Further Development and Validation of the Affordances in the Home Environment for Motor Development–Infant Scale (AHEMD-IS)

Background

Affordances in the home environment may play a significant role in infant motor development.

Objective

The purpose of this study was to further develop and validate the Affordances in the Home Environment for Motor Development–Infant Scale (AHEMD-IS), an inventory that measures the quantity and quality of motor affordances in the home.

Design

A cross-sectional study was conducted to evaluate criteria for content validity, reliability, internal consistency, floor and ceiling effects, and interpretability of the instrument.

Methods

A pilot version of the inventory with 5 dimensions was used for expert panel analysis and administered to parents of infants (N=419). Data were analyzed with Cronbach alpha, intraclass correlation coefficients (ICCs), ceiling and floor effects, and item and dimension interpretability analyses for creation of a scoring system with descriptive categories for each dimension and total score.

Results

Average agreement among the expert panel was 95% across all evaluation criteria. Cronbach alpha values with the 41-item scale ranged between .639 and .824 for the separate dimensions, with a total value of .824 (95% confidence interval [95% CI]=.781, .862). The ICC values were .990 for interrater reliability and .949 for intrarater reliability. There was a ceiling effect on 3 questions for the Inside Space dimension and on 3 questions for the Variety of Stimulation dimension. These results demonstrated the need for reduction in total items (from 41 to 35) and the combination of space dimensions. After removal of questions, internal consistency was .766 (95% CI=.729, .800) for total score. Overall assessment categories were created as: less than adequate, moderately adequate, adequate, and excellent.

Limitations

The inventory does not determine specific use (time, frequency) of affordances in the home, and it does not account for infants' out-of-home activities.

Conclusions

The AHEMD-IS is a reliable and valid instrument to assess affordances in the home environment that promote infant motor development.

Motor development is a critical factor in child behavior,^1–3 being associated with the foundation of cognitive^4,5 and social-emotional⁶ development. In the developing infant, motor behavior is shaped by a combination of environmental, organismic, physiological, and genetic factors.⁷ Among those factors, the home environment has been established as a primary agent for learning and developing the foundation for lifelong behaviors.^8,9 Therefore, it should be no surprise to physical therapists that research findings continue to support the positive link between an adequate home environment and early developmental outcomes, including infant cognitive and motor development.^6–8,10,11 For example, a recent study showed that a more optimal home environment was associated with better cognitive and social-emotional development (after adjusting for social risk) in children born very preterm.⁶

Early studies designed to assess the general characteristics of the home and the relationship to later behavior have shown that one of the most striking and consistent findings has been “availability of stimulating play materials” as a predictor of future mental behavior.^12,13 For motor development, it has been established that a meaningful structure associated with opportunities in the home environment comprises physical space, variety of stimulation (daily activities), and play materials¹⁴ in children aged 18 to 42 months. This structure stimulated our initial interest in the connection between quality of motor opportunities in the home and motor development in infants. That interest also has been widely supported by the physical therapy community, based on the observations that motor assessment and interventions that account for the home and promote change in caregiver-infant interaction can influence and improve the results of clinical practice.¹⁵

Although selected home environment and motor development characteristics have been examined, the fact remains that minimal information is available in relation to the multidimensional effects of home affordances on early motor development. From that perspective, affordances are opportunities that offer the individual potential for motor action, consequently learning and developing a skill or a part of the biological system.¹⁶ The initial efforts in addressing this gap between understanding the home environment and clinical practice related to motor development resulted in creation of the valid and reliable Affordances in the Home Environment for Motor Development (AHEMD)¹⁴ for children aged 18 and 42 months. The AHEMD is a parental self-report instrument designed to assess the quality and quantity of factors (affordances) in regard to physical space, variety of stimulation, and play materials in the home that are conducive to enhancing motor development. To date, the AHEMD has been translated into at least 3 languages^17–19 other than English and been reported in several scientific journals.^7,20–22

Since the reporting and use of that instrument, several comments have been noted on the need for a tool that addresses earlier development. Due to the dramatic changes in motor behavior from the first months of life to the achievement of independent walking (up to 18 months), a version of the instrument needed to be created to address factors in the home environment that potentially affect infant motor development. In addition, it is generally understood by the medical and therapy community that interventions may be most effective if begun early in life, and delays may have long-lasting effects.²³ With that in mind and considering the growing interest of this topic in research and clinical communities, we created a version of the AHEMD for infants: the Affordances in the Home Environment for Motor Development–Infant Scale (AHEMD-IS). The AHEMD-IS is a valid and reliable instrument for measuring the quality and quantity of motor development opportunities provided in the home environment for infants aged 3 to 18 months.²⁴ Steps in its development included use of expert feedback and establishment of construct validity, interrater and intrarater reliability, and predictive validity, involving a total of 113 homes of infants.

