At least 7.2% of infants and toddlers who receive Part C early intervention services under the Individuals With Disabilities Education Improvement Act (IDEA 2004; Pub. L. 108–446) have been diagnosed with intellectual or cognitive impairment or delay (Hebbeler et al., 2007). Another 12.2% have global developmental delay, which may also include children with cognitive delay. Fifteen percent of premature infants are diagnosed with cerebral palsy, and 50% exhibit cognitive, motor, or behavioral problems (Bhutta, Cleves, Casey, Cradock, & Anand, 2002; Doyle, 2004). Children with medical or genetic conditions or who come from impoverished backgrounds are at risk for delays in cognitive, communication, and motor development (Hebbeler et al., 2007). Delays in cognitive development are concerning because cognition provides the foundation for people’s earliest interactions and learning. Early cognitive development includes attention (and joint attention), memory, object relations, causality, imitation, problem solving, and sorting objects. Children at risk for cognitive delay need effective intervention to facilitate their cognitive development, especially for early cognition skills such as joint attention, eye gaze, and imitation.

Because limitations in cognitive functioning affect everyday life (Wolf & Baum, 2011), occupational therapy practitioners typically address the cognitive domain in their practice with infants, toddlers, and young children. Infants, toddlers, and preschoolers are intensely involved in intellectual engagement (National Research Council & Institute of Medicine, 2000). During these preschool years, children are involved in language, spatial reasoning, problem solving, categorization, physical causality, human interactions, and counting: “Complex human reasoning is thus rooted in early childhood” (National Research Council & Institute of Medicine, 2000, p. 147). Strong associations have been found between children’s cognitive skills before they enter kindergarten and achievement in elementary and high school (Hess & Hahn, 1974; Stevenson & Newman, 1986). Brooks-Gunn, Guo, and Furstenberg (1993)  found that preschool cognitive ability predicts high school completion. Research has also shown that executive functioning, which includes self-regulation, sequencing of behavior, flexibility, response inhibition, and planning (Eslinger, 1996), emerges during the early childhood years. Children who are delayed in cognitive development or executive functioning may exhibit behavioral and learning problems. Children with physical delays and cognitive delays struggle with additional barriers (e.g., difficulty reaching for a toy or hugging a parent). Delayed cognitive skills confer a significant risk to children’s learning, behavior, and social interactions.

Occupational therapy practitioners provide cognitive interventions in a variety of early childhood settings. In the neonatal intensive care unit (NICU), intervention is provided to enhance cognitive development for premature or medically fragile infants. Occupational therapy practitioners who work in early intervention programs provide interventions that incorporate individual learning opportunities for children within their natural routine and activities (Dunst, Bruder, Trivette, & Hamby, 2006). In preschool, occupational therapy practitioners provide intervention within specially designed curricula for promotion of multiple developmental domains, including the cognitive domain. Once a child enters kindergarten, cognitive development continues to be supported in multiple ways by occupational therapy practitioners who provide intervention to the child to enhance the child’s participation in the general education curriculum and school environment. In all of these environments, occupational therapy practitioners collaborate with other adults to enhance learning opportunities throughout the child’s natural routines and activities to support participation.

This systematic review examines the research evidence for interventions within the scope of occupational therapy that promote cognitive development in children from birth to age 5 yr. Most of the interventions found were provided by an interdisciplinary team of professionals, and all included outcomes within the scope of occupational therapy. The following research question guided our review: What is the evidence for the effectiveness of interventions within the scope of occupational therapy practice to improve cognitive development in children birth to age 5?

This review was completed as part of the American Occupational Therapy Association (AOTA) Evidence-Based Practice project. The articles included in this review were the result of database searches on articles published from 1990 through April 2010. In addition, we reviewed bibliographies of selected articles for potentially relevant articles. As noted in Arbesman, Lieberman, and Berlanstein (2013), selected articles were recommended by experts in the field and included in the review. Search terms for the review included childhood play behavior, cognitive process, early childhood intervention, early literacy, imitative behavior, imitation skills, joint attention, play, and skill learning. Articles selected for review included studies in which the focus was on infants and young children from birth to age 5 yr. In addition, the interventions studied were within the scope of practice of occupational therapy. Detailed information about the methodology and a complete list of search terms for the entire project dedicated to early intervention and early childhood services can be found in the article “Method for the Systematic Reviews on Occupational Therapy and Early Intervention and Early Childhood Services” in this issue (Arbesman et al., 2013).

