user to practice standing, balancing, bodyweight exercises (such as a squat or lunge), walking or running.
The AlterG’s stride smart technology can provide clients and clinicians with real-time visual feedback of gait kinematics, such as stride length and walking asymmetry, helping them to optimise their movement patterns. This feature is especially useful for those with impaired sensation or proprioception who demonstrate abnormal gait patterns they may not necessarily feel.
What can it be used for?
The AlterG is used in a variety of rehabilitation settings, such as neurology, orthopaedics, sports injury and elderly care, and has been shown to improve cardiovascular fitness in people with limited mobility, increase bone density in the lower limbs, reduce muscle wasting and decrease lower limb swelling (Mishra, 2010).
The AlterG can specifically help neurological patients by enabling them to walk and exercise in a fall-safe environment without an overhead gantry or falls tether requiring the use of a restrictive harness. It also permits them to work on correct walking patterns using the stride smart and video monitoring technology, facilitating walking over longer periods of time, building endurance and working on technique with a reduced bodyweight load. As they improve, the bodyweight support can be reduced towards real-world conditions.
Higher level balance training can also be performed in the AlterG that may otherwise be too dangerous, challenging or painful for the client. For example, dual and multi-task activities are an essential part of day-to-day function and are commonly causes of falls in individuals where processing and automaticity are affected. Use of the AlterG provides a safe environment to practice these activities, such as holding a conversation, reading information or carrying objects whilst walking.
Supporting studies
The AlterG has been investigated in various small scale research trials and has bene demonstrated to:
- Increase endurance, reduce fall risk and enhanced perceived recovery after stroke (Cerise et al., 2015),
- Reduce freezing and improve gait speed and dynamic balance in patients with Parkinson’s disease (Carvallo et al., 2020),
- Improved cardiovascular endurance, gait speed and dynmaic balance in people with multiple sclerosis (Melbourne et al., 2017),
- Improved lower limb performance and locomotion in children with cerebral palsy (Lotfian et al., 2017).
An example from PhysioFunction
At PhysioFunction we specialise in neurological rehabilitation, with a mixed caseload including clients affected by stroke, MS, brain injury, Parkinson’s, Spinal Cord Injury and Cerebral Palsy. We utilise the AlterG with many partially ambulant (those who can step onto the AlterG and stand whilst the device is calibrated) and ambulant patients to enhance their balance, mobility, cardiovascular fitness and confidence.
One of our MS patients presented as independently mobile but with impaired balance and confidence and walking slowly with a wide base of support. Her AlterG sessions consisted of 10 minutes forwards walking at a three per cent incline at 60 per cent of her bodyweight (40 per cent supported by the AlterG). She walked at a self-selected pace, and we used the video monitor so she could visually correct her walking patterns with the help of a therapist. She then completed some single leg balance exercises for five minutes that she would not ordinarily be able to practice due to instability, and then completed 5 minutes of backwards walking at her self-selected pace using the video monitor for visual feedback again.
After six weeks of training her score on the BERG balance test increased by 3 points and her 10 minute walking distance on a standard treadmill increased by 90 metres, demonstrating improved static and dynamic balance, and a greater self-selected walking pace.
References
Cherise., L ; Myler., A Bagwell, J., Powers, C., Fisher, B., E. (2015). Pressure controlled gtreadmill training in chronic stroke. Journal of Neurologic Physical Therapy 39(2):p 127-133,
Carvallo,J., Juarez,M. and Fekete,R., (2020). Anti-Gravity Treadmill Training for Freezing of Gait in Parkinson’s Disease. Journal of brain sciences.
Melbourn, J., Willingham, B., McCully, K., Backus, D. (2017). Anti-Gravity Treadmill Training Improves Walking in a Person with Severe Multiple Sclerosis. The Crawford Research Institute; MS Rehabilitation & Wellness Program;Department of Kinesiology, University of Georgia, Athens, GA.
Lotfian, M., Mirbagheri,A., Dadashi, F., Nourian, R., Mirbagheri, M., (2017) Therapeutic effects of an anti-gravity treadmill (AlterG) training on gait and lower limbs kinematics and kinetics in children with cerebral palsy. National Library of Medicine.
Mishra, D., (2010) Summary of clinical research involving the alter G antigravity treadmill. clinical research update.