Since its creation, the AHEMD-IS has gained in popularity as a clinical tool and as a research outcome measure. Furthermore, the AHEMD-IS has been noted in recent studies of infant development, with general findings supporting the argument that environmental factors are associated with infants' motor development²⁰ and motor affordances can have a positive impact on future motor ability and later cognitive behavior of infants.⁷ In addition, the AHEMD-IS has recently been added as a supporting tool in a major study designed to measure the effects of intrauterine growth restriction.²¹ However, feedback from these studies and our own evaluation strongly suggested the need for a normative sample and standardized scoring system. Here, we present a revision of the AHEMD-IS that includes these psychometric properties. Steps in the further validation and testing involved 3 phases: (1) use of expert opinion for content validity, (2) administration to a large sample and testing of reliability, consistency, and floor and ceiling effects, and (3) retesting of internal consistency and determination of interpretability for the scoring system.

Method

A schematic diagram of the methods for all phases is shown in the Figure.

Figure

Affordances in the Home Environment for Motor Development–Infant Scale (AHEMD-IS) Questionnaire—development, validation, and testing.

Phase 1

Phase 1 addressed content validity through expert review of the instrument.²⁵ The initial version of the instrument had 56 items and 5 dimensions (Inside Space, Outside Space, Variety of Stimulation, Gross-Motor Toys, and Fine-Motor Toys), with 17 items in the space dimensions (10 for the Inside Space dimension and 7 for the Outside Space dimension), 17 in the Variety of Stimulation dimension, and 22 in the Play Materials section (combining Fine-Motor Toys and Gross-Motor Toys dimensions). Due to safety issues, the instrument was analyzed to describe only manufactured toys and materials that were appropriate for infants according to the latest version of the US Consumer Product Safety Commission report²⁶ and a guideline from the Brazilian Association of Toy Makers.²⁷ We selected toys that were representative of each category, age appropriate, and included different price ranges.

After informal feedback from colleagues (researchers and clinicians in the field), we reduced (from 56) and rearranged the number of items to 46 questions (11 in the Physical Space dimension, 13 in the Variety of Stimulation dimension, and 22 in the Play Materials section). The most important alteration was in the structure of the Play Materials section; although all of the items denoted in that section were designed for infants up to 18 months of age, not all were appropriate for infants younger than 11 months.²⁶ Therefore, following the age group recommendations indicated by the US Consumer Product Safety Commission report, we separated items in that section into 2 age categories (3–11 and 12–18 months), with the following note added to the questionnaire: “If your baby's age is between 3 and 11 months, stop here. The following toys are not recommended for children younger than 12 months of age. If your baby is 12 months of age or older, please continue answering the questionnaire.” The following items were reserved for infants older than 12 months: educational toys and shape sorters, soft hand puppets, dolls and other play figures with accessories, house toys (telephone, kitchen utensil sets, tools), stacking (rings, cones) and nesting toys, puzzles (2–6 pieces), locomotor materials (pull or push toys), multiactivity tables, baby swings, rocking toys, and baby tricycles.

After changes based on informal comments and group discussions, we requested formal feedback on basic components, categories, and items from internationally established specialists (researchers, physical therapists, occupational therapists, pediatricians) in the fields of infant and early childhood motor development. In addition to a letter of introduction stating the purpose, a guideline for examining content was developed with criteria based on suitable recommendations.^28–30 The guideline asked reviewers to make comments on each section and use the 4-point Likert scale (1=strongly disagree, 2=mildly disagree, 3=mildly agree, and 4=strongly agree) for evaluation according to the following criteria: clarity (the item is well written, what is asked is clear to the parents); importance (the item is relevant and reflects the aspect to be assessed in the home environment); discrimination (the item has the potential to discriminate home environments that offer more or less the same affordances to infants' motor development); ease of observation (the item represents situations relatively frequently, easily observable by parents); cultural conflict (the item does not present cultural conflict); and orientation to the parents (the item has the potential to inform the parents how to promote affordances that stimulate motor development in the home environment).

