Designing practical balance training
This article deals with the application of taxonomy in the context of therapy with standing and balancing devices (selfservice devices).
The central idea of taxonomy is to ensure an individually tailored therapy (“targeted therapy”)  through the targeted selection of tasks and the equally targeted design of the environment. This approach implements the requirements of the Dutch guideline for task specificity and environmental specificity in therapy for stroke patients [5, 6, 10, 16]. Standing and balancing devices (self-service devices) provide many options here.
One of the most important options for the targeted adjustment of the task is choosing the size of the support surface (see Fig. 1), because foot positioning is probably the most traditional way of shaping. Shaping here refers to systematically increasing the level of difficulty . According to the challenge point framework, the aim is to always challenge the patient at their individual performance limit . The increasing levels of difficulty are: parallel standing, stepping stand, tandem stand, single-leg standing . Crosslegged standing could be added. However, this standing position is not very functional.
Another important component in adjusting the task is to determine the directions in which the body’s centre of gravity should be moved across the support surface. The main directions of movement are anterior-posterior (a-p), mediolateral (m-l) and 2D movements, which result from a combination of a-p and m-l weight shifts (see Fig. 2). Anterior weight shifts are a useful means of practising the “ankle joint strategy”, which mainly activates the distal muscles [11, 13], while m-l weight shifts train lateral movement control. The proximal muscles are mainly required here. In severely affected patients it can also be beneficial to exercise statically, i.e. the body’s centre of gravity should simply be held above the support surface without any visible movement. The aim here is not to fall over.
Weight shifts can also be induced through reaching and grasping movements of the upper extremities (see Fig. 4). This is a very functional approach, because everyday life involves lots of arm and grasping movements while standing. Depending on the target point of the reaching or grasping movement, the direction of the weight shift can be determined . For grasping movements, the level of difficulty of the task can also be adjusted by changing the weight of the object to be lifted (keyword: shaping).
Many neurological and also geriatric patients have difficulties with what is known as sensory weighting. Sensory weighting is the dynamic process of integrating and processing sensory information . The sensory information that the central nervous system uses to control balance is somatosensory, visual and vestibular input. For example, in unfavourable lighting conditions, sensory integration must be weighted in favour of somatosensory input and away from visual input.
People with balance problems often rely excessively on visual acuity . This results in a more or less pronounced gaze fixation. To train sensory weighting, the task can be adjusted accordingly. One option for reducing gaze fixation is to perform gaze sequence or gaze stabilisation tasks. This involves moving the head while the eyes remain stable. The “classic” therapy for sensory weighting is working with closed eyes. It is important to note that it makes sense to give target points for shifting weight that can be sensed by the somatosensory system (see Fig. 5). These target points provide the patient with orientation for the extent of the weight shifts.
Adjusting the environment
Targeted adaptation of the environment provides further interesting therapy options (see Fig. 6). Physical therapy wedges are particularly suitable for specific training of certain aspects of postural control . There are three basic wedge position variations: toes-up, toes-down and both in
combination with a diagonal wedge position, which then has a pronatorial tilting effect. The different wedge positions have different indications . The toes-up position causes a mobilisation of the calf muscles, the toes-down position causes an increased activation of the calf muscles; this can help to improve the ankle joint strategy. The diagonal wedge position causes a pronated position in the lower ankle joint, which is intended to counteract the typical supinated misalignment of the feet in neurological patients. The diagonal position can be combined with both toes-down and toes-up. Further options then arise from the additional inclusion of different foot positions when working with the therapy wedge.
Motivation through exergaming Exergaming allows for an expansion of therapy options (see Fig. 7). Through various game situations, certain aspects of postural control can be trained in a very specific way. The games can have a positive influence on motivation during exercise and are also well-suited for independent training, as permanent supervision by a therapist is not necessary. Exergaming can easily be combined with all the aforementioned aspects of task and environment design.
Finally, a short (and incomplete) list of “typical” balance problems in neurological and geriatric patients [1, 2, 3, 14]:
- limited upper ankle strategy for shifting weight, particularly anterior but also posterior
- medio-lateral instability or limited weight transfer, particularly on the more heavily affected side
- limited sensory weighting
The problem areas of the patient are identified in a prior clinical reasoning session. Then a tailored therapy is developed.
Ultimately, task and environmental specificity are essential criteria for the effectiveness of the therapy. Using imagination and expertise, meaningful and individualised therapy situations can be created with self-service devices.
Therapy using self-service devices can be designed individually and in a targeted manner. It provides many therapy options in a fall-safe environment. In addition to the task and environmental specificity, the effect factor of intensity can also be implemented.
The possibilities and limits of the balance trainer:
Though balance trainers offer many possibilities, they are also limited in some respects.
+ Fall-proof environment
+ Very suitable for severely affected patients
+ Advantages of verticalisation (prophylaxis, alertness etc.)
+ Functional mobilisation of the upper ankle joint
+ Passive and active standing
+ Static and dynamic standing
+ Exergaming –> Fun, independent training
+ Increased standing time
+ Can be used for self-training
- Influence of the device frame on balance control (holding, leaning). One solution is to have the patient’s arms crossed in front of the chest.
- No “free” weight shifts possible within the device frame (move in the frame), the user must move the device frame (move the frame).
- The user must work against the spring resistance of the device frame when shifting their weight. This partly changes the postural synergies.
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Martin Huber is a physiotherapist and received his Master of Science in Neurorehabilitation in 2007. As a therapist, he mainly treats patients with damage to the central nervous system. Since 2010 he has been working on a freelance basis in outpatient physiotherapy with neurological patients. He has been reporting on postural control and task-oriented therapy in well-known scientific journals for several years, and he has been a speaker at various national physiotherapy conferences.