Neurological issues often require orthopedic treatment. Occupational therapists, for example, will see stroke victims and help them regain basic skills such as eating with a fork or picking up small objects. Physical therapists may see patients with drop foot because they experience weakness in the tibialis anterior and the other dorsiflexors in the foot and ankle. Injuries to the nervous system take a lot of time and repetition to rehabilitate, because patients must re-educate the motor pathways to the affected muscles. Biofeedback can make this recovery process two times faster.
Common Causes and Symptoms of Drop Foot
The overarching cause of drop foot is disruption to the common peroneal nerve – a nerve that provides sensation to the lower leg and knee joint. Damage to the common peroneal nerve results in lack of dorsiflexion and therefore an abnormal gait pattern with an absence of heel strike. Common causes of foot drop include: total knee replacement surgery, neurological disorders such as a stroke, fracture or injury to the fibula, patellar dislocation, ankle inversion surgery and so forth. Drop foot is diagnosed when there is no dorsiflexion ability in a non-weight bearing position. It can be assessed through gait analysis and ankle range of motion. Some patients compensate by increasing hip flexion, some drag the top of the foot along the floor, and many can experience neurologic pain from the nerve damage.
Common Exercises for Rehabilitation of Drop Foot
Many exercises aim to improve weakness of the tibialis anterior specific to drop foot. Calf stretches and lower back exercises can also relieve tension and compression on the peroneal nerve, thus helping the tibialis anterior regain function. It is also important to work on strengthening the ankle and improving overall balance while standing and walking. Most exercises emphasize dorsiflexion, as this is the main struggle patients with drop foot face.
Exercises to promote dorsiflexion include:
- toe-heel rocks
- stretching the foot from a seated position with a resistance band
- lifting and holding a ball with both feet from a seated position with legs fully extended
- extending the leg outward from a seated position and repeatedly flexing the ankle towards the torso for 5 seconds
- isometric dorsiflexion with a resistance band
You can also perform isometric knee extension and flexion along with isotonic knee extension. Practicing flexion in the plantar and dorsi directions are both extremely beneficial and can be monitored with biofeedback!
How to use mTrigger for Drop Foot
When using mTrigger for drop foot, electrode placement is the name of the game. The muscles required for dorsiflexion include the tibialis anterior, extensor hallucis longus and extensor digitorum longus. Set up your electrodes on these muscles and perform exercises designed to promote dorsiflexion, as outlined above.
Biofeedback is excellent for reading muscle contractions during dynamic dorsiflexion with or without a resistance band. During contraction, the activation meter should be all the way up, hitting in the green “success zone”. During relaxation, the bar should fall back into the red. All patients are different, so get creative with applying biofeedback to your exercises! To use the mTrigger, first set an attainable MVC goal (maximum voluntary control) to start. Place it around 1000 microvolts and have your patient flex their foot toward their body. If they get into the green zone with ease, set the MVC goal a little higher. If they can only reach the orange or red when flexing as hard as they can, lower the MVC goal. As they gain strength in the tibialis anterior and other muscles related to dorsiflexion and drop foot, set higher targets for the MVC goal. You can even track progress with the Train & Track modules (just make sure you’re setting up your time parameters – learn more about settings here). Give your patients a goal to work toward – show them that their effort matters and that they are getting better with visual feedback and tangible results!
How does biofeedback help in rehabilitating drop foot?
In a study with 20 people suffering from chronic drop foot (see resources below), 10 participants went through conventional physical therapy training while the test group added a biofeedback intervention. After 5 weeks, the biofeedback group had an increase in strength and range of motion that was twice as great as the group that did not use biofeedback. Biofeedback produced better results because it requires patients to engage cognitively. sEMG biofeedback is an extremely active intervention, wherein visual feedback facilitates the motor relearning process. Patients work harder on every rep because they can witness the strength of their muscle contractions, and perform more accurately with real time data to inform and motivate them. Physical therapy can be cumbersome if someone is telling you what to do and you can’t see if it is actually working. Incorporating biofeedback into your practice will undoubtedly speed up recovery.
Article author: Sarah Green