The letter and guidelines were sent by e-mail to 34 specialists, who were requested to return their form by email. The specialists were pediatricians, pediatric physical therapists, pediatric occupational therapists, and researchers in the field of infant motor development. All specialists had a doctoral degree and at least 10 years of experience in the field in different countries: Brazil, Australia, Canada, and United States. Experts who did not reply in a month were reminded of the request. Descriptive analysis was conducted on the scores, and questions were individually reviewed³¹; for acceptance, each criterion item had to be agreed upon by at least 80% of the reviewers.³²

Phase 2

The involvement of human participants for data used in phase 2 was approved by the Methodist University of Piracicaba Human Subjects Committee. Phase 2 involved the testing of reliability, internal consistency, and ceiling and floor effects with the revised questionnaire from phase 1 (now with 41 questions) to 419 parents of infants aged 3 to 18 months (3–11 months, n=252; 12–18 months, n=167). To participate, parents signed a consent form and verified that their infants did not exhibit any abnormal genetic syndromes, congenital malformations, or neurological impairments. Recruitment letters and questionnaires were sent to parents of infants through community health agencies and public and private day care centers in 3 Brazilian states. Three analyses were conducted based on a description of quality criteria for measurement properties²⁰: interrater and intrarater reliability, internal consistency, and floor and ceiling effects. Interrater reliability was determined using direct observation in 16 homes by a pediatric physical therapist with 5 years of experience in the field. The follow-up was conducted within 2 weeks of parental questionnaire responses.

Another 16 parents were asked to answer the questionnaire a second time over a 2-week interval for determination of intrarater reliability. Both types of reliability were analyzed using intraclass correlation coefficient (ICC [2,1]) (agreement) procedures. In order to measure the degree to which the items that make up a latent construct are all producing similar scores, Cronbach alpha coefficients were examined for total score and each of the 5 dimensions. A Cronbach alpha of .7 or above was considered evidence of adequate internal consistency.³³ Frequency analyses were conducted to determine floor or ceiling effects, considered to be present if more than 15% of the respondents achieved the lowest or highest possible score, respectively.³⁴ All analyses were calculated using IBM SPSS version 19.0 for Windows (IBM Corp, Armonk, New York).

Phase 3

Phase 3 addressed internal consistency of the AHEMD-IS and the interpretability analysis of the questionnaire modified after phase 2's results. Interpretability is defined as the degree to which qualitative meaning can be assigned to quantitative scores.³⁴ Frequency analyses were conducted, and the sample quartiles were used to determine the scoring classification system and categories that represented the quantity and quality of affordances in the home environment for infants.

Role of the Funding Source

This work was partially supported by the CNPq–Brazilian Council of Technological and Scientific Development (Process 486077/2011-0 and 308903/2012-9).

Results

Phase 1

Seventeen specialists responded to our request for a detailed evaluation of the instrument. Overall, most experts strongly agreed with the criteria presented in the guidelines. A frequency analysis of the agreement scores (sum of 3 and 4 ratings) by dimensions indicated an average agreement for Physical Space, Variety of Stimulation, and Play Materials, respectively: clarity—88%, 87%, and 97%; importance—94%, 95%, and 98%; discrimination—91%, 95%, and 98%; ease of observation—97%, 98%, and 99%; cultural conflict—90%, 88%, and 92%; and orientation to parents—93%, 94%, and 99%.

Because the overall expert rating was relatively high, we focused on comments that were relevant to certain questions and dimensions. For example, most experts commented on ways to phrase some questions, and we changed (added, removed, or clarified) items based on their suggestions. The general structure of the questionnaire remained the same, with minor changes made in the child and family characteristics, including the removal of a question regarding total family income due to the lack of relevance to the instrument. Three questions were deleted from the Physical Space dimension, and 2 questions related to “support where the child can pull up” and a “room to play.”

The Variety of Stimulation dimension underwent the most revision. For example, a few reviewers suggested the inclusion of “tummy time” under the segment inquiring about how much awake time the infant spends in certain situations. In addition, the wording was changed (ie, from “We/our child” to “I/my child”) because some questions, at this point, were assuming that the infant had 2 parents. In the largest dimension, Play Materials, the major changes involved regrouping and combining certain questions, rewording of the descriptions and questions, and the use of different images and examples of various toys. This dimension ended with 21 questions.

