Static balance, the Clinical Test of Sensory Interaction for Balance (CTSIB)
The Clinical Test for Sensory Interaction of Balance (CTSIB) is a more complex sensory strategy balance test. It is administered by:
1) manipulating the support surface (ie, firm vs foam),
2) visual conditions (ie, eyes open, eyes closed), and
3) vestibular system (sway reference by using a dome or computerized sway platform ), while an individual is asked to maintain their standing balance.
The CTSIB test helps determine which sensory system (visual, somatosensory, or vestibular) the person relies on to maintain balance.
The Clinical Test of Sensory Interaction and Balance is a timed test (normal is 30 seconds) that was developed for systematically testing the influence of visual, vestibular, and somatosensory input on standing balance. This test is inexpensive, requires minimal equipment, and is currently in use by some clinicians. Conditions 1, 2, and 3 involve standing on the floor with eyes open, eyes closed, and wearing a visual-conflict dome. The dome provides a sensory conflict by depriving the subject of peripheral vision and introducing a sway-referenced image. Use of the conflict dome results in a discrepancy between vestibular input stimulated by postural sway and visual flow. Thus, conditions 2 and 3 should examine different aspects of sensory organization of visual information that may require different postural adjustments. That is, condition 2 examines how well subjects maintain balance in the absence of any vision, and condition 3 examines how well subjects maintain balance when vision is present but that information conflicts with vestibular information.
Conditions 4, 5, and 6 involve standing on foam and repeating the visual conditions described for conditions 1 through 3. For each condition, the length of time the subject can maintain standing and the amount of body sway that occurs are assessed.
1: eyes open and firm surface, ( all 3 sensory systems are available here, vision, somatosensory and the vestibular system, normal standing time is at least 30 sec)
2: eyes closed and firm surface, (2 sensory system are available here, somatosensory/vestibular. You take away the vision; patients who are dependent on vision become unsteady here. That is, condition 2 examines how well subjects maintain balance in the absence of vision)
3: eyes open, visual conflict (dome) and firm surface ( All three systems are available, but you have a conflict between eyes and vestibular information, patients who are dependent on vision are unsteady here; condition 3 examines how well subjects maintain balance when vision is present but that information conflicts with vestibular information.)
4: eyes open and unstable surface (foam) ( if patients are dependent on surface/somatosensory inputs, they are unsteady in this position, and number 5 and 6; i.e . all positions on foam/unsteady surface; vision and vestibular system are available)
5: eyes closed and unstable surface ( you have taken away vision and the reliance on the surface/somatosensory system; patients with vision dependency due to somatosensory or vestibular loss are unsteady here)
6: eyes open, visual conflict and unstable surface ( visual conflict can create a problem for patients depending on their vision for balance, patients with somatosensory or vestibular loss are unsteady here)
• Patients dependent on vision become unstable in conditions 2,3, 5 & 6 where we either close the eyes, or have a conflict between vision and the vestibular system
• Patients dependent on surface/somatosensory inputs become unstable in conditions 4,5 & 6 because we stand the patient on a soft surface ( foam)
• Patients with vestibular loss become unstable in conditions 5 &6 because they can’t rely on vision or surface/ somatosensory function
• Patients with sensory selection problems become unstable in conditions 3-6.
Treatment: Treatments may involve the manipulation of sensory input while performing a task. This may be done for any of the three systems responsible for providing sensory feedback. For example, to encourage use of vestibular input, visual and somatosensory information may be challenged. Visual input is challenged by taking it away (e.g., eyes closed) or by destabilization (e.g., involving head and eye movements in the task). Unstable surfaces (e.g., rocker board or rough terrain) or compliant surfaces(e.g., foam) help to challenge somatosensory input. Vestibular input may be manipulated by changing the position of the vestibular organ (e.g., neck extension or repeated head movements).