Thirteen studies met our criteria and were selected for the review. Twelve were Level I studies and 1 was Level IV, indicating a high level of evidence. On the basis of the studies, two general themes emerged: (1) developmental interventions and (2) joint attention interventions (see Supplemental Table 1, available online at http://ajot.aotapress.net; navigate to this article, and click on “Supplemental Materials”). Few studies described the types of developmental interventions that were used. Children’s cognitive development was measured by pre- and posttest scores with the intervention described as early intervention, home visits, or developmental programming. Key findings are summarized for each of the two themes.

Three studies described specific interventions conducted in the NICU with premature infants. Interventions included the Newborn Individualized Developmental Care and Assessment Program (NIDCAP; Kleberg, Westrup, Stjernqvist, & Lagercrantz, 2002; Maguire et al., 2009) and a parent empowerment program (Melnyk et al., 2001). These interventions were provided while the infants were in the NICU. Infants in these interventions were preterm, had various neurological conditions (e.g., brain bleeds), or both.

Studies on the effectiveness of the NIDCAP program had conflicting results. NIDCAP is a multidisciplinary approach that promotes individual, developmental supportive care based on careful observations of the infant (Als & Gibes, 1990). This intervention was designed to enhance interactions between infant and caregiver while the infant was in the NICU. Kleberg et al. (2002)  found that 11 preterm infants who received NIDCAP care displayed significantly higher scores on cognitive development at 1 yr adjusted age compared with the control group. Maguire et al. (2009)  found no significant difference in growth, neurological, or mental development in the 70 infants who received NIDCAP compared with 78 who did not.

Providing parents with information about their child’s health, development, and behaviors as well as activities to promote cognitive development appears to have positive short-term results for low birthweight infants. Melnyk et al. (2001)  evaluated the effectiveness of their parent-focused intervention program, Creating Opportunities for Parent Empowerment (COPE). COPE was designed to educate mothers about low-birthweight infants and provide activities to enhance development (including infant stress cues and infant development outcomes). At 3-mo and 6-mo follow-up, the 20 COPE program infants had significantly higher scores on mental development than the 22 infants in the control group.

Evidence is inconclusive about the effectiveness of interventions that begin in the NICU and are carried over into the home. These programs have not demonstrated long-term effects. Three studies, including a systematic review, considered the effectiveness of interventions across these two settings.

A systematic review by Orton, Spittle, Doyle, Anderson, and Boyd (2009)  of early intervention programs for preterm infants that began in the hospital or home found 11 studies that met their inclusion criteria and reported cognitive outcomes at different ages. The studies demonstrated that developmental interventions resulted in cognitive outcome improvements when measured in infancy (ages birth to 3 yr) and at preschool age (ages 3 to <5 yr), but not at school age (ages 5 to <13 yr).

Resnick, Armstrong, and Carter’s (1988)  hallmark study compared a traditional remedial model in which preterm infants were monitored and received intervention services if needed with a preventive model (experimental group) in which every preterm infant was considered at risk and received daily intervention while in the NICU and twice-a-month intervention in a home developmental program. NICU intervention included providing classical music, total body massage, passive range of motion, and oral stimulation before feeding, and home-based developmental interventions included language enrichment exercises, cognitive and spatial concept exercises, motor exercises, and parenting activities. At 12 mo, cognitive functioning was significantly higher for the 21 infants in the experimental group than for the 20 infants in the control group.

Nelson et al. (2001)  designed a hospital-based sensory program to provide adapted auditory–tactile–visual–vestibular input to preterm infants who were extremely premature or had severe central nervous system injury. At discharge, parents continued the program at home until the infant reached 2 mo adjusted age. No statistically significant difference between the groups was found at 12-mo follow-up. The study found that infants with periventricular leukomalacia had significantly poorer mental development regardless of their group assignment.