Overall, the total number of questions decreased from 46 to 41, with 1 new question added (tummy time) and 5 questions deleted (in the Inside Space dimension, “Is there a playroom [used only for children to play]?” “Does your child usually wear clothes that allow freedom to move and explore?” “On a typical day, how would you describe the amount of awake time your child spends in each of the situations, restrained to a specific space in the floor?” “How do you consider the living space inside your house?” and “How many do you have: audio equipment [CD or tape players and children's music CDs or tapes]?”). In addition, 2 questions were combined into one: “Plush music box animals, stuffed toys, squeeze-squeak toys, cloth toys, water (floating, sponges) toys.”

Phase 2

Table 1 shows the descriptive characteristics for the 419 respondents. For the interrater reliability sample, descriptive characteristics indicated that 9 of the infants (57%) were boys and 7 (43%) were girls. Eleven (68.5%) lived in houses, and 5 (31.5%) lived in apartments. Infants' ages ranged from 4 to 18 months, with 10 (62.5%) between 4 and 11 months and 6 (37.5%) between 12 and 18 months. For parental education, one mother (6%) had some high school or less, 5 (31.5%) were high school graduates, and 10 (62.5%) were college graduates. One father (6%) had some high school or less, 5 (31.5%) were high school graduates, and 10 (62.5%) were college graduates. The sample for intrarater reliability consisted of 16 infants: 8 (50%) were boys, and 8 (50%) were girls; 5 (31%) lived in houses, and 11 (68%) lived in apartments. Infants' ages ranged from 4 to 18 months, with 11 (8%) between 4 and 11 months and 5 (31%) between 12 and 18 months. For parental education, 5 mothers (31.5%) had some high school or less, 5 (31.5%) were high school graduates, and 6 (37.5%) were college graduates. Two fathers (12.5%) had some high school or less, 6 (31%) were high school graduates, and 8 (50%) were college graduates.

Table 1

Descriptive Characteristics for Family and Child–Phase 2

Variable	Measurement
Age (mo)
X	10.38
SD	4.35
Range	3–18
Sex (%)
Female	207 (49.4)
Male	212 (50.6)
Birth weight (g)
X	3,188
SD	527
Range	810–4,720
Gestational age (wk)
X	38.20
SD	2.1
Range	28–42
Prematurity (%)
Yes	47 (12.7)
No	322 (87.3)
Day care attendance (%)
Yes	171 (41.3)
No	243 (58.7)
Housing type (%)
House	358 (85.6)
Apartment	54 (13)
Other	6 (1.4)
Adults living in the house (%)
1	10 (2.4)
2	225 (61.4)
3	58 (14)
≥4	92 (22.2)
Children living in the house (%)
1	231 (55.5)
2	111 (26.7)
3	53 (12.7)
4	21 (5.1)
Rooms in the house (%)
1	68 (16.3)
2	180 (43.1)
3	127 (30.4)
4	30 (7.2)
≥5	13 (3.1)
Time living at this house (%)
<3 mo	14 (3.3)
3–6 mo	21 (5)
7–12 mo	41 (9.8)
>12 mo	343 (81.9)
Mother's education (%)
Some high school or less	15 (3.6)
High school graduate	68 (16.3)
Some college or trade school	216 (51.9)
College graduate	104 (25)
Postgraduate degree	13 (3.1)
Father's education (%)
Some high school or less	23 (5.6)
High school graduate	80 (19.5)
Some college or trade school	228 (55.5)
College graduate	70 (17)
Postgraduate degree	10 (2.4)

For interrater reliability, the results demonstrated an ICC of .990 (95% CI=.960, .997; P<.001, standard error of measurement [SEM]=2.78), and for intrarater reliability, the ICC was .949 (95% CI=.856, .982; P<.001, SEM=7.86). Internal consistency results indicated Cronbach alphas values of .776 (95% CI=.741, .808) for the External Space dimension, .657 (95% CI=.603, .703) for the Internal Space dimension, .639 (95% CI=.584, .689) for the Variety of Stimulation dimension, .763 (95% CI=.704, .814) for the Gross-Motor Toys dimension, .760 (95% CI=.702, .811) for the Fine-Motor Toys dimension, and .824 (95% CI=.781, .862) for the total score.

