Neonatal Intensive-Care Unit Graduates Show Persistent Difficulties in an Intradimensional Shift Card Sort

Abstract

Neonatal intensive-care unit (NICU) graduates, a group at risk for attention problems and attention-deficit hyperactivity disorder, performed an intradimensional shift card sort at 34, 42, 51, and 60 months to assess executive function and to examine effects of individual risk factors. In the “silly” game, children sorted cards (airplanes and dogs) so they were not the same as targets. In the “same” game, they did the opposite. Performance on the “silly” game was poor, especially when it was presented first. Success in following “silly” game rules improved with age and was significantly linked to maternal education and birth weight for gestational age, a measure of intrauterine stress. Degree of central nervous system injury differentiated children who completed the task from children who did not, and it also affected the need to repeat instructions in the “same” game. These results confirm an increased likelihood of impairments in executive function during preschool years in NICU graduates.

ACKNOWLEDGMENTS

We thank the many families who have generously allowed their children to participate in our research. We also thank the doctors, nurses, and staff of Richmond University Medical Center, and the many research assistants at the New York State Institute for Basic Research for their ongoing support. This work has been supported by NICHD grant P01-HD47281, R01- HD21784, and NYS OMRDD. Correspondence regarding this article should be sent to Phyllis M. Kittler, New York State Institute for Basic Research in Developmental Disabilities, Psychology and Infant Development, 1050 Forest Hill Road, Staten Island, NY 10341. E-mail: [email protected]

Notes

RIUG = relative intrauterine growth was calculated as a standard score of birth weight for gestational age based upon norms for infants aged 22 to 50 weeks (Fenton, 2003), with lower RIUG indicating lower birth weight for gestational age. GMDS = Griffiths Mental Development Scale (Griffiths, 1984). CNS Injury Group: None = no detected CNS injury; ABR only = auditory brainstem response (ABR) abnormal and cranial ultrasound (CUS) normal; CUS = varying degrees of structural abnormality on CUS.

¹The Griffiths scores reported in Table 1 may seem high for a NICU group. A major factor accounting for this is that the 1984 version of the (0 to 8 years) Griffiths we administered was normed in the 1960s. (A newly normed 0–8 Griffiths was released only in 2006, too late for use in our ongoing study.) Thus, our scores were susceptible to the rise in IQ known as the Flynn effect (Flynn, 1999; Wolke, Ratschinski, Ohrt, & Riegel, 1994). In addition, they reflect correction for gestational age and selection based on ability to complete all card sorts. Because they were included to factor out general cognitive ability rather than to draw broad conclusions about cognitive outcome, the absolute numbers are not critical.

None = no detected CNS injury; ABR only = auditory brainstem response (ABR) abnormal and cranial ultrasound (CUS) normal; CUS = varying degrees of structural abnormality on CUS. Testable = card sort completed at all ages tested; Untestable = at least one failure to complete a card sort after starting. GMDS = Griffiths Mental Development Scale (Griffiths, 1984)—M (SD).

Game Order: 1 = “same”/“silly,” 2 = “silly”/“same”; RIUG = relative intrauterine growth was calculated as a standard score of birth weight for gestational age based upon norms for infants aged 22 to 50 weeks (Fenton, 2003); GMDS = Griffiths Mental Development Scale (Griffiths, 1984); Gender: 0 = female, 1 = male; CNS Injury Group: 1 = no detected insult, 2 = neurofunctional abnormality only on auditory brainstem-evoked response (ABR), 3 = neurostructural abnormality on cranial ultrasound.

Game Order: 1 = “same”/“silly,” 2 = “silly”/“same”; RIUG = relative intrauterine growth calculated as a standard score of birth weight for gestational age based upon norms for infants aged 22 to 50 weeks (Fenton, 2003); GMDS = Griffiths Mental Development Scale (Griffiths, 1984); Gender: 0 = female, 1 = male; CNS Injury Group: 1 = no detected insult, 2 = neurofunctional abnormality only on auditory brainstem-evoked response (ABR), 3 = neurostructural abnormality on cranial ultrasound.

Game Order: 1 = “same”/“silly,” 2 = “silly”/“same”; RIUG = relative intrauterine growth calculated as a standard score of birth weight for gestational age based upon norms for infants aged 22 to 50 weeks (Fenton, 2003); GMDS = Griffiths Mental Development Scale (Griffiths, 1984); Gender: 0 = female, 1 = male; CNS Injury Group: 1 = no detected insult, 2 = neurofunctional abnormality only on auditory brainstem-evoked response (ABR), 3 = neurostructural abnormality on cranial ultrasound.

Game Order: 1 = “same”/“silly,” 2 = “silly”/“same”; RIUG = relative intrauterine growth calculated as a standard score of birth weight for gestational age based upon norms for infants aged 22 to 50 weeks (Fenton, 2003); GMDS = Griffiths Mental Development Scale (Griffiths, 1984); Gender: 0 = female, 1 = male; CNS Injury Group: 1 = no detected insult, 2 = neurofunctional abnormality only on auditory brainstem-evoked response (ABR), 3 = neurostructural abnormality on cranial ultrasound.

Note. Age at test is years; months. Kloo et al. (2008) and Brooks et al. (2003) used five cards versus six in the current study, so percentages were calculated to allow comparisons. Kloo et al. only administered “same”/“silly” order. Age in the current study was corrected for gestation.