Evidence has indicated that early intervention services provided by various professionals support gains in cognitive development through preschool. Early intervention services enhance the developmental and health needs of infants and toddlers who have disabilities or may be at risk for disabilities. Educating and collaborating with families and caregivers are equally important for these adults to care for the child’s needs. Three studies, all Level I, provided interventions in the home, child care, or preschool settings.

During a 5-yr follow-up study, Barrera, Kitching, Cunningham, Douchet, and Rosenbaum (1991)  did not find evidence of differences in general cognitive scores between the two interventions (parent–infant interaction or a developmental curriculum). In a multisite study of 985 low-birthweight preterm children, Brooks-Gunn, Liaw, and Klebanov (1992)  found significant improvements at 24- and 36-mo follow-up in receptive language and all areas of cognitive development for children who participated in intensive early intervention programs. These programs included weekly in-home intervention during the first year followed by child care at a child development center and parent education classes during Years 2 and 3. Birthweight influenced the intervention effects on cognitive performance, with lower scores in the very low birthweight children. In 2006, McCormick et al. conducted a follow-up on 638 participants in the Brooks-Gunn et al. (1992)  study and found higher scores for children who received developmental intervention; however, the results were not statistically significant. Preterm infants with very low birthweight (≤2,000 g) had more risk factors than other preterm infants, including those with heavier low birthweight (2,001–2,500 g).

Interventions focusing on improving joint attention appear to have positive effects on infants’ and preschoolers’ ability to initiate joint attention. Three Level I and 1 Level IV studies addressed joint attention. Joint attention is the ability to orient to or attend to other people, including sharing attention on an object, shifting eye gaze, and getting others’ attention. Attention is a component of cognitive development and is critical for ongoing learning. Interventions to enhance joint attention included increasing parents’ sensitivity to infant cues, using symbolic play, and incorporating components of Discrete Trial Training (Maurice, Green, & Luce, 1996) and Pivotal Response Training (Koegel, O'Dell, & Koegel, 1987; Koegel et al., 1989). Olafsen et al. (2006)  investigated 71 preterm and term infants whose parents were taught to interpret and respond to their child’s cues during hospitalization and 30 days after discharge. At age 12 mo, the intervention group scored significantly higher than the 75 children in the control group on initiating joint attention, initiating object requests, and responding to social interaction.

Two preschool studies on children with autism that used joint attention interventions (e.g., teaching children to point or share attention through eye contact) and symbolic play interventions (e.g., engage in playing with toys) found children in the joint attention intervention engaged in coordinated looks for significantly longer periods than children in the symbolic play intervention (Gulsrud, Kasari, Freeman, & Paparella, 2007), and children who had higher developmental skills generalized skills faster (Wong, Kasari, Freeman, & Paparella, 2007). Using a multiple-baseline design with 4 children, Whalen, Schreibman, and Ingersoll (2006)  used joint attention interventions with preschoolers who had autism and an average mental age equivalent of 1 yr, 5 mo, as measured using the Bayley Scales of Infant and Toddler Development (Bayley, 1993). Interventions included naturalistic behavior modification techniques and components from Discrete Trial Training and Pivotal Response Training. Assessments at posttreatment and a follow-up 3 mo later found positive increases in social initiations, imitation, play, and spontaneous speech.

Occupational therapy practitioners often provide services to children with cognitive delays to enhance participation and engagement in daily life activities and routines. Thirteen studies to enhance cognitive development using interventions within the scope of occupational therapy were reviewed. Virtually all the studies were Level I and therefore provided high levels of evidence. Several studies had large sample sizes and included longitudinal studies.

As members of early intervention and early childhood programs, occupational therapy practitioners use interventions to enhance development, including cognitive development, in young children. Occupational therapy practitioners partner with family members and caregivers to promote the child’s development by recommending learning opportunities within the family’s daily routines. Interventions to enhance cognitive development that were initiated in the NICU with preterm infants who were at risk for developmental delays demonstrated positive improvements in infancy and at preschool age but not at school age (Orton et al., 2009). Infants with periventricular leukomalacia or very low birthweight (≤2,000 g) were found to have significantly poorer mental development regardless of their group assignment (Brooks-Gunn et al., 1992; McCormick et al., 2006; Nelson et al., 2001).