Ceiling effects were observed in 3 questions of the Inside Space dimension and 3 questions of the Variety of Stimulation dimension, with the following percentages of participants saying “yes” to the questions: “In your home's inside space, is there enough space for your child to play or move around freely?” (90%); “In your home's inside space, is there any furniture or equipment for your child to pull up to a standing position and/or walk?” (97%); “In your home's inside space, is there a special place for toys where your child can choose what to play with and get it without help?” (89%); “I/we usually have a daily time for playing (interacting) with our child” (92%); “My/our child regularly (at least twice a week) plays (interacts) with adults, other than the parent(s)” (93%); and “I/we regularly (at least twice a week) play games with my/our child to practice movements, such as ‘clap hands,’ ‘wave,’ ‘crawl,’ ‘walk,’ etc” (94%).

Phase 3

Based on the ceiling effects and relatively low consistency of the dimensions (Inside Space=.657 and .639 and Variety of Stimulation=.763), 6 questions were removed from the instrument, leaving a total number of 35 questions. After the exclusion of 3 items from the Inside Space dimension, only 2 items were left; therefore, we combined the space dimensions into one dimension, titled “Physical Space.”

An overall problem with responses on the Gross-Motor and Fine-Motor Toys dimensions was observed at this phase: the responses for these dimensions consisted of “none,” “one–two,” “three–four,” and “five or more” toys. None of the respondents used the “five or more” option, which led us to reconsider the number of choices presented. For young babies, having 5 or more toys of the same category is perhaps unrealistic—if they have one toy for each Play Material dimension question, they would have a total of 15 distinct toys. Therefore, we modified the possible responses to “none,” “one–two,” and “three or more.”

Internal consistency results for the revised version indicated Cronbach alpha values of .735 (95% CI=.695, .773) for the Physical Space dimension, .663 (95% CI=.566, .746) for the Variety of Stimulation dimension, .758 (95% CI=.699, .810) for the Gross-Motor Toys dimension, .758 (95% CI=.700, .809) for the Fine-Motor Toys dimension, and .766 (95% CI=.729, .800) for the total score.

The interpretability analysis started with a comparison of the maximum ranges for all dimensions and total score, the ranges indicated by our sample, and the sample cutoff scores (Tab. 2). The scoring system aimed to eliminate ceiling effects (as addressed in the previous phase) and gaps in measurement.³⁵ For all questions, we assigned a score of 1 to a “yes” answer and 0 to a “no” answer, and we assigned scores of 0 to “none,” 1 to “one–two,” and 2 to “three or more” responses. The Variety of Stimulation dimension had 2 ways to assign points—questions 10 to 13 were assigned a score of 3 for “never,” 2 for “sometimes,” 1 for “almost always,” and 0 for “always,” and questions 14 and 15 were assigned the opposite values. The cutoff scores were determined for each age group by examining the cumulative frequency distributions of this normative sample. The goal was to categorize the dimensions of the home and the total score for the home environment into 4 possible facets of adequacy for promoting quantity and quality of affordances for motor development. Thus, descriptive categories were created to reflect the sample quartiles for each dimension and total score. From zero to the 25th percentile, the category generated was “less than adequate”; from the 26th percentile to the 50th percentile, it was “moderately adequate”; from the 51th percentile to the 75th percentile, it was “adequate”; and from the 76th percentile to the 100th percentile, the category was considered “excellent.” Table 3 shows the descriptive categories for raw score ranges in each dimension and total score.

Table 2

Ranges and Quartiles for Each Dimension and Total Score of the Affordances in the Home Environment for Motor Development-Infant Scale (AHEMD-IS) by Questionnaire Age Division-Phase 3

Measure	3–11 mo					12–18 mo
	Physical Space	Fine-Motor Toys	Gross-Motor Toys	Variety of Stimulation	Total	Physical Space	Fine-Motor Toys	Gross-Motor Toys	Variety of Stimulation	Total
Questionnaire range	0–7	0–10	0–12	0–20	0–49	0–7	0–22	0–18	0–20	0–67
Sample range	0–7	0–10	0–12	4–16	6–39	0–7	0–22	0–18	3–17	14–60
25th percentile	1	2	3	9	18	2	6	6	10	27
50th percentile	3	3	5	11	23	4	9	8	12	33
75th percentile	5	5	7	13	27	5	14	11	14	40

Table 3

Affordances in the Home Environment for Motor Development-Infant Scale (AHEMD-IS) Raw Score Ranges and Descriptive Categories

