apart in order to determine the test–retest reliability. The test–
retest reliability for the composite score ranged from 0.86 to 0.92 for the following three age groups: birth to 11 months, 12–23 months, and 24–35 months. The vast majority of test–retest reliabilities were above 0.80 for the three adaptive domains and above 0.70 for each skill area.
Content Validity
The theory and constructs of the ABAS-II (and consequently those items used for the Bayley-III Adaptive Behavior Scale) rely heavily on the AAIDD’s definition of adaptive behavior;
legal and professional standards regarding disability classifi- cation; theDiagnostic and Statistical Manual of Mental Disorders – Fourth Edition, Text Revision: the Individuals with Disabilities Act; and intervention research. Readers are encouraged to see Harrison and Oakland (2003, 2008) and Ditterline, Banner, Oakland, and Becton (2008)for a more complete discussion of the test’s reliability and validity.
a large northeastern city. The family’s apartment is one of four, all part of a large house built in the 1920s and divided into apartments in the late 1960s. Mr Ramirez is a custodian in a downtown apartment building. Mrs Ramirez works part time, in the late afternoon after Mr Ramirez returns from work, in a neighborhood convenience store. Marissa attends Head Start for half a day; Rochelle is cared for only by her parents and her maternal grandparents, who live nearby.
PREGNANCY AND BIRTH
Mrs Ramirez reported her planned pregnancy with Rochelle was unremarkable. Rochelle was born full-term with no peri- or postnatal complications, and weighed 7 pounds, 3 ounces.
Rochelle went home with Mrs Ramirez after an overnight stay in the hospital.
DEVELOPMENTAL HISTORY
As an infant, Rochelle was easy going and displayed no sleeping or eating problems. Rochelle was breast-fed until approximately 14 or 15 months of age.
Rochelle’s development was typical until approximately 11 months of age. Specifically, Rochelle smiled by 2 months, responded to her name by 4 months, and sat unsupported by around 6 months of age. Rochelle had more than 50 words by the time she was 15 months old, and was also speaking in short phrases by 15 months. At the time of this evaluation, Rochelle was not toilet trained; however, Mrs Ramirez reported they have begun to speak about toilet training with Rochelle.
Around 11 months of age, Rochelle’s development began to slow. Specifically, Mrs Ramirez noted concerns with Rochelle’s motor development. Rochelle did not walk by herself until she was 16 months old, and continues to walk with an awkward gait. At age 2, Rochelle began to try to run. However, Rochelle’s running was described as ‘‘looking funny, like she’s about to fall.’’ Mrs Ramirez attributes this lag in Rochelle’s development to lead poisoning.
In terms of temperament and behavior, Rochelle is described as a loving child with family, and somewhat unfriendly and slow to warm up with unfamiliar adults. Rochelle cries easily, experiences mood swings, and can get very angry. Rochelle
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may display anger more often and easier than others her age.
Although she is interested in other children and engages in parallel play when around them, she often gets very upset when they try to take her toys. For example, Rochelle commonly yells or cries when another child tries to take something of hers. Rochelle also will scream at her parents when she dislikes what they are telling her or when they ask her not to yell.
MEDICAL HISTORY
Rochelle was diagnosed with lead poisoning 6 months ago as the result of routine screening during a pediatric well-child check-up. The source of her lead exposure is unknown, but suspected to be a result of lead-based paint in the Ramirez’s apartment. At the time of her diagnosis, her lead level was 20
m
g/dl with a ZPP of 79. Rochelle’s mother hypothesizes that the lead poisoning actually began when Rochelle was approx- imately 11 months of age. At this point, her appetite drastically decreased, and she started to drop below normal growth rates on the growth-chart. Rochelle dropped from right below the 50th percentile to the 8th percentile in a matter of months.Rochelle’s appetite returned recently.
Prior to being diagnosed with lead poisoning, Rochelle had an ear infection which led to a perforation. Other than this incident and her lead poisoning, no documented medical problems have occurred.
Tests Administered
Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III).
Clinical Observation of Behavior
Rochelle presented as a sweet child who initially clung to her mother and eventually established rapport with the examiner.
However, she was quite distractible, very active, and demon- strated a low frustration tolerance. Specifically, if she was unable to do something on the first attempt, Rochelle commonly asked her mom for help, or would say ‘‘can’t do it.’’
Moreover, Rochelle displayed some opposition to following directions from adults, including examiner requests. Her play
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and interactions with materials were much more self-directed, and she showed little desire to engage in some of the activities presented to her.
