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Linda Gonder-Frederick, PhD, is an Associate Professor in the Department of Psychiatry and Neurobehavioral Sciences at the University of Virginia School of Medicine in Charlottesville, VA.
Daniel J. Cox, PhD, ABPP, is a clinical psychologist and professor in the Department of Psychiatry and Neurobehavioral Sciences and the Department of Internal Medicine at the University of Virginia in Charlottesville, VA.
Harsimran Singh, PhD, is a Research Scientist in the Department of Psychiatry and Neurobehavioral Sciences at the University of Virginia School of Medicine in Charlottesville, VA.
Jaclyn A. Shepard, PsyD, is an Assistant Professor in the Department of Psychiatry and Neurobehavioral Sciences at the University of Virginia School of Medicine in Charlottesville, VA.
Chapter 4 Cognitive Difficulties in Children with Type 1 Diabetes
Clarissa S. Holmes, PhD
Research into the cognitive status of youth with diabetes has grown over the last quarter of a century and increased in sophistication. Incorporation of neuroimaging techniques allows better understanding of physiological correlates and substrates of emerging cognitive patterns. Discussion of neuroimaging results is beyond the scope of this chapter but the reader is referred to several recent reviews (Musen 2008a, Holmes 2010). Despite these scholarly gains in understanding the relation between diabetes and cognitive status in youth, familial differences and demographic factors, such as social class status, still remain primary factors that account for significant individual differences in cognition, consistent with results from the general population (Overstreet 1997a, Sattler 2001).
Intellectual Performance
Children with type 1 diabetes (T1D) generally have average or above average intellectual functioning (intelligence quotient [IQ] >85). With an average score of 100 and a standard deviation of 15, individual and family differences in IQ exist, similar to those in the general population (Overstreet 1997a, Northam 2001, Gaudieri 2008). Although overall IQ scores of children with T1D are in the average range, they are slightly lower, by ~3 points, than scores of children without diabetes. A group difference of this magnitude has little clinical significance, although it is of scientific interest.
The Wechsler scales are the most commonly used ability tests in school systems. Different versions are available: for young children <7 years old, the Wechsler Intelligence Scale for Preschoolers (WPPSI-III) (Wechsler 2002); for school-age youth 6–16 years old, the Wechsler Intelligence Scale for Children–IV (WISC-IV) (Wechsler 2003); and for older adolescents over age 16 years, the Wechsler Adult Intelligence Scale (WAIS-IV) (Wechsler 2008). Other scales are available but are less commonly in use, such as the Kaufman Assessment Battery for Children–Second Edition (K-ABC–II) (Kaufman 2004) and the Differential Ability Scales–Second Edition (DAS-II) (Elliot 2007).
Learning Disorders
For most children with diabetes, academic achievement is at grade level (McCarthy 2002) or consistent with IQ (Overstreet 1997b). However, ~5% of children in the general population experience learning disorders in reading, mathematics, or written language with achievement that is substantially below expectation for age, schooling, and level of intelligence (American Psychiatric Association [APA] 2000). Some children with diabetes, especially those with disease risk factors, may show a higher incidence of learning problems (Holmes 1992, Lin 2010).
Assessment of Achievement and Learning Disorders
Diagnostic criteria for learning disorders vary by local educational/school districts. However, the national Diagnostic and Statistical Manual of Mental Disorders IV (DSM IV) criteria of the APA (2000) include the following: average intelligence with academic achievement substantially below IQ, age, or schooling. Often evidence of cognitive “processing” or neuropsychological difficulties (i.e., attention, memory, learning processing problems) is present. A broad survey of skills in language, executive function/planning and attention, visual spatial functioning, memory and learning, and sensorimotor skills is commonly assessed with A Developmental Neuropsychological Assessment–Second Edition (NEPSY-II) (Korkman 2007). Specialized measures of processing skills such as memory can be assessed with the Wechsler Memory Scale–Third Edition (WMS-III) (Wechsler 1997), the Wide Range Assessment of Memory and Learning–Second Edition (WRAML-II) (Sheslow 2003), and the Children’s Memory Scale (CMS) (Cohen 1997). Often these more specialized neuropsychological tests are administered by referral only to a specially trained neuropsychologist outside of the school system. Criteria for special classroom assistance typically require a “clinical threshold” to be reached, usually performance on individually administered achievement tests that is 15 or more points (1–2 standard deviations) below expectation for IQ (APA 2000). Widely used achievement tests available in most school systems include the Woodcock Johnson Tests of Achievement (WJ-III-ACH) (Woodcock 2001), the Wide Range Achievement Test–Fourth Edition (WRAT-4) (Wilkinson 2006), and the Wechsler Individual Achievement Test–Third Edition (WIAT-III) (Wechsler 2009). Like IQ tests, these measures typically provide standardized scores with an average score of 100 and a standard deviation of 15. For most children with diabetes, learning disorders are likely to be ”subclinical” and below the level of severity required for formal diagnosis (APA 2000). Medical insurance often covers the cost of psychoeducational assessment administered by qualified personnel. Local school psychologists provide another cost-free option, although this latter option may entail a long wait for services. Finally, parents may be referred to a licensed private psychologist or a clinic-based psychologist such as in a mental health agency. Reevaluation of learning status is required every three years for children formally diagnosed with learning disorders.
Remedial Services
Studies from the early 1990s document a higher incidence of academic classroom assistance for children with diabetes (Hagan 1990, Holmes 1992). Medical management recommendations were modified for younger children, particularly those under the age of 5 years (Ryan 1985, Rovet 1988) to avoid episodes of severe hypoglycemia that lead to