Age (mo)	Descriptive Categories	Physical Space	Variety of Stimulation	Fine-Motor Toys	Gross-Motor Toys	Total Score
3–11	Less than adequate	0–1	0–9	0–2	0–3	0–18
	Moderately adequate	2–3	10–11	3	4–5	19–23
	Adequate	4–5	12–13	4–5	6–7	24–27
	Excellent	6–7	14–20	6–10	8–12	28–49
12–18	Less than adequate	0–2	0–10	0–6	0–6	0–27
	Moderately adequate	3–4	11–12	7–9	7–8	28–33
	Adequate	5	13–14	10–14	9–11	34–40
	Excellent	6–7	1–20	15–22	12–18	41–67

The following descriptions were added to each category and apply to each single dimension of the home and for total score:

Less than adequate: Environmental opportunities (affordances) for motor development are missing or need improvement. Suggestion: the family should look to add or improve certain dimensions of the home by providing a variety of affordances that can improve their infant's motor development.

Moderately adequate: Environment provides some opportunities (affordances) for motor development but could be improved. Suggestion: implement more affordances that can help stimulate the infant's motor development.

Adequate: Environment shows sufficient quantity and quality of opportunities (affordances). Suggestion: continue using and finding different ways to explore the affordances in the home.

Excellent: Provides ample amount and variety of opportunities (affordances). Suggestion: continue using and finding different ways to encourage the infant's movement and play.

A sample of the final instrument is provided in  Appendix 1.  Appendix 2 provides the separate score sheets for infants aged 3 to 11 months and infants aged 12 to 18 months, with examples of how to use the AHEMD-IS to improve the home environment for motor development.

Discussion

This article reports a revision of the AHEMD-IS. Phase 1, expert opinion of content, resulted in an average agreement of 95% across the all criteria and a reduction of items (from 46 to 41). Phase 2 results showed ICC values of .99 for interrater reliability and .95 for intrarater reliability, with Cronbach alpha values ranging between .64 and .82 for the dimensions and a total value of .82 (95% CI=.78, .86) for internal consistency. Ceiling effects were found on 3 questions of the Inside Space dimension and 3 questions of the Variety of Stimulation dimension. These results demonstrated the need for reduction in total items (from 41 to 35) and combination of the space sections. Results in phase 3 revealed an internal consistency of .77 (95% CI=.73, .80) for total affordances in the home. Considering that the quoted alpha values for each dimension ranged from .66 to .76, with 3 out of the 4 dimensions with an alpha value >.7, the questionnaire can be considered as having satisfactory internal validity.³³ Interpretability of the scores was based on quartile analysis and creation of 4 descriptive categories (less than adequate, moderately adequate, adequate, and excellent) that represent the quality and quantity of home affordances for motor development and its respective dimensions. Overall, the results of all phases combined to demonstrate that the AHEMD-IS is a valid and reliable tool to list and classify the quantity and quality of affordances in the home environment that are conducive to motor development in infants aged 3 to 18 months.

Since its creation, experts in the field of early motor development, including researchers and practitioners, have indicated that this instrument (for example) holds promise for advancing science with regard to environmental factors that should be of interest in helping children acquire motor skills and will address a need and help direct interventionists, families, infant caregivers, and others. Although the first (initial) version of the AHEMD-IS demonstrated reliability and some aspects of validity, use in the field by researchers and clinicians prompted us to continue refining the instrument with the inclusion of an effective scoring system. The AHEMD-IS shows good intrarater (.94) and interrater reliability (.99) compared with similar instruments such as the Daily Activities of Infants Scale³⁶ (.77 and .76). The AHEMD-IS also compares favorably with the Infant Toddler Home Observation for Measurement of the Environment in regard to internal consistency values for total score (.82).³⁷

Overall, we were able to follow quality criteria guidelines proposed by Terwee and colleagues,³⁴ with the steps described in this study complementing the preliminary validity guidelines established in 2011. Our goal was to make the instrument as succinct and direct as possible. We feel that this goal was accomplished in some important areas. The version published in 2011 had 56 items, whereas the revision presented here has 35 items. As a consequence, the point ranges for the dimensions and total score are not large (eg, the highest possible number of points in the Fine-Motor Toys dimension for infants between 3 and 11 months of age is 10 points. The instrument is a relevant and concise measure but as a result possesses limited range measurement that is a characteristic of affordances feasible for infants between 3 and 18 months of age. Nonetheless, the criteria for the scoring system took into account the range restriction and established quartile cutoffs that were sensitive to this limitation.