Despite these difficulties, Rochelle appeared at ease with the examiner and the testing situation. Moreover, Rochelle appeared to enjoy playing with the examiner and the testing materials. Each of Rochelle’s parents were competent and nurturing in their interactions with Rochelle. Both her mother and her father encouraged Rochelle to continue trying when items were difficult, telling her what a good job she was doing when she was appropriately following the lead of the examiner.
The Bayley-III was administered over three 1-hour sessions, as Rochelle’s behavior and distractibility warranted frequent breaks and opportunities for self-directed play to complete the tasks. The administration was not rushed, allowing Rochelle to engage in self-directed activities throughout the course of the evaluation. Thus, the results of this assessment are thought to demonstrate a valid report of Rochelle’s developmental capa- bilities and difficulties.
Evaluation Results
DEVELOPMENTAL ASSESSMENT
The Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III), is an individually administered instrument whose primary purposes are to identify children with devel- opmental delay and to provide information for intervention planning. The Bayley-III assesses infant and toddler develop- ment across five domains: Cognitive, Language (Receptive &
Expressive), Motor (Gross & Fine), Social-Emotional and Adaptive. Assessment of the former three scales is conducted using items administered to the child. Assessment of the latter two scales relies on primary caregiver responses to a question- naire. The results from this scale are summarized inTable 6.2.
The Cognitive Scale includes items that assess sensorimotor development, exploration and manipulation, object related- ness, concept formation, memory and other aspects of cognitive processing. Rochelle’s cognitive abilities as measured by the Bayley-III are in the average range (Cognitive standard score¼95; 37th percentile) and consistent with a child her age.
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Rochelle had difficulty when asked to complete timed items.
Specifically, Rochelle was more interested in exploring objects and self-directing her interactions with the objects than following the examiner’s lead. Rochelle may be able to display behaviors assessed by some of the items for which she did not get credit; however, she was unable to receive credit for these items because she was unable to demonstrate this capacity during the standardized administration of items. Conversely, Rochelle was able to engage in game-like, problem-solving TABLE 6.2 Bayley-III Data for Rochelle Case Study
Domain
Composite score (mean[100, SD[15)
Scaled score (mean[10,
SD[3) Percentile rank
Language 129 97
Receptive Language 15
Expressive Language 15
Motor 88 21
Fine Motor 10
Gross Motor 6
Social Emotional 105 11 63
Adaptive Behavior 60 0.4
Communication 4
Community Use 5
Functional Pre Academics 7
Home Living 5
Health & Safety 4
Leisure 4
Self Care 3
Self Direction 5
Social 4
Motor 6
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items with ease. For example, she was easily able to find hidden objects and correctly place shapes on a form-board. Rochelle also used representational play with ease. She pretended to mix up food and feed it to a teddy bear, then she fed herself and placed the bear down for a nap and covered it.
The Language Scale is composed of receptive and expression communication items that form two distinct subtests. Rochelle’s overall language composite score on the Bayley-III was the same as or better than 97 percent of her same-age peers (Language standard score¼129, 97th percentile).
The Receptive Communication subtest of the Bayley-III includes items that assess preverbal behaviors; vocabulary development related to objects and pictures, social referencing, and verbal comprehension. Rochelle’s receptive communica- tion skills as measured by the Bayley-III are in the superior range, and above what is expected for a child her age (Receptive Communication scaled score¼15). Rochelle was able to point to various actions, including waving, sleeping, eating, drinking, reading, and riding. Additionally, Rochelle demonstrated an understanding of possessives when she was able to identify a boy’s car and a cat’s ball. However, she experienced more difficulty discriminating between the possessive pronouns his, hers, him, me, my, you, and your.
The Expressive Communication subtest includes items that assess preverbal communication such as babbling, gesturing, joint referencing, and turn taking, and vocabulary development such as naming objects and pictures. Rochelle’s expressive communication skills as measured by the Bayley-III also are superior and above what is expected for a child her age (Expressive Communication scaled score¼15). She utilizes multiple word questions and uses different word combinations when expressing her needs, wants, and ideas. However, Rochelle experiences more difficulty responding verbally to questions that begin with ‘‘what’’ and ‘‘where,’’ using plurals, and naming colors.
Rochelle’s overall motor skill development as assessed by the Motor Scale of the Bayley-III is at the low end of the average range (Motor standard score¼88, 21st percentile). The Motor Scale of the Bayley-III is divided into a Fine Motor and a Gross Motor subtest. Rochelle’s use of small muscle groups (i.e., her
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