Brain Sci. 2020

Authors: Anne Hoffmann, Angel Wang, Natalie Berger, Lisa Corderio, Rebecca Shaffer, Nicole Tartaglia, Craig Erickson, and Elizabeth Berry-Kravis

At the time of this writing, three Fragile X specialty clinics are collecting supplemental information for FORWARD. They assess and collect longitudinal (over time) data on a group of tests to measure cognitive and behavioral function in the FXS population so that we can specifically understand the course of development in FXS. This is one of the two publications that was a result of those efforts.

Summary

Although it is widely known that language development is delayed in the majority of individuals with FXS, there has been limited understanding on how to best assess language in FXS. This research examined the standard assessments commonly used to capture language and cognition in individuals with FXS. The research aimed to describe cognition and language in FXS using the data from a large group, while trying to understand if the standard assessments are feasible (able to be done accurately) and valid (reflect reality) in FXS and then compared the assessment results to caregiver report. Findings suggested:

  • Commonly used evaluations to measure language can be very difficult to use in FXS and may result in scores that are not useful or inaccurate. Because individuals with FXS generally have delays in their language development, age-specific evaluations often do not contain the properly lower ranged selection options needed to provide a useful score to properly assess abilities of those with FXS, resulting in many individuals receiving the lowest score possible on certain tests. This is called a floor effect. Because of this floor effect, it is not possible to gain important information such as the individual’s strengths and weaknesses. Administering these tests out of age range can lead to inability of comparison across other areas being evaluated and does not allow for comparisons to the general population.
  • When looking at language delays across ages, individuals ages 7–20 with FXS have a slower rate of progress relative to their peers who are typical. This delay in language development becomes more apparent as individuals become older.
  • The comparison between caregiver report and assessment report scores showed that caregivers portrayed language as being at a lower level than what the standardized assessment tests showed.
  • Most individuals with FXS are able to participate in standardized assessments. Behaviors are not a limiting factor, finding the best test to capture the individual is the challenge.

Why This Is Important

These results speak to the need for assessments that provide a wider range of items so individuals with FXS can achieve an accurate score and capture progress as they gain language skills. This study also shows the importance of clinical expertise when choosing assessments for individuals with FXS. The widely used assessments for language may overlook areas of relative strengths and weaknesses, which will make it difficult to determine appropriate intervention targets and capture any progress. Clinicians will likely need to combine several measures to determine an accurate language profile, especially for older individuals who are missing foundational language skills.

Lack of appropriate evaluation tools is a challenge for all populations with intellectual and developmental disabilities. As clinical trials continue to increase, so does the need for valid outcome measures. Possibilities for alternative assessment tools could include dynamic assessment (the assessment task is modified during testing depending on the participant’s abilities) and communication sampling (which provides a more natural view of communication abilities), which are both appropriate for a wide range of language abilities.

What Are the Next Steps

Future research should continue to explore alternative means of capturing skills accurately, as well as the development of standardized outcome measures that are appropriate for a wide range of language abilities.

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