One of the limitations identified with the development process includes the fact that the experts who participated in phase 1 were based across South America and North America, which may have resulted in culturally biased opinions. However, we do want to point out that the AHEMD version for children aged 18 to 42 months has been used effectively in other countries, including Japan,¹⁷ Taiwan,¹⁸ and Lebanon,¹⁹ with slight modifications on some items to adjust for potential cultural factors.

When interpreting the results of the AHEMD-IS, especially in relation to an infants' developmental level, it is important to take into account that the questionnaire does not include certain areas of an infant's experience such as out-of-home activities.²³ In addition, the report produced by the AHEMD-IS might provide only a snapshot of an environment that may be constantly changing. Moreover, the quantity and quality of affordances in the home are related to socioeconomic status. A previous study using the AHEMD-IS has established that socioeconomic status indicators (annual income, parental education) significantly influenced the availability of physical space and play materials.²³

Demonstrating that the home environment can be accurately measured is but a first step toward a research and intervention program for infants.³⁶ Studies regarding the effects of the home and infant motor development were not as popular until recently, and we believe that the AHEMD-IS is an appropriate tool to provide researchers and clinicians with the opportunity to assess, understand, and intervene with the home environment. It is generally understood by the medical and therapy communities that interventions may be most effective if begun early in life, and delays may have long-lasting effects.²³ In addition, with proper adaptation and validation, one of the most promising future applications of the AHEMD-IS is the potential to help identify resources in the home that may help the infant who is impaired or at risk. Moreover, additional studies should investigate the concurrent and predictive validity of the instrument, with measures of motor and overall development (eg, Bayley Scales of Infant Development) as well as other assessments that measure the environment and participation of infants (eg, Daily Activities of Infants Scale).

The results of this study suggest that the instrument has the potential to be very useful to the physical therapist. There is substantial evidence that the instrument can significantly contribute to the understanding of an infant's motor development status,²⁰ assess and predict child growth and development,²¹ and capture how the home promotes affordances for motor and cognitive development.⁷ As previously mentioned, the instrument, in its current form, has noteworthy clinical promise. Our results also support the common practice in physical therapy of having professionals advise patients on home activities, including assessment and recommendations for intervention. In general, such recommendations involve how to utilize different aspects of home space, toys, stimulation, and activities that are part of an infant's everyday life.²² Thus, the instrument can aid in narrowing the gap between analysis of the home environment and clinical practice, which may significantly contribute to a better understanding of an infant's development and goals of the therapist.

In conclusion, steps in the revision of the AHEMD-IS confirmed a valid and reliable instrument for the assessment of infants 3 to 18 months of age. The instrument now consists of 35 items divided into 4 dimensions (Physical Space, Variety of Stimulation, Fine-Motor Toys, and Gross-Motor Toys) and a total score that can be categorized into 4 descriptions of home motor affordances (scoring system): less than adequate, moderately adequate, adequate, and excellent. The results suggest that this tool can be a useful instrument for measuring the quantity and quality of affordances in the home environment that are conducive to an infant's motor development.

This work was partially supported by the CNPq–Brazilian Council of Technological and Scientific Development (Process 486077/2011-0 and 308903/2012-9).

Appendix 1

Appendix 1

Affordances in the Home Environment for Motor Development Infant Scale (AHEMD-IS) Inventory (3–18 Months)^a

^a

© This questionnaire was developed by the Developmental Motor Cognition Lab, University of Texas at Arlington (USA), the Motor Development Lab, Texas A&M University (USA), and the Neuromotor Development Lab, Methodist University of Piracicaba (Brazil). All rights reserved.

Appendix 2

Appendix 2

Affordances in the Home Environment for Motor Development Infant Scale (AHEMD_IS) Score Sheets^a

^a

© The questionnaire score sheets were developed by the Developmental Motor Cognition Lab, University of Texas at Arlington (USA), the Motor Development Lab, Texas A&M University (USA), and the Neuromotor Development Lab, Methodist University of Piracicaba (Brazil). All rights reserved.

Author notes

Dr Caçola, Dr Gabbard, and Dr Santos provided concept/idea/research design and writing. Dr Santos provided data collection, fund procurement, participants, facilities/equipment, and institutional liaisons. Dr Caçola, Dr Montebelo, and Dr Santos provided data analysis. Dr Gabbard provided consultation (including review of manuscript before submission).