Consensus of the Fragile X Clinical & Research Consortium

An Introduction to Assessing Children with Fragile X Syndrome

Reading Time: 55 min.|Last Updated: Dec. 2021|First Published: June 2011|Download PDF

Note: There is another version of this document available for clinicians, providers, and other professionals who wish to learn more about specific assessment measures and tools, including their strengths and weaknesses, and a list of references. See Assessment of Individuals with Fragile X Syndrome: Detailed Recommendations for Clinicians, Providers and Other Professionals.

Assessment and assessment tools: Tests, questionnaires, interviews, etc., to measure a person’s skills.

Assessor or examiner: The person conducting the assessment.

Cognitive flexibility: The brain’s ability to transition from thinking about one concept to another.

Lability: Liable to change; easily altered, as in rapid changes in mood.

Level of development or functioning: Assessments are used to determine cognition, communication, sensory processing abilities, and motor skills.

Maladaptive behaviors: Actions or tendencies that do not allow an individual to adjust well to certain situations; and prevents them from making behavior adjustments that are in their own best interest. These actions are typically disruptive, potentially harmful to self or others, and can range from mild to severe.

Neuromotor testing: Evaluates motor functions through the age at which a skill is expected to be mastered.

Norm-referenced test or standardized measure: Designed to compare and rank test takers in relation to others of the same age (established by prior testing of large samples of typically developing individuals at various ages). Also, a form of test that requires all test takers to answer the same questions, and scored in a “standard” or consistent manner, making it possible to compare the relative performance of individual students or groups of students.

Phenotype: A set of observable characteristics or traits of an individual resulting from the influences of genetics and the environment.

Psychometric test: Quantitative tests that give numeric scores or age equivalents for the measurement of psychological variables such as intelligence, aptitude, and personality traits.

Psychometric standards: A standard and scientific method used to measure an individual’s mental capabilities and behavioral style.

Reliability: The extent to which test scores are consistent across different occasions of testing, editions of the test, or raters scoring the test taker’s responses.

Response inhibition: Refers to the ability to suppress responses or actions that are not appropriate or no longer adaptive to a situation.

Self-harm or injurious behaviors: Behaviors that cause physical harm to the individual. Examples include hand biting or head banging.

Side conversation: Strategy to minimize anxiety and hyperarousal in an individual with Fragile X syndrome by minimizing direct communication.

Stimming: Self-stimulatory, repetitive motor behaviors that serve a purpose or provide positive internal feedback for the individual. Examples include hand flapping and rocking.

Response to intervention: A process used by educators to help students who are struggling with a skill or lesson; every teacher will use interventions (a set of teaching procedures) with a student to help them succeed in the classroom and should use quantitative (numeric) measurement to determine whether the student is responding to the intervention appropriately by making progress. Also known as RTI.

Validity: The extent to which a test accurately measures what it’s supposed to measure.

Working memory: A form of memory that allows a person to temporarily hold a limited amount of information in their mind to have it ready for immediate mental use. It is considered essential for learning.


Assessment of individuals with delayed development is important for many reasons.

Foremost among those reasons is to provide the family and the educational, medical, and therapeutic team around them clarity in identifying strengths and needs and aligning these to supports and interventions.

Multidisciplinary team assessments are used to design educational intervention programs that address the individual’s needs based on their current “level of functioning” or “developmental level.”

Other important reasons are to recognize any delays as early as possible to allow for early educational interventions and to create a baseline so future assessments can show if progress is being made and to make adjustments to ensure best outcomes.

Assessment of individuals with Fragile X syndrome (FXS) has numerous challenges, ranging from choice and limitations of instruments to behavioral and emotional factors in the individual that may impact the testing process to scoring and interpretation. Fortunately, decades of research and clinical experience related to assessment — including recent detailed studies of the performance of several measures as outcome measures for clinical trials — have provided very useful guidance.

This document covers several important general considerations for the clinical assessment of people with Fragile X syndrome, including (these are also found in our table of contents above):

We will also cover the primary domains of assessment, including recommended assessments:

Plus additional sections on assessment of:

Fragile X Phenotype

A phenotype is a set of observable characteristics or traits of an individual resulting from the influences of genetics and the environment.

All assessors (the person conducting the assessment, also referred to as examiner) should have an intimate understanding and awareness of the cognitive, behavioral, social-emotional, academic, speech-language, and neuromotor phenotypes of Fragile X syndrome. This ensures that they will:

  • Choose appropriate assessment tools
  • Administer the assessment in ways that are sensitive to the common challenges encountered
  • Recognize critical strengths and weaknesses when they are present
  • Interpret and report meaningful and accurate results

The Fragile X syndrome cognitive phenotype may include particular difficulties with:

  • Sequential processing of information
  • Attention
  • Working memory
  • Response inhibition (This refers to the ability to suppress responses or actions that are not appropriate or no longer adaptive to a situation.)
  • Cognitive flexibility
  • Math

The Fragile X syndrome behavioral phenotype is often characterized by:

  • Hyperactivity and impulsivity
  • Inattentive behaviors
  • Repetitive or stereotyped behavior and speech (which may be characterized as features of autism)
  • Self-injury
  • Irritable or aggressive behavior

The Fragile X syndrome social-emotional phenotype includes symptoms of:

  • Anxiety
  • Irritability
  • Mood changes
  • Obsessive or perseverative actions
  • Social approach-avoidance (including gaze avoidance)
  • Social communication delays (which also may be characterized as autism)

The Fragile X syndrome academic phenotype often includes skills that are delayed in all areas, or where there is a deficit, including with reading, writing, and math.

