External (Field) Evidence to Support Practice
External evidence can come in many forms. Evidence found at the AAC Institute site is generally based on quantitative measurement of communication performance.
Evidence can be organized in different ways. Some evidence is based on individuals with specific conditions.
Amyotrophic Lateral Sclerosis (ALS)
Motor Neuron Disease (MND)
Evidence can be specific to particular topics. For example, the false notion that communication rate using word prediction is generally faster than spelling continues to persist. Research addressing this topic is available at:
Other evidence may have been generated based on able-bodied subjects in a research study. The validity and applicability of evidence is a function of many factors. A system of categorizing evidence has been developed by the AAC Institute. It is based on the evidence classification system developed by the American Academy for Cerebral Palsy and Developmental Medicine (AACPDM).
Although research evidence can be based on both qualitative and quantitative data, only papers that include quantitative performance measurement of communication generated using commercially available systems are included in the database. Visitors to the website are encouraged to search other sources of research to find all the evidence required to answer their questions. Many different types of evidence and empirical data may be found that relate to your questions. Various sources for research can be found under links
to other resources. The table below serves as one entry point into the AAC Institute database of AAC practice evidence. Generally, areas of evidence that are represented higher in the table have higher validity. However, even non-empirical evidence should have value. Research based on subjects who rely on AAC is generally considered stronger than evidence based on subjects who do not rely on AAC.
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Subjects who rely on AAC
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Subjects who do not rely on AAC
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Level |
(a) |
(b) |
(c)
Group Research |
(d)
Single Subject Research |
(e)
Non-Empirical Research |
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I
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·Randomized controlled trial ·All or non case series |
·N-of-1 randomized controlled trial | ·Randomized controlled
trial ·All or non case series |
·N-of-1 randomized controlled trial | |
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II
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·Non-randomized controlled trial ·Prospective cohort study with concurrent control group | ·ABABA design ·Multiple baseline across subjects |
·Non-randomized controlled trial ·Prospective cohort study with concurrent control group | ·ABABA design ·Multiple baseline across subjects |
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III
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·Case-control study
·Cohort study with historical control group |
·ABA design | ·Case-control study ·Cohort study with historical control group |
·ABA design | |
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IV
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·Case series and registries without control group | ·AB design | ·Case series and registries without control group | ·AB design | |
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V
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·Descriptive case series or case reports |
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Other external evidence to support clinical practice.
Review of External Evidence Related to AAC Dynamic Display Technology
