Help for SwayStar™ (4.7.3.265)
The underlying principle for all balance testing is to measure the fundamental ability of a subject to integrate different aspects of sensory inputs into a unitary balance command during stance and gait, especially when this ability is challenged.
WARNING!
All tasks should be performed with the aid of one or two assistants as “spotters“ if the instability of the subject is great enough for there to be a danger of falling during testing or if the subject has a fear of falling. If the test person has to receive help from a spotter, or opens his eyes during a test with eyes closed, or touches the ground with the non-stance foot during 1-legged stance tests then the trial is ended, then a recording should be stopped and on saving the “Yes but .. the patient lost control of balance” or Retry buttons should be pressed ( See section 3.2.7 Recording – Saving).
Standing tasks are the easiest to perform but can be challenged by modifying the efficacy of visual (eyes closed) and proprioceptive (one-legged standing and foam support surface) feedback. There are four two-legged and three one-legged pre-defined stance protocols available in SwayStar™ on first installation.
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Two legged (4 tasks) |
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The subject is asked to stand naturally with the feet slightly separated: |
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standing with eyes open on a normal surface |
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standing with eyes open on a foam support surface |
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standing with eyes closed on a normal surface |
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standing with eyes closed on a foam support surface |
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One legged (3 tasks) |
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The subject is asked to stand on one leg of his choice. It may be necessary to have the subject try one leg or the other first before starting recording: |
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standing with eyes open on a normal surface |
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standing with eyes open on a foam support surface |
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standing with eyes closed on a normal surface |
Note: With eyes closed, most people cannot maintain balance while standing on one leg on a foam support.
Other standing protocols have been developed to accommodate special needs. For example, a series of protocols already exist for testing subjects with Parkinson's disease. These are known as shoulder pull or retro-pulsion tests with the subject pulled from behind (left backwards, right backwards and backwards with the subject warned, (expected) or not (unexpected).
Another task, cone of stability, involves the subject leaning as far as possible in 8 directions, moving solely like a stiff pendulum about the ankle joints.
Walking tasks involve more complex uses of sensory inputs and varied motor control. These tasks naturally lead to an increase in trunk sway in subjects who have a balance deficit when compared to normal subjects. There are four gait (one with barriers) and two tandem walking protocols available in SwayStar™ on first installation.
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Gait (4 tasks) |
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walking normally 3 meters five (approximately 5 steps) with the eyes closed |
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walking 3 m while horizontally rotating the head, left to right, in rhythm with the steps |
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walking 3 m while pitching the head, up and down, in rhythm with the steps |
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walking over a set of four low (24 cm high) barriers placed 1 m apart |
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Tandem steps (2 tasks) |
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The subject places one foot directly in front of the other (heel to toe) for 8 steps, eyes open, with and without foam. The subject is requested to watch his foot placement. |
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Walking up and down a set of stairs or a slope requires shifting from one foot to the other at a changed height combined with forward movement and fixation on step edges or slopes.
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Stairs (1 tasks) |
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Walking up a set of stairs with two upward and two downward steps |
Note: If there are handrails for the stairs, the subject should be instructed not to touch the handrails. If the handrails are touched during the protocol, it is to be interpreted as a fall and the protocol should be terminated.
The subject changes from a sitting position with arms hanging by the sides to a standing position (the stool should have no armrests). Three protocols are possible.
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Rising from a stool (3 tasks) |
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get up and go (walking 3 m) |
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get up twice, sitting down in-between |
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get up twice FAST, sitting down in-between |
The subject is asked to stand upright, as straight as possible, with feet normally apart. The goal is to reach, or bend as far as possible, toward an object or mark located in front or to the side of the subject. There are three reaching protocols.
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Lateral reaching (2 tasks) |
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The subject attempts to pick up an object placed laterally at the level of the fingertips (hand hanging at the subject’s side). The object is placed at a distance from the subject, relative to his/her height, at 25 cm for each meter tall (4 inches per 12 inches height). The task should be performed without bending the knees, simply bending the trunk laterally. To avoid knee bending, the subject is instructed to lift the opposite leg, i.e., if the object is on the left, the right leg is lifted; if the object is on the right, the left leg is lifted. The arm may also be raised. |
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Reach laterally with object on the right |
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Reach laterally with object on the left |
· Trunk flexion (1 task)
The subject is asked to flex as far forward as possible without bending the knees, then to straighten up as rapidly as possible.
Currently there are no default protocols listed under “other”. The user may define a protocol as such.