The Fragile X syndrome speech, language, and communication phenotype includes delays or disorders in all areas of speech and language, but particular features are:

  • Rapid speech
  • Cluttering (speech that sounds rapid and unclear or disorganized)
  • Repetitive or stereotyped speech (which may be characterized as a feature of autism)

The Fragile X syndrome neuromotor phenotype can include:

  • Hypotonia (abnormally low level of muscle tone)
  • Delayed fine and gross motor skills
  • Difficulty with coordination

These early symptoms may be the first presenting signs that lead to Fragile X syndrome testing and diagnosis.

It is important to note the many positive aspects often found in children and adults with Fragile X syndrome, including that they can be very social and friendly, and can have excellent imitation skills and strong visual and long-term memory. They also often like to help others, want to please and make others happy, are nice, are thoughtful, and have a wonderful sense of humor.

Principles of Assessment Selection

One of the most important aspects of Fragile X syndrome that must be considered in the assessment process is developmental level.

Given that most males and many females function in the intellectual disability (or ID) range, knowing a developmental age estimate prior to assessment (often based on an initial interview with a caregiver and behavioral observations) will greatly aid the assessor in their choice of instruments and starting points for tests.

There are several factors to consider when choosing an assessment for a person with Fragile X syndrome:

Assessments should demonstrate the usual psychometric standards of reliability and validity.

Use assessments that have established reliability and validity specifically in individuals with Fragile X syndrome. This provides added assurance that the tool is more likely to be helpful. If FXS-specific assessments are not available, the next best option is to confirm that the tool is valid for people with similar disabilities (general intellectual disability) but who do not have Fragile X syndrome.

Because of the range of abilities (particularly among females or males with mosaic Fragile X syndrome), assessments that are appropriate for those with an intellectual disability may not be appropriate for all individuals with Fragile X syndrome.

Important Note:
Assessments and measures, including behavioral and emotional, are developed using typically developing people. What this means is that an assessment is likely to yield scores that compare the individual with Fragile X syndrome to their age-peers, not to other people of the same developmental level.

In addition, some assessments may be inappropriate because they do not accommodate for the behaviors and other characteristics of those with Fragile X syndrome.

Lastly, assessments developed for older adolescents and adults, especially, may have materials and items less suited for individuals with Fragile X syndrome with lower mental or developmental ages, thus making it harder for them to engage and participate.

One may wish to discuss these issues with the assessor in advance of the assessment.

Assessment Strategies

There are several considerations for administration and scoring of developmental testing for young children with Fragile X syndrome.

Children with Fragile X syndrome may benefit from multiple opportunities to demonstrate skills when inattention interferes or they have difficulty engaging. It is especially important for clinicians to pair performance on developmental measures with parent-report since assessments completed by clinicians alone may not completely capture a child’s full range of skills.

Similarly, reporting on skills that are observed during an evaluation, but outside of the developmental test, may also provide a more complete picture of a child’s functioning. For example, a clinician might consider observing and noting receptive and expressive language skills that are observed throughout an evaluation (for example, during informal behavior observations) rather than only what is seen during administration of a given assessment.

Lastly, those with Fragile X syndrome will likely benefit from clinicians moving between developmental domains to administer items. For instance, shifting between cognitive items (such as administering a puzzle) and language items (such as identifying pictures in a book) often maintains engagement more effectively than requiring or expecting a child to complete all items in a single domain in consecutive order. Such flexibility allows the assessor to follow a child’s lead, encourage sustained motivation and attention, and improve overall rapport. Note that, depending on the assessment or test, the examiner may not have the flexibility of changing the order of items. If the examiner breaks standards, they will likely put this in the narrative of the report.


One of the primary limitations of developmental testing is that results represent only a snapshot of a person’s full skill set. It is often difficult for clinicians to fully capture the range of skills a person has based on a measure that is typically completed in 45–60 minutes, especially if behavioral factors exist such as aggression, tantrums, sensory processing issues, self-harm, hunger, thirst, or fatigue. When present, developmental testing will often underestimate true abilities, and thus it is especially important to pair results with caregiver-report.

