The occurrence of developmental problems for maltreated children younger than the age of 3 is summarized in these prevalence data:
- Twenty-three percent to sixty-five percent of maltreated children demonstrate cognitive delays (Egeland & Sroufe, 1981; Klee, Kronstadt, & Zlotnick, 1997; Leslie et al., 2005; Reams, 1999; Silver et al., 1999; National Survey of Child and Adolescent Well-Being, CPS Sample Component Wave 1 Data Analysis Report April, 2005).
- Fourteen percent to sixty-four percent of maltreated children demonstrate speech and language delays (English, Upadhyaya et al., 2005; Reams, 1999; Silver et al., 1999; National Survey of Child and Adolescent Well-Being, CPS Sample Component Wave 1 Data Analysis Report April, 2005).
Differences in rates most likely occur as a result of the type of cognitive assessment used (e.g., screener versus full battery); determination of mild, moderate, or severe forms of the delay; and type and severity of maltreatment in the study population. Nevertheless, these rates of cognitive and language delays in young maltreated children exceed those found in the general population (Simpson, Colpe, & Greenspan, 2003). In one study, abused preschoolers scored on average 20 points lower than nonabused preschoolers on the Stanford-Binet Intelligence Scales and the Peabody Picture Vocabulary Test (Hoffman-Plotkin & Twentyman, 1984). The majority of research also suggests that children who are physically abused or neglected have higher rates of cognitive language delays than those who experience other types of maltreatment (i.e., sexual and emotional abuse). Available studies of sexually abused children, although based on small samples, suggest that these children perform significantly lower on verbal and performance subtests than their nonmaltreated peers (Porter, Lawson, & Bigler, 2005). Despite lower scores on cognitive tests, sexually abused children still tend to have scores for verbal, performance and full-scale IQs that are in the normal range (Jones, Trudinger, & Crawford, 2004; Porter et al., 2005).
Although some studies demonstrated that, after controlling for socioeconomic status (SES), there were no differences in cognitive functioning between maltreated and nonmaltreated groups (e.g. Samet, 1997), most studies have found that maltreatment affects cognitive functioning, even after controlling for the influence of low SES (Beers & De Bellis, 2002; Yasik, 1998). Pears and Fisher (2005) compared the cognitive abilities of maltreated preschool children in foster care with a group of nonmaltreated preschoolers, all with similar SES backgrounds, and found that maltreated children exhibited significantly lower scores on visuospatial, language, and general cognitive functioning than nonmaltreated peers. Neglected and emotionally abused preschoolers performed much worse in visuospatial, language, memory, and executive functioning tasks than children who were physically or sexually abused.
Eigsti and Cicchetti (2004) also looked at language development among maltreated and nonmaltreated children while controlling for SES. The language skills of 5-year-old children who had been maltreated before the age of 2 years (mostly neglect and physical abuse) were compared with nonmaltreated peers, all of whom had similar SES and demographic characteristics (e.g., age, gender, ethnicity, maternal education, financial assistance). Results indicated that both the maltreated and nonmaltreated groups demonstrated delays in expressive communication (i.e., words children are able to articulate) skills. Specifically, those in the maltreated group showed a 16-month delay in their use of syntax whereas those in the nonmaltreated group displayed a 13-month delay. However, maltreated children performed significantly worse than nonmaltreated children with respect to expressive syntax. The receptive vocabulary (i.e., words children are able to understand) of the maltreated group was in the low-average range whereas the nonmaltreated group performance was in the average range. Taken together, maltreatment may further impair the development of cognitive and language skill after controlling for the effects of SES.
As young maltreated children mature they begin to experience problems in school, maltreated children are less inclined to engage in autonomous academic exploration and require external motivation before they can initiate and engage in an educational task (Koenig, Cicchetti, & Rogosch, 2000; Toth & Cicchetti, 1996). They also exhibit poor work habits and receive lower grades in math and English during the elementary years (Rowe & Eckenrode, 1999). Maltreated children in foster care are more likely to receive special education services (Goerge, VanVoorhis, Grant, Casey, & Robinson, 1992) and are more likely than their nonmaltreated peers to be held back (Shonk & Cicchetti, 2001). Research has found that maltreated children are more likely to be retained in kindergarten and first grade than their nonmaltreated peers (Rowe & Eckenrode, 1999), although some of these effects may be attributed to disruptions in schooling that result from involvement with Child Welfare Services.
In brief, a large portion of maltreated infants, toddlers, and preschoolers may exhibit cognitive delays as well as problems with expressive and receptive communication, which is especially salient among young children with histories of physical abuse and neglect. The cognitive abilities of maltreated children are lower than nonmaltreated children from low socioeconomic backgrounds and drastically lower than their nonmaltreated middle-class peers. Cognitive and language delays become more apparent when children reach school age and those delays then negatively affect academic achievement.