As a generality, exercise is therapeutic for people of all age groups, and specific training produces improvements in muscle strength and endurance no matter what the age of the individual. Exercise also provides benefits in agility, balance, cardiovascular conditioning, metabolism, work capacity and weight control, as well as often fostering a greater sense of well being for the individual.
Physical exercise requires muscle work. Each muscle in the body is controlled or driven by a specific motor nerve (or nerves), and each motor nerve is ultimately derived from spinal roots coming out of the spinal cord. To produce weakness, Guillain Barré Syndrome (GBS) attacks the motor nerves at the root level and along the course of the specific nerves heading to their respective muscles. Once the acute illness phase of GBS subsides, strength only redevelops according to the extent of the recovery of each motor nerve.
Physicians and therapists measure the strength of muscles at the bedside and in their clinics or offices by manual muscle tests. Manual muscle testing checks the strength of a muscle contraction across a joint, such as the biceps muscle strength is tested with the patient exerting as much force as he/she can to bend their elbow while the examiner attempts to pull the elbow out straight.
If the examiner finds the strength of the patient's muscle to be too great to overcome, then the strength is graded as normal or 5/5. If the examiner overcomes the patient's muscle pull, then the strength is graded as good, or 4/5. If the patient is just strong enough to bend the elbow against gravity, without any resistance by the examiner, then the strength is graded as fair or 3/5. If the patient is not able to move the joint against gravity but is able to move the joint fully with it eliminated, then strength is graded as poor, or 2/5. If even in a gravity eliminated position, the joint can only barely move or the muscle can only feebly tighten, then the strength is graded as trace, or 1/5. A paralyzed muscle unable to move the joint or even be perceived by the examiner is graded as zero or 0/5.
As a very gross over-simplification, muscle strength can be derived from the percentage of functioning axons of motor nerves. Normal strength (5/5) can be achieved with 50 to 100% of functioning axons. Good strength (4/5) is achieved with around 40% of functioning axons. Fair strength (3/5) indicates about 30%, poor strength (2/5) about 20%, and trace strength (1/5) about 10% of functioning axons of the motor nerve.
For the post GBS patient with normal strength (5/5) throughout, the muscular response to exercise can return to normal, like before the GBS. Progressive resistive exercises can produce the same degree of effort and muscular response as before the GBS. There may be a more perceptible limit in strength and endurance to specific exercise, but through training and diligence, improvement may be forthcoming.
For the post GBS patient with good strength (4/5), the muscular response to progressive resistive exercises may either be an improvement in strength towards normal if the recovery of the motor nerves is substantial or if there is not a substantial recovery there may still be some degree of improvement without the ability to reachieve the previous levels of maximal muscle performance like before the GBS. Exercise can produce less of a muscle “burn” sensation before fatigue occurs. At times, if overworked, the muscle may temporarily fail to achieve the power demand until rested.
For the post GBS patient with fair strength (3/5), the muscular response to exercise may be either a limited improvement in strength, or muscle fatigue and performance failure depending on the work load. Patients must be cautioned that they may experience abrupt fatigue or performance failure in this strength range. Physician and therapist direction is mandatory in order to provide specific direction for optimizing the types of exercises and avoiding harm.
The post GBS patient with poor strength (2/5) or trace strength (1/5) should exercise in gravity eliminated position or in a pool or spa. Exercise must be designed to maintain and possibly improve strength and function while maintaining range and preventing complications. Just performing activities of daily living may be quite enough of an exercise. Adaptive aids are frequently useful. Again, physician and therapist direction is mandatory in order to provide specific directions, the types of exercise, and avoiding harm.
Unfortunately, if a sufficient number of functions axons of the motor nerves do not recover or regenerate to the next higher level of potential muscle strength, (like from a 2/5 to a 3/5, a 3/5 to a 4/5, or from a 4/5 to 5/5), strengthening efforts will not be rewarded with an improvement in strength. Muscle atrophy becomes prominent when motor nerve axons are irreversibly lost, such as with 0/5 and prolonged 1/5 grades of strength. No type or amount of exercise has ever been shown to regenerate lost motor nerve axons.
In summery, each post GBS patient should consult with their neurologist, rehabilitation physician and/or therapist about what types of exercise regimens are best suited to their own personal medical needs, keeping in mind the resources of their own specific geographic locale – community and home environment – as balanced by personal and family commitments.