Assessment from Multiple Perspectives, Sources, and Settings

As with any assessment, collecting information from multiple sources, perspectives, and settings will provide a more reliable and accurate measurement. This may be especially critical for people with Fragile X syndrome who can show highly variable behaviors and abilities depending on mood states, features of the environment (loud, crowded, or novel), timing of medications, or how comfortable and familiar they are with the assessor. It may be important to consider whether testing over one or multiple testing sessions is appropriate.

In all testing areas, collecting observations or ratings from more than one caregiver and a rater outside the home, such as a teacher, is encouraged so as to minimize any unintentional bias resulting from having just a single rater. For example, in the cognitive domain, try to obtain records of prior testing and include assessments of diverse areas of function, including executive function, verbal comprehension, processing speed, memory, and arithmetic reasoning.

In sum, the administration and interpretation of one assessment tool should never pass for a thorough evaluation. Instead, the combination of the following is necessary for comprehensive assessment:

  • Thorough record review
  • Family interview and school or vocational placement report
  • Performance on appropriate standardized measures
  • Behavioral observation
  • Educated and thoughtful clinical judgment

Preparation and Approach to Testing

General Information

Many preparations, strategies, and accommodations can be used to maximize the chances for a successful and valid clinical assessment of someone with Fragile X syndrome. These considerations are described in more detail below.

Unique aspects of Fragile X syndrome are anxiety, hyperarousal, and sensory processing difficulties. It is critical to consider these during testing. Many individuals are already anxious prior to the start of an evaluation. Eye contact, touch, unexpected noise, as well as the fatigue that may come with performing physically and emotionally difficult tasks can all lead to increased hyperarousal.

Paying attention to signs such as increased perspiration (especially in the palms), redness in the cheeks or ears, rapid breathing, increased gaze avoidance, or attempts to avoid the task with conversation (often seen in higher functioning or more verbal individuals) can help the assessor intervene earlier by minimizing eye contact, using side conversations, increasing breaks, offering rewards, etc., to reduce anxiety and hyperarousal.

In a comprehensive clinical assessment, various tasks can be interspersed in the evaluation with intentional breaks that include opportunities to move. The assessor should pace the testing session to maximize performance and maintain ease and engagement of the person being tested. Experienced assessors familiar with the needs of those with Fragile X syndrome are adept at taking proactive breaks to maintain the pace and flow and allow for a productive assessment experience.

Observing the child’s response patterns while attempting a task is valuable in assessing how the child solves a problem. This provides valuable diagnostic information when developing school strategies to improve learning.

In general, parents and other caregivers, and those conducting the assessment, should always be sensitive to the child’s need for breaks and rest, food and beverage breaks, and a comfortable environment free of distractions and neither too warm nor too cool.

Except for the very youngest of children, who may not understand verbal descriptions of a planned visit to a unique setting (if that is the case), children and adults with intellectual disability may benefit and have lessened anxiety if they receive an advance description of what will be happening. However, in some cases, such a description can actually increase anxiety. Therefore, parents will need to make a judgment call about how much and when they should begin to prepare their child for an assessment session.

Lastly, the assessor should allow appropriate time for the individual to become comfortable in the testing environment and to develop appropriate rapport prior to starting the assessment.

Presenting tasks with clear verbal and visual supports that denote beginning and end can be particularly useful when assessing individuals with Fragile X syndrome. For example, provide empty boxes that are crossed off (or filled with a sticker of their choice) after completing a task. For example: Telling them “when all the coins are in the box,” or after counting together to 10.

Consideration of the testing environment itself is also imperative, as sensory sensitivities and hyperarousal can impact performance. Reducing the amount of light, closing blinds to eliminate visual distraction, positioning the assessor between the individual and the door, and decreasing auditory interruptions (such as announcements over a speaker or loud fans or clocks) will help to encourage the best effort of the person being assessed and promote focus and sustained attention. Utilizing the expertise of an occupational therapist on the team to train the assessment team on how to support sensory needs and manage anxiety and hyperarousal can be very helpful.

Young children with Fragile X syndrome may be hyperactive and may be better able to respond to test items if they are not confined to a chair; others will benefit from the added structure and confinement of a seated position. These young children often need a lot of breaks, and all individuals with Fragile X syndrome may do best with testing spread across one or more days to minimize fatigue and frustration.

Many people with Fragile X syndrome respond well to humor or to comments about favorite interests, which can help to reduce anxiety and improve rapport.

Prior to the Test

The assessor should obtain information from the caregiver about expected challenges and past experiences with testing and should collect information about items or activities that may be especially motivating to use as rewards during the testing process.

It will be important to communicate with the caregiver about what to expect of the testing environment and schedule. Some assessors utilize a visual schedule that can be sent ahead of time to preview what will happen in order to reduce anxiety and increase predictability. To minimize anxiety and increase rapport, one idea is to send a friendly photo (or link to photos), or a short video of the assessor and testing environment before the testing day. People with Fragile X syndrome are often remarkable in their ability to recall names and faces and this can be used to ease anxiety, as they will often recognize the assessor immediately upon introduction.

