When choosing a material to simulate tissues or structures, it can be helpful to evaluate how well the material performs in terms of several categories of fidelity. Five categories (Visual, Tactile/Haptic, Response to Manipulation, Auditory, and Olfactory) of fidelity are described below on a scale from 1 (low) to 5 (high).
| Level
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Description
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| 1
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Crude representative shape - Not recognizable. The material used to simulate the tissue/structure does not match anatomical accuracy, such as shape, color, size, and relationship to other landmarks or structures.
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| 2
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Rudimentary representative shape - Using this material, the tissue/structure is vaguely recognizable. This may include appropriate shape, color, size, or location with respect to nearby structures.
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| 3
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Reasonable visual representation - The tissue/structure is recognizable due to the material being somewhat accurate in shape, color, size, and location with respect to other nearby structures. At this level, the simulated tissue/structure is able to be used for identifying and differentiating anatomy.
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| 4
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Detailed visual representation - The tissue/structure is immediately recognizable due to shape, color, size, and contextual details modeled with the material. The simulated tissue/structure can be used for advanced anatomical identifications.
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| 5
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Exceptional visual quality - The material offers photo-realistic representation and precise anatomical accuracy. Human tissue is the gold standard.
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| Level
|
Description
|
| 1
|
Poor tactile feedback - The material does not feel like the structure/tissue. For example, the material may not stretch, compress, break, or bend when handled, palpated, or grasped. This level may also indicate a lack of attention to surface properties (stickiness, slipperiness, dryness, accurate temperature, etc.)
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| 2
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Rudimentary tactile feedback - The material vaguely resembles the feeling of the tissue/structure. The simulator’s physical feedback is somewhat realistic when handled (stretching, compressing, breaking, bending, or other surface properties).
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| 3
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Reasonable tactile feedback - The material fairly emulates the feeling of the simulated tissue/structure. The material provides the sensation of the tissue/structure in one or more types of handling (stretching, compressing, breaking, bending, or other surface properties).
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| 4
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Detailed tactile feedback - The material adequately emulates the feeling of the simulated tissue/structure. The material offers the sensation of the tissue/structure through multiple types of handling (stretching, compressing, breaking, bending, or other surface properties).
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| 5
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Exceptional tactile feedback - The material realistically emulates the tissue/structure. The material offers precise and varied feedback and accounts for many handling sensations (stretching, compressing, breaking, bending, or other surface properties).
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| Level
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Description
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| 1
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Limited response to manipulation - Interactions with the material do not yield realistic tissue/structure responses or the response may also be inappropriate or misleading. The material does not slice, cut, pierce, or tear like real tissue upon procedural interactions like suturing, blunt dissection, sharp dissection, cutting with scissors, etc. Material also does not mimic realistic reactions like bleeding or leaking.
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| 2
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Basic response to manipulation - Interactions with the material yield responses somewhat similar and appropriate to the tissue/structure. The material may slice, cut, pierce or tear similar to tissue; however, it does not mimic the same forces required. (e.g. too little or too much force) Material may attempt to imperfectly mimic reactions like bleeding or leaking.
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| 3
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Moderate response to manipulation - Interactions with the material are similar to real tissues. It cuts, slices, pierces and tears similarly to tissue and may have some functional behaviors like bleeding or leaking. The material offers tool-force interactions that approximate the tissue/structure. At this level, this material is appropriate for practicing basic tissue interactions like suturing, dissection, etc.
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| 4
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Detailed response to manipulation - Interactions closely mimic real tissue responses in terms of slicing, cutting, piercing, and tearing and have precise force interactions. Material may bleed or leak upon interaction
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| 5
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Highly responsive to manipulation - Interactions closely mirror real-world experiences, providing accurate and nuanced feedback to users. Material is excellent for building appropriate psychomotor skills for force application and dynamic response to materials that bleed or leak fluid.
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| Level
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Description
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| 1
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Unsuitable auditory cues - Fails to emit appropriate sounds that effectively convey the state of the tissue/structure. This may include sounds from the material itself or sounds generated from tools engaging with the material. May also give erroneous auditory information due to the characteristics of the material.
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| 2
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Subtle auditory cues - Material produces some auditory feedback when interacted with, however, the cues are not useful for understanding the status of the procedure.
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| 3
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Clear auditory cues - Material emits recognizable and procedurally appropriate sounds in response interactions. At this level, the materials can begin to provide usable feedback to the learner as to the status of the procedure. However, the accuracy and variability of the sound is limited.
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| 4
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Detailed auditory cues - Material emits detailed sounds that can inform procedural status. Material is able to support changes in sound quality such as pitch, echo, or timbre that indicate changes in the tissue/structure.
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| 5
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Excellent auditory feedback - Material produces sounds that precisely signal changes in status of the tissue/structure. These sounds are realistic to the local anatomy and relevant to the procedure.
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| Level
|
Description
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| 1
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No olfactory feedback provided - The material lacks any representation of procedurally relevant odors. At this level materials may also contain odors that misdirect the learner.
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| 2
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Minimal olfactory feedback - The material contains odors, however, these are anatomically inaccurate or not useful as feedback for the status of the tissue/structure during the procedure.
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| 3
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Moderate olfactory feedback - The material has odors that may imply the state or condition of the tissue/structure and could be useful as feedback during the procedure. However, the accuracy, timing, and variability of the odors is limited.
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| 4
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Detailed olfactory feedback - The material has recognizable and specific odors that are actively helpful to the procedure. Presence of odors upon specific interactions may be prioritized over biologically accurate scents. (Scented water instead of urine)
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| 5
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Exceptional olfactory feedback - Accurate representation of tissue/structure odor in relation to status, conditions, or specific interactions. At this level, the material may present a wide range of odors with biological realism.
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