SENSORY ORGANIZATION TEST (SOT)
Description
SOT Report
Functional Implications
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Description
The SOT protocol objectively identifies abnormalities in the patient's use of the three sensory systems that contribute to postural control: somatosensory, visual and vestibular. During the SOT, useful information delivered to the patient's eyes, feet and joints is effectively eliminated through calibrated "sway referencing" of the support surface and/or visual surround, which tilt to directly follow the patient's anteroposterior body sway. By controlling the usefulness of the sensory (visual and proprioceptive) information through sway referencing and/or eyes open/closed conditions, the SOT protocol systematically eliminates useful visual and/or support surface information and creates sensory conflict situations. These conditions isolate vestibular balance control, as well as stress the adaptive responses of the central nervous system. In short, patients may display either an inability to make effective use of individual sensory systems, or inappropriate adaptive responses, resulting in the use of inaccurate sense(s).
The SOT protocol is comprised of six sensory conditions:
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Sot Comprehensive Report
- Equilibrium Score quantifies the Center of Gravity (COG) sway or postural stability under each of the three trials of the six sensory conditions. Effective use of individual sensory inputs is determined from the overall pattern of scores on the six conditions. The composite equilibrium score, the weighted average of the scores of all sensory conditions, characterizes the overall level of performance.
- Sensory Analysis ratios are used in conjunction with the individual equilibrium scores to identify impairments of individual sensory systems.
| Ratio |
Comparison |
Functional Relevance |
Somatosensory
(SOM) |
Condition 2
Condition 1 |
Patient's ability to use input from the somatosensory system to maintain balance |
Visual
(VIS) |
Condition 4
Condition 1 |
Patient's ability to use input from the visual system to maintain balance |
Vestibular
(VEST) |
Condition 5
Condition 1 |
Patient's ability to use input from the vestibular system to maintain balance |
Preference
(PREF) |
Condition 3 + 6
Condition 2 + 5 |
The degree to which a patient relies on visual information to maintain balance, even when the information is incorrect. |
- Strategy Analysis quantifies the relative amount of movement about the ankles (ankle strategy) and about the hips (hip strategy) the patient used to maintain balance during each trial. Normal, stable individuals move primarily about the ankle joints when the surface is stable and shift to hip movements as they become less stable.
- Cog Alignment reflects the patient's COG position relative to the center of the base of support at the start of each trial of the SOT. Normal individuals maintain their COG near the center of the support base.
- The shaded area on each graphic represents performance outside of the normative data range. Green bars indicate performance within the normal range; red bars indicate performance outside the normal range.
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Functional Implications
Accurate organization of sensory information is critical to maintaining balance within the variety of environments encountered in daily life. An inability to organize sensory information appropriately can result in instability in environments where visual cues are diminished (darkness, lack of contrast/depth cues), the surface is unstable or compliant (sandy beach, gravel driveway, boat deck, etc.), or conflicting visual stimuli are present (busy shopping mall, large moving objects such as a nearby bus, etc.). Inability to appropriately organize sensory information can lead to or be exacerbated by impairments in COG alignment and/or selection of movement strategies.
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