It is important to establish whether the caregiver will be present in the testing room. Some younger children or particularly anxious individuals may need this to even enter the testing room, and thus will require the caregiver to be present throughout. Others will do much better without the caregiver present. Finally, a third group seems to do well with the caregiver initially present and then later excused.

Flexibility from the assessor is crucial, and the assessor may have to use different strategies throughout the process. For example, multiple breaks may be successful at the beginning of testing, but later may need to be reduced in order to maintain attention and motivation.

The assessment team may consider gathering information about interest areas and favorite topics so that they can personalize the materials and interactions, as familiarity can help to establish rapport.

Test Day

To name just a few considerations, on test day the person being assessed should be:

  • As rested as possible
  • Adequately fed (and prepared with snacks)
  • Equipped with any necessary vision correction (glasses, contacts) and communication devices
  • Physically healthy
  • Following their typical medication protocol

The amount of time for testing may be either much shorter than usual for a typically developing person (if the person with Fragile X syndrome is unable to progress very far on test items), or it may be much longer than usual (if the person is agitated, needs many breaks, etc.) so it is best to schedule more time than typically expected if possible, and to be flexible regarding breaks and pauses during the assessment.

Accommodations That Can Be Made to the Testing Process

A visual schedule can be quite helpful so the person being assessed can see the tasks that must be completed shown in sequence (using either photos or symbols) and so they can cross them off as they’re completed. A practice or warmup period may be helpful.

Initial testing items should be easy, and should be organized and already displayed for the individual so that testing can start immediately to generate success right from the beginning. Keeping a good pace is also important to reduce anxiety caused by waiting on the clinician to get materials organized and ready. A detailed explanation of the testing process is often unhelpful and may increase anxiety.

Inserting breaks into the testing, with access to favorite interests or toys, may help support motivation. However, special consideration should be given to whether the individual will be able to successfully transition back to structured activities after access to their favorite objects or interests.

When utilizing accommodations or “breaks from standardization” during testing, the key concept to keep in mind is to provide adjustments to the testing process — if doing so allows the person with Fragile X syndrome to demonstrate their ability and knowledge without altering the items or skills being measured. For example, it may be necessary to provide more practice items or instructions to ensure understanding of a task, or the assessor may need to repeat an item if the person is distracted. Some standardized tests allow for practice as part of the protocol.

Use of Rewards to Encourage Participation

Additional accommodations may include use of a token economy system (earning small rewards throughout testing leading up to a bigger prize after completion). This should be done using simplified instructions, allowing them to use a fidget toy or other object, and offering encouraging praise for appropriate effort.

When using a token economy system or other reward-based system, it is often important to find out from the caregiver beforehand what has worked with the individual in the past (such as stickers vs. goldfish snacks) and to consider whether certain rewards may be too distracting and disruptive (such as tablets). When possible, it can be extremely helpful for the individual to identify rewards from a “menu” to ensure cooperation and motivation.

Assessment Domains


Assessment of cognitive function typically includes IQ testing and various domains such as executive function (attention, inhibitory control, cognitive flexibility, working memory), processing speed, and visual perception — which is the ability to interpret, understand, and define incoming visual information.

The assessment process may include activities such as completing puzzles and having individuals answer questions about what they see.

IQ and other cognitive tests can be a very important component of an overall assessment. They provide caregivers, teachers, and other providers a sense of developmental level. These measures can be a useful predictor of daily functioning and level of independence, and they can help to form improved treatment, curriculum, and transition plans.

It is quite common for IQ scores to decline over time in children with Fragile X syndrome. This is usually not because of a loss in ability – in fact, skills often increase across development, just not as quickly as a typically developing child. Thus, as the “gap” between Fragile X syndrome development and typical development widens over time, these scores often decrease.

Note that the use of IQ tests for special education eligibility and placement varies from state to state. Many IQ tests are available, and each test has different strengths and weaknesses.

IQ tests generate standard IQ, index, or composite scores, which are almost always represented along a normal distribution where 100 is the average score in the general population. It is important to recognize that tests use many different types of tasks to generate these overall IQ scores and some tests have been researched more thoroughly in individuals with Fragile X syndrome than others, including adjustments or accommodations in the administration or scoring, which can greatly improve their accuracy and eliminate floor effects (getting the lowest possible score on the tests so their true level of ability can’t be measured).