Cognitive development relates to other areas of development; therefore, even short-term gains should be considered. Providing parents with information about their preterm infant and activities to stimulate development or recognize their child’s cues was found to enhance cognitive outcomes (Kleberg et al., 2002; Melnyk et al., 2001). Considering all preterm infants to be at risk and providing them daily intervention in the NICU and twice-a-month intervention in early intervention produced significantly higher cognitive functioning at age 12 mo (Resnick et al., 1988). Low-birthweight preterm infants who received weekly early intervention services in their home for the first year and then at child care centers for 2 additional years had significantly higher cognitive functioning at age 3 yr.

Joint attention is an important cognitive and social interaction skill. Often, children with autism or cognitive delays do not demonstrate this skill. Interventions that focused on increasing a parent’s sensitivity to his or her infant’s cues were effective in increasing infants’ joint attention by age 12 mo (Olafsen et al., 2006). Preschoolers with autism improved their joint attention skills more with interventions focused on joint attention (e.g., pointing, sharing coordinated looks) than on symbolic play with toys (Gulsrud et al., 2007; Wong et al., 2007).

The initial early childhood review was much broader in scope and was revised to focus on cognitive outcomes. Some of the follow-up studies included children older than age 5 yr. Many of the cognitive interventions were not described in detail and could not be replicated. Some of the interventions were curricula designed by the authors; however, no data regarding the curricular design or reliability of the program were provided. Some interventions were very short, for example, only 2 mo in length. Although the studies investigated interventions that were applicable to occupational therapy practitioners, none of these studies were conducted by occupational therapists.

Almost all of the studies were Level I randomized controlled trials. Several studies had large sample sizes and were conducted over several years. A variety of settings were included (e.g., home, child care center, NICU) as were a variety of interventions (e.g., NIDCAP, early intervention from professionals, parent–child intervention).

Occupational therapists assess and provide interventions to promote developmental skills, including cognitive development, and daily life performance in children with disabilities or at risk for disabilities. Further research and practice suggestions include the following:

• Occupational therapists should conduct research with young children in their natural context to identify the impact of cognitive and executive functioning on daily life skills and learning.

• Research should identify effective cognitive interventions that have long-term effects on children with various disabilities (e.g., prematurity, attention deficit disorder, autism).

• Research should identify effective intervention protocols for specific populations and outcomes.

• Research should be conducted on occupational therapy interventions to develop young children’s cognitive functioning needed for early literacy skills such as alphabetic principle, formation of letters, visual searching for matching letters or numbers, and motor planning.

• Service delivery should always include partnerships with family and caregivers.

• An evidence-based developmental curriculum should be used to enhance cognitive development in young children.

• Cognitive development and executive functioning should be addressed within the daily life skills of young children and their families.

A systematic review of interventions focused on cognitive outcomes indicated improvements during infancy and at preschool age but mixed findings at school age. Effective interventions for preterm infants included early intervention programs in the NICU, home, child care center, and preschool that incorporated parent education (e.g., child development, ways to enhance parents’ sensitivity to their children’s needs, and encouragement of responsive interactions). Preschoolers with autism increased joint attention with specific joint attention interventions that coupled behavioral interventions with child-directed play. Additional research by occupational therapists using interventions to enhance cognitive development within daily activities and contexts for children with disabilities or at risk for disabilities is needed. In particular, further study of interventions that promote preliteracy skills such as joint attention, imitation, memory, problem solving, and decision making is needed.

We acknowledge the following people who assisted in this evidence-based review while students in the Master of Occupational Therapy Department of St. Ambrose University: Meghan E. Barnett, Meredith A. Carr, Breanne L. Hinkle, Jennifer L. Kluever, Nicole M. Rowold, and Amanda L. Wheelock.

*Indicates studies that were systematically reviewed for this article.