Recommended Assessments — Intelligence or Measures of Early Development

  • Stanford Binet Intelligence Scales, Fifth Edition (Stanford-Binet 5)
  • Wechsler Intelligence Scales (Wechsler scales) — Note: Best used for females and higher functioning males.
  • Leiter International Performance Scale (Leiter-3)
  • Differential Ability Scales, Second Edition (DAS-2)
  • Kaufman Brief Intelligence Test (KBIT-2)

Recommended Assessments — Executive Function

Working memory:

  • Wechsler Digit Forward and Backward
  • SB-5 Sentence Memory
  • Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) List Learning
  • Woodcock-Johnson Test of Cognitive Abilities Memory for Words

Visual memory:

  • Leiter-R Spatial Memory
  • SB-5 Block Span
  • Kaufman Assessment Battery for Children, Second Edition (K-ABC II Atlantis)

Assessment of executive function using caregiver and teacher rating scales:

  • Behavior Rating Inventory of Executive Functions (BRIEF) preschool and school-age versions
  • Conner’s Parent Rating Scales
  • Swanson, Nolan, and Pelham Rating Scale (SNAP-IV)


Adaptive Behavior and Daily Living Skills

The terms, “adaptive behavior,” “daily living skills,” “adaptive skills,” “functional skills,” and “adaptive functioning,” are often used interchangeably. They encompass multiple areas of functioning separated into three domains: conceptual, social, and practical skills. Among other skills within each of these domains, communication and socialization, personal self-care skills, and domestic and community living skills, are emphasized.

Adaptive behaviors include real-life skills such as grooming, getting dressed, following school rules, managing money, cleaning, and making friends. Measuring an individual’s adaptive behavior is a critical component as, over the last several years, adaptive behavior is increasingly emphasized as an important criterion for defining intellectual disability.

Furthermore, severity of intellectual disability is now characterized by delays in adaptive behavior and not IQ in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5)↗. In addition to aiding in diagnosis, results from adaptive behavior measures may also be used to determine special education eligibility, to plan and implement intervention and rehabilitation services, and to track and monitor progress. Given the reliance on measures of adaptive behavior, reliable and valid standardized assessment is increasingly important.

Recommended Assessments

  • Vineland Adaptive Behavior Scales, Third Edition (VABS-3)
  • Adaptive Behavior Assessment System, Third Edition (ABAS-3)

Maladaptive Behaviors

Maladaptive behaviors include challenging behaviors such as aggression, temper tantrums, or self-injury.

Maladaptive behaviors may be attempts to communicate discomfort (as when asked to make a quick transition or to do an activity they do not want to do), or to reduce anxiety and hyperarousal. Identifying and quantifying these behaviors is a critical component of assessment in Fragile X syndrome as it can aid in tracking response to treatment, as well as in identifying targets for intervention and possible obstacles to learning.

Assessment Strategies

The importance of and reliance upon caregiver-report in maladaptive behavior assessment cannot be understated. As such, an important step in the administration of questionnaires can be to discuss the time period for reporting — for example, discuss what was going on in the household 30 days ago. Providing examples when specific behaviors are not described in the questionnaire or interview can help to improve the accuracy of ratings.

Functional Behavior Assessments (FBA)

These assessments are an in-person observation and data-collection tool that can also be very useful in determining why certain behaviors may be occurring. These assessments can help determine if certain behaviors are specific to certain environments, which can help to inform the overall diagnostic picture. Functional behavior assessments can also help to track behavioral change over time, which may help to identify shifts in an individual’s behavior that may be suggestive of an underlying concern.

A functional behavior assessment (or FBA) typically starts with interviews with the child’s caregivers (parents and educators), where the specific maladaptive behaviors are described in detail. The interview also identifies antecedents, or things that occur right before the maladaptive behavior and make them more likely to occur, as well as consequences that maintain the behavior and make them more likely to occur.

With the maladaptive behaviors defined, direct observations of the individual are conducted in the environments in which the maladaptive behaviors typically occur. These observations help identify the pattern of antecedent-behavior-consequence, which then can be used to determine the function, or purpose, of the child’s behavior. This information is then used to identify replacement skills that the child can perform instead of the maladaptive behavior to get their needs met.


The reliance on caregiver questionnaires for assessment of behavior can be a limitation, as various forms of bias and limited recollection of behaviors can affect results. Additionally, the majority of measures have no way of accounting for the level of disruption to the individuals, their family, or others. This is especially important when considering treatment intervention and prioritization, as self-harm behavior occurring only once a day is different from relatively harmless repetitive behavior like stimming or perseverative questioning. Functional behavior assessment does gather more detailed information than checklists on the frequency, intensity, and duration of maladaptive behaviors, but limitations are that they are time-consuming and require specialized training and experience.

Recommended Assessments

  • Aberrant Behavior Checklist – Community, Second Edition (ABC-C-2)
  • ABC-Fragile X (ABC-CFX)

Note that these above are just two different ways of scoring the same questionnaire.

Parent-caregiver report:

  • Behavior Problems Inventory (BPI)
  • Restricted and Repetitive Behavior Scale – Revised (RBS-R)
  • Vineland Adaptive Behavior Scales, Third Edition (VABS-3) Maladaptive Behavior domain

Social and Emotional Functioning

The social-emotional phenotype includes prominent symptoms of anxiety (notably social anxiety and specific phobias), irritability or emotional lability, obsessive or perseverative thoughts, and poor coping mechanisms.


The presence of anxiety is common in Fragile X syndrome and has been previously documented at rates higher than other intellectual disability populations. The higher rates of anxiety in Fragile X syndrome compared to general intellectual disability suggests that the FMR1 full mutation that causes Fragile X syndrome presents an increased risk for anxiety and has been found to be independent of other clinical factors (i.e., intellectual disability, autism diagnosis, gender, age, etc.). As such, a thorough clinical assessment and treatment of anxiety should be included in the Fragile X syndrome standard of care.

Assessment Strategies

Clinicians will often observe that individuals with Fragile X syndrome exhibit heightened anxiety symptoms when initially meeting an individual or in a new situation. As such, it is important to allow time for the individual to become more comfortable in order to assess how their behavior may change with time. Additional probes regarding whether preparation for an event or situation helps or hinders an individual’s success, frequency of avoidance and withdrawal, as well as discussion of the sequence of events leading up to aggressive or hyperarousal episodes, will help bring clarity to possible anxiety-provoking scenarios.

Regarding the assessment of anxiety: Assessments of anxiety in people with Fragile X syndrome almost always must rely heavily on caregiver-report. An exception to this might include a higher functioning male or female who has relatively good insight into their emotions and body sensations, and who can verbalize well. Getting information from multiple sources (mother, father, teacher, other) usually leads to the most comprehensive picture of anxiety symptoms. Though there is no “test” that can be given to measure anxiety in Fragile X syndrome, the assessments below can help bring clarity and insight to an individual’s anxiety.

Recommended Assessments (with caregivers)

  • Anxiety Disorders Interview Schedule – Parent (ADIS-P)
  • Anxiety, Depression and Mood Scale (ADAMS)
  • Pediatric Anxiety Rating Scale – Revised (PARS-R)

Academic Skills

The assessment of academic skills, also referred to as educational testing, is important for educational and vocational planning.

Academic skills pertain specifically to reading, writing, and math skills. Obtaining information about current levels of academic functioning is essential for identifying learning goals, selecting appropriate curriculum materials, informing objectives for instruction, and determining the need for additional intervention and related services (for example, assistive technology, occupational therapy, or environmental modifications).

Often academic testing is used in an individualized education plan (IEP) in school, which provides goals, objectives, accommodations, and modifications to a curriculum to meet the unique needs of a student. (Refer to the General Educational Recommendations for Fragile X Syndrome.)

Academic skills are assessed using standardized measures that are norm-referenced and provide similar types of scores as IQ tests. Qualitative measures, such as curriculum-based assessments, that are based on academic content specifically taught in the classroom, may also be used. For children with Fragile X syndrome, it is often important to supplement the results of standardized testing with informal assessment and work samples.

Note: Children with Fragile X syndrome often outperform predictions made about their academic functioning based on their score on an IQ test. Academic functioning can be influenced by environmental factors — such as size of classroom, location of seating, amount and type of noise, unusual smells, anything that might affect sensory processing — and presentation of materials. Additionally, the presence of autism spectrum disorder (ASD) can impact acquisition of academic skills.

Assessment Strategies

Strategies to consider include breaking down tasks and changing the presentation of instruction in a stepwise fashion, using visuals (to assess math concepts, for example), and using additional cues to support how a student approaches a task. These strategies are not considered “standardized,” but they can really help facilitate understanding of what the person is able to do under the most optimal circumstances.

Recommended Assessments

  • Wechsler Individual Achievement Test-II (WIAT-III)
  • Woodcock-Johnson Tests of Achievement-III (WJ-III Tests of Achievement)
  • Kaufman Test of Educational Achievement, Second Edition (KTEA-II)
  • Oral and Written Language Scales, Second Edition (OWLS-II)
  • Bracken School Readiness Assessment, Third Edition
  • Diagnostic subtests of the DAS-2 (Differential Ability Scales, Second Edition)

Speech, Language and Communication

Speech refers to the actual production of sounds and words.

Language refers to the content of what we say (vocabulary and word choice).

Communication is the broadest category of them all and includes not just spoken words, but also nonverbal forms of communication such as crying, reaching, pointing, and looking.

Communication abilities are critical to social functioning, as well as to learning about the world in both formal situations, such as school, and informal situations, such as interactions with peers.

The inability to communicate can create a cascade in which many aspects of functioning, especially behavioral functioning, are increasingly negatively affected. Assessment of speech, language, and overall communication is important for guiding education, therapy, and even vocational training throughout the life course. There is an array of measurement tools to assess language in individuals with Fragile X syndrome, each with advantages and disadvantages.

Measures and the Use of Standardized Tests

Standardized tests have the advantages of clearly specified procedures. This ensures consistency in administration and allows comparison of the performance of the individual with Fragile X syndrome to typically developing individuals of the same age. Doing so allows for gauging the extent of delay in language for the individual with Fragile X syndrome.

A disadvantage, however, is that standardized assessments are often not sensitive enough to measure subtle gains in language skills across time, particularly during adolescence and adulthood, or in response to treatment.

Another disadvantage of such tests is that they measure language in situations very different from everyday social interactions, which means that performance on such a test may not always be a good indicator of how an individual with Fragile X syndrome actually uses and understands language or communicates in situations that are personally meaningful, such as school or on the job.

Assessment Strategies

The examiner should select a test based on the skills currently being displayed by the individual rather than strictly by chronological age.

Recommended Assessments

  • Preschool Language Scales, Fifth Edition (PLS-5)
  • Clinical Evaluation of Language Fundamentals – Preschool, Second Edition (CELF-P2)
  • Clinical Evaluation of Language Fundamentals, Fifth Edition (CELF-5)
  • Comprehensive Assessment of Spoken Language, Second Edition (CASL-2)

Parent-caregiver report:

  • MacArthur Bates Communicative Development Inventories (MB-CDIs) — For earlier stages of language development, allow tracking of current and emerging communication skills.
  • Children’s Communication Checklist, Version 2 (CCC-2) — For children between the ages of 4 and 16 who are using phrase speech (at least three-word utterances).

Natural Communication Sampling

Natural communication sampling procedures involve collecting and analyzing audio or video recordings of samples of spoken language from an individual with Fragile X syndrome in one or more structured but naturalistic interactions with an examiner or adult care provider. It is important that each interaction is structured and scripted so that it is reasonably consistent every time the individual is assessed.

When consistency is ensured, natural communication samples can provide excellent measures of an individual’s communication skills, including not only spoken language, but also the use of gestures and vocalization in prelinguistic or minimally verbal individuals.

Note: Assessment of natural communication sampling is a general approach to assessment. It can be used to provide a comprehensive analysis of the person’s language and help identify targets for language intervention. It can also provide a rough estimate of the extent of delay.

The Occupational Therapy Practice Framework: Domain and Process (OTPF) (American Occupational Therapy Association, 2014) defines the domain of practice of the profession. Occupational therapy’s (OT) domain encompasses those areas that parents and research reports tell us create the most difficulty in daily life situations for children, teens, and adults with Fragile X syndrome: play, social participation, sleep, family routines, independent living, and employment. Within this scope, assessments for sensory and motor skills as foundations for all of these areas of daily life function are often included in the occupational therapy assessment.

Occupational therapists have expert knowledge and skills in addressing these areas of occupational performance, including the contextual factors that influence performance, and they use a holistic view of the person and all of their interrelated systems and functions. Thus, the profession of occupational therapy, with its broad scope and focus, offers families numerous possibilities for assistance.

Neuromotor Functioning

Neuromotor development and functioning includes many aspects, such as general strength and motor skills, as well as motor speed/response time, dexterity, precision, balance, and coordination. Neuromotor skills are integral to the development of many other skills including daily living skills, cognition, and language. Note that while the physician or a psychologist may conduct neuromotor testing, an occupational therapist or physical therapist is best trained to administer and interpret neuromotor assessments.


Neuromotor assessments evaluate motor functions through the age at which a skill is expected to be mastered. Many comprehensive developmental tests include the domain of motor skills, especially for infants and toddlers. Even though these tests may be administered “out of age range,” they can provide very useful information. For example, an age equivalent score can tell us that the person’s motor function is most like a typically developing child of a given age.

Assessment Strategies

There are helpful strategies to consider when directly assessing neuromotor functioning in Fragile X syndrome. As it relates to standardized administration, verbal instructions may need to be adjusted to better match the language abilities of the individual. For example, pointing and saying “leg up” while demonstrating on the mirrored side (the examiner’s right leg for the examinee’s left leg) instead of “lift your left leg up.” More teaching or demonstration examples may need to be provided.

Within the test battery suggested for neuromotor testing, the Movement Assessment Battery for Children (MABC) is unique in that it includes photographs of the items. This type of support increases the nonintrusive guidance that allows for better test administration.

Finally, as prompting and guiding is needed, it should be noted that prompting should move from least intrusive (use of a visual model prior to any other guidance, and add a gesture or verbal guidance, depending on the task) to most intrusive (physical touch of any kind, including hand over hand) to provide the individual with the opportunity to perform the skill in the most independent manner possible. This successive prompt approach can also provide the clinician information as to what types of support may lead to success in intervention and therapies.

Recommended Assessments

  • Movement Assessment Battery for Children, Second Edition (MABC-2)
  • Quick Neurological Screening Test, Third Edition (QNST-3)
  • Vineland Adaptive Behavior Scales, Third Edition (VABS-3) Motor Skills domain (parent report)

Clinical observations of movement skills (as is common for occupational and physical therapy assessments), which may include looking at movement skills of the eyes, body, limbs, mouth, and hands, is important to complement any standardized testing and to aid in interpreting test results as well as making well-rounded recommendations. The testing results should summarize general motor functioning as well as give information about general gross and fine motor capacities. Also, testing in this area often identifies the need for referral to ophthalmology if ocular or eye-motor needs are identified.

Sensory Processing and Self-Regulation Functioning

Assessment of sensory processing and self-regulation capacities is important for individuals with Fragile X syndrome due to the specific phenotypic impact on these areas.


General occupational therapy assessments:

  • School Function Assessment (SFA)
  • Pediatric Evaluation of Disability Inventory Computer Adaptive Test (PEDI-CAT)
  • Children’s Assessment of Participation and Enjoyment and Preference for Activities of Children (CAPE/PAC)
  • Transdisciplinary Play-Based Assessment (TPBA)
Other Important Considerations In The Assessment Of Individuals With Fragile X Syndrome

Infant and Toddler Development

Assessment of developmental delays is recommended to occur as soon as differences are noted or a diagnosis of Fragile X syndrome is made. When Fragile X syndrome is identified prenatally or early in a child’s life, it is often encouraged for these children to be seen by a Fragile X specialist every three to six months before age 2, and at least yearly following their second birthday. Reevaluation of an individual’s skills is needed to inform treatment and education plans, and to track progress over time.


Comprehensive developmental measures assess skills across domains including early cognitive skills, (problem solving), language skills (receptive and expressive), and motor skills (fine and gross). While developmental measures do not directly assess social skills and play, as a unique domain these skills are often captured across items in the cognitive and language domains. For example, participation in social routines (for example, playing peekaboo), being attentive to nursery rhymes, and engaging in back-and-forth play are assessed in the language domain, whereas functional and pretend play skills are assessed in the cognitive domain. In addition, a child’s general approach to structured, adult-led tasks can also be observed and informally assessed during developmental testing

Recommended Assessment

  • Bayley Scales of Infant and Toddler Development, Fourth Edition (Bayley-4)


Fragile X syndrome is the most common, known single gene cause of autism spectrum disorder (ASD). While Fragile X syndrome accounts for an estimated 1% to 6% of all autism cases, many individuals with Fragile X syndrome are co-diagnosed with autism.

Readers should review the 2020 updated version of Autism Spectrum Disorder in Fragile X Syndrome for a more in-depth understanding of the relationship between autism and Fragile X syndrome.


Autism is defined by the presence of specific social communication and behavioral criteria. As such, assessment for autism, which can be associated with Fragile X syndrome, typically includes a combination of caregiver-report and in-person behavioral observation by a specialist knowledgeable about the relationship between autism and Fragile X syndrome.

Assessment Strategies

For those who are first diagnosed with Fragile X syndrome, pursuing an autism-specific assessment often calls for a different approach to evaluation and intervention. This is primarily due to the presence of relative strengths in social interest and motivation, as well as increased symptoms of hyperarousal and anxiety. Often these increased symptoms of hyperarousal and anxiety may manifest as extremely difficult externalizing behaviors, such as complete withdrawal from social interaction, task refusal, or severe aggressive or self-injurious behaviors. Therefore, additional considerations need to be made when conducting an autism-specific assessment.

Recommended Assessments

  • Autism Diagnostic Observation Schedule, Second Edition (ADOS-2)
  • Screening Test for Autism in Two-Year-Olds (STAT)
  • Autism Screening Instrument for Educational Planning, Third Edition (ASIEP-3)
  • Autism Diagnostic Interview, Revised (ADI-R)


The assessment of an individual with Fragile X syndrome must be comprehensive and accommodate the unique aspects of the person. Assessment must utilize tools that are appropriate — feasible, scorable, and valid — for use in Fragile X syndrome and commensurate with the individual’s developmental level.

Professionals are continually working to improve the assessment process and guide the selection of the most appropriate measures for use in Fragile X syndrome and recommendations will be updated accordingly.

Throughout the assessment process, assessors should always remember that individuals with Fragile X syndrome possess numerous strengths such as humor, desire to engage, social interest, visual memory, and sensitivity to others. Whenever possible these strengths should be noted and reflected within the assessment results.

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Authors’ Note

This document was excerpted by Robert Miller and Jayne Dixon Weber from a more comprehensive document, Assessment of Fragile X Syndrome — Detailed Recommendations for Clinicians, Providers and Other Professionals, authored by David Hessl, Lisa Cordeiro, Adrienne Villagomez, Elizabeth Coan, Leonard Abbeduto, Anne Hoffman, Angela John Thurman, and Lauren Schmitt. The document represents the current consensus of the members of the Fragile X Clinical & Research Consortium and includes specific edits by members Holly Harris, Marcia Braden, Tracy Murnan Stackhouse, Barbara Haas-Givler, and Amy Esler.

The Fragile X Clinical & Research Consortium was founded in 2006 and exists to improve the delivery of clinical services to families impacted by any Fragile X-associated disorder, and to develop a research infrastructure for advancing the development and implementation of new and improved treatments. Please contact the National Fragile X Foundation for more information at (800) 688-8765 or


If you’re a parent or caregiver and have questions about the information presented here, we’d love to hear from you! You can reach out to Missy Zolecki using the contact info or our contact form below.

Missy Zolecki

Missy Zolecki,
Community Empowerment
(800) 688-8765